Hysteresis Identification and Compensation-Based Robust Control for Flexible-Joint Manipulators Using Command-Filtered Backstepping

Flexible-joint manipulators (FJMs) have emerged as critical actuators in motion control applications, driven by escalating performance demands in high-precision technologies. However, the presence of nonlinear hysteresis and multiple disturbances inevitably deteriorates the trajectory tracking accuracy of FJMs. To this end, a composite backstepping controller (CBSC) with integrated hysteresis compensation and uncertainties attenuation is proposed in this paper. Unlike previous studies in which hysteresis and disturbance are handled without classification, the nonlinear hysteresis effect is modeled and considered into the controller design, and the rest uncertainties are estimated by the hysteresis model-embedded generalized proportional integral (GPI) observers. On this basis, a HDE-based BSC strategy is proposed to realize precise trajectory tracking control of FJMs even under both hysteresis and disturbances of matched/mismatched channels. The stability analysis is provided, and simulations are conducted to validate the efficacy of the proposed controller.