Workspace tracking trajectory for 7-DOF ANAT robot using a hierarchical control strategy

Abstract

This paper presents a new hierarchical control strategy for a hyper redundant articulate nimble adaptable trunk (ANAT) robot. The objective is to track a desired trajectory in the robot's workspace. The pseudo-inverse of the Jacobian is used to transform the desired trajectory from the workspace to the joint space. The control strategy consists in controlling the last joint by assuming that the remaining joints are stable and follow their desired trajectories. Then going backward to the (n-1)-th joint, the same strategy is applied and so on until the first joint. In each step, the sliding mode technique is used to develop the control law. This control algorithm was experimented on a 7 DOF ANAT manipulator and gave effective results and good trajectory tracking in the workspace.