CARTESIAN-BASED CONTROL OF A DEFORMABLE ROBOT MANIPULATOR

A Cartesian-based control scheme which is composed of an adaptive and a servo control law is proposed for a six-degree-of-freedom spatial robot manipulator system consisting of interconnecting rigid and deformable components. The adaptive portion of the control strategy is used to linearize and decouple the equations of motion governing the dynamic behavior of the end-effector, while the servo part of the control strategy drives the reduced system using the feedback gains in the Cartesian coordinate space. By using the proposed control scheme, the control forces for achieving a desired trajectory of the end-effector are first calculated in the global Cartesian space, and then, the equivalent joint actuating forces (torques), which can be implemented in a real system, are determined via the velocity transformation. The dyanmic performance of the system is simulated by using a mathematical model developed by the Cartesian-based Lagrangian formulation. Because of the sudden change in the system topology due to the grasping impact between the end-effector of a robot arm and a presumed object, the pieced interval analysis method is used to model the dynamic system in the neighboring subintervals governed by different sets, and number of, configuration constraints. The control effects of compensating the jump discontinuities due to the impact are shown by the simulation results. © 1990.