A Fully Analog Intelligent Servo-Valve Amplifier Enabling Wide-Band Pressure Control of Pneumatic Actuators

Pneumatic actuators are widely used in precision manufacturing, robotics, and compliant actuation systems owing to their simplicity and high power density.However, strong nonlinearities induced by air compressibility and valve flow dynamics fundamentally limit the achievable control bandwidth and precision.Although digital pressure control techniques can partially mitigate these effects, their reliance on high-speed sampling and complex signal processing introduces latency, cost, and architectural constraints that hinder further bandwidth expansion.This paper proposes a fully analog intelligent servo-valve amplifier that enables broadband pressure control of pneumatic actuators by structurally preserving the functionality of a robust digital pressure controller.A mathematical model of a nozzleflapper servo-valve-driven pneumatic actuator is derived, and its dynamics are identified through frequency response measurements.A robust pressure control architecture-comprising a current amplifier, a two-degree-of-freedom pressure controller, and a disturbance observer (DOB) is systematically designed and embedded into an integrated analog circuit, thereby eliminating sampling and computational delays.Simulation results confirm stability and performance equivalence between the analog and digital realizations.The proposed amplifier is experimentally validated in an active vibration isolation setup, achieving a 30 Hz pressure control bandwidth (-3 dB of the closed-loop pressure transfer function) with minimal deviation from the digital controller.The proposed intelligent servo-valve amplifier as a general, low-latency actuation platform for broadband pneumatic systems, with direct relevance to precision vibration control and compliant actuators such as pneumatic artificial muscles.