A formulation of joint disturbance torque and its application for independent joint controlled robotic manipulators

In this paper, a formulation of joint disturbance torque is proposed for the independent joint controlled manipulators. The Lagrange Euler dynamic equation is examined, and joint disturbance torque is defined to be the joint torque components that are functions of joint position, velocity and acceleration. This definition includes all effects of joint coupling, varying effective inertia, and the gravity. The dynamic equation of motion for a 2-DOF planar robot is analyzed as an example. The explicit conditions for the minimum and maximum joint disturbance torques are identified, and the effect of link parameters on the joint disturbance torques is studied. As an application example, a solution of the optimal path placement problem is presented where, for a given straight line path segment, the location of the path in the robot workspace that results in a robot joint motion with the minimum joint disturbance torques is obtained