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Fluidics Feedback Control System

IP.com Disclosure Number: IPCOM000081972D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Firdaus, A: AUTHOR

Abstract

The fluidics feedback control system described here is used for remote sensing of miniature mechanisms in motion, by sampling the transient pressure levels.

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Fluidics Feedback Control System

The fluidics feedback control system described here is used for remote sensing of miniature mechanisms in motion, by sampling the transient pressure levels.

The sensing system utilizes the principle that when an actuator is in motion, the line pressure driving the actuator will not reach the maximum dead-end pressure. As the actuator reaches the end of the motion, the line pressure will quickly reach the dead-end pressure actuating the circuit signalling end of travel.

Utilization of this basic principle is illustrated in Fig. 1, showing a circuit configuration used for sensing the motion and limit points of a double-acting cylinder.

Fig. 2 shows the circuit transient states from the time a process controller gives the mechanism a command to move, to the time the sensing system sends a feedback signal indicating end of motion. In the example graph, only one line pressure is illustrated.

In Fig. 1 when the solenoid valve SV1 or SV2 is actuated to retract the cylinder CY1, the pressure LP1 or LP2 starts to increase, and the piston starts to move. During the transient state the line pressure, LP1 or LP2 is below the reference pressure RP1 or RP2 which is set slightly below the dead-end pressure. When the cylinder CY1 reaches the end of its stroke, the line pressure LP1 or LP2 equals the dead-end pressure, thus triggering the appropriate Schmitt trigger 0l or 02 indicating that the cylinder has reached the end of its stroke.

The princ...