Velocity jump reduction for manipulator with single joint failure

Aiming at the velocity jump caused by joint failure of manipulator, a method is proposed to reduce velocity jumps in both Cartesian space and joint space. Based on the analysis of velocity jump, the reduction problem is turned into an optimization problem of finding the best compensation vector for joint velocity. The gradient of the reduced manipulability is applied to represent the weight for joint velocity redistribution, and the orthogonal matrix of null space is introduced to construct the compensation vector. As a result, the compensation for the joint velocity during the entire task cycle can be achieved. The simulation result shows the effectiveness of the proposed method in reducing the velocity jump in both joint space and Cartesian space, and the optimization coefficient of compensation vector can be achieved. Then the limitation of constant coefficient is studied in further and the coefficient form is corrected for better reduction performance.