Model-based position control for a solenoid actuated valve

Abstract

An improved position control for a solenoid actuated valve, wherein the solenoid is activated based on the combination of a feed-forward component based on a model of the steady state operation of the valve and a closed-loop feedback component that responds to changes in the commanded position and compensates for any inaccuracy in the steady state model. The method involves a valve characterization procedure in which the actual force generated by the solenoid is measured for various combinations of valve position and solenoid current, resulting in a table of coil current in terms of developed force and valve position. In operation, the model is used to estimate the solenoid force required to achieve the commanded valve position under steady state operating conditions, and a controller addresses the table to obtain a feed-forward coil current command as a function of the commanded valve position and the estimated solenoid force. The feed-forward command is combined with a closed-loop feedback coil current command, which in turn, is used to develop a corresponding PWM duty cycle, given the solenoid temperature and the magnitude of the supply voltage.

Dependencies are inferred from the claim text.