Transport carriage system and method for controlling running of transport carriage

• US 9,098,084 B2
• Filed: 10/24/2011
• Issued: 08/04/2015
• Est. Priority Date: 02/14/2011
• Status: Active Grant

• Current Assignee: Murata Machinery Limited (Muratec)
• Original Assignee: Murata Machinery Limited (Muratec)
• Inventors: Murakami, Takeshi, Kumazawa, Tsuyoshi, Sato, Hajime
• Primary Examiner(s): Cheung, Calvin
• Assistant Examiner(s): WEEKS, MARTIN A
• Application Number:
  US13/984,935
• Publication Number:
  US 20130317675A1
• Time in Patent Office: 1,380 Days
• Field of Search: 701/19
• US Class Current: 1/1
• CPC Class Codes: G05B 19/416 characterised by control of velocity, acceleration or deceleration G05B19/19 takes precedence
• CPC Class Codes: G05B 19/4189 characterised by the transport system
• CPC Class Codes: G05B 2219/43048 Step change in reference, soft start, smoothing reference
• CPC Class Codes: G05B 2219/43162 Motion control, movement speed combined with position
• CPC Class Codes: G05B 2219/50393 Floor conveyor, AGV automatic guided vehicle
• CPC Class Codes: G05D 1/021 specially adapted to land vehicles
• CPC Class Codes: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

In a transport carriage system, multiple transport carriages travel along a common track and each transport carriage includes a servo system that performs servo control with respect to traveling of the transport carriage, and an intermediate instruction of the servo system is generated in a predetermined cycle by an acceleration/deceleration control unit of a traveling control unit. A smoothed instruction is generated for the predetermined cycle by smoothing the generated intermediate instruction over a plurality of cycles with a smoothing unit of the traveling control unit, and the servo system is controlled based on the smoothed instruction that was generated.

Claims

1. A transport carriage system wherein a plurality of transport carriages travel, the system comprising:

a common track on which the plurality of transport carriages travel;

a servo system that is provided in each of the transport carriages and performs servo control with respect to traveling of each of the transport carriage; and

a traveling control unit that is arranged and programmed to control the servo system and includes an acceleration/deceleration control unit that is arranged and programmed to generate an intermediate instruction for the servo system for a predetermined cycle and a smoothing unit that generates a smoothed instruction for the predetermined cycle by smoothing the intermediate instruction over a plurality of cycles;

wherein

the acceleration/deceleration control unit is arranged and programmed to generate the intermediate instruction with respect to a current cycle for each predetermined cycle such that the transport carriage travels at a maximum velocity in a range that satisfies at least one constraint condition regarding traveling of the transport carriage, and to store the at least one constraint condition in a variable manner;

the at least one constraint condition includes a restriction regarding the maximum velocity of the transport carriage; and

the at least one constraint condition is determined based on data stored, generated, or sensed by the traveling control unit.

2. The transport carriage system according to claim 1, wherein the smoothing unit is arranged and programmed to generate the smoothed instruction by obtaining a moving average of the intermediate instruction over a plurality of cycles.

3. The transport carriage system according to claim 2, wherein the traveling control unit further includes a filter that generates a servo position instruction by removing one of high frequency components and signals in a vicinity of a characteristic frequency of the transport carriage from the smoothed instruction and inputs the servo position instruction to the servo system.

4. The transport carriage system according to claim 1, wherein:

the at least one constraint condition includes a plurality of constraint conditions;

the acceleration/deceleration control unit is arranged and programmed to generate the intermediate instruction so as to satisfy the plurality of constraint conditions;

the plurality of constraint conditions include restrictions regarding at least the maximum velocity, a maximum acceleration, and a maximum deceleration of the transport carriage.

5. The transport carriage system according to claim 4, wherein the intermediate instruction is defined by one of a target position for the current cycle and a target velocity for the current cycle.

6. The transport carriage system according to claim 5, wherein

the transport carriage system further comprises a ground-based host controller that is arranged and programmed to provide a destination instruction to the transport carriages,

the traveling control unit is provided in each of the transport carriages,

the traveling control unit further includes a communication unit that is arranged and programmed to communicate with the host controller and other transport carriages, and a destination change unit that is arranged and programmed to change the destination indicated by the instruction from the host controller based on current positions, current velocities, and destinations received from other transport carriages, and to output the changed destination, and

the acceleration/deceleration control unit is arranged and programmed to generate one of the target position and the target velocity for the current cycle based on a deviation between the destination output by the destination change unit and the current position of the transport carriage.

7. The transport carriage system according to claim 6, wherein

the transport carriages each further include a vehicle-mounted power supply arranged to drive the servo system, and a power controller that is arranged and programmed to manage the vehicle-mounted power supply, and

the traveling control unit further includes an acceleration restriction unit that is arranged and programmed to change the maximum acceleration in accordance with a signal from the power controller.

8. The transport carriage system according to claim 7, wherein the vehicle-mounted power supply is defined by a power receiving coil that is arranged to receive power from a common contactless power feeding apparatus that is provided so as to be ground-based, and a capacitor that is arranged to accumulate received power.

9. The transport carriage system according to claim 4, wherein:

the traveling control unit includes an acceleration restriction unit and at least one sensor; and

the acceleration restriction unit is arranged and programmed to change the maximum acceleration, the maximum deceleration, an amount of change in the maximum acceleration, and an amount of change in the maximum deceleration of the transport carriage according to values measured by the at least one sensor.

10. The transport carriage system according to claim 9, wherein the at least one sensor includes a stress sensor or a vibration sensor.

11. The transport carriage system according to claim 4, wherein:

the transport carriages each include a vehicle-mounted power supply arranged to drive the servo system, and a power controller that is arranged and programmed to manage the vehicle-mounted power supply;

the maximum acceleration of each of the transport carriages is restricted according to an amount of power that is supplied by the vehicle-mounted power supply.

12. The transport carriage system according to claim 1, wherein the constraint condition regarding the maximum velocity of the transport carriage reduces the range of the maximum velocity of the transport carriage near an end of the common track.

13. The transport carriage system according to claim 1, wherein the constraint condition regarding the maximum velocity of the transport carriage reduces the range of the maximum velocity of the transport carriage relative to a velocity of another transport carriage.

14. The transport carriage system according to claim 1, wherein the traveling control unit includes a track data storage unit that is arranged and programmed to store a plurality of constraint conditions regarding the maximum velocity of the transport carriage at a plurality of positions along the common track.

15. A transport carriage traveling control method for controlling traveling of a plurality of transport carriages,

the plurality of transport carriages traveling along a common track,

the transport carriages each including a servo system that performs servo control with respect to traveling of the transport carriage,

the method comprising:

an intermediate instruction generation step that generates an intermediate instruction with respect to a current cycle for the servo system in a predetermined cycle such that the transport carriage travels at a maximum velocity in a range that satisfies at least one constraint condition regarding traveling of the transport carriages, with an acceleration/deceleration control unit of a traveling control unit;

a smoothing step that generates a smoothed instruction for the predetermined cycle by smoothing the intermediate instruction over a plurality of cycles with a smoothing unit of the traveling control unit;

a control step that controls the servo system based on the smoothed instruction that was generated; and

a step that stores the at least one constraint condition in the acceleration/deceleration control unit in a variable manner;

wherein

the at least one constraint condition includes a restriction regarding the maximum velocity of the transport carriage; and

the at least one constraint condition is determined based on data stored, generated, or sensed by the traveling control unit.

16. The transport carriage traveling control method according to claim 15, further comprising a step of generating a servo position instruction by removing one of a high frequency components and a signal in a vicinity of a characteristic frequency of the transport carriage from moving averaging of the smoothed instruction with a filter of the traveling control unit, the step being executed in each predetermined cycle, wherein

in the control step, the servo position instruction is input to the servo system in the predetermined cycle.