Adaptive fault tolerant control for a class of MIMO nonlinear systems with input and state constraints

Xu Jin, Raymond H. S. Kwong
2015 2015 American Control Conference (ACC)  
Adaptive Fault Tolerant Control For Nonlinear Systems With Constraints In this thesis, fault tolerant control (FTC) design for nonlinear systems with input and output/state constraints are studied. To handle the input constraints, auxiliary systems are integrated with the controller. To deal with output constraints, Barrier Lyapunov Functions (BLFs) are used. When state constraints are in force, command filters are used in conjunction with BLFs. A novel adaptive fault tolerant cooperative
more » ... ng control (AFTCTC) scheme is developed for a class of input and output constrained nonlinear multiagent systems. Exponential convergence of the cooperative output tracking error into a small set around zero is guaranteed, while the constraints on the output will not be violated. The results are then extended to the design of a novel adaptive fault tolerant control (AFTC) scheme for a class of input and state constrained multi-input-multi-output (MIMO) nonlinear systems, where the constraints on the system state will not be violated. ii Acknowledgements I would like to express my deep gratitude to my research supervisor, Professor Raymond Kwong for his guidance, enthusiastic encouragement and helpful critiques of this research work. I sincerely appreciate his precious time devoted to improving my writing, which is crucial in crafting this thesis. There are countless occasions when Professor Kwong stayed late after the office hours, even late in the evenings for revising my works, which will always be remembered and appreciated. I would also like to use this valuable opportunity to express my appreciation to my undergraduate research supervisor, Professor Jianxin Xu (IEEE Fellow, Electrical and Computer Engineering, National University of Singapore), for his great help and encouragement to pursue my academic dream. I wish to thank Professor Mou Chen, the first author of references [60] and [61], for the discussion over email regarding auxiliary systems, which is important in helping me understand the concepts. Last but not least, I want to express my deep love to my family back in China, who have always been supportive and worrying about me during the last 26 years. I am also grateful to all my friends made in China, Singapore, Canada and the US, for all kinds of support and help. iii other. Failure to consider such constraints may result in degradation of system performance, or even hazards and system failure in the worst case. This is an important consideration when the system is subject to faults, which may perturb the system in an undesirable way that could lead to the violation of constraint requirements. Therefore, the effective handling of constraints has also received much attention from the research community. In the literature, usually two types of system constraints are discussed, but often separately. One is the control input constraint, which means that due to hardware limitations, the actuator can only supply a limited range of signals to the system. The other is the constraint on the system state and/or output, which requires that the system state/output to remain in some compact sets during system operation. Such requirements may come not only from system specifications, but also from safety considerations. For example, the velocity and acceleration of a bus on the road should be limited, where the velocity constraint is most commonly due to safety considerations, and the acceleration constraint may be due to hardware limitations and the comfort of drivers and passengers. In a robotic team, if the position of a certain agent is deviating too much from the position of the leader, it may lose contact with the leader, as some commonly used communication modules like XBEE can work effectively only within a certain range. As a result, such an agent may be lost in operation. When a team of unmanned aerial vehicles (UAVs) is passing between buildings with narrow gaps or pathways, if the position of a particular UAV deviates too much from the desired trajectory generated by the leader, it may hit the wall or other obstacles and become damaged. How to ensure the desired system performance under the effects of system faults and input constraints, while guaranteeing that the system state/output constraint requirements are not violated during operation, is an interesting and important research topic that deserves attention. To the best of our knowledge, this has not been addressed properly yet in the literature. A review of the state of the art will be given in Chapter 1. Introduction
doi:10.1109/acc.2015.7171068 dblp:conf/amcc/JinK15 fatcat:xrqbsd3wrfeizlyu5tam3hocey