| In recent decades, the manipulator system plays a more and more important role invariable fields, it improves the quality and efficiency of the production, promotes theindustrial automation process, furthermore, it makes a fortune to mankind on the high risktasks, homework, building, transportation and health, etc. With the improvement ofoperational and mobility, the networked and intelligent manipulator system should bespread more widely. However, the fixed mounted manipulator faces to difficulty in fulfillthe tasks when it needs large task space. In order to enlarge the task space and dexterity,the mobile manipulator is urgently needed. For the tasks with heavy payload in highassembled precision, the vehicle hydraulic flexible manipulator system is operated byhuman beings in majority, but due to the different operational level, it always could notreach the requirement, sometimes even an accident. Therefore, it should be better that thevehicle hydraulic flexible manipulator system can complete the assembly and transportautomatically.As a interconnected nonlinear system, it is difficulty in trajectory tracking to thevehicle hydraulic flexible manipulator system with external disturbance and unmodelleddynamics, meanwhile, the elastic vibration during operation and the residual vibration inthe movement end appear inevitable, which are harmful to the operation precision andmechanical structure, also the economic losses, or even worse. In this case, if thetraditional nonlinear feedback controller is applied to the system directly, it has not only acomplexity controller design procedure, large computational burden and a poor real time,but a poor control performance, more importantly. Thus, a suitable controller for thesystem should be designed for the trajectory tracking and vibration suppression, whichhas theoretical significance and potential applications.Focus on the vehicle hydraulic flexible manipulator system, this thesis studies on asecond order sliding mode control scheme based on singular perturbation theory. And thisthesis is organized as follows, in which the main research works are included.Firstly, the dynamic model is established by the assumption mode and Lagrangetheorem, then the coupling relationship between manipulator and hydraulic servo systemis constructed by a driven Jacobian matrix, and the entire system dynamic model isobtained.Secondly, on the basis of the dynamic model aforementioned, according to themultiple time scales theory, the system order is reduced by ignoring fast variable, and byintroducing the boundary calibration term, twice decompositions based on singularperturbation is realized to describe the entire model in three time scales, that is, the slow subsystem the sub-fast subsystem and the fast subsystem describe the wide rangemovement, elastic vibration and the hydraulic servo driven, respectively. This scheme cansimplify the controller structure and design procedure.Thirdly, a backstepping sliding mode controller based on the entire dynamic model isemployed to realize the precisely trajectory tracking and elastic vibration suppression. Toovercome the chattering phenomenon caused by the discontinuous control signal fromtraditional sliding mode control, second order sliding mode controller and optimalcontroller are designed for slow subsystem and sub-fast subsystem obtained by thedual-parameter singular perturbation decomposition model, and a precisely trajectorytracking performance and suppressed vibration are derived. And then consider theparameter uncertainty and external disturbance, an adaptive sliding mode controller isdesigned for fast subsystem to guarantee the control torque satisfy the requiredperformance of the hydraulic servo driven system.At last, the simulations for the vehicle hydraulic flexible manipulator show theeffectiveness of these proposed schemes. A summary is given, and other aspects of theresearch experience on the system modeling, singular perturbation and dynamical controlfor further Research of the issues are discussed. |
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