Research On Key Security Technology Of The Lifting Stage

With the continuous growth needs in people’s spiritual aspect, traditional stage performance has been difficult to meet people’s visual pursuit. Stage performance is becoming more and more diversified, which will impel the function and structure of the modern stage control system more complex. So the security of stage control system becomes the main issue. In view of this, the thesis regards the actual landing stage of a theater as the plant and combines the current actual lifting stage system PLC + vector frequency converter + AC motor of traditional mode, which puts the emphasis on the research of multi motor synchronous control of the lifting stage and fault diagnosis and fault-tolerant control of the encoder. The specific content of this thesis is:1) the design of lift stage control systemThis part considers the control system of lifting stage of a theater as background,analyzing the involved security related issues. According to the secure requirements and the control of the lifting stage, a series of protected designs including interlocking and limit are added to guarantee the basis safe protection of the stage performance.2) the research on the synchronous control strategy of the multi motor forecast function of the lifting stageAimed at solving the non-synchronous problem of the lifting stage caused by outside interference and motor parameter perturbations, the controller of the predictive function of a single motor is designed and the synchronous control method based on predictive functional control algorithm and deviation coupling compound is constructed linked positional deviation coupling, which is based on the parallel synchronous control commonly used in Engineering. Due to the strong robustness and excellent dynamic performance of the prediction function and its mean position deviation coupling compensation control, synchronous control system of the lifting stage is improved. Meanwhile, The simulation results further show that the control strategy has better robustness and higher control precision than the PI control,which weakens the safety hazard aroused by unsatisfied synchronization performance of stage multi-motor drive.3) the study of fault diagnosis and fault tolerant control strategy of dual encoder based on KPLS and SPRTIn view of the strong robustness and excellent performance of predictive functioncontroller and combined with dual encoder structure of the actual lifting stage system,the fault diagnosis and fault-tolerant control scheme of dual encoder is proposed,which treats predictive function controller as the control core and supplies the combination of data driven KPLS modeling methods and the SPRT. Using historical data of the lifting stage, the KPLS prediction model of control input, speed encoder and position encoder are respectively established. Model predictions and the actual output of the encoder generates residuals in the actual runtime. The fault-tolerant closed-loop of analytical or software redundancy of the dual encoder runs by adopting sequential probability ratio(SPRT) for fault detection and combining appropriate switching mechanism of failure.The simulation results show that this method can make the fault diagnosis of dual encoder reliable and switch safe fault-tolerant control by analytical or software redundancy between position and speed, which can ensure the safety of lifting stage system under the failure of sensor.