Predictive Pressure Control of a Monopropellant Powered Actuator

This work presents a model-based predictive control methodology applicable to systems with discrete input values (on/off) subject to a pure time delay. Specifically, the goal of this work is to develop a controller that will track a desired pressure for a monopropellant-powered pneumatic system with binary on/off input valves. The pneumatic actuator is pressurized by the catalytic decomposition of the liquid monopropellant hydrogen peroxide. The challenge is tracking a proportional output with a binary input, which means the output amplitude is not proportional to the input amplitude, but is proportional in time. This requires the controller to predict the future states for each of the two input candidates, on or off. The error between the predicted future states and the current desired states is calculated for each of the inputs. The control candidate that produces the smallest predicted Lyapunov function value is chosen. This results in the controller tracking a time delayed version of the desired pressure signal. Experimental results of the predictive controller demonstrate the effectiveness of this idea.