A method for calibrating an actuator system for a turbocharger variable
nozzle, the actuator system comprising an electronically controllable
actuator coupled with a variable-geometry member of the nozzle and
operable for causing movement thereof, and an electronic controller
operable for controlling the actuator, the electronic controller having a
memory for storing data. The method comprises (a) supplying a flow of
fluid through the nozzle, (b) causing a continuous or stepwise movement
of the actuator so as to move the variable-geometry member to cause a
continuous or stepwise change in flow rate of the fluid through the
nozzle, monitoring the changing flow rate, and recording at least two
different points representing two different actuator positions and
corresponding flow rates, and (c) storing in the memory of the electronic
controller a multi-point calibration representing actuator position as a
function of an input parameter designed to achieve a desired flow rate.