Semi-active Vibration Control Of Flexible Space Structures Based On MFC Piezoelectric Actuators

Vibration will inevitably occur in the on-orbit operation of flexible spatial structure.Due to the special space environment and its own low frequency and dense frequency characteristics,the unnecessary vibration caused by internal and external factors is not easy to decay in a short time,which will not only reduce work efficiency,affect work accuracy,and even produce fatigue failure and reduce service life.The traditional passive vibration control method is simple and does not require external energy supply,but has poor control effect on low-frequency vibration.Although the active vibration control method has good control effect,the device is complex and has high energy consumption.The emergence of MFC(Macro Fiber Composite)provides a new idea for better solving this problem.The semi-active vibration control method based on MFC piezoactuator not only has good vibration suppression effect,but also has low energy consumption,which has become an important research direction for vibration suppression of large flexible spatial structure.In this paper,the flexible spatial structure is taken as the research object,and the semi-active vibration control method with MFC as the actuator is studied and improved.Firstly,the MFC layout position,model specification selection evaluation criteria and structural coupling unit of MFC and controlled object are studied in this paper.The strain energy theory,the modal contribution ratio method and the residual energy method are used for the corresponding evaluation to determine the appropriate MFC model and number,and the location of MFC layout in the spatial structure.Then,the coupling element between MFC and the controlled object structure is studied,and a new equivalent load method is proposed on the basis of the load analogy method.Secondly,the SSDV(Synchronized Switch Damping based on voltage source)semi-active vibration control method is improved.According to the basic principle of SSDV,the control voltage in the form of trapezoidal wave is used to replace the original rectangular wave voltage,which avoids the high-frequency vibration of the structure.An adaptive SSDV control method based on BP neural network is proposed to realize the independent optimization of the control voltage amplification coefficient.From the perspective of the analysis and identification of vibration response signals,the dense modal fuzzy control method and the discrete modal fuzzy control method based on Kalman filter are proposed respectively for the multi-modal vibration form,and the vibration control of multiple modes is completed.Finally,the experimental platform is built,and the semi-physical simulation experiment is carried out using the flexible cantilever beam as the controlled object.The research results of this paper are verified and summarized.