Guidance, navigation, and control system for a vehicle

• US 8,090,491 B2
• Filed: 07/26/2006
• Issued: 01/03/2012
• Est. Priority Date: 07/26/2005
• Status: Active Grant

• Current Assignee: Macdonald Dettwiler and Associates Limited
• Original Assignee: Macdonald Dettwiler and Associates Limited
• Inventors: Barfoot, Timothy D., Marshall, Joshua A., Mukherji, Raja, Ward, Robert
• Primary Examiner(s): Hellner, Mark
• Assistant Examiner(s): Mawari, Redhwan
• Application Number:
  US11/922,706
• Publication Number:
  US 20090043439A1
• Time in Patent Office: 1,987 Days
• Field of Search: 701/23, 701/25, 701/200, 701/208, 701/301, 180/116, 180/167, 180/168, 180/169, 700/253, 318/580, 318/587
• US Class Current: 701/25
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2050/0028 Mathematical models, e.g. for simulation
• CPC Class Codes: B60W 2552/00 Input parameters relating to infrastructure
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: G05B 2219/40555 Orientation and distance
• CPC Class Codes: G05B 2219/45004 Mining
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0261 using magnetic plots
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30
• CPC Class Codes: G05D 1/0297 by controlling means in a control room
• CPC Class Codes: G08G 1/20 Monitoring the location of vehicles belonging to a group, e.g. fleet of vehicles, countable or determined number of vehicles
• CPC Class Codes: G08G 1/202 Dispatching vehicles on the basis of a location, e.g. taxi dispatching

Abstract

A guidance, navigation, and control method and system for an underground mining vehicle wherein an operator directly or indirectly guides the vehicle along a route as vehicle-mounted sensors including odometric sensors and rangefinders log motion data to a file which data is processed into a route profile including a vehicle path, a sequence of submaps along the path, and a profile of desired speed as a function of distance along the path. Thereafter the vehicle automatically repeats the route as represented by the route profile without an operator using the sensors and the maps to determine vehicle location.

Claims

1. A self-propelled vehicle with a guidance, navigation and control system for automated operation in a passageway environment, comprising:

a) a vehicle including one or more odometric sensors, one or more rangefinder sensors mounted on said vehicle, and a microprocessor including memory storage, said one or more odometric sensors and one or more rangefinder sensors being connected to said microprocessor, said vehicle being configured for microprocessor controlled operation with said microprocessor being interfaced with a throttle/engine system, transmission system, and braking system of said vehicle through a drive control means to adjust a speed of travel of said vehicle, and said microprocessor being interfaced to a steering system of said vehicle through a steering control means to adjust a direction of travel of said vehicle;

b) teaching means including

i) means for conducting a training run of a vehicle path through said passageway environment by driving said vehicle through said passageway environment, and

ii) data logging means to acquire raw sensor data from said one or more odometric sensors and said one or more rangefinder sensors during said training run of said vehicle path and storing said raw sensor data in a log file in said microprocessor memory storage;

c) profiling means for processing said raw sensor data stored in said log file and producing therefrom a route profile and storing said route profile in said microprocessor memory storage, said route profile including

i) information representing a vehicle path through said passageway environment,

ii) a sequence of local metric submaps of said passageway environment along said vehicle path, and

iii) a speed profile defined as a function of distance along the vehicle path; and

d) playback control system to automatically drive said vehicle along said vehicle path from said route profile stored on said microprocessor memory comprising

i) localization means for determining longitudinal, lateral, and heading errors of said vehicle with respect to the vehicle path by comparing said raw sensor data from said odometric sensors and said rangefinder sensors to said local metric submaps, said steering control means adjusting the direction of travel of said vehicle for ensuring said vehicle closely tracks said vehicle path from said information representing said vehicle path stored in said route profile by using said lateral and heading errors and knowledge of said vehicle'"'"'s dynamics,

ii) speed estimation means for estimating a speed of said vehicle from data from said odometric sensors, said drive control means adjusting the speed of travel of the vehicle for ensuring said vehicle closely tracks said speed profile stored in said route profile by using said estimated speed and knowledge of said vehicle'"'"'s dynamics, and

iii) safety means for instructing said vehicle to stop in the event of an emergency situation arising.

2. The self-propelled vehicle according to claim 1 wherein said information representing said vehicle path is generated by using said raw sensor data from the odometric sensors and a kinematics model of the vehicle.

3. The self-propelled vehicle according to claim 1 wherein said odometric sensors include either a drive-shaft encoder and a hinge-angle encoder, an inertial measurement unit, or both, and wherein said data logging means is configured to record information from said drive-shaft encoder and hinge-angle encoder, said inertial measurement unit, or both.

4. The self-propelled vehicle according to claim 1 wherein said odometric sensors include any one of a first wheel encoder mounted on a wheel axle of said vehicle, a second wheel encoder mounted on a drive shaft of said vehicle, a third wheel encoder mounted on its own shaft equipped with its own wheel that is in constant contact with a wheel of said vehicle, or any combination thereof, and wherein said speed estimation means for estimating the speed of said vehicle from odometric data comprises means for first estimating a distance traveled from signals from any one or combination of said first, second and third encoders, by multiplying the number of encoder revolutions by a calibrated factor, and then means for differentiating this signal with respect to the time taken to travel this distance.

5. The self-propelled vehicle according to claim 1 wherein said means for conducting a training run of a vehicle path through said passageway environment by driving said vehicle through said passageway environment includes an operator manually driving the vehicle through said passageway environment, or configuring said self-propelled vehicle for tele-operation and remotely driving the vehicle through said passageway environment.

6. The self-propelled vehicle according to claim 1 wherein said sequence of local metric submaps are constructed using sensor data from both said one or more odometric sensors and said one or more rangefinders, and wherein said local metric submaps include grids of cells, wherein each cell takes on a cell value of either ‘

occupied’

or ‘

not occupied’

such that a cell is assigned to be ‘

occupied’

if it is estimated that a region of said passageway represented by the cell contains an obstacle, and a cell is assigned to be ‘

not occupied’

if the region of said passageway represented by the cell contains free space that is possibly traversable by said self-propelled vehicle.

7. The self-propelled vehicle according to claim 6 wherein a spacing and boundaries of said sequence of local metric submaps are constructed using knowledge of a sensing range of said one or more rangefinder sensors and such that there is sufficient overlap in regions represented by contiguous local metric submaps so as to ensure that data from said one or more rangefinder sensors always lie within the boundaries of at least one local metric submap in said sequence of local metric submaps.

8. The self-propelled vehicle according to claim 6 wherein the cell values for a specified local metric submap in said sequence of local metric submaps are determined by using sensor readings from said one or more rangefinder sensors logged while the self-propelled vehicle is on a segment of the vehicle path in the passageway environment contained within boundaries of said specified local metric submap.

9. The self-propelled vehicle according to claim 8 wherein determining the cell values for the local metric submap is done through the use of a ray-tracing algorithm stored in said microprocessor memory storage to mark those cells from a vehicle position out to a measured rangefinder reading as ‘

not occupied’ and

cells a short distance beyond as ‘

occupied’

, then taking a tally of the cell values over all the laser data used for each local metric submap and a final cell value determined by using the most common value for that cell.

10. The self-propelled vehicle according to claim 1 wherein said localization means for determining longitudinal, lateral, and heading errors of said vehicle with respect to said vehicle path includes processing means for estimating a longitudinal distance along the vehicle path and lateral and heading errors of the self-propelled vehicle with respect to the vehicle path using data from said one or more odometric sensors to dead-reckon said vehicle'"'"'s position and orientation, and processing means for using data from said one or more rangefinder sensors for correcting said dead-reckoned vehicle position and orientation using said sequence of local metric submaps representing the passageway environment along the vehicle path, as represented in the route profile.

11. The self-propelled vehicle according to claim 10 wherein said processing means for using for correcting said dead-reckoned vehicle position and orientation using said sequence of local metric submaps includes means for minimizing the error between said data from one or more rangefinder sensors and the expected rangefinder data for an appropriately selected set of possible positions and orientations of the vehicle given an estimated location of the vehicle along said vehicle path, as represented in said route profile, as determined by dead-reckoning.

12. The self-propelled vehicle according to claim 1 wherein said steering control means includes a path-tracking controller for updating steering commands sent to the vehicle'"'"'s steering system by the steering control means based on a current lateral and heading errors, wherein said path-tracking controller includes stored knowledge of the vehicle'"'"'s kinematics and dynamics, including the vehicle'"'"'s steering kinematics, the vehicle'"'"'s rotational dynamics, and its steering actuator dynamics.

13. The self-propelled vehicle according to claim 1 wherein said drive control means is configured to compare an estimate of the vehicle'"'"'s actual speed, which is provided by said speed estimation means, to a desired speed of the vehicle, which is provided by said speed profile, at its current distance along the vehicle path, which is provided by the localization means, and wherein this comparison is performed by computing a speed error, which is the difference between the desired vehicle speed and the actual vehicle speed, so that the drive control means then uses this speed error to alter drive commands being sent to the vehicle by using stored knowledge of the vehicle'"'"'s engine/driveline dynamics, vehicle translational dynamics, and wheel-ground interaction dynamics.

14. The self-propelled vehicle according claim 1 wherein said profiling means for producing said speed profile, includes providing a target speed for the self-propelled vehicle at all points along the vehicle path wherein said speed profile is generated using a set of preprogrammed rules.

15. The self-propelled vehicle according to claim 14 wherein said set of preprogrammed rules includes assigning high speeds to sections of the vehicle path that are relatively straight, assigning lower speeds to sections of the vehicle path with a higher curvature such that during automated operation of the vehicle the vehicle will slow down while going around corners, and wherein said speed profile is produced so as to provide smooth acceleration from a stop and smooth deceleration to a stop.

16. The self-propelled vehicle according to claim 1 including a radio receiver, and wherein said microprocessor is configured to acquire information relating to radio frequency identification (RFID) tags, and to acquire information relating to a communications system infrastructure.

17. The self-propelled vehicle according to claim 1 including one or more inclinometer sensors mounted on the vehicle for acquiring information relating to pitch/roll of the vehicle and interfaced with said microprocessor.

18. The self-propelled vehicle according to claim 1 including one or more sensors for sensing a transmission gear of the vehicle, engine speed of the vehicle, and pressures in any hydraulic cylinders required to steer the vehicle, and said one or more sensors configured to store readings in the microprocessor memory storage.

19. The self-propelled vehicle according to claim 1 wherein said playback control system is configured to send steering, throttle, braking, and transmission setting commands to the vehicle by initiating said localization means, initiating said speed estimation means and adjusting the speed and direction of travel of said vehicle if needed, and detecting unexpected obstructions at a sufficiently high frequency to ensure the vehicle plays back the route profile well and reacts to problems such as unexpected obstructions.

20. The self-propelled vehicle according to claim 19 wherein said sufficiently high frequency is a frequency in a range from about 10 to about 100 times per second.

21. The self-propelled vehicle according to claim 1 including one or more cameras mounted on said vehicle.

22. The self-propelled vehicle according to claim 1 wherein said safety means for instructing said vehicle to stop in the event of an emergency situation arising includes any one or combination of

said microprocessor accepting stop signals from one or more external sources,

said microprocessor generating internal stop signals based on data from said one or more rangefinder sensor(s), and

said microprocessor generating internal stop signals based on data from said one or more odometric sensor(s).