Research On Active Fault Tolerant Control For Sensor Fault In Multi-motor Synchronous System Of Stage

With the rapid development of science,technology and culture in China,the application of stage machinery control systems has been more and more extensive.In order to achieve a specific performance effect,the stage machinery system has the characteristics of high switching frequency of different equipment,complex and changeable movements,and accurate time nodes in the operation process,which makes the modern stage machinery control system more complete in function,but also more complex in structure,and the probability of failure increases accordingly.In addition,the performance process of "resolve emergence situation on stage like fire fighting",undoubtedly increased the stage control system of high reliability requirements.To this end,through in-depth analysis of the operating mode of the stage control system and the factors affecting its safety,starting with the most common multi-motor synchronous control,aiming at the problem of poor control performance and sensor failure,the following innovative research work is focused on:1)Synchronous control strategy and parameter optimization based on active disturbance rejection control and deviation couplingAiming at the influence of load disturbance and nonlinear uncertainty on the performance of synchronous control during stage operation,based on the mathematical model of PMSM,the speed synchronization controller based on active disturbance rejection control(ADRC)in the vector control mode is designed.The synchronous control structure of the deviation coupling improves the synchronization performance of the system;Considering the important role of the extended state observer(ESO)in the ADRC compensation control,the nonlinear ESO has many parameters and complicated tuning,which makes its engineering application limited.For this point,linear ESO(LESO)is used to estimate the disturbance and nonlinear uncertainties while observing system state;With frequency domain method,the performance of convergence,fastness,noise suppression and robustness which decided by parameter selection are analyzed in detail,and the steps of parameter adjustment are determined.Under vector control architecture,the work mentioned above will supply guidance for the excellent performance of designed LESO and providing more effective estimation,compensation and control of ADRC.2)Sensor fault diagnosis and fault-tolerant integrated design based on LESO-SPRT and reliability quantitative evaluationAiming at the problem of sensor faults in the stage multi-motor synchronous control system,considering the limitation of the existing speed estimation methods,based on the principle of sensorless vector control,LESO is used to realize the full range and high precision estimation of speed in the current loop.With the estimated speed comparing with the measured speed,fault diagnosis is realized by residual analysis of sequential probabilityratio test(SPRT).When fault sensor isolation and system fault tolerance are realized by direct switching estimation of speed,chattering and insufficient reliability caused by direct switching of SPRT diagnosis results are considered.Fault diagnosis reliability based on SPRT kernel is constructed.The evaluation factor is quantified and a smooth reconfiguration strategy based on reliability factor is designed to eliminate the switching dynamics,improve the reliability of diagnosis and the timeliness of fault-tolerant implementation.Especially with the introduction of reliability factor,the quantitative evaluation of sensor fault diagnosis reliability and the design of smoothing reconstruction fault tolerance can be integrated.3)Sensor fault diagnosis and fault-tolerant design based on multi-scale morphology and redundant signal reconstructionThe method based on the observer design requires an accurate mathematical model,but the task becomes more difficult as the system becomes more complicated.So signal processing method of multi-scale morphological is adopted to detect sensor fault after analyzing failure mode.By means of the redundant information of the speed and displacement sensors obtained from the stage system,the tolerance of the fault sensor is realized by constructing numerical integrator and differentiator.In the process,considering the existing problems of differentiator such as complex forms,many tuning parameters and limited noise suppression ability,an improved tracking differentiator based on hyperbolic tangent function is designed after analyzing the characteristics of integrated control functions deeply.And its convergence is proved in mechanism.The introduction of the improved differentiator enhances the differential performance,reduces the number of tuning parameters,and improves the fault tolerant performance of the system.4)Sensor fault diagnosis and fault-tolerant design of modified weighted mean feedback based on complex networkMulti-motor synchronous control of the stage carries characteristic of rich hardware,redundancy structure and information.Inspired by the concept of coupling matrix in the synchronous output of complex networks,a distance-based similarity matrix which characterizes the consistency of measurement data of different sensors is designed.The tasks of detecting,positioning and estimating of the faulty sensors are realized by the correlation of the related elements and eigenvalues in the matrix.According to the fault diagnosis results,the isolation of faulty sensor and fault tolerance of system are realized by designing feedback mechanism with improved weighted mean.The similarity matrix is generated by the data,while it's element composition reflects the structural characteristics of the system,which has the mechanism characteristics of the model.So the method can be considered combining model-based and data-driven method organically.It possesses the advantages of models and data,and provide reference value for fault diagnosis andfault-tolerant design of complex systems.5)Construction of stage 4 motor synchronization semi-physical experimental platform and experimental researches on 3 types of active fault tolerance methodsIn order to verify the validity of the theoretical method above,combined with the existing experimental conditions,the "PLC + Inverter + PMSM + encoder" is constructed in accordance with the actual stage engineering control mode.Communication among Matlab,PLC and converter are established with OPC and field-bus technology.Based on the Matlab verification algorithm,the 4 motor synchronous control semi-physical experimental platform,which takes actual motor as controlled object,is used to further experimentally testimony and also verify some of the theoretical results obtained above.Finally,the conclusion obtained from experiment is consistent with the simulation.The construction of the experimental platform,while verifying the validity of the theoretical algorithm,also provides an effective approach of testing engineering applicability and supplies a referential way for practice activity of engineer.