Adaptive Energy-Bounding Approach for Robustly Stable Interaction Control of Impedance-Controlled Industrial Robot With Uncertain Environments

Even though impedance control approaches are useful for robot interaction control, they can guarantee stability only for the assumed range of the environments. This paper presents a new adaptive energy-bounding approach (EBA) that can maintain a desired contact force at steady state while guaranteeing robust contact stability for impedance-controlled industrial robots that are contacting with very uncertain environments beyond the assumed range of the environments. The proposed adaptive EBA that is applied to impedance-controlled industrial robots interacting with incompletely specified real environments is an extension of the haptic EBA, which was previously developed for stable haptic interaction with virtual environments. Moreover, the adaptive EBA estimates online control parameters to improve performance while assuring stability for the system. Theoretical analyses on the performance and experimental results demonstrate the effectiveness of the proposed approach.