Study on trajectory control for six-DOF joint robot

While the robot passes through the singular configuration, small motion within the working space will cause the joint velocity to tend to infinity and then result in the robot out of control. In order to solve the problem, the issue on trajectory control for six-DOF-joint robot to pass through singular configuration was studied in this paper and a new control mode was put forward. By using line geometry and reciprocal screw theory, the linear dependent joint axes and the task space unfeasible motions are identified. By rearranging the rows and columns of the corresponding Jacobian matrix, the correspondence between the feasible motion and the joint movement in the vicinity of singular configurations was obtained and as a result, the accurate trajectory of robot was tracked. In addition, a numerical example was given to demonstrate the feasibility of the proposed method.