Societe De Fabrication D'instruments De Mesure (s.f.i.m.)

Jacques Delattre

Philippe Gouze

Jacques Neuvessel

A position-controlled actuator includes a motor supplied with power by a power supply circuit controlled at least by an error signal. A speed reducer converts rotary movement of the motor into linear movement over a given travel. An output sensor indicates the position of the actuator and an error signal computation circuit compares a commanded position of the actuator to a calculated position. The output sensor supplies a binary position signal taking two different values according to the position of the actuator relative to its mid-travel position. The binary position signal is applied to a power up logic circuit which, when the actuator receives an activation instruction, switches the input of the motor power supply circuit to the output sensor so as to apply the binary position signal to the motor power supply circuit until the value of the binary position signal changes, whereupon the power up logic circuit switches the input of the motor power supply circuit to the output of the error signal computation circuit. The calculated position of the actuator is supplied by a circuit receiving a motor position signal from at least one motor sensor on the motor. One application of the actuator is to autopilot flight control of a helicopter.

Position-controlled actuator

An actuator suitable for autopilot control of a helicopter tail rotor comprises a direct current motor, a non-reversible gearbox, a speed reducer driving an output shaft, a friction device disposed between the non-reversible gearbox and the speed reducer and a friction exceeded sensing device adapted to cut off the supply of power to the motor.

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Valpuiseaux, France

Jacques Delattre