Performance analysis of a three-channel control architecture for bilateral teleoperation with time delay

Bilateral control is one of the control methods of teleoperation systems. Human operators can feel reaction force from remote environment by means of this control scheme. This paper presents a novel control architecture for bilateral teleoperation with/without time delay. The proposed bilateral control system has three communication channels between master and slave robots. In concrete terms, this system has two transmission channels of position and force information from the master side to the slave side and one transmission channel of force information from the slave side to the master side. The master controller of the proposed three-channel teleoperation system does not include a position controller, i.e. only force control is implemented in the master side, in order to improve operationality in the master side. The three-channel controller with time delay as well as without time delay gives better performance (higher transparency) than other conventional controllers such as four-channel controllers and so on. In the proposed controller, models of a slave robot and communication time delay are not required differently from conventional methods, and robust acceleration control is achieved by using the disturbance observer (DOB). Hybrid matrices are utilized to analyze four-channel and three-channel control systems. Transmission characteristics of force and position information between master and slave robots are clarified in the analysis. The validity of the proposed method is confirmed by experimental results.