SEARCHING SYSTEM FOR ORIGINAL POINT OF ACTUATOR

摘要

PURPOSE:To search an original point in an economical way with small hardware by controlling the displacement value of an actuator with an open loop using an inclined voltage generating circuit and then deciding the position of the actuator based on the original point by a position sensor. CONSTITUTION:The original point of an actuator 7 whose displacement value increases or decreases in proportion to the input voltage value is detected by an original point sensor 9 for positioning of the actuator 7. For this purpose, said input voltage value is linearly increased from the minimum voltage value to which the actuator 7 can correspond as the time elapses. Otherwise an open loop control circuit 10 is provided to change the maximum voltage value to the minimum voltage value and the position information on the actuator 7 is detected by a position sensor 8 when the sensor 9 detects that the actuator 7 is reached its original point. In such a way, the actuator 7 is made cross its original point by the circuit 10 which produces the inclined voltage. Then a switch 5 is changed over for correction of the position information of the sensor 8 and the position of the actuator 7 is controlled based on its original point.