| The extensive use of flexible systems in scientific research and industrial production makes it a hot topic.Flexible systems have many advantages such as lightweight,low cost and easy operation.They play a significant role in intelligent manufacturing,marine engineering,livelihood services and aerospace.There are a large number of objects that can be described by flexible systems,such as flexible beams,marine risers,high-rise buildings and flexible manipulators.Compared with rigid systems,flexible systems offer various benefits,including great flexibility,minimal energy consumption,rapid operational speed and excellent safety.However,there are also some research challenges,such as the intricate nature of system making it hard to get the accurate model,the impact of vibration on the performance of closed-loop system,the coupling between various system states,and difficulty in control and optimization design based on distributed parameter systems.Most existing research on flexible systems is based on lumped parameter models,which offer the benefits of straightforward modeling and uncomplicated control design.Nonetheless,dynamic models represented by ordinary differential equations tend to overlook important details about the dynamic features of flexible systems,leading to inaccuracies in their depiction of the system behavior.Therefore,to overcome the technical challenges of active control and optimal design of flexible systems in complex environments,this research considers control and optimization methods of flexible systems and their applications in actual production,and develops the relevant theories and key technologies of active boundary control for flexible beams,robust adaptive fault tolerant control for marine risers,optimal control for high-rise buildings,and tracking control for flexible manipulators.Firstly,considering the input backlash and the output constraint in practical environments,the dynamic model of flexible systems is obtained.The adaptive inverse backlash dynamics is proposed to compensate the input nonlinearity.To fulfill the output constraint,the barrier Lyapunov function is suggested,while the active boundary control is devised to accomplish vibration suppression.Secondly,for the coupled flexible system of sea surface vessel,marine riser,and underwater equipment,considering the problem of actuator failure in practical ocean engineering,a multi-actuator structure is proposed to cope with the situation where some actuators completely fail.Moreover,the impact of unknown external disturbances and uncertainties in system parameters is taken into account,and a robust adaptive fault tolerant control is developed on the basis of the cascaded model.Thirdly,in order to suppress the vibration of high-rise buildings,a pendulum with a large inertial load is used to compensate for the vibration of the building.The coupled system model is established by Hamilton’s principle.The active boundary control method is designed,and optimization design is introduced that merges adaptive dynamic programming with parallel control algorithms.Fourthly,for the flexible manipulators,considering the problems of vibration control and tracking control,two subsystems are derived by utilizing the singular perturbation method.An optimal control scheme based on adaptive dynamic programming is put forward,which achieves the vibration suppression and optimizes the angle tracking control with installing the actuator and sensors at boundary.The focus of this paper is on the investigation of the dynamic characteristics of different flexible systems,and the establishment of system models.To meet the requirements of vibration suppression and trajectory tracking,boundary control and optimization design methods are presented.The effectiveness of these methods is demonstrated through both numerical simulations and real experiments.The outcomes of this study hold significant theoretical implications,and can potentially contribute to the advancement of flexible systems. |
