Robust H∞ loop-shaping controller design for temperature and air flows control of a passive nonlinear air conditioning unit

Abstract

This paper designs a controller of a passive nonlinear air-conditioning unit based on a loop-shaping approach, with respect of the environmental conditions for micro-climate in growth chambers and greenhouses. The control problem consists in mixing two prescribed air flows and tracking the mixed output set point temperature. Simulations were carried out on the closed-loop formed by connecting the controller to the nonlinear original system. The synthesized controller based on the H∞ loop-shaping technique provides robust stability and performance. Using the v-gap metric, the controller was shown to stabilize a large class of systems with uncertainties in power heating coefficients.