A novel extended reaction force/torque observer with impedance control

Abstract

This paper proposes a new extended version of the reaction force observer (RFOB) for high -precision motion control systems. The RFOB has been proven to be useful for many applications in the literature. However, because of the low-pass filter present inside of the RFOB, it has certain limitations. In this study, a new algorithm is proposed to compensate for filtering -based errors in the classical RFOB structure. The algorithm includes the differentiation of the observed force and scaling with a proper value. However, since the force has a noisy nature, differentiation also affects the signal's stability and performance. To resolve this issue, a new controller algorithm coupled with the proposed RFOB is formulated and implemented. The mathematical derivation of the proposed structure along with experimental validations for different force references are shown to provide a complete analysis. The results obtained from the experiments prove that the proposed observer -controller structure outperforms the existing force control architectures.