Research On Anti-Disturbance Tracking Control Algorithm For Nonlinear Systems Based On Double Event-Triggered

In the actual control system,the existence of external disturbance and internal noise inevitably will seriously affect the dynamic performance of the system.Therefore,how to design an effective anti-disturbance algorithm has always been a hot topic in the field of automatic control.Among them,disturbance observer based control(DOBC)is a typical active anti-disturbance method.Because of its simple structure,fast tracking and easy implementation,it has been successfully applied to power electronics,aerospace and robot systems.However,the DOBC method will introduce interference estimation information into controller design,which will produce a lot of redundant data and reduce data transmission efficiency.On the other hand,event-triggered mechanism is an effective method to perform data transmission on demand by presetting trigger conditions.Because of its ability to reduce data redundancy and guarantee system performance,it has received much attention in the field of control theory.At present,most studies are designed for trigger conditions with a single variable.With the increasing complexity of the system,univariate triggering cannot meet the demand of multi-source information control.Based on above analysis,for nonlinear control systems with unknown disturbance,combining DOBC and sliding mode variable structure method,this paper proposes a dual event-triggered mechanism based on system state and disturbance estimation.On this basis,the dual trigger compound anti-disturbance control input is designed to achieve the multiobjective control requirements of the closed-loop system.The main contents of the paper are as follows:(1)The anti-disturbance tracking control of nonlinear system based on double eventtriggered is studied.For a class of dynamic systems with unknown disturbance and nonlinear terms,the integral of system state and output error is augmented,and the disturbance observer is designed to realize the dynamic estimation of disturbance.Based on different trigger conditions of augmented state and disturbance estimation respectively,a dual event-triggered mechanism of "first-come-same-trigger" is proposed to solve the data redundancy problem of multi-source information transmission.Furthermore,a compound anti-disturbance controller is designed under the condition of double trigger.Combining unilateral Lipschtiz condition,convex optimization algorithm and Barbalat lemma,it is verified that the closed-loop system has good stability,dynamic tracking and lower bound of minimum trigger time is greater than zero,that is,Zeno phenomenon is avoided.Finally,the simulation results show the feasibility of the proposed control strategy.(2)The anti-disturbance tracking control of unmatched disturbance system based on double event-triggered and sliding mode variable structure is studied.A disturbance observer is constructed based on the augmented model to realize the dynamic estimation of unknown unmatched disturbance.Under the double trigger mechanism of "first to the same trigger",integrated sliding mode surface and compound anti-disturbance are designed,so that the state of the controlled system can reach the sliding mode surface smoothly.Combined with convex optimization algorithm,the control gain and interference estimation gain which make the closed-loop system stable are solved,which proves that the augmented system has good dynamic tracking performance.Further,analyze that the Zeno phenomenon caused by the trigger does not occur.Finally,simulation results based on A4D model show that the proposed algorithm has good anti-disturbance performance.(3)The anti-disturbance control of nonlinear system with double trigger based on network transmission is studied.For a class of nonlinear systems with network transmission and unknown disturbance,a discrete event-triggered mechanism is designed to control the amount of data packets sent during network transmission.At the same time,combined with the external disturbance model,the effective disturbance observer is constructed to realize the dynamic tracking of unknown disturbance,and then the triggering conditions of continuous events are designed for the disturbance estimation.Based on disturbance estimation trigger and discrete state trigger period,a composite anti-disturbance controller is designed.Combined with unilateral Lipschtiz condition and convex optimization algorithm,it is proved that the closed-loop system has good stability and the minimum interval of two adjacent triggers is greater than zero.Finally,the simulation results show that the design algorithm has good anti-disturbance performance and resource saving rate.