Electronic Tachometer for Linear Actuators
Original Publication Date: 1985-Sep-01
Included in the Prior Art Database: 2005-Feb-19
An electronic circuit is disclosed that will provide velocity feedback for position control servo systems employing linear actuators in place of rotary drive motors. The tachometer voltage is generated directly from an optical diffraction grating, or any position transducer having the ability to generate quadrature signals (90-degree phase relationship), without the use of a discrete rotary tachometer. The circuit shown in Figs. 1 and 3 is used to generate a voltage proportional to the velocity and direction of a linear actuator. This design uses the phase relationship of the quadrature (sin and cos) signals derived from an optical diffraction grating, as might be used for measuring distance with a linear encoder.