Control method for synchronous high speed motion stop for multi-top loaders across controllers

• US 8,046,102 B2
• Filed: 05/17/2007
• Issued: 10/25/2011
• Est. Priority Date: 05/17/2007
• Status: Active Grant

• Current Assignee: Fanuc Robotics America Incorporated (Fanuc Corporation)
• Original Assignee: Fanuc Robotics America Incorporated (Fanuc Corporation)
• Inventors: Orr, Ian, Tao, Jianming, McGee, H. Dean, Motley, Richard, Wong, Ho Cheung, Tsai, Chi-Keng
• Primary Examiner(s): Nguyen; John
• Assistant Examiner(s): KIM, KYUNG J
• Application Number:
  US11/750,082
• Publication Number:
  US 20080288109A1
• Time in Patent Office: 1,622 Days
• Field of Search: 700/255, 901/49, 209/584, 209/900, 198/370.01
• US Class Current: 700/255
• CPC Class Codes: B25J 9/1666 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 19/4061 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 2219/39088 Inhibit movement in one axis if collision danger
• CPC Class Codes: G05B 2219/39097 Estimate own stop, brake time, then verify if in safe distance

Abstract

A synchronous high speed motion stop for a series of multi-top loaders residing on “n” controllers on one rail achieves effective detection of the servo-error status and shut off of the trailing controller'"'"'s servo power within 3 ITP time. The control method reduces the unnecessary error recovery because it only shuts off its immediate trailing controller without aborting its leading controller, allowing the leading controller to complete the cycle tasks. The cascade control method produces a synchronous high-speed motion stop for the robots across the controllers and effectively prevents the collision between the robots.

Claims

1. A control method for a series of multi-top loaders residing on “

n”

controllers on one rail, comprising the steps of;

a. an unanticipated event occurring at a first robot associated with a first controller;

b. posting of an error resulting from the event at a current interpolate loop time of the first robot;

c. starting a motion control system to perform a high speed stop within the same interpolate loop time of the first robot;

d. the motion control system sending a control signal via a hardwired robot digital output to an immediate trailing controller; and

e. the control signal triggering an over travel circuit of the trailing controller.

2. The control method of claim 1, and further comprising the step of after the control signal triggering the over travel circuit, a motion control system of the trailing controller posting an error within the same interpolate loop time.

3. The control method of claim 2, and further comprising the step of after the trailing controller performing a high speed stop comprising motion control system posting the error, the trailing controller shutting off drive power to a servo system and applying robot brakes to a robot associated with the trailing controller.

4. The control method of claim 3, and further comprising the step of after performing a high speed stop comprising shutting off drive power and applying robot brakes to the trailing controller robot, if the trailing controller is a last one in a series of “

n”

controllers, then exiting the program.

5. The control method of claim 3, and further comprising the step of after performing a high speed stop comprising shutting off drive power and applying robot brakes to the trailing controller robot, if said trailing controller is not a last one in a series of “

n”

controllers, repeating said step d.

6. A control method for a series of multi-top loaders residing on “

n”

controllers on one rail, comprising the steps of;

a. an unanticipated event occurring at least two robots associated with a first controller;

b. posting of an error resulting from the event at a current interpolate loop time of the at least two robots;

c. starting a motion control system to perform a high speed stop within the same interpolate loop time of the at least two robots;

d. the motion control system sending a control signal via a hardwired robot digital output to an immediate trailing controller; and

e. the control signal triggering an over travel circuit of the trailing controller.

7. The control method of claim 6, and further comprising the step of after a control signal triggering the over travel circuit, a motion system of the trailing controller posting an error within the same interpolate loop time.

8. The control method of claim 7, and further comprising the step of after posting an error by the trailing controller, the trailing controller performing a high speed stop comprising shutting off drive power to a servo system and applying robot brakes to all robots associated with the trailing controller.

9. The control method of claim 8, and further comprising the step of after performing a high speed stop comprising shutting off drive power and applying robot brakes, if the trailing controller is a last one in a series of “

n”

controllers, then exiting the program.

10. The control method of claim 8, and further comprising the step of after performing a high speed stop comprising shutting off drive power and applying robot brakes, if the trailing controller is not a last one in a series of “

n”

controllers, repeating said step d.

11. A synchronous high-speed motion stop apparatus comprising:

at least two multi-top loaders;

a controller associated with each of said multi-top loaders;

a single rail supporting said multi-top loaders in series along said rail; and

said controllers configured for performing a cascading high speed stop of said multi-top loaders on said rail, wherein said cascading high speed stop comprises the steps of;

a. an unanticipated event occurring at one of said at least two multi-top loaders;

b. posting of an error resulting from the event at a current interpolate loop time of said one multi-top loader;

c. starting a motion control system to perform a high speed stop within the same interpolate loop time of the one multi-top loader;

d. the motion control system sending a control signal via a hardwired robot digital output to an immediate trailing one of the controllers; and

e. the control signal triggering the over travel circuit of the trailing controller.

12. The synchronous high-speed motion stop apparatus of claim 11, wherein said interpolate loop time is 12 milliseconds.

13. The synchronous high-speed motion stop apparatus of claim 11, wherein said multi-top loaders travel with speeds as high as 3000 mm/sec along said rail.

14. The synchronous high-speed motion stop apparatus of claim 11, wherein said multi-stop loaders are located within 70 mm of each other along said rail.

15. The synchronous high-speed motion stop apparatus of claim 11, said control method further comprising the step of the motion system of the trailing controller posting an error within the same interpolate loop time.

16. The synchronous high-speed motion stop apparatus of claim 15, and further comprising the step of after posting the error, the trailing controller performing a high speed stop comprising shutting off drive power to a servo system and applying robot brakes to an associated one of the at least two multi-top loaders.

17. The synchronous high-speed motion stop apparatus of claim 16, and further comprising the step of after performing a high speed stop comprising shutting off drive power and applying robot brakes, if the trailing controller is a last one in a series of “

n”

controllers, then exiting the program.

18. The synchronous high-speed motion stop apparatus of claim 16, and further comprising the step of after performing a high speed stop comprising shutting off drive power and applying robot brakes, if the trailing controller is not a last one in a series of “

n”

controllers, repeating said step d.