Fault Diagnosis And Fault Tolerance Control Of The Large Aperture Telescope Main Axis

The light collection ability and observation ability of the telescope will become stronger as the aperture increases.However,the increase in the aperture of the tele-scope will also make the servo control system more and more complicated,and greatly increase the probability of failure.Therefore,it is very important to study the fault diagnosis and fault-tolerant control technology for the telescope servo control system.First,this dissertation studies the fault diagnosis and fault-tolerant control of the inverter in the telescope servo control system.The operation state of the permanent magnet synchronous motor after the inverter failure is analyzed,and the relationship between the operation state of the motor inverter after the open circuit failure and the motor parameters and the operation state before the failure is summarized.By analyz-ing the current characteristics after the fault,a simple and efficient diagnosis method for single or multiple tubes simultaneous open-circuit faults of the permanent magnet syn-chronous motor inverter is proposed.Both simulation and experimental results prove the effectiveness of the algorithm;The open-circuit fault diagnosis method of the invert-er cannot meet the operating conditions of the ultra-low-speed motor in the diagnosis time.By analyzing the transient characteristics of the inverter,a diagnosis method that can quickly diagnose the open-circuit fault of the ultra-low-speed motor inverter is pro-posed.This method does not require a full-cycle current signal as an input.In the case of a motor shutdown due to an open-circuit inverter fault,the faulty power tube can be located and can be directly integrated into the motor control program.The effect of real-time monitoring,the simulation and experimental results obtained support our conclusion;In order to distinguish the open circuit fault of the inverter from the open circuit fault of the motor phase winding,a diagnosis method of the open circuit fault of the inverter and motor phase winding based on vector voltage injection is proposed;On the basis of the diagnosis of the faulty power tube,in order to enable the motor to still run under the extreme condition of failure,a permanent magnet synchronous motor fault-tolerant SVPWM control algorithm is proposed;At the end of this chapter,the inverter diagnosis and fault-tolerant control algorithms are integrated,and the inverter fault-tolerant control strategy framework for the telescope spindle servo control system is proposed.Secondly,this dissertation studies the fault diagnosis and fault-tolerant control of the current sensor in the telescope servo control system.Aiming at the permanent mag-net synchronous motor servo control system designed for 3 current sensors,a current sensor fault diagnosis method based on current signal amplitude tracking algorithm is proposed;Further,a diagnosis method based on coordinate transformation is designed for the servo control system of a permanent magnet synchronous motor with two cur-rent sensors;On the basis of fault diagnosis,a dynamic compensation strategy is first proposed;The traditional observer-based fault diagnosis method for current sensors has poor performance at low speeds,a robust fault-tolerant controller based on model reduction theory and a fault-tolerant control algorithm based on second-order ADRC controller are designed;At the end of this chapter,the current sensor diagnosis and fault-tolerant control methods are integrated,and the current sensor fault-tolerant con-trol strategy framework for the telescope spindle servo control system is proposed.Then,in this dissertation,the modeling and fault diagnosis of the short-circuit fault of the motor winding in the telescope servo control system are studied.A mathematical model in the natural coordinate system of the permanent magnet synchronous motor turn-to-turn under short-circuit fault is proposed.By analyzing the fault response of the proposed model,a method for diagnosis of the inter-turn short-circuit fault of the per-manent magnet synchronous motor based on frequency tracking algorithm is proposed.The effectiveness of the proposed algorithm is proved by destructive experiments of real motors.