Method of compliance control of a manipulator
AssigneeInternational Business Machines Corporation
InventorsHiroshi Ishikawa, Chihiro Sawada
Life of this patent
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Abstract
A method of compliance control of an industrial manipulator having a high position rigidity is achieved by integrating the motion equation to obtain a position displaced by a detected external force, calculating the trajectory of a position in a joint coordinate system with inverse kinematics, differentiating the calculated trajectory to obtain the trajectories of velocity and acceleration, and performing position control using these latter trajectories. The result is allowance of the compliance to be specified in any desired Cartesian coordinate system in the form of second-order perturbations including stiffness and damping. Moreover, the specified compliance can be realized with separation of the compliance specifications from the system feedback gain.
Claims7
A method for compliance control in a manipulator system having a hand wherein a force exerted upon the hand to be controlled is detected and the position of the hand is controlled on the basis of the detected force, comprising the steps of:
- specificying predetermined parameters for compliance and goal values for position and force applied to the hand;
- solving a second-order equation of motion for the hand in a global coordinate system which includes said specified predetermined parameters for compliance, goal values for position and force applied to the hand, and a value for detected force, to generate a first signal commensurate with a position trajectory of the hand in the global coordinate system which satisfies the equation of motion;
- transforming said first signal commensurate with a position trajectory of the hand in the global coordinate system into a second signal commensurate with a position trajectory of the hand in a coordinate system specific to the hand;
- generating a third signal commensurate with a velocity trajectory and an acceleration trajectory of the hand in the specific coordinate system from said second signal commensurate with a position trajectory of the hand in the specific coordinate system, and
- performing position control of the hand responsive to said second signal and to said third signal so that the hand follows said position trajectory, velocity trajectory, and acceleration trajectory of the hand in the specific coordinate system.
Dependencies are inferred from the claim text.