AIR OR FLUID SERVO DRIVE Russian patent published in 2013 - IPC F15B9/03 

FIELD: machine building.

SUBSTANCE: proposed servo drive is intended for systems with high-precision control over parameters of revolution. Servo drive comprises first and second reciprocating actuators composed of air or fluid cylinders with output links engaged with drive shaft via reciprocation-to-rotation converters, drive shaft turn current angle transducer, first and second signal generators, and first and second actuator control circuit. First control circuit comprises first subtractor and sine converter, while second control circuit comprises second subtractor and cosine converter. Outputs of said subtractors are connected to fluid control valves of appropriate actuators. First and second outputs of command signal generator are connected to first inputs of first and second subtractors. Output of drive shaft turn transducer is connected to second inputs of first and second subtractors via sine and cosine converters, respectively, while first and second command signal generator comprises device to set variation of drive shaft turn angle in time and said sine and cosine converters. Output of the device to set variation of drive shaft turn angle in time is connected to inputs of said sine and cosine converters, their outputs making first and second outputs of command signal generators. Besides, it comprises pressure gages, correctors and adders. Note that pressure gages are connected with chambers of air or fluid cylinders and corrector. Inputs of the latter are connected with subtractors while its outputs are connected to adders arranged between subtractor and air or fluid control valve of every cylinder.

EFFECT: uniform angular velocity of shaft revolution, ruled out external effects caused by hydroelectric units and loads.

2 dwg