COMMUNICATIONS SPOOLER FOR A MOBILE ROBOT

• US 20120097783A1
• Filed: 10/24/2011
• Published: 04/26/2012
• Est. Priority Date: 03/26/2003
• Status: Active Grant

• Current Assignee: Flir Detection, Inc. (Teledyne Technologies Incorporated)
• Original Assignee: iRobot Corporation
• Inventors: Pack, Robert Todd, Sawyer, Tyson, Won, Chikyung, More, Grinnell
• Granted Patent: US 8,485,330 B2
• Time in Patent Office: Days
• US Class Current: 242/416
• CPC Class Codes: B65H 75/425 attached to, or forming part of a vehicle, e.g. truck, trailer, vessel
• CPC Class Codes: B65H 75/4484 Electronic arrangements or adaptations for controlling the winding or unwinding process, e.g. with sensors
• CPC Class Codes: B65H 75/4486 Electric motors
• CPC Class Codes: F41H 11/16 Self-propelled mine-clearing vehicles; Mine-clearing devices attachable to vehicles
• CPC Class Codes: F41H 7/005 Unmanned ground vehicles, i.e. robotic, remote controlled or autonomous, mobile platforms carrying equipment for performing a military or police role, e.g. weapon systems or reconnaissance sensors F41H11/16 takes precedence
• CPC Class Codes: F42B 15/04 using wire, e.g. for guiding ground-to-ground rockets
• CPC Class Codes: H02G 11/02 using take-up reel or drum

Abstract

A cable handling system mounted to a mobile robot to dispense and retrieve cable at zero tension includes a cable reel drive and a downstream tension roller drive that includes an idler. As a cable passes through the tension roller drive, position along the length of the cable and/or the cable speed is monitored accurately by a sensor attached to the idler. A system controller in communication with the sensor controls the cable reel drive and the tension roller drive for dispensing and retrieving cable downstream of the tension roller drive.

Claims

1-25. -25. (canceled)

26. A motor control system in a cable handling system for a mobile robotic platform, the system comprising:

a predetermined continuous operation thermal limit for a motor;

a motor controller for providing a signal to the motor; and

a dynamic thermal limiter electrically connected to the motor controller, the dynamic

thermal limiter adapted for monitoring at least one motor variable, wherein the motor controller

permits the motor to exceed the continuous operation thermal limit based at least in part on

information from the dynamic thermal limiter during motor operation.

27. The motor control system of claim 26, wherein the at least one motor variable is selected from the group consisting of motor current and motor temperature.

28. The motor control system of claim 26, further comprising a dynamic thermal limit for the motor, wherein the dynamic thermal limit is greater than the continuous operation thermal limit.

29. The motor control system of claim 28, wherein the motor controller reduces a current to the motor if the measured motor variable exceeds the dynamic thermal limit.

30. The motor control system of claim 26, wherein the motor controller terminates a current to the motor if the measured motor variable exceeds an emergency thermal limit for the motor.

31. A method for controlling tension of a cable in a cable handling system for a mobile robotic platform comprising a cable routed from a cable reel to a cable roller and to an idler roller in rolling contact with the cable, the method comprising:

monitoring rotation o f the cable roller;

monitoring rotation of the idler roller;

calculating slippage of the cable based at least in part on the cable roller rotation and the idler roller rotation; and

controlling the cable reel based at least in part on the slippage.

32. The method of claim 31, wherein during operation, cable on at least one side of the cable roller is at substantially zero tension.

33. The method of claim 31, wherein the rotation of at least one of the cable roller and the idler roller is monitored by at least one of a digital encoder, an incremental encoder, and a sensor.

34. The method of claim 31, further comprising preloading a sensor associated with at least one of the cable reel, cable roller, and idler roller.

35. A method of controlling a length of cable between a cable reel and a cable roller in a cable handling system for a mobile robotic platform, the method comprising:

rotating the cable roller to move a first length of cable;

estimating a second length of cable remaining on the cable reel;

computing a length of cable located between the cable reel and the cable roller, based at least in part on the first length of cable and the second length of cable; and

rotating the cable reel to adjust the length of cable located between the cable reel and the cable roller.

36. The method of claim 35, further comprising:

providing an idler roller in contact with the cable such that a movement of the cable causes a corresponding rotation of the idler roller;

measuring a third length of cable based at least in part on the corresponding rotation of the idler roller; and

computing the length of cable located between the cable reel and the cable roller, based at least in part on the third length of cable.

37. The method of claim 35, wherein the estimating step comprises:

monitoring a rotation of the cable reel;

monitoring a rotation of the cable roller; and

comparing the rotation of the cable reel and the rotation of the cable roller.

38. The method of claim 37, further comprising maintaining tension on the length of cable located between the cable reel and the cable roller.

39. The method of claim 37, wherein the comparing step is based on the ratio of the rotation of the cable reel and the rotation of the cable roller.

40. The method of claim 37, further comprising scaling the result of the comparing step by a coefficient.

41. The method of claim 40, wherein the coefficient comprises at least one of a cable reel internal diameter, a cable reel hub width, a cable diameter, and a cable packing fraction.

42. The method of claim 38, wherein the computing step comprises:

estimating the length of cable located between the cable reel and the cable roller; and

comparing the estimated length of cable with a distance between the cable roller and a predetermined location on the cable reel, wherein the predetermined location is based at least in part on the second length of cable.

43. A method for compensating for a mass of a cable on a cable reel in a cable handling system for a mobile robotic platform, the method comprising:

estimating a length of cable on the cable reel;

generating a correction factor based at least in part on the estimation; and

modifying a power input to the cable reel based at least in part on the correction factor.

44. The method of claim 43 wherein the correction factor compensates for a distribution of the mass of the cable on the cable reel.