Constrained Nonlinear Disturbance Observer for Robotic Systems

Disturbance observer (DOB) is a well-known two-loop control structure that imparts robustness to a controller with a simple implementation. As a nonlinear DOB for the robotic systems, we proposed so-called nonlinear robust internal-loop compensator (NRIC) framework in our previous work. In this paper, we further extend the NRIC in such a way that an optimization scheme can be embedded in the control structure. The proposed method is called constrained NRIC (C-NRIC), because the optimization allows us to impose constraints, by which a controller acquires additional properties. As a particular use case of the C-NRIC framework, we design contact-responsive motion controllers that enables a robot to react to unknown interactions while accurately tracking the desired trajectory in free motion. The effectiveness of such designs is validated through the real-world experiments.

Contact : Ji Wan Han (jw.han@kaist.ac.kr)

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Related Publications

2024 ICRA "Constrained Nonlinear Disturbance Observer for Robotic Systems" J. W. Han, D. Park, and M. J. Kim [IEEE]