An efficient motion control algorithm for robots with wrist singularities

An efficient algorithm is developed for the motion control of manipulators in the neighborhood of wrist singularity. The method, based on a scheduling scheme, guarantees a robot´s location accuracy, maintains a desired Cartesian motion speed, and does not involve the complex computations of a robot´s Jacobian and its inverse. In case studies, three algorithms, namely the maximum joint rates, the iterative method, and the proposed scheduling method, are compared. The scheduling scheme generally gives more satisfactory results in terms of location and orientation accuracies. It is believed that the combination of simple computation, acceptable orientation error, and the ability of maintaining desired speed should make the proposed method very attractive in practical application