Position signal processor for hydraulic cylinder

摘要

The stroke position of a piston rod of a hydraulic cylinder and a rotational (angular) position of a rotary member are detected. There are provided a pair of sensors that produce sinusoidal waves corresponding to the positioning scale markings on a moving member and the outputs of the sensors are pulse-width-modulated with high-frequency sinusoidal waves. - The modulation is effected in a selected range that does not include peak values of the sinusoidal waves produced by the sensors. Using the sinusoidal waves as modulating signals, the pulse width of the sensor output can be modulated linearly. (21pp Dwg.No.1/10) GBAB- GB2248302 B A position sensing system, characterised by the fact that it comprises a pair of sensors spaced relative to the direction of displacement for producing sinusoidal wave signals, 90 deg. out of phase with respect to each other, corresponding to the position scale markings, means for pulse-width modulation by the output of at least one of the sensors of high-frequency sinusoidal waves as a carrier signal, and means for calculating position signals based on the duty ratio of the pulse-width modulated signals. - (Dwg.1) - GB2248302 B A position sensing system, characterised by the fact that it comprises a pair of sensors spaced relative to the direction of displacement for producing sinusoidal wave signals, 90 deg. out of phase with respect to each other, corresponding to the position scale markings, means for pulse-width modulation by the output of at least one of the sensors of high-frequency sinusoidal waves as a carrier signal, and means for calculating position signals based on the duty ratio of the pulse-width modulated signals. - (Dwg.1) USAB- US5280238 A The system includes a pair of sensors spaced apart in the direction of displacement for producing sinusoidal wave signals corresp. to position scale markings extending in the direction. The outputs of the sensors are pulse-width-modulated using high-frequency sinusoidal waves as modulating signals, and position signals are generated based on the duty ratio of the pulse-width modulated signals.