QUASI-STATIC COMPENSATION OF FORCE ERRORS FOR FLEXIBLE MANIPULATORS

This paper deals with the problem of controlling the interactions of flexible manipulators with their environment. For executing a force control task, a manipulator with intrinsic (mechanic) compliance has some advantages over a rigid manipulator. On the other hand, the deformations of the arm under the applied load give rise to errors in the evaluation of the kinematic model of the arm based on its rigid model. Since force feedback is usually provided by a force/torque sensor placed at the end-effector, kinematic errors reflect in force sensing errors, when a force task is specified in the world frame. This paper addresses the problem of evaluating these errors, and of compensating for them with suitable joint angle corrections. A solution to this problem is proposed in the simplifying assumptions that an accurate model of the arm flexibility is known, and that quasi-static corrections are of interest.

[1]  Y. H. Chen,et al.  Robust control of a flexible manipulator arm , 1988, Proceedings. 1988 IEEE International Conference on Robotics and Automation.

[2]  Friedrich Pfeiffer,et al.  A flexible link manipulator as a force measuring and controlling unit , 1991, Proceedings. 1991 IEEE International Conference on Robotics and Automation.

[3]  Mohsen Shahinpoor,et al.  Stability considerations for a two-link force-controlled flexible manipulator , 1990, Proceedings., IEEE International Conference on Robotics and Automation.

[4]  Warren P. Seering,et al.  Understanding bandwidth limitations in robot force control , 1987, Proceedings. 1987 IEEE International Conference on Robotics and Automation.

[5]  R. Roberts,et al.  The effect of wrist force sensor stiffness on the control of robot manipulators , 1985, Proceedings. 1985 IEEE International Conference on Robotics and Automation.

[6]  Delbert Tesar,et al.  Deflection prediction for serial manipulators , 1988, Proceedings. 1988 IEEE International Conference on Robotics and Automation.

[7]  H. Das,et al.  Inverse kinematic algorithms for redundant systems , 1988, Proceedings. 1988 IEEE International Conference on Robotics and Automation.

[8]  W. Wolovich,et al.  A computational technique for inverse kinematics , 1984, The 23rd IEEE Conference on Decision and Control.