When robot makes contact with environment, hybrid control is required. In this case, uncertainty and strong interaction between robot and environment make the control difficult. Therefore, this thesis applies the TDC(Time Delay Control) algorithm, which is robust against uncertainty and disturbance of plant, to hybrid control. The stability of control system is analyzed with Nyquist stability criterion. Previous good experimental results in hybrid control still shows the following problems; 1) chattering at steady-state, 2) dynamic coupling effect of robot, 3) performance degradation due to tilted environment. In this thesis, the alternative solutions are proposed for the above three problems. First, as a solution for the first problem, the resolution of A/D conversion used in force sensor is improved by incorporating a novel scheme. Also, as solutions for the second problem, two methods are suggested. The first one uses trajectory input instead of step input for position command, and the second one uses accurate mass matrix instead of constant mass matrix in control law. Finally, as a solution for the third problem, use of force signal instead of position is suggested. The effectiveness of the proposed methods is illustrated with computer simulations and experimental results.
