Research On Robust Stability Of Sampleddata Control Systems With Time Delay  Posted on:20150425  Degree:Master  Type:Thesis  Country:China  Candidate:B T Xu  Full Text:PDF  GTID:2348330518470308  Subject:Control theory and control engineering  Abstract/Summary:  PDF Full Text Request  With the development of computer technology and semiconductor prices fall, the digital system has been widely applied to national defense, scientific research and other fields of public life etc.. Therefore, the sampleddata control systems as the basis of computer control,which requirements higher function. At the same time, timedelay widely exit in the actual project which will not only affect the performance of system, but also may cause the control system even instability. So, the robust stability analysis and design problems of the sampleddata control systems become a theoretical and engineering meaningful research problem.The robust stability of the sampleddata control systems with input delay are systematically studied in this paper. On frequency domain,based on the equivalent H?schema approach, the reason of conservativeness is pointed out, and then the frequency response method is studied for the systems. On time domain, in terms of Lyapunov function and a linear matrix inequality(LMI) method, the robust control design of the sampleddata systems with uncertain delay are systematically studied. Main works are summarized as follows:1. The robust stability analysis of sampleddata control systems with input delay is considered which using the equivalent H? approach. Based on the verification of the lifting technique approach in the former literature,the activity reason of conservativeness is pointed out. Then, using an discretetime uncertainty to replace the continuoustime uncertainty of the sampleddata control systems,so the robust stability analysis for sampleddata control system is transformed into the robust stability analysis for traditional discretetime control system,and thus the resulting conservativeness is reduced.2. As the conservativeness of the equivalent H? approach, a simple and intuitive robust stability analysis method  the frequency response characteristics of the sampleddata system is provided. The sampleddata control system with input delay is regarded as the interconnection of two parts. One is the delayindependent and the other is dependent on the uncertain delay. Then the frequency response of the sampleddata control system with uncertainty delay is computed, and the robust stability is determined according to the frequency characteristic. The proposed method is not conservative. And the method for the average delay system is also suitable.3. The robust control design of the sampleddata systems with uncertain delay which based on the discrete uncertain sampleddata systems model is considered. The method is that the continuoustime uncertain plant of sampleddata system replaced by pure discretetime systems,and then the robust controller design of uncertain sampleddata system is transformed into the robust stability and design problem of discrete systems with input delay.By using the Lyapunov function established the robust stability criterion of the sampleddata control systems, and given the design method of robust controller which based on the criterion with the parameterization of controller. The controller keeps the sampleddata systems robust stabilization and show good robustness for the perturbation of the structure.4. Robust stability problem of sampleddata control system with input delay is proposed .Unlike existing results, the controller treat input timedelay itself as an integer multiple of the sampling period, and then transform into the state delay continuoustime model. By using the socalled inputdelay approach, a controller design technique for the input delay systems is provided. Based on LyapunovKrasovskii function method, and combined with the linear matrix inequality, the stability problem of the sampleddata system with input time delay is discussed, and given the design method of robust controller.  Keywords/Search Tags:  Sampleddata control systems, Time delay, Robustness stability, Frequency response, Linear matrix inequality(LMI)  PDF Full Text Request  Related items 
 
