Control of a Nonlinear Pressure-Regulating Engine Bleed Valve in Aircraft Air Management Systems

This paper presents an adaptive control algorithm, based on the ℒ ₁ adaptive control method, for controlling the pressure of engine bleed air in a commercial aircraft. The pressure is affected by a control valve that is part of a larger air management system which includes control valves for temperature and flow rate as well as a heat exchanger or precooler. A system model is presented including valve hysteresis due to backlash and dry friction. Simulations are conducted for a control valve subject to unmeasured disturbance, and the adaptive control results are compared to those of a traditional proportional-integral controller.