Demagnetization Analysis and Velocity Tracking Control of In-wheel Motor

The error caused by irreversible demagnetization damages the accurate velocity tracking of an in-wheel motor in a mobile robot. A current feedforward vector control system based on ESO is proposed to compensate it for the demagnetization motor. A demagnetization mathematical model is established to describe a permanent magnet synchronous motor, which took the change of permanent magnet flux linkage parameters as a factor to count the demagnetization error in velocity tracking. The uncertain disturbance estimation model of the control system is built based on ESO, which eliminates the system error by the feedforward current compensation. It is compared with the vector control method in terms of control accuracy. The simulation results show that the current feedforward vector control method based on ESO reduces the velocity tracking error greatly in conditions of motor demagnetization less than 30%. It is effective to improve the operation accuracy of the mobile robot.