Parallel Control Method for a Bilateral Master-Slave Manipulator

Abstract

In this paper, a new control method for a bilateral master-slave manipulator is proposed. The proposed method yields stable and fast response of the control system. These are essential to obtain a precise position control and a sensitive force reflection control.
In the conventional position-force control method, each control loop of the master and the slave arms are connected in series to construct a bilateral control loop. Therefore the total phase lag through the bilateral control loop becomes twice as much as that of one arm control. Such phase lag makes the control system unstable and control performance worse.
To improve the stability and the control performance, we propose “parallel control method.” In the proposed method, the control loops of the master and the slave arms are connected in parallel so that the total phase lag is reduced to as much as that of one arm.
The stability condition of the proposed method is studied and it is proved that the stability of this method can be guaranteed independent of the rigidness of a reaction surface and the position/force ratio between the master and the slave arms while the stability of the conventional method depends on them.