The Design Of Fault Tolerant Controller For Networked Control System Based On Event Triggering And Application

The biggest characteristic of Networked Control System(abbreviation:NCS)is that the control loop is closed by some digital networks,the controlled object,sensor,controller and actuator are connected by network,and data transmission is carried out by networks.Thus,it has the advantages of low installation and maintenance costs,high reliability,high flexibility,and less wiring.NCS is a remote monitoring system that enables resource sharing among users with different geographical locations in a certain area,and is widely used in the fields of science and engineering.However,the existence of time-varying delay will reduce stability and the performance of the system,and sometimes cause the system state to diverge.Moreover,this kind of regular sampling and transmission of data is easy to control,but when the system enters the vicinity of the stable point and the data changes slowly,there will be few changes or even repetition of the transmitted data when using a certain period for transmission,and this data will increase the transmission quantity of the network.Therefore,the introduction of the“event triggering mechanism”.Stability is the basic requirement of control system design,and satisfying certain performance indexes is also the important step to weigh the system's excellence.In practical application,the traditional DC servo motor control is based on the automatic control theory,taking DC servo motor as the controlled object,and developing a new networked DC servo motor control mode has become an inevitable trend.Therefore,it is of great practical value and application prospect to study the fault-tolerant controller design of networked system based on the event triggering mechanism and its application in servo motors.The main research contents are as follows:Fault detection observer is designed for the continuous linear time-varying delay system with unknown actuator faults and disturbances.By introducing a simple LKF including the cross terms of variables and quadratic terms multiplied by a higher degree scalar function,combining with the idea of the integral inequalities and quadratic convex combination,without delay decomposition we designed a H_?fault estimation observer.The existence condition of the observer is expressed in the form of LMIs,which is easy to verify by the mature toolbox.The theory based for the design of fault tolerant controller for NCS.An example is used to verify the feasibility of the proposed theory.The event trigger mechanism is introduced.For NCS based on the event trigger mechanism,a normal state feedback controller is designed firstly to enable the system to have good dynamic performance during normal operation.Secondly,an observer-based active-passive hybrid fault-tolerant controller is designed.The fault-tolerant controller not only can effectively tolerate faults within the fault set,but also can slow down the degradation of system performance for unknown faults outside the fault set,ensuring that the system is not only stable but also has certain disturbance rejection performance when known faults occur.Since the design involves the switching of multiple controllers,if the output values of the controllers are different,there must be jitter when different controllers switch.In order to reduce switching jitter as much as possible,a smooth switching function is introduced here.The effectiveness of the design method is verified by a numerical example.The effectiveness of the design method is verified appling in actural object.The above-mentioned design takes DC servo motor as the controlled object and combineing the traditional DC servo motor control principle with the networked control system theory a new network-based DC servo motor control mode is developed.