Abstract:For PMSM, the accuracy of the encoder feedback is very important. But in some harsh environments, the accuracy of the encoder feedback has been influenced, so there are no sensors to control the servo motor. By using sensorless control in AGV, AGV will still be able to make work properly and accurately in some harsh environments. By sliding mode observer and filter estimates, PMSM running was estimated to replace the PMSM encoder feedback in normal operation, in order to achieve the PMSM sensorless control. In the case of low speed, the motion control way to PMSM was changed to avoid big velocity fluctuation caused by slot effect and some other factors.The reliability of the program was proved by test.