Tracking Control for Thermofluidic Systems With Input Constraints and Relative Degree One

This paper proposes a general control approach for first-order input-affine systems of arbitrary finite system order. The control scheme, which is based on an inversion of the system dynamics in combination with an adaptation of the reference values, guarantees close-to-optimal tracking of systems with input constraints. After the presentation of the control scheme for the SISO case, stability, performance and robustness properties are investigated. Then, a first application in the form of a cooling cycle is presented in which the proposed approach shows a nearly identical performance to an alternative offline optimisation. The control scheme is extended to MIMO systems by means of a prioritization of outputs and an online solution of linear programming problems. For this scenario, a nonlinear real-world example is discussed in the form of a vapor compression cycle. The achieved performance of the control scheme is demonstrated by simulation results.