A Novel Piezo-Hydraulic Fast Steering Mirror With Integrated Sensing Unit

This article presents a novel compact, large-aperture piezo-hydraulic fast steering mirror (FSM) that effectively addresses the inherent tradeoff among high resonant frequency, large tilt range, and significant load capacity in conventional systems. The core innovation employs a hydraulic microdisplacement amplifier operating on Pascal’s principle, featuring an orthogonally arranged input-output configuration. This design enables substantial stroke amplification of the piezoelectric stack actuator (PZT-stack) and minimizes additional mass, thus maintaining high dynamic response characteristics. Furthermore, a support-sensing unit designed via a topology optimization approach simultaneously achieves maximized structural stiffness and real-time orientation sensing capability while eliminating the need for external sensors. A prototype accommodating a 180 mm diameter mirror within a compact dimension of 200 mm × 200 mm × 75 mm was fabricated and experimentally characterized. Experimental results showcase high natural frequencies of 325.6 Hz (x-axis) and 320.2 Hz (y-axis), wide deflection angles up to 2.09 mrad under 150 V driving voltage, and cross-axis coupling below 8.1%. Integration with a disturbance rejection proportional-integral-derivative (PID) controller achieves positioning accuracy better than 4.5μrad and a rapid rise time under 8.8 ms. This article demonstrates the FSM’s efficacy for high-precision beam steering and establishes a new paradigm for next-generation motion platforms.