Design and analysis of a large-aperture high-bandwidth piezo-actuated fast steering mirror

This paper presents the design, analysis and experimental evaluation of a piezo-actuated fast steering mirror (FSM) with large aperture and high bandwidth, intended for precise control of large-diameter beam pointing in an optical imaging system. To address the inherent trade-off between achieving a large aperture and maintaining high bandwidth, we employ a compact architecture. In this architecture, direct integration of the mirror with the flexure hinge is implemented to minimize the moment of inertia and maximize structural stiffness. Furthermore, a novel multifunctional flexure design is introduced, incorporating flexure hinges, preload mechanisms, and motion mechanisms. This integrated flexure is engineered to simultaneously: 1) minimize system complexity; 2) reduce overall size and mass; and 3) significantly improve both system stiffness and assembly precision. Subsequently, a series of finite element analyses (FEA) were conducted to validate the design’s feasibility and to determine key parameters by evaluating structural stiffness, stroke capability, stress distribution, and modal characteristics of the solution. Following this, the FSM prototype was manufactured and assembled. Eventually, experimental tests were carried out to further verify the effectiveness of the proposed design. The experimental results demonstrated that the first resonant frequency of the FSM with a 75 mm aperture exceeded 3000 Hz, and its maximum stroke range surpassed ± 1100 μrad, thus providing a solid basis for the development of a high-bandwidth control system.