A new approach to force and position control of robot manipulators

Trajectory control of a robot manipulator when motion is constrained by the environment represents an important class of control problems. We consider the problem of controlling the position and force of a robot manipulator during contact tasks. Based on a dynamics model developed earlier, both position and contact force are modeled as the state variables of the system. These variables are simultaneously controlled using a nonlinear feedback compensator. Using Lyapnouv's theory, a sufficient condition, which guarantees that the closed loop system remains "practically stable", is presented. The simulation of a two-link planar robot manipulator following a semi-circle surface is given to illustrate the result.