Research On Time Delay Vibration Control Of Precision Instrument Workbench

In the field of national defense construction,mechanical processing,instrumentation industry,facility construction and engineering machinery,precision instrument workbench has a wide range of applications.Workbench system at work will always be their own and the external environment of the interference generated vibration,affecting the stability of the workbench system,and the stability of the workbench system is the core of precision machining,and its control methods and control strategies directly determine the success or failure of the mechanical processing,so it is important to reduce the vibration of the workbench system by an effective way.Commonly used vibration damping method is divided into no damping and damping vibration.However,these methods have some shortcomings.Only when the external excitation frequency is consistent with the natural frequency of the additional dynamic vibration absorber or the difference is small,the dynamic vibration absorber can reduce the vibration of the main system,but it is easy to produce the formant.In view of the above problems,this paper studies the precision instrument workstations with active control technology.The purpose of this paper is to improve the vibration of the workbench system by introducing the delay-fractional-order state feedback combined control technique into the table system.The main contents of the thesis are as follows:⑴ The research workbench system,under the action of simple harmonic excitation,takes the energy of the main system of the workbench as the objective function.Through the mode search method to optimize the dynamic vibration absorber stiffness and damping parameters,compared with the workbench system in the additional power absorber and no additional vibration of the vibration device,in the workbench system with additional power absorber can play a good damping effect.Then take the damping power shock absorber as an example,and application of fractional derivative control technique.It is found that the damping shock absorber has a better damping effect in a certain frequency range,which lays the foundation for the follow-up study.⑵ The delay feedback control is introduced into the workbench model,and the stability of the system is analyzed by the stability switching method.The stability interval of the system is obtained.The optimal objective function based on the vibration response is established in the frequency domain,and the optimal delay feedback parameter is obtained by using the particle swarm optimization algorithm(PSO).The damping technique can obtain the damping effect of the workbench system by simulation.⑶ The fractional derivative theory and the delay feedback control theory are applied to the precision instrument table system to study the influence of the fractional derivative and the delay coupled control on its vibration.By increasing the number of control parameters more comprehensive improvement of the performance of the workbench.In the workbench system,add the time delay state feedback with fractional derivative.According to the amplitude and frequency characteristics of the ground excitation,the system vibration target function is established in the frequency domain.The optimal feedback coefficient and the delay and fractional order are obtained by optimization analysis.In the time domain,the simulation analysis is carried out,and the fractional derivative and the time-delay damping active control technology can be used to reduce the vibration of the system.It is shown that the time-delay fractional-order dynamic vibration absorber has a great advantage over the traditional passive vibration absorber and provides the theoretical basis for active control technology.