Circle theorem-based realization of nonlinear force control for teleoperation under time delay

The communication delay is one of the major problems existing in the bilateral teleoperation system since it largely degrades the performance. This study treats the acceleration-based bilateral control (ABC) as a basic controller. According to the analyses, it is shown that a trade-off between the operationality and the reproduction performance of the kinesthetic contact exists in designing the ABC under time delay. For addressing this, adjustment of the force control gain according to the situations of the bilateral control is proposed. For ensuring the stability of the system with the nonlinear controller, circle theorem is applied to the proposed system. Experimental results show that the proposed system can realize stable operation as well as the improved performance over the bilateral control system with constant gain.