Memory-based SO(3) Representations for Impedance Control

Impedance control is commonly utilized in tasks requiring physical interaction because it can deal with environmental uncertainties. However, task space impedance control is valid only locally due to the compactness of SO(3). Impedance controllers based on classical SO(3) representations cannot realize the desired impedance behavior when crossing pi-turn.

To address this problem, we present a memory-based SO(3) representation by integrating the past exponential coordinates, and we name it as extended exponential coordinates (EEC). EEC can represent rotations continuously, and reconstruct the true rotation using the exponential map. The EEC-based impedance control scheme is also proposed and, real-world experiments validate that the proposed controller can realize natural motion.

Contact: Jinyeong Jeong (jinyeong.jeong@kaist.ac.kr)

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Related Publications

J. Jeong, H. Mishra, C.Ott, and M. J. Kim, "A Memory-based SO(3) Parameterization: Theory and Application to 6D Impedance Control with Radially Unbounded Potential Function", IEEE ICRA 2022 [IEEE]

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