Patent ID: 7066189

Claim:
A servovalve system for regulating fluid flowing within a fluid circuit, the servovalve system comprising: a housing; a spool slidably disposed within the housing; a stepper motor operatively connected to the spool and being configured to move the spool relative to the housing in order to manipulate the flow of fluid within the fluid circuit; a controller electronically connected to the stepper motor and configured to generate a quantity of driver signals, each one of the driver signals being representative of a desired amount of stepper motor rotation in order to effectuate incremental spool motion relative to the housing; and a position sensor electronically coupled to the stepper motor, the position sensor being configured to sense an actual amount of stepper motor rotation and generate a quantity of position signals representative thereof; wherein the controller is operative to record the quantity of position signals corresponding to the quantity of driver signals, determine a signal ratio of the quantity of the position signals to the quantity of the driver signals, and generate a diagnostic signal when the signal ratio reaches a threshold value representative of a predetermined level of mechanical resistance of spool motion relative to the housing.