Friction Identification and Compensation for SPMSM Using Robust Adaptive Observer

In order to mitigate the substantial influence of nonlinear friction torque on the performance of permanent magnet synchronous motor (PMSM)-based servo systems, this article proposes an online robust adaptive friction compensation (RAFC) scheme. By establishing a robust adaptive observer based on the LuGre friction model, the speed tracking performance at low speed and zero speed crossing is improved. The proposed observer utilizes the universal approximation properties of radial basis function (RBF) and considers the boundness of unknown identified parameters, effectively guaranteeing the convergence of observation error and robustness to parameter perturbations. In addition, the proposed method does not require any pre-experiments to fit model parameters, making it easier to implement and highly versatile. Finally, this article employs a surface-mounted servo motor to analyze observer convergence using Lyapunov analysis methods and presents the experimental results that validate the effectiveness of the compensation scheme.