Abstract

Tele-operation has been a hot topic for a long time in computer science and electrical engineering fields since it has been applied in many different domains such as dangerous operating environments, deep-sea operations, and multiple operations through network. At the same time, bilateral control technology has resulted in significant interests by people, since information such as force reflection will improve the perception of the operator to interact with environment with great capabilities. As a result, stability of bilateral systems is of particular importance as unstable force reflection could hurt the human operator. However, in tele-operation systems, time delay always exists and it varies with the network performance, and this time delay, even very small, will destabilize an originally stable system. That is why that stability problem is so important and critical in the tele-operation bilateral systems. This is the main motivation for this thesis research. In this thesis, wave transfer method is investigated and introduced into the stability and control of bilateral tele-operation systems. However, using a wave variable tele-operation system with a PD controller to maintain the position tracking of the slave side has resulted in undesired position drifts. Sliding mode control is an effective robust control method and is particularly useful for solving tracking problems. The control objective is to force the system dynamics approach to the sliding surface and remain on it for all the future time to eliminate or minimize the tracking errors. Consequently, the designed sliding-mode controller as validated and verified in the simulation results decreases the tracking error and guarantees the slave track the master position quite satisfactorily for bilateral tele-operation system with varying time delay. The contribution of this thesis is the investigation of the model of the phantom haptic device and analysis of the tele-operation system using the phantom device as master and slave manipulator. The designed wave variable sliding mode controller guarantees the stability of the tele-operation system having time varying communication delays