Interaction Stability of Force Feedback Device and Admittance Adaptive for Unknown Environment

This work designs a force feedback teleoperation system based on admittance control, and proposes an admittance adaptive algorithm to ensure the stability of the interaction between the system and unknown stiffness environments. In the designed teleoperation system, admittance control serves as force feedback interface. The difference of contact force between the master and slave robot is used as the input of the admittance model, and the position command of the master and slave robot are calculated. However, there is a gap between the system behavior and the nominal admittance model due to position execution errors. This gap causes the system to have an interaction instability problem, which generates high-frequency and high-amplitude oscillations. In this paper, the interaction stability of the system is analyzed based on the theory of passivity, and the proposed adaptive algorithm adjusts the admittance parameter by observing nonpassive behaviors. Experiments prove the effectiveness of the algorithm on the teleoperation system.