In-line actuator monitoring and control apparatus

Claim 1

An in line monitoring and control apparatus comprising in combination: first and second actuator units arranged in a redundant configuration, said first and second actuator units being hydraulically operated and controlled by electrical input signals respectively, said first and second actuator units having their respective output force applied to a force summing means, said first and second actuator units each operating on a differential pressure, said first and second actuator units each providing an actuator position signal, and first and second decision logic units to respectively provide control signals to said first and second actuator units, said first decision logic unit providing a first control command and a first position command to said first actuator unit, said second decision logic unit providing a second control command and a second position command to said second actuator unit, said first decision logic unit receiving a first actuator position signal from said first actuator means, said second decision logic unit receiving a second actuator position signal from said second actuator unit, said first and second decision logic units respectively compare said first and second actuator position signals with the respective first and second position command to determine an actuator unit failure, said first and second decision logic units each receive a first and second differential pressure signal from said first and second actuator units, said first and second decision units each utilizing said first and second differential pressure signal to determine an actuator unit failure, said first or second decision logic units providing a shut-off command to the failed actuator unit.