Control Design And Experimental Study Of Variable Speed Tilting Flywheel

Variable Speed Tilting flywheel(VSTF)is a new type of spacecraft attitude control execution and measurement device.is a new type of spacecraft momentum exchange and attitude measurement device.It has the functions of three-axis momentum exchange and two-axis attitude measurement at the same time,which can effectively reduce the mass,volume and power consumption of the attitude control system,and improve integration And efficiency,so the application prospects in micro-satellites are very broad.This paper mainly takes VSTF as the research object.Based on the double-frequency Bode diagram,the PD controller and the adaptive notch filter are designed.The simulation model and the physical prototype experimental platform are used to verify the effectiveness of the two control schemes.Modal decomposition processes and analyzes experimental signals.And the experimental signal is processed and analyzed based on the variational mode decomposition(VMD).Firstly,the mechanical structure and working principle of the VSTF system are introduced.By analyzing the conversion relationship of the VSTF in four different coordinate systems,a complete nonlinear dynamic equation based on the Lagrangian method is established,and it briefly introduces the complete nonlinear model of the VSTF established by Sim Mechanics,which provides a simulation platform for controller design and active vibration control problem analysis.Secondly,according to engineering needs,the Lagrangian nonlinear dynamic model of the VSTF is simplified,and the complex coefficient transfer function is derived from this,and then the double-frequency Bode diagram stability criterion is used to determine the open-loop system of the VSTF.Aiming at the problem of system nutation instability caused by the inertia link of the torque device,a PD controller is designed based on the double-frequency Bode diagram;an adaptive notch filter is designed for the one-time frequency vibration problem caused by the unbalance of the rotor,and a simplified simulation model and a complete nonlinear simulation model are used to verify the effectiveness of these two control schemes.Thirdly,the basic principle and algorithm process of the variational mode decomposition(VMD)method are introduced,and then the frequency spectrum analysis of the experimental signal of the VSTF prototype is carried out,and the simulation signal and the experimental signal collected by the prototype sensor are subjected to the variational modal decomposition.For the tilt angle signal and the current signal,the influence of the number of decomposed mode on the VMD results is investigated,and the different mode signals decomposed are analyzed.Finally,based on the physical prototype experimental platform of the VSTF,open-loop sweep frequency experiments,PD control experiments and active vibration control experiments are carried out.Sweep frequency experiments were carried out under open loop conditions,and the object identification was completed.Based on the transfer function fitted by the experimental data,the PD controller and experimental verification were carried out.Then,the effect of active vibration control of the adaptive notch filter with two update phase methods under constant speed and variable speed conditions is experimentally verified and comparatively analyzed.