Design Methodology of a Pneumatic Force-Control Servo System for a Ball Screw Test Bench

Force control in pneumatic systems is particularly challenging due to the strong nonlinearities and the compressibility of air. To support the preliminary design of the control architecture, simple, fast, yet accurate linearized models are required before moving to detailed nonlinear analyses for final tuning. This paper presents the derivation and validation of a design methodology for a pneumatic force-controlled servo system, applied to a novel test bench for ball screw characterization, where an electromechanical actuator and a pneumatic forcecontrol system are coupled to reproduce realistic load conditions. A fully parametric linearized model is developed to support earlystage design and control synthesis. Its performance is assessed by comparison with a high-fidelity nonlinear model, showing strong predictive capabilities and excellent agreement in the frequency response across a broad range of operating frequencies.