Active vibration control based on the equivalent dynamic model of a large space telescope truss structure

With the development of the observation technology and the improvement of resolution requirements, a new membrane diffraction large space telescope is proposed to realize real-time high-resolution earth observation. Due to its light weight, high optical imaging accuracy and large folding ratio, the membrane diffraction space telescope has an extensive development prospect. Vibration of the large space truss inevitably occurs in the space environment. Such vibration will last continuously, influencing normal earth imaging of the space telescope. Thus, it is necessary to adopt an appropriate control method to suppress structural vibration. Considering the great structural degree of freedom, the equivalent dynamic model of the space telescope is established to simplify the vibration controller design in this paper. First, the truss lattice is equivalent to a micro-polar beam based on the energy-equivalence principle, and then the equivalent dynamic model of the telescope structure is built with Finite Element Method. Second, the linear quadratic regulator is adopted to design a vibration active controller on the basis of the equivalent dynamic model. Next, through proper transformations, the transformed active controller is used to control the vibration of the original space telescope structure. Finally, the correction of the equivalent dynamic model and the validity of the proposed active control strategy are verified by numerical simulations. The simulation results demonstrate the designed active controller in this paper could effectively suppress the vibration of the space telescope.