Improved position control strategy for EGR valve actuator

A method of controlling exhaust gas recirculation by means of an EGR valve (55). An electromagnetic actuator (41) is associated with a housing (47) to transmit movement of an actuator output (75) into reciprocating movement of the EGR valve in response to changes in an electrical input signal (95), and the method comprises generating (93) a compensator gain value to modify the electrical input signal (95). The improved method provides a valve position sensor (79) and generates a position signal (97) representing instantaneous valve position. The next step is storing (105) a first relationship (DCTHLD) of the electrical input signal (95) required to change the instantaneous valve position, then, during ongoing operation, generating (105) a then-current, second relationship (DC) of the electrical input signal (95) required to change the instantaneous valve position. Next is comparing (105) the second relationship (DC) to the first (DCTHLD) and generating (111) a corresponding difference factor, then using (111) that difference factor to modify (93) the compensator gain value correspondingly. This method enables the system to adapt to changes in system friction.