Kinematic Control of Robot with Degenerate WristNational Aeronautics and Space Administration, Scientific and Technical Information Branch, 1984 - Bionics - 34 pages Kinematic resolved-rate equations allow an operator with visual feedback to dynamically control a robot hand. However, when the robot wrist is degenerate, the computed joint angle rates exceed operational limits, and unwanted hand movements can result. The generalized matrix inverse solution can also produce unwanted responses. In this paper, a new method is introduced to control the robot hand in the region of the degenerate robot wrist. The method uses a coordinated movement of the first and third joints of the robot wrist to locate the second wrist joint axis for movement of the robot hand in the commanded direction. There is a brief delay for the coordinated movement (which is accomplished in an optimal manner). The method does not entail infinite joint angle rates and appears to be a beneficial method of control. |
Common terms and phrases
appendix arm in figure axis for movement brief delay Commanded hand rotational commanded rotational velocity commanded value Computed hand rotational control a robot control the robot control with rate coordinate system coordinated movement coordinated wrist movement degenerate condition degenerate region degenerate wrist condition Denavit-Hartenberg parameters entail infinite joint equa equation 15 figure 9(b hand axis system hand rotational rate individual joints infinite joint angle Jacobian matrix joint angle rates joint axis systems Keith Barker Langley Research Center magnitude matrix from coordinate matrix inverse motion NASA nondimensional operator commands orientation produce unwanted responses rate limiting Resolved-Rate Control robot arm robot hand axis robot hand rotates robot wrist second wrist joint three rotational joints translational velocity variation in 04 Velocity From Joints velocity of robot wrist is degenerate Wrist joint angle wrist joint axis wrist to locate Wx)c Wx/M wy/M wz)c X5 normal θς Өд