A Motion-impedance-force Controller for Uncertain Robotic Systems

Over the last decades, issues related to the impedance and the force control and their integration with motion control for uncertain plants are attracting considerable interest. This paper discusses a controller that can realize these three control strategies without changing the structure or the controller parameters. The proposed controller can simultaneously achieve motion tracking, compliance with a desired impedance during interaction, and pure force control when regulating interaction forces. A key feature of the controller is its ability to smoothly alternate between these modes in unstructured environments, without requiring a mode recognition mechanism. The detailed controller design incorporates operational space dynamics, enabling dynamic adjustment of control strategies based on both position and force tracking errors. This approach provides a robust and flexible solution for robotic systems operating in environments with varying levels of uncertainty and interaction force demands. Simulations and experimental results demonstrate the effectiveness and robustness of the proposed system in achieving high-performance task execution across all operational modes.