Contents I. Introduction
Robot trajectory planning, which is one of the basic processes involved in the operation of robots, affects the stability and accuracy of a robot. It is an indispensable aspect of a robot control system, and has continuously gained considerable attention from researchers. Robot trajectory planning comprises Cartesian space planning and joint space planning. The latter has the advantage of easily fulfilling design requirements and motion constraints because the control system directly affects the joint, thereby avoiding singular point and joint mutation. In addition, the computation of the inverse kinematics of a redundant manipulator is unnecessary. Nevertheless, joint space planning is used only for jobs without path requirements. Cartesian space planning is visual and intuitive. However, fast inverse kinematics calculation should be realized within robot control. Moreover, this approach cannot ensure the lack of singularity. For jobs with strict requirements on the instantaneous variation law of path and pose, such as continuous spraying operations, trajectory planning must be performed in Cartesian coordinate space [1].
