Aiming at the inherent vibration problem of permanent magnet synchronous motor sliding mode control system

an improved terminal sliding mode load torque observer was designed. By analyzing the intrinsic connection between the rotational speed estimation error and the load torque estimation error in the traditional observer

the angular speed error control function of the observer and the load torque error control function were separately designed

so as to eliminate the observational error caused by the coupling relationship between the two. The observed load disturbance was proportionally converted into current feed-forward compensation for the sliding-mode speed controller. This measure reduced the amplitude of the discontinuity term in the sliding-mode speed controller

weakened the chattering of sliding mode control

and enhanced the load disturbance rejection capability of the motor control system. Secondly

an improved sliding mode speed controller was adopted to replace the traditional sliding mode speed controller

which was equipped with a parameter adaptive double power reaching law. The proposed reaching law can further suppress sliding mode chattering and accelerate the response speed of the control system. Finally

the simulation and experimental results demonstrate that the proposed method can quickly and accurately observe load perturbations. Through feed-forward compensation

the inherent chattering of sliding mode control is effectively suppressed

which improves the steady-state performance

dynamic performance and anti-interference ability of the control system.