General subtask controller for redundant robot manipulators

This paper will utilize the property of self-motion for redundant robot manipulators by designing the general subtask controller that control the joint motion in the null-space of the Jacobian matrix. The general subtask controller is used for minimizing the total joint motion and for singularity avoidance in this study. Specifically, objective function for each subtask is formed and then the gradient of the objective function is used in the subtask controller to either minimize the joint motion or avoid singularities while tracking a given end-effector trajectory. A 7-DOF LWA4-Arm (SCHUNK) is modeled first in SolidWorks® and then converted to MATLAB® Simulink using SimMechanics CAD translator for the simulation tests of the controller. The kinematics and dynamics equations are derived to be used in the controllers and the simulation results are presented for the 7-DOF redundant robot manipulator operating in 3D space.