Real-Time Implementation of a Kinematic Optimization Scheme for Seven-Degree-of-Freedom Redundant Robots with Spherical Wrists

Abstract

A computationally efficient, kinematic optimization scheme is presented for seven-degree-of-freedom robots with spherical wrists. This scheme uses the gradient projection method, and it does not require the generalized inverse of the Jacobian. An efficient formulation for determining joint velocities is obtained. Thus, this control scheme is well-suited for real-time implementation, which is essential if the end-effector trajectory is continuously modified based on sensory feedback. A comparison of the computational complexity with previously available schemes is presented. Implementation of this scheme on a Motorola 68020 VMEbus-based controller of the seven-degree-of-freedom manipulator at the ORNL Center for Engineering Systems Advanced Research (CESAR) is described.