Teleoperation Systems Design Using Singular Perturbation Method and Sliding Mode Controllers

The purpose of designing a controller for a teleoperation system is to achieve stability and optimal operation in the presence of factors such as time-delay, system disturbance, and modeling errors. This paper proposes a new method of controller design based on singular perturbation for the bilateral teleoperation of robots through Internet. This study provides sliding mode controller based on the singular perturbation model which is robust on time-varying delay. Using singular perturbation method, the teleoperation system is decomposed into fast and slow subsystems. Teleoperation systems usually have complex dynamic and controller designing is difficult for them. This method is a novel step toward reducing order modeling. In this paper, teleoperation system dynamic was decomposed into two states, slave and error (different from master and slave) and a sliding mode controller was designed for each state. Despite the communication channel in teleoperation systems, it is difficult and almost impossible to design controller based on full-order system. Therefore, many researchers have focused on controller design based on master and slave subsystems. This study shows that the singular perturbation is a proper method for controller design in master or slave, based on slave and error subsystem models with the effect on the total system. It is intended here to reduce the tracking error between the master and the slave. For different values of time-delay, the positions of master-slave were compared. This comparison was also applied for master and slave control signals based on singular perturbation. In all schemes, the effectiveness of the system was shown through simulations and comparisons between the various schemes were presented.