Researches On Robust Fault Detection And Fault Tolerant Control Of Timedelay Systems  Posted on:20140726  Degree:Doctor  Type:Dissertation  Country:China  Candidate:S Q Wang  Full Text:PDF  GTID:1318330482955776  Subject:Control theory and control engineering  Abstract/Summary:  PDF Full Text Request  In practical engineering applications, due to the continuous expending scale of control system, increasing complexity and the huge investment, the system reliability and security should be improved urgently. However, in the event of faults on actuators, sensors, or other system components, the desired performance of closedloop control system can not be ensured, and even instable. The technology of fault diagnosis and fault tolerant control is an effective method to solve this problem. In order to improve the performance of fault detection filters and fault tolerant controllers, in this thesis, by utilizing the parameterdependent Lyapunov function and LMI technique, we systematically and further study the problems of robust H? performance analysis, statefeedback controller and filter synthesis design, and fault tolerant control for timedelay systems (networked control systems). A systematically new fault detection and fault tolerant control methodologies is presented. Parts of our developed theories are applied to the fault detection niters and fault tolerant controllers designs of computersimulated trucktrailer system and unstable batch reactor model by simulations. The results obtained in this thesis have less conservatism and computational complexity, because the delay decomposition approach, reciprocally convex technique and inputoutput method were applied in the treatment process of the delay. The main research can be briefly described as follows:1. The fault detection problem for discretetime fuzzy networked systems with timevarying delay and multiple packet losses is investigated.The communication links between the plant and the FFDF are assumed to be imperfect, and the missing probability is governed by an individual random variable satisfying a certain probabilistic distribution over the interval [01]. The discretetime fuzzy networked system is first transformed into the form of interconnection of two subsystems by applying an inputoutput method and a twoterm approximation approach, which is employed to approximate the timevarying delay. Our attention is focused on the design of FFDF such that, for all data missing conditions, the overall fault detection dynamics are inputoutput stable in mean square and a guaranteed performance is ensured. Sufficient conditions are first established via H? performance analysis for the existence of the desired FFDF, meanwhile, the corresponding solvability conditions for the desired FFDF gains are characterized in terms of the feasibility of a convex optimization problem.2. The fault detection problem for NCSs with discrete and infinite distributed delays subject to random packet losses and nonlinear perturbation is studied. Different from existing results for FD, the proposed ones are toward closedloop design problem, that is, the controller gain, and the FDF gains are designed simultaneously. Both sensortocontroller and controllertoactuator packet losses are modeled as two different mutually independent Bernoulli distributed white sequences with known conditional probability distributions. By utilizing an observerbased FDF as a residual generator, the FD for networked nonlinear systems with mixed delays and packet losses is formulated as an H? modelmatching problem. Attention is focused on designing the FDF in the closedloop system setup such that the estimation error between the residuals and filtered faults is made as small as possible, and at the same time, the closedloop networked nonlinear system is exponentially stable in the meansquare sense.3. The fault tolerant, fuzzy control for a class of NNCSs with state delay and actuator failures is studied. By utilizing the input delay approach, an equivalent continuoustime generalized TS fuzzy model with both interval timevarying networkinduced delay and data packet dropout is obtained. By employing the delay decomposition approach, the information of the delayed plant states can be taken into full consideration. The sufficient condition is formulated in the form of a nonconvex matrix inequality, of which a feasible solution can be obtained by solving a minimization problem in terms of LMI with cone complementarity linearization algorithm. The key features of the approach include the use of a tighter bounding technique (reciprocally convex combination lemma) and the introduction of uncorrelated augmented matrix items into the Lyapunov functional, by which the less conservative condition is get.4. The robust fault tolerant controller design approach is provided for NCSs with state delay and stochastic actuator failures. By utilizing the input delay approach, an equivalent, continuoustime generalized time delay system with both state and input is obtained. New delaydependent sufficient conditions that ensure the asymptotic meansquare stability of NCSs with stochastic actua tor failures are derived in terms of LMIs. It is realized by employing a new LyapunovKrasovskii function in the decomposed integral intervals and the inversely weighted convex combination of quadratic terms of integral quantities is handled directly by reciprocally convex combination technique. Moreover, the proposed approach involves neither slack variable nor any model transformation. 5. The reliable H? control is investigated for discretetime TakagiSugeno (TS) fuzzy systems with timevarying delay and actuator faults based on inputoutput approach when the state is available and unavailable respectively. A discretetime homogeneous Markov chain is used to represent the stochastic behavior of actuator faults. The discretetime TS fuzzy system is transformed into the form of interconnection of two subsystems by employing a new model transformation for the delayed state variables. Inputoutput approach (Scaled Small Gain (SSG) Theorem) is developed to analyze the stochastic stability. By using a parameter dependent Lyapunov function, sufficient conditions for the inputoutput mean square stability and existence of the H? performance are established. Meanwhile, the reliable H? fuzzy controller design method is also presented.Finally, concluding remarks are given. Some unsolved problems and development direction for the robust fault detection and fault tolerant control of timedelay systems (NCSs) are proposed. Furthermore, the prospects of the further study are given.  Keywords/Search Tags:  Fault detection, fault tolerant control, timedelay systems, networked control system, TS fuzzy system, networkinduced delay, data packet dropout, measurement quantization, linear matrix inequality  PDF Full Text Request  Related items 
 
