Apparatus and method of distributing object handling

• US 6,278,907 B1
• Filed: 11/24/1999
• Issued: 08/21/2001
• Est. Priority Date: 11/24/1999
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Rai, Sudhendu, Fromherz, Markus P. J.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Marc, McDieunel, Marc, McDieunel
• Application Number:
  US09/449,339
• Time in Patent Office: 636 Days
• Field of Search: 700/255, 700/246, 700/251, 700/260, 700/261, 700/264, 700/258, 700/262, 700/263, 700/252, 700/248, 701/23, 701/87, 701/201, 701/301, 318/567, 318/568.1, 318/568.12, 901/1, 901/2, 901/46, 901/47, 713/145, 713/213
• US Class Current: 700/255
• CPC Class Codes: B65H 2220/01 indicating an entity as a function of which control, adjustment or change is performed, i.e. input
• CPC Class Codes: B65H 2220/03 indicating an entity which is measured, estimated, evaluated, calculated or determined but which does not constitute an entity which is adjusted or changed by the control process per se
• CPC Class Codes: B65H 2301/4452 Regulating space between separated articles
• CPC Class Codes: B65H 2511/24 Irregularities, e.g. in orientation or skewness
• CPC Class Codes: B65H 2513/40 Movement
• CPC Class Codes: B65H 43/00 Use of control, checking, or safety devices, e.g. automatic devices comprising an element for sensing a variable

Abstract

A modular object handling system has a multi-level control architecture, which includes a system controller that coordinates the functions and/or operations of individual module controllers, that in turn control corresponding actuators, to provide a desired system function. The system controller performs the overall trajectory planning by taking the constraints of each of the module actuators into account. The system controller may compensate for deviations of objects from their planned trajectories by contemporaneously redetermining trajectories and trajectory envelopes to encode the various combinations of the system constraints and task requirements. The trajectory envelopes can denote regions around other trajectories to indicate control criteria of interest, such as control and collision boundaries. However, by predetermining the trajectories and trajectory envelopes, and comparing the current state of an object with the predetermined trajectory envelopes, the system controller can even more quickly determine the extent to which the state satisfies the criteria. Thus, this system simplifies on-line determinations to merely include a comparison between a particular object, a particular trajectory and the corresponding trajectory envelope. It is also desirable to predetermine multiple trajectories, as well as trajectory envelopes associated with each of the multiple trajectories, for each object. The apparatus and methods of the invention can then monitor the status of each object, and switch between the multiple predetermined trajectories in order to actively improve energy usage efficiency. The apparatus and methods can also modify the trajectories of other objects to avoid collisions with the object whose trajectory was originally switched.

Claims

1. A method of handling objects, comprising:

selecting one of a plurality of objects to be handled;

selecting one trajectory of a set of predetermined trajectories in a trajectory space to accomplish a system function, the selected predetermined trajectory having a trajectory envelope that indicates at least one criterion of interest;

determining an actual position in the trajectory space of the selected object;

determining whether the actual position in the trajectory space of the selected object is within the trajectory envelope of the selected predetermined trajectory; and

selecting another trajectory of the set of predetermined trajectories upon determining that the actual position in the trajectory space of the specified object is not within the trajectory envelope of the selected predetermined trajectory.

2. The method according to claim 1, further comprising controlling the object based upon whether the actual position in the trajectory space of the specified object is within the trajectory envelope.

3. The method according to claim 1, wherein specifying another trajectory includes specifying another trajectory of the multiple trajectories that is closest to the actual position in the trajectory space of the specified object.

4. The method according to claim 1, wherein specifying another trajectory includes specifying another trajectory of the multiple trajectories based upon proximity to the actual position in the trajectory space of the specified object and proximity to the one specified trajectory.

5. The method according to claim 1, wherein specifying another trajectory includes specifying another trajectory that is closest to the actual position in the trajectory space of the specified object while also being adjacent to the one specified trajectory.

6. The method according to claim 1, further including determining a trajectory in the trajectory space for another object.

7. The method according to claim 6, further including specifying a minimum allowed gap separating the trajectory in the trajectory space of the other object from the specified trajectory in the trajectory space of the specified object.

8. The method according to claim 7, further including modifying the trajectory in the trajectory space of the other object upon determining that the trajectory in the trajectory space of the other object is separated from the other specified trajectory of the one specified object by a distance less than the minimum allowed gap.

9. An object handling apparatus usable with objects that are movable along a path, comprising:

a device that determines an actual position in a trajectory space of a specified object;

at least one actuator that performs an operation on the specified object;

at least one module controller that controls the operation of the at least one actuator;

a system controller that plans a system function based on the operation of the at least one actuator and based on whether the actual position in the trajectory space of the specified object is within a trajectory envelope, the trajectory envelope indicating control criteria of interest relative to one specified trajectory among multiple trajectories in the trajectory space that accomplishes the system function, the system controller specifying another trajectory of the multiple trajectories other than the one specified trajectory upon a determination that the actual position in the trajectory space of the specified object is not within the trajectory envelope.

10. The object handling apparatus according to claim 9, further comprising a memory that stores multiple predetermined trajectories and a predetermined trajectory envelope for each predetermined trajectory.

11. The object handling apparatus according to claim 10, wherein the memory stores a collision envelope.

12. The object handling apparatus according to claim 10, wherein the memory stores a collision envelope that is defined between an early collision boundary that indicates the earliest time that the specified object can embark from a location and not collide with another object, and a late collision boundary that indicates the latest time that the specified object can embark from the location and not collide with another object.

13. The object handling apparatus according to claim 10, wherein the memory stores a control envelope for each predetermined trajectory.

14. The object handling apparatus according to claim 10, wherein the memory stores a control envelope that is defined between an early collision boundary that indicates the earliest time that the specified object can embark from a location and still accomplish a task, and a late collision boundary that indicates the latest time that the specified object can embark from the location and still accomplish the task.

15. The object handling apparatus according to claim 10, wherein the memory stores multiple trajectory envelopes.

16. The object handling apparatus according to claim 10, wherein the memory stores multiple trajectory envelopes for each of the multiple trajectories that indicate different control criteria of interest.

17. The object handling apparatus according to claim 9, wherein the at least one module controller determines a proximity of the actual position of the specified object to boundaries that define the trajectory envelope, and controls the at least one actuator to accomplish the system function with improved efficiency based upon the proximity.

18. The object handling apparatus according to claim 9, wherein the system controller specifies another trajectory of the multiple trajectories that is closest to the actual position in the trajectory space of the specified object.

19. The object handling apparatus according to claim 9, wherein the system controller specifies another trajectory of the multiple trajectories based upon proximity to the actual position in the trajectory space of the specified object and proximity to the one specified trajectory.

20. The object handling apparatus according to claim 19, wherein the system controller specifies another trajectory that is closest to the actual position in the trajectory space of the specified object while also being adjacent to the one specified trajectory.

21. The object handling apparatus according to claim 9, wherein the system controller determines a trajectory in the trajectory space for another object.

22. The object handling apparatus according to claim 21, wherein the system controller specifies a minimum allowed gap separating the trajectory in the trajectory space of the other object from the specified trajectory in the trajectory space of the specified object.

23. The object handling apparatus according to claim 22, wherein the system controller modifies the trajectory in the trajectory space of the other object upon a determination that the trajectory in the trajectory space of the other object is separated from the other specified trajectory of the one specified object by a distance less than the minimum allowed gap.