The problem of determining collision-free joint space trajectories for redundant robots is considered, and the command-generator approach is used to generate such trajectories. In this approach, a distance objective function is defined and is optimized along the robot joint trajectories through a vector in a null space. Algorithms for implementing this optimization problem are fully developed. It is shown that the proposed collision-free trajectory generation scheme is efficient and practical. Extensive simulation results of a four-link robot example are presented and analyzed.>

A joint-trajectory-generation scheme for redundant robots is proposed which uses the redundancy to improve motion performance according to certain objective functions. The objective function can be either analytical or nonanalytical. For nonanalytical objective functions, a least-squares scheme is proposed to estimate the gradient vector. In addition, an approximation scheme is developed to compute the pseudoinverse of the Jacobian. Application of the scheme to a 4-link revolute planar robot manipulator is demonstrated through simulation. Several motion performance criteria are considered and their results analyzed.>

An approach is presented for the design of simple robust independent joint controllers which result in linear decoupled joint motions. In this approach each joint is treated as a simple inertial systems plus a disturbance torque representing all the unmodeled dynamics. By means of a very simple procedure, the disturbance is instantly estimated and rejected, thus allowing simple PD control to be used. The controllers are inherently robust. Experimental evaluations of the controller on a PUMA 560 are are performed, and the experimental results are presented.>