Study On Boundary Vibration Control Of Rotatable Flexible Beam Structures

With the continuous development of science and industry,the precision of equipment is increasingly required in modern industrial production.The new generation of industrial equipment is developing towards the direction of light weight,high speed and precision,and the flexible material with its light quality,good ductility is widely applied to various fields of industrial production,such as flexible solar panels in the aerospace industry,offshore risers for deepwater oil exploration,the arm of the crane,and flexible manipulators of intelligent robots.However,flexible materials also have inherent defects.Due to their material characteristics,it is easy to produce vibration in the working state,which will seriously affect the operating accuracy and service life of the equipment.Therefore,the research on vibration suppression of flexible materials has very important theoretical and application value.The specific content of this paper is summarized as follows:1.In this paper,two types of typical flexible rotating beam structures,the flexible manipulator model and the spacecraft flexible sailboard model,are studied.In order to attain better control performance and avoid the control spillover problem,the infinite dimensional partial differential equations combined with the finite dimensional ordinary differential equations are used to describe the dynamic model of the flexible manipulator and the flexible sailboard.2.The vibration suppression and angle control problems of flexible manipulators considering asymmetric output constraints and external disturbances are discussed.In order to make the manipulator can quickly and accurately complete the operation,this paper develops a disturbance observer in matrix form to counteract the effects of external disturbances.Asymmetric barrier Lyapunov functions are introduced to ensure that the angle tracking error and position error of the tip within the limits.To realize the rapid response of rotation and vibration suppression,two boundary controllers are designed for the flexible manipulator,which are respectively applied to the rotation center and the end of the manipulator.The stability of the closed-loop system is demonstrated based on the Lyapunov theory,and simulations are carried out using MATLAB to verify the effectiveness of the control algorithms.3.For the spacecraft flexible sailboard system,considering the influence of input nonlinearity,asymmetric output constraint,system parameter uncertainty and external disturbance,the backstepping method combined with boundary control method are adopted for control design.The unknown terms of the system are approximated by RBF neural networks,which can eliminate the effects of input nonlinearity and the uncertainty of system parameters.The improved barrier Lyapunov function is used to guarantee the asymmetric output constraint of the system.The closed-loop stability of the system is demonstrated based on the Lyapunov theory,and the numerical simulation results show the effectiveness of the control algorithm.