A novel robust adaptive integral terminal sliding mode control for permanent magnet synchronous motors

To meet the requirements of high-end applications of permanent magnet synchronous motor (PMSM) servo systems, addressing the drawbacks of traditional sliding mode control (SMC), such as slow convergence, low tracking accuracy, and significant high-frequency chattering, as well as the limitations of existing integral sliding mode control, including insufficient anti-disturbance capability and gain design dependent on disturbance boundary information, this paper proposes a novel robust adaptive integral terminal sliding mode control method. First, a new integral terminal sliding surface incorporating integral and nonlinear components is designed. This surface overcomes the conventional trade-off between dynamic response and steady-state accuracy, utilizing the integral term to eliminate steady-state error and the nonlinear term to accelerate convergence during large-error phases, thereby optimizing both dynamic responsiveness and steady-state precision. Second, a dual-layer adaptive mechanism is constructed to update control gains automatically, enhancing the system’s anti-disturbance capability. A barrier function based on speed tracking error is introduced, which directly constrains the error and dynamically adjusts switching gains according to the magnitude of deviation without prior knowledge of uncertainty bounds. This avoids chattering amplification due to gain overestimation. Finally, the stability and finite-time convergence of the proposed method are rigorously proved using Lyapunov theory. Experimental results demonstrate that the proposed method outperforms SMC and integral terminal sliding mode control (ITSMC) in tracking accuracy, dynamic performance, and chattering suppression.