This application is a divisional of U.S. application Ser. No. 12/688,838, filed Jan. 15, 2010, which claims the benefit of each of U.S. Application 61/145,543, filed Jan. 17, 2009, U.S. Application 61/248,448, filed Oct. 3, 2009, and U.S. Application 61/258,006, filed Nov. 4, 2009, the contents of each of which are incorporated herein by reference.
The present invention relates to the guidance and control of an automated guided vehicle (hereinafter AGV) generally, and more particularly, in one embodiment, to a system that enables an AGV to transport both regularly and irregularly shaped loads between a storage location and an access location by assuming an offset position relative to a guidance system such as, for example, an in-ground guidance wire.
Conventional parking garages are transforming the landscape to meet the demand for high capacity storage. In urban centers, where space above and below ground is at a premium, the owner of a parking facility is constrained by a fixed footprint and a certain amount of vertical space extending from such footprint. Multi-level garages can only extend so high without becoming an eyesore or unwieldy to navigate. Furthermore, self-park and/or attendant-park locations must account for extra space on either side of a vehicle for human access to and around the vehicles.
In addition, each storage location has an associated amount of overhead that must be accommodated by the facility owner. For example, most facilities usually allow more than adequate space in front of each storage location to allow for typical ingress and egress. Also provided are typical human amenities such as hallways, stairways, elevators, fire escapes, appropriate lighting, and possibly vending machines, bathrooms, office space for onsite personnel, security gates, cameras, alarm systems, and the like. Self park facilities also frequently promote accidental contact between cars due to driver error, and create opportunities for thieves, vandals and other undesirables. Accordingly, for each storage location at a given site, there is an associated amount of extra space necessary to accommodate user access and traffic, as well as an associated amount of additional resources for human amenities, security and the like.
The required level of overhead limits the number of vehicles that can be stored at a site and adds considerably to the cost of operating a parking facility. There is a need, therefore, for an automated storage system that overcomes the need for human-related overhead, that is efficient to construct and operate, and that does not require additional space or property necessary to accommodate sporadic human access.
Existing and established methods of maneuvering an AGV along an in-floor guidance wire use either a single antenna precisely centered on the front of the AGV, or a pair of antennas precisely centered on the front and rear of the AGV relative to the direction of travel. Conventional AGV guidance systems use only the antenna currently leading the AGV, or the “front” antenna based upon the AGV's direction of travel, to follow the in-floor guidance wire. The trailing or “rear” antenna on an AGV equipped with two antennas is inactive until the AGV reverses direction, at which point the rear antenna effectively becomes the “front” antenna and takes over the AGV system guidance responsibilities. The in-floor guidance wire is laid out in a loop connected to, and energized by, a frequency generator, which transmits an alternating current frequency through the guidance wire. Each guidance antenna for the AGV contains two inductor coils, which individually generate an output voltage based upon the coil's proximity to the magnetic field generated by the frequency carrying guidance wire. By balancing the relative strength of the signal output from each of the two inductor coils on the front antenna, and subtracting the strength of the output from one coil from the strength of the output from the other coil, and then adjusting the steering of the AGV to target the point where the “subtractive output” from both coils is equal to zero, the control system of the AGV dynamically adjusts the steering of the AGV to keep the center of the antenna, and therefore the center line of the AGV relative to the direction of travel, approximately centered over the in-floor guidance wire. Often these systems deploy guidance wires in a grid fashion, with one set of wires effectively forming an “X axis” and another forming a “Y axis” to allow AGVs to maneuver in two directions along the wire grid by turning to follow different axis wires and travelling in different directions along the different grid axes. At other times these conventional systems use a gradually curving wire with a fairly large turn radius to allow the AGV to follow a single wire to travel in an alternate direction.
There are three common problems/limitations of existing AGV guidance systems:
- 1) When the AGV travels to a position where either outer edge of an antenna inductor coil suddenly passes beyond the vertical plane of the in-floor guidance wire, the antenna produces a signal which is the same regardless of which side of the wire the antenna is on. Because the system is unable to positively identify which direction of travel is required to re-acquire the guidance wire, an “off wire” alarm condition usually occurs that stops the AGV and requires human intervention to return the AGV to the guidance wire and reactivate it. Alternately, the AGV can follow a limited search pattern to find the guidance wire, but with the risk of searching too far in the wrong direction and becoming further lost and/or risking a possible collision with objects outside the normal AGV travel lane.
- 2) The “centered only” travel path greatly limits the ability of AGV systems to efficiently process and transport asymmetrically proportioned items, and with the result that AGV systems are primarily implemented to handle items which have very limited, or at least very predictable, variations in size and shape.
- 3) The “subtractive output” analysis of the coil signal has some weakness and reliability issues which can cause guidance system problems if there are variations throughout the course of travel in the distance between the antennas and guidance wire or other items which impact the relative strength of the magnetic field generated by the guidance wire signal.
One embodiment of the present invention uses substantially similar in-floor guidance wire systems with significantly different antennas and inductor coil configurations, and processes the output from the inductor coils through an onboard programmable microprocessor which analyzes the relative strength of signal output of one or more inductor coils as a ratio of the total strength of signal output currently detected by all coils, or a selection of other adjacent coils, to determine the precise position of the antenna, and therefore the AGV, relative to the guidance wire, rather than merely targeting a “subtractive output” value approaching zero.
The present system employs significant advances in guidance control methodology that more efficiently uses an in floor wire based guidance system. Instead of a dynamic steering system that always attempts to guide the AGV to a position where the output from two coils is approximately balanced, resulting in the MTV always being approximately centered relative to its direction of travel over the guidance wire, the guidance system of the invention can purposefully shift the AGV to track at a specific and dynamically variable offset distance relative to the guidance wire by following the wire at any point within the outer cumulative boundary of an array of two or more inductor coils. This is accomplished by directing the AGV to follow a specific output reading, which equals a numeric expression of an exact position relative to the in-floor guidance wire, based upon an analysis of the relative strengths of the output from two or more inductor coils. This allows the AGV to deliberately follow an “offset track” in which the center line of the AGV in respect to direction of travel varies as needed and specified relative to the position in the floor of the guidance wire.
An advantage of this “offset track” system is that it enables an AGV to transport asymmetrically shaped items, such as automobiles, which may have a different front overhang (center of front wheel to farthest front extension of the automobile) versus rear overhang (center of rear wheel to farthest rear extension of the automobile) sideways down a transport aisle without significantly expanding the transport aisle's total width relative to the total overall length of the automobile being carried. By shifting the AGV to one side or the other of the guidance wire to compensate for the asymmetrical aspect of the load being carried, the AGV can travel down an aisle approximately the same size as the maximum width of the load while still following a single stationary guidance wire permanently located in the middle of the transport aisle.
Furthermore, the guidance technology of the present invention incorporates more than two inductor coils into a single antenna, forming in those instances an extended antenna array. In this configuration the programmable microprocessor assigns a distinct relative value to each point along the extended antenna array. The AGV guidance system can then be directed to follow the guidance wire at any specific point along the entire length of the array, increasing the amount and specificity of obtainable offset relative to the in-floor guidance wire and/or the center line relative to the direction of travel of the AGV, from several inches, to several feet or more up to the entire length of the antenna array as needed. This allows the total building footprint required for travel lanes and/or storage locations within a structure designed for the storage, transport and retrieval of items which may have an asymmetrical aspect to be significantly decreased at considerable savings in construction, maintenance and real estate related costs.
The manner in which the microprocessor analyzes the output signal from the array of inductor coils enables an AGV guidance control system to affirmatively know which side of the in-floor guidance wire it has passed in the event that an AGV antenna should move so far to one side that the outer most coil extends beyond the in-floor guidance wire. An AGV so equipped can correct its course back toward the in-floor guidance wire until the antenna again detects its presence without the need to immediately experience an off-wire shut down and human intervention.
The use of onboard programmable microprocessor ratio analysis also allows the AGV guidance system to better compensate for variations in wire depth or signal strength without the need for precision of guidance wire installation or the guidance problems which can occur in conventional wire guidance systems.
The onboard programmable microprocessor combined with other AGV steering and guidance control system innovations incorporated in aspects of the present invention enable the front and rear antennas of an AGV equipped with two antennas per direction of travel, to be used simultaneously for steering and control. Such a two antenna guidance system gathers and processes information from both the front and rear antenna on a single AGV to provide a more accurate steering and tracking system and to enable an AGV to perform more complex and exact maneuvers in applications requiring very exact steering. This ability can also be used to provide a steering and control system with increased amounts of feedback from the additional active antenna sensor to verify correct handling, steering, tracking, and drive performance is being realized by the AGV so equipped.
The expanded sensing range and precision with which location relative to a guidance wire can be determined by the antenna array, in accordance with aspects of the present invention, enables another previously unavailable method of following a grid of guidance wires. This is facilitated by mounting four or more antenna arrays on each AGV, for instance one on each side of a roughly rectangular AGV (here referred to as front, back, left side and right side, though an AGV may not actually be limited to assignment of only those four specific directions). While actively travelling in either direction along one guidance wire (called an “X axis” wire in this example), either the front antenna array or both antenna arrays (i.e. the front and rear arrays) will be following the guidance wire at any offset amount which may be specified. The other one or two antenna arrays (in this example referred to as left and right) can simultaneously detect any “Y axis” wires as they are crossed to determine current approximate position of an AGV relative to its direction of travel. In certain situations the relative position and change in relative position of these cross wires as compared to the moving AGV could be used to calculate or confirm in comparison to other system indicators the position, heading, and speed of travel of an AGV. When an AGV approaches a “Y axis” wire that is to be followed, the two “side antennas” will detect the presence of that wire as soon as it enters into the sensing range of the side antenna arrays. Using the output of the microprocessor aboard the antenna arrays, the AGV is directed to slow and stop relative to a newly acquired “Y axis” guidance wire at the exact location, including offset if any as required, and then safely follow the “Y axis” wire based upon the potential asymmetry of its load. At this point all four antenna arrays are positively sensing an exact location relative to both the “X” and “Y” axes ensuring the AGV and load are properly positioned. An AGV with multidirectional travel capability then immediately begins to proceed down the “Y” axis, without having to execute a turning maneuver, with the previous front and rear antennas effectively becoming side antennas sensing crossing grid wires, and the previous side antennas becoming front and rear guidance antennas. This enables a potential decrease in total transit and load processing time and improved system efficiency because the direction of an AGV can be changed without having to allow for a wider turn radius at corners or provide for additional space in travel aisles to accommodate asymmetrical loads. This capability also decreases costs associated with storage system footprint, construction and maintenance.
The greater precision and flexibility of the invention's microprocessor equipped antenna array, combined with the enhanced control system of the invention, the ability to coordinate or confirm positioning through the simultaneous use of multiple antennas, and methodology for enabling an AGV to transport a load with asymmetrical physical characteristics will allow previously impossible transport and storage operations to occur in a very efficient manner. For example, an asymmetrical load, in this case an automobile, which is driven forward into a system loading area, can be acquired by an AGV and brought into the system, then transported sideways or perpendicular to the direction of travel down a travel lane at an offset, and then turned 180 degrees so that upon retrieval it can later be driven forward out of the system. Upon departure, and due to the previously described 180 degree turn, the AGV will travel at an opposite offset relative to the retrieval lane. This adjustment can occur automatically, and the “new” offset orientation can be used by the AGV to transfer the load down other travel lanes, on to and off of vertical conveyors, and into storage spaces or loading areas as needed to complete the desired storage and retrieval operations.
Thus there is provided an automated storage system for vehicles or the like that is provided with a guidance system that interacts with a remote-controlled transport system that transports a vehicle between an access location, such as a drive-up location, and a storage location. More particularly, in one embodiment, omni-directional, battery-powered, wirelessly-controlled AGVs are provided with a positioning and guidance system that allows their travel paths to be shifted relative to an in-floor guidance wire by incorporating antenna arrays composed of two or more inductor coils and a programmable microprocessor which assigns a distinct value to each position within the length of the array, and a control system methodology that the AGV uses to offset its guidance path relative to the in-floor guidance wire. Also provided is an AGV guidance control system which affirmatively knows which side of the antenna has passed beyond an in-floor guidance wire in the event that an “off-wire” condition occurs that could enable an AGV to reliably correct back to a position over the in-floor guidance wire without a guidance system shut down and human intervention. Aspects of the present guidance system are better able to compensate for variations in wire depth or signal strength than conventional wire guidance systems and provide an AGV possessing multidirectional travel capability with a more efficient mode of maneuvering, which can increase system efficiency and decrease costs associated with storage system footprint, construction and maintenance.
FIG. 1illustrates a conventional two-antenna AGV oriented to an in-floor guidance wire.
FIG. 2Ais an elevational view andFIG. 2Bis a plan view of the AGV antenna ofFIG. 1.
FIG. 3is one embodiment of an enhanced AGV including a plurality of variable offset positioning antenna arrays of the present invention.
FIG. 4 (FIGS. 4A-4F) illustrate elevation and plan views of one antenna fromFIG. 3showing a two coil version with a programmable onboard microprocessor enabling an AGV to track at an offset relative to an in-floor guidance wire.
FIG. 5 (FIGS. 5A-5C) illustrates one embodiment of a multiple coil antenna with a programmable onboard microprocessor in various centered and offset positions relative to the in-floor guidance wire.
FIG. 6 (FIGS. 6A-6C) illustrates one embodiment of a control method incorporating the multiple coil antenna ofFIG. 5.
FIG. 7illustrates one embodiment of an enhanced AGV having two variable offset positioning antenna arrays and various offset positioning relative to a guide wire.
FIG. 8 (FIGS. 8A-8B) illustrates one embodiment of an enhanced AGV having four variable offset positioning antenna arrays and various offset positioning relative to X-axis and Y-axis in-ground guide wires.
FIG. 9demonstrates one embodiment of an AGV that acquires an off-centered load, the AGV being capable of traveling at an offset to a central guidance wire.
FIG. 10demonstrates one embodiment of an AGV traveling at an offset to a central guidance wire enabling it to traverse around an obstacle blocking a travel aisle.
FIG. 11demonstrates a comparison of a conventional AGV with one embodiment of an AGV of the present invention showing the utilization of a narrower travel lane for the AGV of the present invention.
FIG. 12demonstrates another comparison of a conventional AGV with one embodiment of an AGV of the present invention demonstrating the advantage of the AGV of the present invention and using its control method to being able to transport asymmetrical items which might be long and narrow by following one wire axis down a travel lane that is wide enough to accommodate the length of the item, then shifting sideways and following a different wire axis into narrower storage lanes and/or storage racks without having to allow for room to turn the AGV or the load into the storage aisles.
FIG. 13demonstrates one embodiment of the use of an ACV of the present invention to transport and re-orient a load between a loading area and a storage area.
FIG. 14Ais a schematic view of one embodiment of a control system for a facility utilizing the enhanced ACV of the present invention.
FIG. 14Bis a diagram of one embodiment of a control system constructed in accordance with the invention.
FIG. 14Cis an exemplary and non-limiting block diagram of a control system in accordance with an embodiment of the invention.
FIG. 15illustrates one embodiment of a facility for use with an embodiment of the AGV of the present invention having storage arrangements and travel paths.
FIG. 16illustrates various storage solutions for a load carried by an AGV of the present invention.
FIGS. 17A-17Dillustrate one embodiment of a control method and use of an AGV to acquire a load from a storage location.
FIGS. 18A-18Cillustrate one embodiment of a control method and use of an AGV to re-route a travel path around an obstruction.
FIGS. 19A-19Dillustrate one embodiment of a control method and the use of multiple AGVs to retrieve a load from a blocked storage location.
FIG. 20is a flowchart describing the process for computing the position value as performed by the microprocessor in accordance with an embodiment of the invention.
FIG. 21is a top view of an alternative embodiment of an AGV in accordance with the present invention.
FIG. 22illustrates one embodiment of the AGV of the invention carrying a vehicle tray.
FIG. 23is one embodiment of an edge view ofFIG. 22.
FIG. 24illustrates one embodiment of an AGV of the invention carrying a storage locker.
FIG. 25is one embodiment of an edge view ofFIG. 24.
FIG. 26illustrates an alternative embodiment of an AGV of the invention traveling along a diagonal path.
This disclosure describes the best mode or modes of practicing the invention as presently contemplated. This description is not intended to be understood in a limiting sense, but provides an example of the invention presented solely for illustrative purposes by reference to the accompanying drawings to advise one of ordinary skill in the art of the advantages and construction of the invention. In the various views of the drawings, like reference characters designate like or similar parts.
FIG. 1is a diagrammatic view of one example of a conventional AGV50centered over an in-floor guide wire system having an “X”-axis guide wire70and a “Y”-axis guide wire75. Conventional AGV systems are often deployed in a grid of X-axis and Y-axis wires to allow AGVs to perform two-dimensional travel maneuvers along the grid by turning to follow different axis wires and travelling in different directions along the different grid axes. At other times these systems use a gradually curving wire with a fairly large turn radius to allow the AGV to follow a single wire to travel in an alternate direction (seeFIG. 12for example). As discussed herein, the X and Y directions are generally orthogonal and understood with reference to a plan or top view, i.e. looking down on the AGV where the X direction designates horizontal movement and the Y direction designates vertical movement along a floor layout, although it is also understood that the X and Y directions are relative and are designated herein for purposes of convenience and for ease in understanding the relative positioning of the AGV and its environment.
In the embodiment ofFIG. 1, the conventional MTV50has a front antenna60and a rear antenna65and is centered over guidance wires70and75. Existing and established methods of maneuvering an AGV along an in-floor guidance wire utilize either a single antenna precisely centered on the front of the AGV (antenna60inFIG. 1), or a pair of antennas (antennas60and65inFIG. 1) precisely centered on the front and rear of the AGV (50inFIG. 1) relative to the direction of travel D as shown inFIG. 1. Conventional AGV guidance systems use only the antenna currently leading the AGV, or the front antenna based upon the AGV's current direction of travel, to follow the in-floor guidance wire. The trailing or rear antenna is generally inactive until the AGV reverses direction, at which point it becomes the front antenna and takes over the AGV system guidance responsibilities.
FIG. 2Ais an elevation andFIG. 2Bis a plan view of the front antenna60ofFIG. 1. The antenna60contains two inductor coils62and64, which individually generate an output voltage based upon their proximity to the magnetic field of the frequency carrying guide wire70. The in-floor guidance wire (70, 75) is generally laid out in a loop (see loops920and930inFIG. 14Afor example) connected to, and energized by, a frequency generator (see frequency generators925and935inFIG. 14Afor example), which transmits an alternating current frequency through the guide wire. By balancing the relative strength of the signal output from each of these two inductor coils62, 64on the antenna70, and subtracting the strength of the output from one coil from the strength of the output from the other coil, and then adjusting the steering of the AGV50to target the point where the subtractive output from both coils is equal to zero, the control system (not shown) of the AGV50dynamically adjusts the steering of the AGV50to keep the center of the antenna60, and therefore the center line of the ACV50relative to the direction of travel, approximately centered over the in-floor guidance wire70.
However, as noted previously, conventional AGV systems have many drawbacks that limit the ability of the AGV to react to unexpected travel conditions, such as blockages in a travel lane, or to perform operations that require the AGV to position in an offset condition relative to a guidance wire system. The two antennas, two coil system described inFIGS. 1-2Blimits a conventional AGV's travel to a centered position relative to a guidance system, which results in an inefficient system as compared with the AGV array and control method of the present invention.
FIG. 3illustrates one embodiment of an AGV100of the present invention centered over an in-floor mounted guide wire system having an “X”-axis guide wire70and a “Y”-axis guide wire75, it being understood that the guidance system as a whole is preferably comprised of a network or matrix of guide wires attached to a central control system (seeFIGS. 14A and 14B). The AGV100further comprises a plurality of antennas110, 120, 130, and140that are designated for purposes of easy reference as front antenna110, rear antenna120, upper antenna130, and lower antenna140. As will be described in greater detail below, the arrangement of antennas aligned along both the X- and Y-axes provides one aspect for greater flexibility in movement and guidance of the AGV100relative to the guide wire network.
FIGS. 4A-4Fillustrate one embodiment of one of the enhanced antenna arrays ofFIG. 3, which for purposes of explanation will be referred to as antenna110or the front antenna110fromFIG. 3. FIGS. 4A, 4C and4E are elevations andFIGS. 4B, 4D and4F are plan views of antenna110. However, it will be appreciated that the same configuration could be applied to each antenna on AGV100. The antenna110of the embodiment ofFIGS. 4A-4Ffurther comprises a plurality of inductor coils112and114and a programmable onboard microprocessor116enabling the AGV100to travel at an offset relative to the in-floor guidance wire70. While only two inductor coils112and114are shown, more than two inductor coils are contemplated as will be described below. Inductor coils112and114in the antenna110generate an output voltage as in a conventional MTV antenna, and are used to keep the AGV100centered over the guidance wire70when desirable, in one embodiment, the onboard programmable microprocessor116receives and performs a mathematical analysis of the inductor coil output currents, then produces a new output signal of its own. This enables the AGV100 (FIG. 3) to travel with its antennas110, 120, 130and140centered over the guidance wire70as shown inFIGS. 4A and 4B, or intentionally shift a controllable and variable distance to either side of the guidance wire70as shown inFIGS. 4C through 4F, while still reliably following the guidance wires. This offset from the center line could extend up to, and slightly beyond, the width118 (FIG. 4A) of the antenna array110if desired.
FIGS. 5A through 5Cillustrate elevation views of an alternative embodiment of an antenna array210for use with an AGV100that is positioned relative to a guide wire70. Antenna210further comprises a plurality of inductor coils220, 230, 240, 250, 260and270positioned relative to a center line212of the antenna210, and an onboard programmable microprocessor280, in one aspect, the onboard programmable microprocessor280analyzes the output from the array of inductor coils220-270to keep an AGV centered over an in-floor guidance wire70when that is desirable as shown inFIG. 5A. Alternatively, the onboard programmable microprocessor280can allow an AGV equipped with an antenna210to intentionally and precisely follow a course shifted off of the center line212relative to the guide wire70as shown inFIGS. 5B and 5C. The plurality of inductor coils220-270coupled with the onboard programmable microprocessor280allows an AGV to seamlessly shift its location over the guidance wire70to any position along the length of the array of inductor coils so as to shift the center line212of the AGV a precisely controllable amount in relation to the guidance wire70, far beyond the distance at which a conventional AGV guidance antenna would be able to detect the magnetic field produced by the frequency carried through the guidance wire70.
In one embodiment of the invention, the antenna array200is capable of sensing multiple frequencies simultaneously of a single guidance wire70or multiple guidance wires. When multiple frequencies are utilized the system control computer instructs the AGV to select the desired frequency. In accordance with another embodiment of the invention multiple guidance wires can be utilized. The wires may be operable at a single frequency or each wire may have a different frequency.
In accordance with the principles of the invention, the onboard programmable microprocessor280analyzes the outputs of the inductor coils220-270in the antenna array210and assigns a value to each point along the array relative to the output generated by each of the individual inductor coils. Each of coils220-270has a unique index number and it outputs an alternating current (AC) that is a function of the proximity of the coil to the guidance wire70and the current magnitude in the wire70. The output of each coil is processed by an electric circuit (not shown) adapted to generate a digital signal that can be analyzed by the microprocessor280. In an exemplary embodiment, this can be achieved by rectification of the AC signal to produce a DC signal, and then converting the DC signal into a digital signal using an A/D convertor.
The microprocessor280generates a position value representing the location of the antenna210relative to the guidance wire70. The position value is determined based on a pair of coils220-270having the strongest signals. This approach reduces the dependency in the electromagnetic field of the guidance wire70.
FIG. 20shows an exemplary and non-limiting flowchart1500describing the process for computing the position value as performed by the microprocessor280in accordance with an embodiment of the invention. At S1510, signals corresponding to the output signals of each coil220-270are received and recorded by the microprocessor280. Each coil's current is preferably sampled by an A/D at ˜1000 times per second (although other sampling rates are contemplated), where the coil output is related to the proximity of the coil to the guide wire and current magnitude in the wire, and where each coil can be individually identified such that the microprocessor knows which signal is from which coil. At S1520, two of the recorded signals having the largest value are determined. These signals will be referred hereinafter as Va and Vb and the indexes of the coil producing signals Va and Vb will be referred to as Ia and Ib respectively. As mentioned above, each of coils220-270is associated with a unique index number. At S1530, it is determined whether the signals Va and Vb are from adjacent coils. If so, execution continues to S1550. If it is determined that signals Va and Vb are not from adjacent coils, the validity of such signal is checked at S1540to determine whether the maximum signal, out of Va and Vb, is below a predefined threshold. If S1540results with a negative answer, execution terminates; otherwise, execution continues to S1550.
At S1550, a CoilPair parameter is set to a value of the minimum of the indexes Ia and Ib of the coils. For example, if coil240and coil250are determined to be Ia and Ib, then the CoilPair parameter is set to240. At S1560, an Offset value is computed by multiplying a coil separation distance (d) value by the CoilPair parameter, i.e., Offset=d*CoilPair. At S1570, the relative position (RelPos) between the selected pair of coils is computed by multiplying the coil separation distance (d) by a SignalPercentage value, i.e., RelPos=d*SignalPercentage. The SignalPercentage is the ratio between the maximum signal, out of Va and Vb, and the sum of the signals Va+Vb. The coil separation distance (d) is the distance between the coils220-270. At S1580a determination is made whether the index Ia is larger than the index Ib. If so, at S1590the position is computed as follows:Position=Offset−d/2+RelPos.
If it is determined at S1580that index Ia is not larger than index Ib, the Position is computed at S1595using the following equation:Position=Offset+d/2+RelPos.
FIG. 6A-6Cillustrate one embodiment of an analysis used to determine the relative positioning of an antenna210as shown inFIGS. 5A-5Cfrom the center line212and the guide wire70. The onboard programmable microprocessor280analyzes output from multiple inductor coils220-270in the antenna array and assigns a value to each point along the array relative to the output generated by each of the individual inductor coils. In the example shown inFIGS. 6A-6C, the centered relationship between the antenna array and the guidance wire70would produce a value of ˜245 (i.e. centered between coils240and250), though actual output numbering range could vary based upon the application or control system used. If an AGV travels off of the guidance wire70too far to the right for example, the analysis of the onboard programmable microprocessor280would so indicate and output a corresponding value or other appropriate form of communication signal to the AGV control system. In the example ofFIG. 6B, a value of less than 220 indicates to the AGV control system that the AGV needs to travel to the left in order to return to a centered position over the guidance wire70as shown inFIG. 6A. If an AGV travels off of the guidance wire70too far to the left as shown inFIG. 6C, the onboard programmable microprocessor280generates an output which is indicative of its position. In the example ofFIG. 6C, any value greater than 270 indicates to the AGV control system that the AGV needs to travel to the right in order to return to its centered position over the guidance wire70as shown inFIG. 6A. The extent to which an AGV may be displaced from a guidance wire70or the like will depend on a variety of factors, including but not limited to the frequency strength of the guidance wire70, the sensitivity of the inductor coils and the manner in which such components are associated by the onboard programmable microprocessor.
The expanded reach of an antenna array as illustrated inFIGS. 6A-6C, for example, decreases the risk of an AGV experiencing off-wire shut down situations where the AGV loses control contact with the guidance wire network. AGVs equipped with the enhanced antennas as described herein have a much larger travel window white still maintaining contact with the magnetic field created by the in-floor guidance wire network. In addition, upon losing contact with the magnetic field created by the guidance wire, the control system enables a positive indication of which direction of travel is required to regain contact with the magnetic field created by the in-floor guidance wire system through the use of an indicator coil positioning value system as illustrated inFIGS. 6A-6Cfor example. Other control systems are contemplated. Thus, an AGV equipped with enhanced antennas and under an appropriate control system and method could perform maneuvers to return to the guidance wire without having to experience an off-wire shut down, which would necessitate human intervention. In addition, while conventional AGV systems may be designed to avoid travel lane paths and maneuvers that could produce an off wire situation, thus limiting some options for operational efficiencies, the control system and AGV of the present invention allows for more complex AGV maneuvers to be routinely performed without service interruptions and therefore allows more efficient operational performance and more efficient use of space.
FIGS. 7 through 8Billustrate two non-limiting embodiments of an AGV200and300illustrating aspects of the present invention, with the AGV200ofFIG. 7incorporating front and rear antennas202and204and the AGV300ofFIGS. 8A and 8Bincorporating a plurality of antennas312, 314, 316and318along each side of the AGV300. FIG. 7illustrates one embodiment of an AGV200positioned relative to a guide wire70and utilizing a front antenna202and a rear antenna204having a construction similar to the antenna210ofFIGS. 5A through 6Cincluding a plurality of inductor coils and an onboard programmable microprocessor (not specifically show). Thus, when AGV200moves along a guide wire70in the direction of travel indicated by arrow206, the AGV200could move from a position208athat is centered over the guide wire70 (see, for example, the antenna ofFIG. 5A), to a position208bthat is slightly offset relative to the wire70 (see, for example, the antenna ofFIG. 5B), to a position that is considerably offset relative to the wire70 (see, for example, the antenna ofFIG. 5C). In the embodiment ofFIG. 7, the AGV200can operate with only the front antenna202providing guidance information, or by using both antennas202and204to confirm both the leading and trailing edges of AGV positioning and guidance.
FIGS. 8A and 8Billustrate one embodiment of an AGV300positioned relative to an X-axis guide wire70and a plurality of Y-axis guide wires75a, 75b, 75cand75d, the AGV300utilizing a plurality of antennas312, 314, 316and318along each side302, 304, 306and308respectively of the AGV300. Each of the antennas312, 314, 316and318preferably has a construction similar to the antenna210ofFIGS. 5A through 6C. FIG. 8Aillustrates AGV300in a first location320centered over guide wires70and75aand spaced from a target location340of the AGV that is offset from both the X-axis guide wire70and the Y-axis guide wire75d. As will be described below, the offset positioning of an AGV relative to a guide wire network can occur for a variety of reasons, such as, for example, if the AGV needs to acquire a load (seeFIG. 9) that is not centrally positioned relative to the guide wire network. FIG. 8Billustrates the movement of the AGV300from the first location320to an intermediate location330and then to the target location340. Movement along the X-axis guide wire is controlled by the interaction of the antennas312and316with the onboard programmable microprocessor (not shown) and the AGV control system (not shown), where the antennas312and316shift the position of the AGV300relative to the X-axis guide wire70. A determination of the positioning of the AGV300relative to the Y-axis wires75a-75dalso guides the AGV300from the first location320to the target location340where, for example, the antennas314and318monitor or count the Y-axis75band75cpassed to indicate the positioning of the AGV300relative to the Y-axis network and to ensure that in the embodiment ofFIG. 8Bthe AGV300stops along the Y-axis75d. Thus, FIG. 5Bdemonstrates one embodiment of a control method used to allow an AGV300to follow a guidance wire70in the direction of travel with one pair of antennas312and316while sensing the location of guidance wire cross wires75a-75dusing another pair of antennas314and314, and utilizing output from both pairs of antennas to determine the AGV's exact location within a grid of guidance wires and travel to an exact position within the guidance wire grid expressed as a specific relationship to the position of specific X and Y axis guidance wires.
FIGS. 7 through 8Billustrate aspects of the invention of an AGV equipped with two or more pairs of antenna arrays that is capable of traveling through a storage or travel area equipped with multiple axes of an in-floor guidance wire grid and to follow and track, centered or at variable offsets, multiple axes of wires within the grid to reach an exact target location specified by a control system. The travel path is generally dictated by a control system (seeFIGS. 14A-14C) which could instruct the AGV to follow the grid pattern (i.e. travel so far in the X direction, then so far in the Y direction), or to cut across grid lines at an angle as described in connection withFIG. 26below to arrive at the designated location by the most efficient or most preferable path available. As will be described below, this is very advantageous in an AGV-based storage or warehousing application where travel lanes and storage spaces could be dynamically sized, laid out, and assigned based upon current needs and the size, shape and transfer plan for a specific item or items to be stored, rather than having to be determined ahead of time for a limited number of anticipated purposes during the storage system design process. This also allows AGV-based storage systems to be far more flexible and accommodating than non AGV-based systems currently in use and drastically improve their cost efficiency and longevity of operation.
FIG. 9illustrates one embodiment of an AGV400having antennas410and420to travel along a guidance wire70to acquire an off-centered load430 (an automobile in this example) within a loading area440. The AGV400, with control and guidance from other devices, sensors, measuring implements, or human intervention, could shift from a centered position450ain relationship to the guidance wire70to an offset position450bin order to approach and acquire the target item430along position450c, which is not situated exactly centered relative to the in-floor guidance wire70. This aspect could be used to handle irregularly shaped items or items which were placed imprecisely by imperfect human or mechanical operations. For example, items unloaded into an automated warehouse by human workers and not placed exactly on center in a loading area could have their exact position detected by sensors within the loading area or communicated by human workers through a human machine interface system, and an AGV equipped with the antennas and control system of the present invention could shift off center as needed to correctly approach and acquire the target item, then shift back on center or to an appropriate offset as needed, to transport the acquired item to the appropriate location within the system. In an automated parking example, where an AGV is used to acquire an off-center target vehicle in a loading area, for example, the ability of the AGV to travel offset to a guidance wire effectively centers the AGV relative to the vehicle it is intended to acquire. Thus, the AGV would then travel into position below the target vehicle, lift it for transport, then return as desired to a position of being centered on the guidance wire, or offset the appropriate amount to travel with the automobile on board as indicated by the automobile's distinct characteristics and the preferred path of travel out of the loading area.
In addition to simply acquiring off-center loads, the ability to dynamically shift the position of an AGV relative to the location of the guidance wire is also very beneficial in diminishing disruptions of operations due to temporary mechanical failures or obstacles within an AGV system. If a disabled piece of equipment or a temporary obstacle such as on oil spill, building damage, repair work, or the like should interfere with or partially block a portion of a travel lane, under conventional methods of operation that section of the travel lane would need to be entirely shut down. However, if remaining space within the travel lane allows, AGVs equipped with the antenna array and/or control method of embodiments of the present invention could simply be directed to shift as required on the guidance wire when passing this particular point in the system as shown inFIG. 10, for example, and continue at least limited travel operations through that area until the source of the obstruction had been removed or repaired. FIG. 10, for example, illustrates an AGV500having antennas510and520and that is centered over a guidance wire70within a travel lane530defined by boundaries532and534. When the AGV500encounters an obstruction540along its travel direction505, the control system (not shown) in conjunction with the antennas510and/or520enable the AGV500to dynamically shift its position relative to the guidance wire70a sufficient amount in order to clear the obstruction530and still remain within the boundaries532and534of the travel lane530.
FIG. 11illustrates a comparison between the use of a conventional AGV50 (see alsoFIG. 1) and the space-saving advantage gained by using one embodiment of an AGV600incorporating an antenna array610, 620and control method of the invention when carrying an asymmetrical load630down a travel lane640, or onto and off of a conveyor650, or into a storage location, for example. The ability to dynamically shift the position of the AGV600into an offset position relative to a guidance system within a travel lane enables the use of a narrower overall travel lane or smaller conveyor system or smaller storage location as the case may be. In one example of one embodiment, the conventional AGV50picks up automobile630by lifting under the automobile's tires as described in connection with U.S. Patent Application 61/145,543, filed Jan. 17, 2009, and incorporated herein by reference, carrying the automobile630sideways down a travel lane640 (perpendicular to the automobile's normal forwards/backwards travel orientation) using conventional AGV guidance antenna60and65 (see alsoFIG. 1), and proceeds along the travel lane640with the guidance wire70centered under the AGV50, which would in turn be centered under the automobile's wheel base. In one specific example, assume that the largest vehicle to be accommodated in an automated AGV based parking system is a 1999 General Motors “Suburban” Sports Utility Vehicle. This vehicle is 219.9 inches long, and has a front overhang (center of front wheel to farthest front extension of the automobile) of 36.2 inches and a rear overhang (center of rear wheel to farthest rear extension of the automobile) of 52.8 inches. In order for the AGV50to be able to carry this vehicle630down the travel lane640, facing in either direction (i.e., facing “forward” or “backward” within the lane), the minimum allowable space required would be 219.9 inches plus the difference in front and rear overhangs (16.6 inches), or a total of 236.5 inches plus any required clearances for safety factors, and thus the travel lane640would have a minimum width defined by boundaries642and644as shown inFIG. 11. This same additional 16.6 inches of length would need to be added to each storage space which could accommodate this automobile, and to each conveyor650which would transport it between levels within a parking structure. This results in approximately 7.5% more building footprint, mechanical space, building materials, and associated construction costs to accommodate the vehicle630within the system than the actual exact physical size of it would require. However, by using an embodiment of the AGV600of the present invention to shift the point on the antenna arrays610, 620at which the AGV600is following the guidance wire70precisely 8.3 inches of offset towards the rear of this automobile630, the travel lane640, storage spaces, and conveyors can be set at the actual maximum automobile size of 219.9 inches, plus any required clearances for safety factors, and have a minimum width defined by boundaries646and648. In a large parking structure or automated warehouse, 7.5% savings in real estate and construction costs can equal hundreds of thousands of dollars per project.
FIG. 12illustrates a comparison between the use of a conventional ACV50 (see alsoFIG. 1) and the space-saving advantage gained by using one embodiment of an AGV700incorporating an antenna array710, 715, 720and725and control method (not shown) when carrying a load730that is asymmetrical or long and narrow as shown, for example. As shown on the left side ofFIG. 12, if it is desired to move the load730with a conventional AGV50from a first position740to a second position750, or from guide wire70to75a, the AGV50must first travel along the guide wire70using antennas60and65until the AGV encounters guide wire75a, at which point the AGV50must rotate, clockwise in this example, along a travel path745on that the antennas60and65can acquire the guide wire75afor guidance of the AGV50along guide wire75a. Thus, when switching directions between an X-axis guide wire such as70and a Y-axis guide wire such as75a, the travel lane or footprint must be dimensioned to accommodate the largest dimension of the load730in both directions as shown. However, as shown on the right side ofFIG. 12, if it is desired to move the load730with an embodiment of the AGV700of the present invention from a first position760to a second position770, or from guide wire70to guide wire75b, movement along guide wire70toward guide wire75bis controlled and guided using antennas710and720. Upon contact of the AGV700with guide wire75b, the AGV700shifts direction along guide wire75bwith antennas715and725assuming guidance and control of the AGV700along guide wire75b. The AGV700may utilize an omnidirectional drive and steering mechanism as set forth in U.S. Application 61/248,448, filed Oct. 3, 2009, incorporated herein by reference herein, to shift the direction of movement of the AGV700between axes70, 75bwithout altering the position of the load730as required with the conventional AGV50as shown on the left side ofFIG. 12. Thus, movement of the same load730with the enhanced AGV700from an X-axis direction to a Y-axis direction requires a much smaller travel lane765and a much more compact travel footprint that need only be dimensioned to accommodate the smallest dimension of the load730or of the AGV700, without having to allow for room to turn the AGV700or load730and without necessarily requiring, nor precluding, the use of other forms of sensors to confirm the AGV's physical location at the junction of the guide wires70and75bfor example.
FIGS. 13-19Dillustrate non-limiting embodiments of an AGV in an automated storage facility of the type that stores automobiles or the like. In one example, an automated parking facility includes loading areas for drop-off and pick-up of vehicles by customers and storage areas for such vehicles that are preferably routinely accessed only by AGVs or the like. While a parking facility is shown and described for purposes of convenience, it will be appreciated that the embodiments of the AGV guidance and control system of the present invention could be used to transport any type of load from a first position to a second position along a variety of travel lanes under the control and guidance of a control system and network of control means such as structural, in-floor guidance systems and/or wireless systems or combinations of the same. Other control means are contemplated. The system of the present invention enables more efficient use of space overall and in particular in the manner of travel throughout the system footprint, with respect to boundaries and obstructions, and in the positioning, placement and access of storage positions. The omnidirectional movement of the AGV combined with the enhanced antenna array and the ability to dynamically move into an offset condition relative to guidance systems wires or the like creates considerable flexibility in movement and positioning within travel and storage areas.
FIG. 13illustrates one embodiment of an AGV800, having antennas802, 804, 806and808, that is used to acquire an asymmetrical item890, in this case a vehicle with a different front overhang892and rear end overhang894, from a loading area810and transport the vehicle890to a storage area812and a particular storage location820. The AGV800initially situated along the intersection of guide wires70aand75atravels along guide wire75aunder the control and guidance of antennas804and808until it acquires the vehicle890in the loading area810, which vehicle890has been driven into the loading area810so that the front overhang892faces the storage area812. The actual acquisition of the vehicle890by the AGV800can be accomplished using a plurality of gripping arms on the vehicle tires896as set forth in U.S. Application 61/145,543, filed Jan. 17, 2009, incorporated herein by reference, or by being parked upon a vehicle tray which the AGV could then pick up and transport as discussed, for example, inFIGS. 21-23. The acquisition of the vehicle890is illustrated by arrow830and the return of the AGV800with vehicle890to the guide wire70within travel lane850is illustrated by arrow832. All of the antennas802, 804, 806and808preferably cooperate in conjunction with a control method and onboard programmable microprocessor during the return of the AGV800to the intersection of the guide wires70aand75a.
Because the AGV800in this embodiment is situated relative to the vehicle890by the tires896of the vehicle890, the position of the AGV800may require a particular offset relative to the guide wire70ain order to keep the front and rear overhangs892and894of the vehicle890within the boundaries854and858of the travel lane850. The travel lane850is dimensioned to accommodate the width and length of most vehicles should it be desired to transport a vehicle in either orientation. Arrow834illustrates the movement of vehicle890along the travel lane850using the AGV800that is offset downward relative to the guide wire70awith antennas802and806providing guidance and offset control of the AGV800during movement relative to the guide wire70a. In the embodiment ofFIG. 12, the AGV800rotates the vehicle890within the travel lane850along arrows836to reverse the orientation of the vehicle890relative to the travel lane850, and to reverse the offset direction relative to the guide wire70s, so that the vehicle890can be later returned to the loading area810and driven out of the loading area810in a forward direction. The rotation of the vehicle890also enables the vehicle890to be stored in a front-facing condition. WhileFIG. 13illustrates rotation of the vehicle890within the storage area810, it will be appreciated that rotation can occur in the loading area810through the use of a turntable (not shown) or the like, or alternatively the rotation need not occur at all if it is not important during the storage operation or, for example, if another loading area (not shown) is provided on the opposite side of the storage area810that allows departure of the vehicle in a forward direction. In an embodiment where rotation occurs within the storage area810, a control system (not shown) may be utilized to determine the best location for rotation taking into consideration the dimension of the vehicle relative to the travel lanes and any potential obstructions that would otherwise prevent rotation in certain areas.
After rotation, the AGV800and vehicle890continues along the travel lane850in accordance with arrow838using anew offset value relative to the guide wire70auntil the AGV800reaches guide wire75busing antennas802, 804, 806and808to verify position and direction of the AGV800relative to the guide wires70aand75b. In the present embodiment, the AGV800then follows guide wire75bin accordance with arrow840while the antennas804and808are centered relative to guide wire75buntil AGV800reaches guide wire70b. In order to appropriately position vehicle890relative to the storage location820along guide wire75c, antennas802and806must assume an offset condition relative to the guide wire70bso that movement of the AGV800in accordance with arrow842will result in the desired positioning of the vehicle890relative to the guide wires70band75c. The ultimate placement of a vehicle890within a storage location (820for example) can be determined by a variety of factors including, but not limited to the dimensions of the vehicle, the available space and the available travel lanes in and around the storage area812. Thus, by using the antenna arrays802, 804, 806and808and control methods included in this invention (as illustrated in one possible example of many possible combinations of motions inFIG. 12), the AGV800and vehicle890could travel throughout the storage system along a guidance wire grid (seeFIGS. 14A-14B) detecting X- and Y-axis wires and following travel lanes centered or offset relative to the guidance wires as needed until reaching a designated storage location at the correct offset position relative to and within the storage location to deposit the vehicle for storage. The operation of turning the vehicle could occur either on the way to storage or when travelling from storage to exit at the loading area as is most efficient in each system, but with the ultimate result of the vehicle being able to be driven into the system going forward and out of the system going forward, and turned by the ACV within the system, without having to make all travel lanes, vertical conveyors (not shown) and storage locations large enough to be able to accommodate vehicles with different front and rear end overhangs when facing in either direction.
FIG. 14Aillustrates one embodiment of a system layout900including a storage facility905having a plurality of storage locations910, a guidance wire grid formed from X-axis guidance wires920energized by an X-axis frequency generator925and Y-axis guidance wires930energized by a Y-axis frequency generator935, a plurality of loading areas940, a vertical conveyor950to move between vertically-stacked system levels (not shown), a plurality of AGVs960, a control system970such as a PLC control system in wired and/or wireless communication972with AGVs960and controlling loading areas940, vertical conveyors950and AGVs960, and a server or some other type of control system980providing coordination, routing and inventory instructions to AGV system through the control system970or directly to the facility905. The facility905is preferably provided with dedicated travel lanes such as, but not limited to travel lanes990and992, for movement of AGVs960and vehicles (not shown) to be transported by AGVs960between the loading areas940and the storage locations910.
FIG. 14Bshows an exemplary and non-limiting diagram of an automated parking system900aconstructed in accordance with one embodiment of the invention. The system900alocates and tracks the location of AGVs960aand guides them to parking or storage locations from an access location using, in the illustrated embodiment, radio frequency identification (RFID) and proximity sensing techniques. Specifically, a vehicle (not shown) is mounted on an AGV960a, which includes a plurality of antenna arrays that, in one embodiment, transmit radio frequency (RF) signals to a radio modem908a. The antenna arrays keep the AGV960aaligned along its path by sensing the position of guide wires920a, 930ain the floor in relation to the antenna arrays of the AGV960a. The guide wires920a, 930amay be, for example, a RF wire or magnetic strip. Other guide means are contemplated. The intersection of two guide wires are referred to, in the embodiment ofFIG. 14B, as storage bays904a, each of which may include at least a RFID circuit906ato determine the overall location of the AGV systems960a. To determine the overall location of an AGV, an RFID chip may be used at each storage bay location and along predetermined intervals along pathways. Using these two sensing systems, the facility owner can precisely guide and track the location of each AGV960a. In the present embodiment, charge stations are also provided to charge the batteries in the AGV during times of non-use. Other charging means are contemplated.
RF signals generated by the RFID circuits and/or proximity sensors are transmitted to one or more radio modems908awhich output data modulated in the RE signals to a computing device970a. The radio modems908aand the computing device may be connected in a network established using a network switch955a. The computing device970acoordinates the proper retrieval and parking (storing) of a vehicle or the like mounted on an MTV960afrom a storage location to an access or retrieval location, and vice versa. In order to move an AGV960afrom one location to another, the computing device970acontinuously processes the location information, as transmitted by the antenna array and/or REID circuits, and generates signals that instruct the AGV960ato follow a particular direction relative to the wire grid. The generated signals are wirelessly transmitted by the radio modem908ato a wireless receiver installed in the AGV960a.
In one embodiment of the invention a user can interface with the system900athrough, for example, a graphical user interface (GUI), an interactive voice response (IVR) interface, a web browser, SMS text messaging, and the like, enabling the user to access information about his/her vehicle, pay for parking and/or other services, check balances, provide retrieval instructions, etc. The user's inputs are processed by the computing device970a. For example, the user may request that his/her car be ready for pick-up at a certain time. The computing device970athen executes a process for retrieving the vehicle from its parking location to an access location to be ready for the user at the requested time. With this aim, the computing device970aaccesses a database (not shown) used to store the parking location of the vehicle, computes a path from the current location to the access location and communicates the path for the AGV960ato take to retrieve the vehicle. The computing device970aalso computes the amount due for payments, where payments are made through a payment server (not shown). In one embodiment of the invention, the computing device970agenerates control data and statistical reports, and maintenance and notification alerts. In order to allow continuous operation of the system900aand to prevent a single point failure, the system900aincludes a redundant computing device975afor backing up the computing device970a. In certain embodiments, uninterruptible power supplies (UPS) devices978aand a backup power generator980aare also utilized in the system900a.
FIG. 14Cshows an exemplary and non-limiting block diagram of a vehicle control unit (VCU) processor900cprovided on an AGV (not shown). The VCU900ccommunicates with a power module910c, guidance and position sensors920c, a communications module930cadapted to transmit/receive signals from a computing device (such as device970afromFIG. 14B) and a servo module940cprovided with servo motors941c, encoders942c, proximity sensors943cand amplifiers944cadapted to transmit and receive signals to/from the VCU900cand a hardware emergency stop945c. The guidance and position sensors920cfurther comprises a plurality of antenna arrays921cas described herein, each provided with a bandpass filter922c, multiple inductor coils923c, a microcontroller924cand an amplifier925c, and a RFD location reader926cfor reading the guide wire system. Also provided is a maintenance panel950cfor access to input ports and the like if it is desired to perform maintenance on or otherwise physically connect with the VCU900c. The VCU900cis adapted to process input signals entered through panel950cand input ports, one example for such input signal being a RESET signal. The VCU900cis further capable of producing safety alerts960c, for example, such as routine audible or visual warning signals or event specific alerts based on inputs received from an obstacle avoidance module (not shown).
In one embodiment, the VCU900ccomputes precise heading information for an AGV from feedback provided by the antenna arrays and the onboard microprocessor. Guide wire and wire cross locations as well as center points of storage locations are previously surveyed and stored in a database. The master computer processor uses laser scan data from the retrieval or loading bay to calculate travel offsets based on the offset of the vehicle from the wheelbase, where Offset=(Xwb−Xv)/2 (where Xwb is the dimension from the front of the vehicle to the center of the wheelbase, and Xv is the dimension from the front of the vehicle to the center of the vehicle). Offsets for guide wires paths, wire cross locations, and storage locations are determined by observation Heading information is then used to compute vehicle yaw to correct for heading error. Each steering wheel is directed to an Ackermann angle to achieve the desired yaw. In one embodiment, the traffic master (master computer processor) creates a path of waypoints to the desired destination, where each waypoint consists of heading (vehicle travel direction), vehicle orientation, and path offset. These commands are preferably communicated to the AGV over wireless communication.
FIG. 15illustrates one embodiment of a facility1000that comprises a plurality of storage locations1010occupied by a plurality of shapes1020representative of different sized vehicles with varying wheelbases and front/rear overhangs positioned in storage locations1010. In the illustrated embodiment, the dashed line rectangles also represent and define the maximum possible vehicle size to be stored within a storage location1010. Each storage location1010is defined by a portion of an X-axis guidance wire1030and a portion of an Y-axis guidance wire1040that are part of a larger guidance wire network within the facility1000for the guidance, positioning and movement control of AGVs1050within the storage locations1010and a dedicated travel lane1060. The AGVs1050are each preferably equipped with a plurality of antenna arrays1052, 1054, 1056and1058as described above for omnidirectional movement that is either centered or offset relative to the guidance wire network. In the illustrated embodiment ofFIG. 15, the vehicles1020are all centered relative to the X-axis and Y-axis guidance wires1030and1040respectively along their wheel base to form AGV travel lanes1032and1042 (only two being shown) centered on the X-axis and Y-axis guidance wires1030and1040respectively. In a preferred embodiment, the longest dimension of an AGV1050when travelling in compact mode (the preferred mode of travel when the AGV is not carrying a vehicle) is shorter than the wheel base of all vehicles1020stored along a particular guide wire1030so that the AGV1050is capable of scooting under vehicles1020such that its longitudinal axis is oriented along either an X-axis guide wire or a Y-axis guide wire. In other words, movement of the AGV1050could occur with either the antennas1052and1056, or with antenna1054and1058aligned with the X-axis guidance wire. With ultra-compact vehicles such as Smart™ cars with shortened wheel bases or the like, or in cases of vehicles with especially low undercarriage clearances it may be necessary to rotate the AGVs prior to scooting under the vehicles or to limit travel between the wheelbases of the vehicles in some portions of the facility.
One benefit of the overall control system of the present invention is that the structural elements of each vehicle, including size, wheel base, overhangs and the like are captured by system sensors and utilized by the control system of the invention to efficiently arrange vehicles relative to storage locations and/or other vehicles, and such information is also used for guidance of vehicles within travel lanes1060and relative to travel lane boundaries, obstructions and the like. Furthermore, the ability of AGVs to scoot under vehicles enables the facility1000to maximize storage location density and minimize the number of required travel lanes1060. Another benefit of the overall system is that storage locations can be dynamically arranged and re-arranged depending on the structural dimensions of a vehicle and the available space in a particular storage location area. For example, three adjacent storage locations currently allocated to accommodate three maximum-size vehicles could be dynamically re-designed and re-allocated by the master control system to accommodate more than three smaller vehicles. Alternatively, a single storage location allocated to accommodate a single maximum-size vehicle could be dynamically re-allocated by the master control computer to accommodate two ultra-compact vehicles front-to-back or end-to-end as desired, for example. In addition, spaces around structural columns and like could be populated with grid wires to provide access to an AGV. Therefore, instead of assigning permanent and dedicated storage locations during system layout and creation, the master control computer can take advantage of the enhanced antenna array control and guidance system and wire grid network to dynamically assign spaces and storage locations to accommodate smaller or fewer objects or objects of varying configuration in real time and to adjust the storage capacities to meet demand as needed.
FIG. 16illustrates one example of a facility1100that comprises a plurality of storage locations1110occupied by a plurality of vehicles1120, X and Y guidance wires1130and1140respectively, an AGV1150having antennas1152, 1154, 1156and1158, a plurality of conveyors1160and1162, and a dedicated travel lane1170. The AGV1150and vehicle1122, upon exiting conveyor1160, are able to travel to any of the open storage locations1110a, 1110b, 1110cor1110d. The ultimate determination of where vehicle1122is stored may depend of a variety of factors including, but not limited to the anticipated storage time of the subject vehicle1122, anticipated storage times of other vehicles in the facility, load balancing of vehicles on a floor-by-floor basis, and so on.
FIGS. 17A-17Dillustrate one example of a facility1200that comprises a plurality of storage locations1210occupied by a plurality of vehicles1220, X and Y guidance wires1230and1240respectively, an AGV1250having antennas1252, 1254, 1256and1258, a plurality of conveyors1260and1262, and a dedicated travel lane1270having a plurality of overflow locations1272, 1274, 1276, 1278. FIG. 17Billustrates the storage of vehicles1222and1226in overflow locations1272and1276respectively. FIG. 17Cillustrates the retrieval of vehicle1220afrom storage location1210a, whereby AGV1250first picks up vehicle1226and delivers it to overflow storage location1278in accordance with arrow1280, and then ACV1250acquires vehicle1220afrom storage location1210aand delivers it to travel lane1270in accordance with arrow1282, and then AGV1250delivers vehicle1220ato the conveyor1260in accordance with arrow1284, FIG. 17Dillustrates the retrieval of vehicle1220bfrom storage location1210b, whereby AGV1250first picks up vehicle1222and delivers it to the now-empty storage location1210ain accordance with arrows1290and1292, and then AGV1250acquires vehicle1220bfrom storage location1210band delivers it to travel lane1270in accordance with arrow1294, and then AGV1250delivers vehicle1220bto the conveyor1260in accordance with arrow1296. Of course, inFIG. 17C, AGV1250could also first pick up vehicle1226and deliver it to overflow storage location1274, and then AGV1250could acquire vehicle1220afrom storage location1210aand deliver it to travel lane1270, and then AGV1250could deliver vehicle1220ato the conveyor1262instead of conveyor1260. The movement of AGVs and vehicles is controlled by a master control system (not shown) through any of a variety of possible communication systems though most likely a wireless data network with receivers on the AGVs and any other sensor and receiver system employed to implement such control and guidance (see, for example, FIGS. 149 and 14C).
FIGS. 18A-18Cillustrate one example of a facility1300that comprises a plurality of storage locations1310occupied by a plurality of vehicles1320, X and Y guidance wires1330and1340respectively, AGVs1350and1352and a plurality of travel lanes1360and1362following X-axis and Y-axis guide wires respectively and having temporary overflow locations. In the embodiment ofFIGS. 18A-18C, there is a problem with AGV1352carrying vehicle1322such that it creates an impassable obstruction along travel lane1362. FIGS. 18A-18Cillustrate one method of dynamically re-routing travel lane1362to create a new travel lane1362a(FIG. 18C). First, in a non-limiting method, it is desired for AGV1350to deliver vehicle1320afrom storage location1310ato storage location1310b, whereby AGV1350follows path1380 (FIG. 18A) by scooting under stored vehicle1320cuntil it reaches and acquires target vehicle1320a, and then delivers vehicle1320aalong path1382 (FIG. 18B) to target location1310b. Then, as shown inFIG. 18C, vehicle1320cis delivered from storage location1310cto storage location1310dalong path1384, which frees up storage locations1310a, 1310cand1310eto form the new travel lane1362a. This new temporary travel lane1362ais thus established dynamically by the control system (not shown) for Y axis movement within the system to route around the temporary obstruction1352and1322until the problem causing it can be corrected through remote or onsite remedial intervention. Additional vehicles shown above and below the arrow points defining the travel lane1362acould also be moved into temporary or overflow storage locations one space to the right of their current location in order to extend the “Y” axis Travel Lane if and as needed.
FIGS. 19A-19Ddemonstrate the ability to dynamically coordinate multiple AGVs to retrieve a target load isolated from travel lanes with improved AVG guidance and control system using variable offset positioning antennas. Specifically, FIGS. 19A-19Dillustrate one example of a facility1400that comprises a plurality of storage locations1410occupied by a plurality of vehicles1420, X and Y guidance wires1430and1440respectively, AGVs1450, 1452, 1454and1456and a plurality of travel lanes1460and1462following X-axis and Y-axis guide wires respectively and having temporary overflow locations. FIG. 19Aillustrates the AGVs in standby positions awaiting commands from the control system (not shown). When it is determined that vehicle1420aneeds to be retrieved from storage location1410a, an optimal retrieval route1480for vehicle1420ais determined and plotted by the control system. As shown inFIGS. 19B and 19C, AGVs1450, 1452, 1454and1456are directed to follow paths1481, 1482, 1483and1484respectively in order to acquire vehicles1420a, 1420b, 1420cand1420drespectively in storage locations1410a, 141.0b, 1410cand1410drespectively. As shown inFIG. 19D, AGV1452moves vehicle1420bto empty storage location1420e, AGV1454moves vehicle1420cto empty storage location1420f, and AGV1456moves vehicle1420dto empty storage location1420g, whereby a new travel lane1462ais formed for the retrieval of vehicle1420a.
FIGS. 21-25illustrate non-limiting embodiments of an alternately-constructed AGV1600designed to move either automobiles parked on vehicle trays1700or storage lockers1800from loading areas (not shown) to storage areas (not shown) and then retrieve them on demand. The system of the present invention is, in one respect, an evolution of the automated storage system of U.S. application Ser. No. 12/032,671, filed Feb. 16, 2008, the contents of which are incorporated herein by reference, although the present system incorporates a controllable and guidable AGV whereas the '671 application system does not. Unlike the previous embodiments described in the present application, the AGV1600comprises a rigid framed rectangular body1610that does not expand or contract as described, for example, in U.S. Application 61/145,543, filed Jan. 17, 2009, incorporated herein by reference. The AGV1600drives under a vehicle tray1700or storage locker1800to be acquired which in one of many possible embodiments is sitting up on four legs1710or1810, and then lifts the vehicle tray1700or storage locker1800at preferably four contact points1620by use of a hydraulic pump motor and hydraulic lifters1630. Instead of the target vehicles or loads (not shown) being parked on a concrete floor in a loading area as shown, for example, inFIG. 13herein, the vehicles pull onto the vehicle trays1700that are suitably supported by and provided in the loading areas. The vehicle trays1700are preferably elevated relative to the remainder of the system travel area so that the AGV1600does not need to change elevation between the loading area and the storage area, which is not a concern in the previous embodiments where the AGV scoots under the vehicle body for acquisition thereof.
Once the vehicles (or other loads) are on the trays1700, they are treated similar in all aspects to vehicles handled in previously described embodiments, where the vehicle-laden tray becomes the load that is delivered by the AGV1600from the loading area to the storage area. The vehicle-laden tray is preferably initially scanned by the control system to determine the exact dimensions of the tray with vehicle, after which an AGV1600is dispatched to acquire them whereby they are then picked up and transported from the loading area, through retrieval lanes at offsets as appropriate, up or down vertical conveyors as needed, until they are delivered to a storage location. In the embodiment ofFIGS. 21-23, the load or the vehicle always remains on top of the tray1700as it is moved through the system rather than being lifted by its tires and then deposited in a storage location. Just as in previously-described embodiments, the AGV1600travels across standard floors and follows a wire guidance grid that is optimized by the implementation of an enhanced AGV antenna array provided on the AGV1600as described previously and with actions coordinated by a traffic master server system. The AGV1600of the current embodiment uses an omni-directional drive and steering system that is preferably larger and based upon a stewing gear rather than that shown in U.S. Application 61/248,448, filed Oct. 3, 2009, the contents of which are incorporated herein by reference, in order to accommodate larger loads necessitated through the transport of storage containers1800or the like. In all other aspects, however, the overall system is substantially similar to the previously described systems, though not quite as efficient in use of space due to the use of vehicle trays and the height of the trays on legs, but still having the advantage of being able to store cars of different lengths in different length spaces and being able to shift vehicles sideways and perform coordinated retrievals just like the previously-described AGV systems. The system using the AGV1600has an advantage of being able to handle higher maximum load weights, on that large vehicles or self-storage lockers1800are easily handled by it. Similar to the previously-described AGV systems, the AGV1600is preferably battery powered with in-floor charging stations, uses wireless communications, and has four drive wheels1640.
FIG. 26illustrates yet another embodiment of an AGV1700carrying a load1710such as a vehicle and having antenna arrays1702, 1704, 1706, 1708that demonstrates a “skewed crabbing” technique. InFIGS. 7 through 8B, for example, and the majority of the other figures described herein, the travel path is generally dictated by a control system that instructs the AGV to follow horizontal or vertical paths along an X-Y grid pattern with dynamic offsets as required to meet obstacles or other environmental conditions. FIG. 26illustrates a diagonal travel path within an X-Y wire grid framework defined by X-axis guide wires70a-70eand Y-axis guide wires75a-75d, where the AGV1700is positioned such that the antennas are simultaneously positioned over multiple X-axis and Y-axis guide wires. Such a positioning of the AGV1700would be useful for acquiring loads whose center axes are not just offset from the guide wires, but also whose axes are not parallel to them, and for packing non-rectangular loads more economically. Control and guidance of the AGV1700is performed by a skewing command from the traffic master control system to the AGV1700, which adds a skew angle as an offset to the current heading to position the front and rear antenna readings to correspond to the commanded skew angle from the traffic master control system.
InFIG. 26, each antenna array is preferably constructed to distinguish between multiple guide wires at the same time. For example, antenna1706spans between guide wires70b, 75dand70c, while antenna1708spans between guide wires70cand75c. In the embodiment ofFIG. 14A, for example, the X-axis guide wires920are energized with a certain X-axis frequency925, while the Y-axis guide wires930are energized with a certain Y-axis frequency935. In the embodiment ofFIG. 26, the AGV antenna arrays can distinguish between multiple X-axis guide wires70of the same frequency and multiple Y-axis guide wires75of the same frequency as long as the respective guide wires are separated by a sufficient distance and as long as the antenna inductor coils are sufficiently arranged and controlled by the master control system to distinguish between the respective guide wires relative to the overall position of the AGV relative to the guide wire layout. In an alternative embodiment, each X-axis guide wire and each Y-axis guide wire could be provided with a distinct frequency that is sensed by the inductor coils in the antenna arrays so that positioning of the AGV1700relative to the guide wire layout can be focused to a specific inductor coil on a specific antenna array relative to a specific guide wire within the guide wire layout. Such a system may be preferred depending on the spacing of the guide wires so it is not necessary to discriminate between multiple guide wires of the same frequency solely through the spacing of such wires relative to the AGV. In other words, with multiple distinct frequencies, the traffic master control system can dynamically and angularly skew and offset the positioning of the AGV1700through the simultaneous processing of multiple frequencies across multiple antenna arrays and by targeting select guidance and positioning sensors within the antenna arrays.
While the present invention has been described at some length and with some particularity with respect to the several described embodiments, it is not intended that it should be limited to any such particulars or embodiments or any particular embodiment, but it is to be construed with reference to the appended claims so as to provide the broadest possible interpretation of such claims in view of the prior art and, therefore, to effectively encompass the intended scope of the invention. Furthermore, the foregoing describes the invention in terms of embodiments foreseen by the inventor for which an enabling description was available, notwithstanding that insubstantial modifications of the invention, not presently foreseen, may nonetheless represent equivalents thereto.