Coordinated joint motion control system

• US 20040267404A1
• Filed: 08/26/2004
• Published: 12/30/2004
• Est. Priority Date: 08/31/2001
• Status: Active Grant

• Current Assignee: Board of Regents Nevada System of Higher Education (State of Nevada)
• Original Assignee: Board of Regents Nevada System of Higher Education (State of Nevada)
• Inventors: Danko, George
• Granted Patent: US 7,457,698 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• CPC Class Codes: B25J 9/1607 Calculation of inertia, jacobian matrixes and inverses
• CPC Class Codes: B25J 9/1651 acceleration, rate control
• CPC Class Codes: E02F 3/437 providing automatic sequences of movements, e.g. linear excavation, keeping dipper angle constant
• CPC Class Codes: E02F 3/438 Memorising movements for repetition, e.g. play-back capability
• CPC Class Codes: E02F 3/439 Automatic repositioning of the implement, e.g. automatic dumping, auto-return E02F3/438 takes precedence
• CPC Class Codes: E02F 9/2037 Coordinating the movements of the implement and of the frame
• CPC Class Codes: E02F 9/2041 Automatic repositioning of implements, i.e. memorising determined positions of the implement for dipper-arms or bucket-arms E02F3/434, E02F3/437, E02F3/438, E02F3/439 take precedence
• CPC Class Codes: G05B 2219/39062 Calculate, jacobian matrix estimator
• CPC Class Codes: G05B 2219/39224 Jacobian transpose control of force vector in configuration and cartesian space
• CPC Class Codes: G05B 2219/40495 Inverse kinematics model controls trajectory planning and servo system

Abstract

A coordinated joint control system for controlling a coordinated joint motion system, e.g an articulated arm of a hydraulic excavator blends automation of routine tasks with real-time human supervisory trajectory correction and selection. One embodiment employs a differential control architecture utilizing an inverse Jacobian. Modeling of the desired trajectory of the end effector in system space can be avoided. The invention includes image generation and matching systems.

Claims

1-32. -32. (cancelled)

33. A coordinated joint control system for controlling a coordinated joint motion system, the coordinated joint motion system comprising:

a) a support system;

b) an end effector movable relatively to the support system by the joint motion system;

c) multiple links to link the end effector to the support system;

d) multiple joints connecting the multiple links one to another, to the support system and to the end effector, each joint permitting relative movement between the members directly connected by the respective joint;

e) multiple actuators to effect said relative movement between the connected members, the multiple actuators being controlled by the coordinate joint control system; and

f) an operator interface;

wherein the coordinated joint motion system is capable of execution of an automated end effector trajectory without human intervention and can receive inputs through the operator interface enabling a human supervisor to change the end effector motion or position or motion and position during execution of the automated trajectory.

34. A control system according to claim 33 comprising an internal feedback loop to determine a mathematical model of the coordinated joint motion system and provide a model-based forward predictor for directly controlling the joint actuators, optionally by employing a differential control architecture.

35. A control system according to claim 33 comprising an internal feedback loop to generate a differential inverse kinematics model of the machine configuration for a given end effector position.

36. A control system according to claim 35 wherein the internal feedback loop comprises an inverse Jacobean matrix relating the joint-space variables as a vector, to an input vector of Cartesian variables.

37. A control system according to claim 33 wherein link position control is based on the Cartesian acceleration components of the multiple links, evaluated from an a priori trajectory and human supervisor corrections input to the operator interface using a differential time base.

38. A control system according to claim 33 wherein the control system comprises a control computer and operates without generating an integrated path in control computer model-space, and differentiating the trajectory for joint variable control during real-time machine control, optionally without requiring internal joint position control loops.

39. A control system according to claim 33 wherein the control system comprises a Cartesian position control loop to apply each motion component to the joint actuators through visual feedback to the human supervisor.

40. A control system according to claim 33 wherein the control system enables a human supervisor to employ velocity control to adjust and correct the end effector position.

41. A control system according to claim 33 wherein the operator interface comprises a control box employing at least one manually movable member to input control signals and optionally a computer interface for selection of a trajectory.

42. A control system according to claim 41 wherein the at least one manually movable member comprises multiple joysticks and in that the control system can distribute a control signal from a single joystick to multiple joint actuators.

43. A control system according to claim 33 wherein the coordinated joint motion system comprises a mining or construction machine, optionally an excavator.

44. A control system according to claim 43 wherein the multiple links comprise a boom revolutely connected to the machine, an arm revolutely connected to the boom and a tool, optionally a bucket, revolutely connected to the arm.

45. A control system according to claim 33 wherein the multiple joints are revolute or prismatic multiple joints.

46. A control system according to claim 33 wherein the control system comprises, during execution of the end effector trajectory an electronically stored differential trajectory for the end effector and in that the control system integrates the differential trajectory in real time to provide the actual end effector trajectory.

47. A control system according to claim 46 wherein the control system lacks an electronically stored a priori end effector trajectory utilized for execution of the end effector trajectory.

48. A coordinated joint motion system comprising a control system according to claim 33.

49. A coordinated joint control imaging system for imaging a coordinated joint motion system, the coordinated joint motion system comprising:

a) a support system;

b) an end effector movable relative to the support system by the joint motion system;

c) multiple links to link the end effector to the support system;

d) multiple joints connecting the multiple links one to another and to the support system and the end effector, each joint permitting relative movement between the connected members; and

e) multiple actuators to effect said relative movement between the connected members, the multiple actuators being controlled by the coordinate joint control system;

wherein the imaging system comprises an internal feedback loop to determine a mathematical model of the coordinated joint motion system and provide a model-based forward predictor for directly controlling the joint actuators, optionally by employing a differential control architecture.

50. A joint control imaging system according to claim 49 wherein the imaging system comprises an internal feedback loop to generate a differential inverse kinematics model of the machine configuration for a given end effector position.

51. A joint control imaging system according to claim 49 wherein the internal feedback loop comprises an inverse Jacobean matrix relating the joint-space variables as a vector, to an input vector of Cartesian variables.

52. A joint control imaging system according to claim 49 wherein the image generated is matched to an input image, optionally an anatomical image.

53. A joint control imaging system according to claim 49 wherein the coordinated joint motion system comprises a mining or construction machine, optionally an excavator and the image generated is used to facilitate machine control.

54. A method for controlling a coordinated joint motion system, the coordinated joint motion system comprising:

a) a support system;

b) an end effector movable relative to the support system by the joint motion system;

c) multiple links to link the end effector to the support system;

d) multiple joints connecting the multiple links one to another and to the support system and the end effector, each joint permitting relative movement between the connected members; and

e) multiple actuators to effect said relative movement between the connected members, the multiple actuators being controlled by the coordinate joint control system;

the method comprising execution of an automated end effector trajectory without human intervention;

and including a human supervisor changing the end effector motion or position during execution of the automated trajectory.

55. A method according to claim 54 comprising determining a mathematical model of the coordinated joint motion system, providing a model-based forward predictor and directly controlling the joint actuators using the forward predictor and employing a differential control architecture.

56. A method according to claim 54 comprising generating a differential inverse kinematics model of the machine configuration for a given end effector position.

57. A method according to claim 54 relating the joint-space variables as a vector, to an input vector of Cartesian variables employing an inverse Jacobean matrix.

58. A method according to claim 54 evaluating the Cartesian acceleration components of the multiple links from an a priori trajectory and human supervisor corrections input to the operator interface using a differential time base and employing the Cartesian acceleration components of the multiple links to control the end effector position.

59. A method according to claim 54 comprising differentiating the trajectory for joint variable control during real-time machine control without requiring internal joint position control loops and without generating an integrated path in control computer model-space.

60. A method according to claim 54 comprising applying each motion component to the joint actuators employing a Cartesian position control loop and visual feedback from the human supervisor.

61. A method according to claim 54 comprising a human supervisor adjusting and correcting the end effector position by employing velocity control.

62. A method according to claim 54 wherein the at least one manually movable member comprises multiple joysticks and the method comprises distributing a control signal from a single one of the joysticks to at least two of the multiple joint actuators.

63. A method according to claim 54 performed on a mining or construction machine.

64. A method according to claim 54 wherein the control system integrates an electronically stored differential trajectory in real time to provide the actual end effector trajectory without employing an electronically stored a priori end effector trajectory.