Electrohydraulic servovalve with flow gain compensation

An electrohydraulic servovalve system having a motor responsive to electrical signals for positioning a valve member to control the flow of fluid therethrough, said valve includes round ports and said valve member overlays said round ports thereby providing flow characteristics including a deadband region, an intermediate flow region and a full flow region,

• said system comprising:
• a) a source of electrical command signals:
• b) means for receiving said electrical command signals;
• c) means coupled to said receiving means for tailoring said command signals and providing a tailored signal including a plurality of amplifiers, each of said amplifiers having a different gain, at least one of said amplifiers including means for limiting the output signal thereof;
• d) a first one of said amplifiers providing a first signal to compensate for said deadband region, a second one of said amplifiers providing a second signal to compensate for said intermediate flow region and a third one of said amplifiers providing a third signal to compensate for said full flow region;
• e) means for summing the output signals from said amplifiers,
• f) a position sensor coupled to said electrohydraulic servovalve system for providing an electrical signal representative of position;
• g) means for comparing said position signal and said tailored signal for developing an input signal to said motor;
• and
• h) means for coupling said input signal to said motor, whereby a substantially linear flow characteristic results.