Designing Multirate Control for a Robotic Manipulator in the Presence of Disturbance

In the present paper, multirate control method is used for mechanical robotic manipulators. Also, the process of designing the reference state vector for mechanical manipulators is presented in this paper. For this purpose, a prototype robot is assumed in which highly precise rotary encoders are mounted at the outer side of the joints. The robot dynamics is time-continuous while the relevant controls are time-discrete. Since these systems are always exposed to unwanted disturbances, the present paper introduces a passivity-based control that, in contrast to the reverse dynamic controls, doesn't require linearization. In this regard, first, the modified form of the Lyapunov-based control and, then, the discretized equations are presented. The multirate controller is implemented on the discretized structure and, thereby, its effect on the estimation precision of the angles of the joints is examined in comparison with the single-rate controls. The present paper introduces a practical method for designing and executing the multirate feedforward control of robotic me-chanical manipulator. First, to eliminate the effect of disturbance, a passivity-based con-trol was designed and it was shown that it, unlike the reverse dynamic control, didn't require linearization.