Planning of straight line manipulator trajectory in Cartesian space with torque constraints

Abstract

Most of the existing off-line trajectory planning schemes focus on the requirements that the trajectory must be smooth and continuous. This paper, based on discrete time trajectory analysis, extends these concepts and includes the manipulator dynamics in the planning of straight line trajectory in the Cartesian space. The planning of straight line trajectory is performed in the Cartesian space and requires optimization in the jointvariable space. An iterative forward and backward search algorithm coupled with a modified forward search algorithm are developed to determine the joint values at each control set point on the given straight line within the bounds imposed by the smoothness and torque constraints. These sets of joint position, velocity and acceleration will be used as referenced inputs to the manipulator controller for the joint-variable space control [1] or can be used to determine the corresponding Cartesian position, velocity, and acceleration on the straight line for the Cartesian space control. The proposed straight line trajectory planning will be useful for obstacle avoidance and the resolved motion adaptive control [2].