To improve the tracking capability and sensorless estimation accuracy of a permanent magnet linear synchronous motor (PMLSM) control system, a sensorless control system based on a continuous terminal sliding mode controller (CT-SMC) and fuzzy super-twisted sliding mode observer (F-ST-SMO) was designed. Compared with a conventional slide mode control, CT-SMC can reach the equilibrium point in limited time to ensure the continuity of control and achieve fast tracking of reference speed. Based on the PMLSM design of F-ST-SMO, a super-twisted sliding mode algorithm is used to replace the traditional first order sliding mode algorithm. Meanwhile, fuzzy rules are introduced to adjust the sliding mode gain adaptively, which replaces the fixed gain of traditional SMO and reduces chattering of the system. Finally, the effectiveness and superiority of the designed control system are proven by simulation and experiment.

Laser detection technology has manypromising applications in the field of motor speed and position measurement. Accurate and fast measurement of position information of spherical rotor is very important for motor control. In this paper, we propose a method for non-contact measurement of the angular velocity of a multi-DOF spherical motor using the Doppler effect of the laser, and further obtain the position information of the motor rotor. The horizontal laser beam from the laser generator is divided into a reference beam I and a measurement beam II through a beam splitter, and the measurement beam II reflects and undergoes Doppler effect after irradiating the rotating motor. The two beams pass through the photoelectric conversion module to obtain the corresponding frequency difference signals to derive the angular velocity and position information of the motor rotor. The correctness of the method is verified experimentally. The results show that the coordinate error of Z and Y axes is less than 2 mm, thatthe error of Z-axes is less than 0.2 mm, and that the method can better measure the spherical rotor position information of the motor.