Research On Fault Detection And Fault Tolerant Control Of Permanent Magnet Synchronous Motor Position Sensor

With the continuous development of space exploration technology,the demand for the volume and weight of spacecraft far exceeds the carrying capacity of the rocket.A large number of space machines and manipulator systems are needed to complete the on-orbit assembly,maintenance,repair and other work.As a typical extravehicular multi degree of freedom mechatronics system,the performance of space robot will decline or even fail under the bad space environment.Therefore,fault detection and fault-tolerant control technologies for space robots have caused widespread domestic and foreign attention.Firstly,starting from the structure of joint motor servo drive system of space manipulator,the principle and output signal characteristics of resolver and Hall sensor are introduced respectively,and the square wave control method of permanent magnet synchronous motor is analyzed.Then,through the mathematical model of permanent magnet synchronous motor,the vector control strategy and SVPWM modulation method of permanent magnet synchronous motor are analyzed.The SVPWM modulation method and RPWM modulation method are compared by simulation.It is concluded that SVPWM modulation method has advantages in the control effect of motor speed and torque.Secondly,the fault detection and fault-tolerant control of the failed resolver are deeply studied.Firstly,the on-line fault detection of the resolver is completed based on the discrete hall position sensor information.Secondly,the principle of motor rotor position estimation based on the digital hall position sensor information is analyzed,and the adverse effect of the installation error of the hall sensor on the rotor position estimation is analyzed,hall interval boundary correction and Kalman filter are used to improve the accuracy of rotor position estimation.Based on the estimation method of first-order Taylor expansion formula,the rotor position is estimated by using the reduced-order Luenberger position observer and hybrid position observer.The simulation and experiment show that the rotor position estimation method has the advantages of high accuracy,good dynamic performance and independent of motor parameters.In order to further improve the fault-tolerant ability of joint position sensor,the fault detection and fault-tolerant control of hall position sensor are studied.Hall edge state and hall scalar feature sequence fault detection algorithm are used to realize single and two hall sensor fault detection respectively;Furthermore,according to the current hall sensor fault type and hall state,the reduced-order Luenberger position observer and hybrid position observer are used to complete the compensation of rotor position estimation signal and realize the fault-tolerant control of joint motor.In the hall sensor fault-tolerant control,the hybrid position observer fault-tolerant control method has better fault-tolerant performance than the reduced-order Luenberger position observer.It has the advantages of small estimation position error,small motor speed and current fluctuation.