Partially Decoupled Impedance Motion Force Control Using Prioritized Inertia Shaping

Abstract

To achieve precise motion force control (MFC) when a robot interacts with the environment, selecting an appropriate control approach is crucial. A task space disturbance wrench can induce coupled accelerations between different subspaces due to the inherent coupling of task space inertia. Shaping the inertia matrix can potentially reduce or amplify this coupling effect. Inspired by impedance motion force control (IMFC), which can decouple the actuation wrench and external disturbances simultaneously, we propose partially decoupled impedance motion force control (PD-IMFC) to balance the trade-off between natural inertia conservation and motion force decoupling. The control method can be readily extended to multi-task cases, i.e., the prioritized asymmetric inertia shaping, which is the least sensitive to model uncertainties and sensing noises compared to fully or symmetric partially decoupled cases. Besides showing its relation to existing MFC approaches, the proposed approach is further extended to multiple recursively decoupled subspaces for improved force and moment tracking.