US 4,304,375 A · Electrically controlled elevator

Abstract

A helicopter elevator (12, 13) is driven by an electrical actuator (20) to position the elevator (12, 13) to an optimum angle of incidence for given flight conditions. The actuator (20) is included within a servo loop which responds to a command signal derived from an electronics module (69). Transducers which measure longitudinal cyclic position (40), collective pitch position (41) and air speed (42) generate signals which are summed in a summation unit (43). The output of the summation unit (43) is passed through a signal multiplier (45) which has the gain thereof set inversely proportional to air speed. A trigger unit (56) activates the signal multiplier (45) at an air speed above a preset threshold. An integrator (54) integrates the sum of the outputs of the longitudinal cyclic position transducer (40) and air speed transducer (42) to compensate for different center of gravity aircraft loadings. Duplicate electronic systems are provided to drive a pair of servo motors (36a, 36b) with brakes provided to lock the actuator (20) when an electronic failure is detected.

Claims30

Dependent claims

A helicopter control system for positioning a servo driven elevator, comprising:

(a) a longitudinal cyclic command sensor,
(b) a collective pitch position sensor,
(c) an air speed sensor,
(d) means for combining the outputs of said sensors to produce a summation signal,
(e) means for modifying said summation signal by a factor which changes inversely relative to said air speed, and
(f) means for applying said modified summation signal as the input to said servo.

3 more elements

A helicopter control system for positioning an elevator, comprising in combination:

(a) a first system including,
(i) a first longitudinal cyclic command sensor,
(ii) a first collective pitch position sensor,
(iii) a first air speed sensor,
(iv) means for combining the outputs of said first sensors to produce a first summation signal,
(v) means for modifying said first summation signal by a factor which changes inversely relative to said air speed,
(vi) means for combining the outputs of said first sensors to produce a second summation signal,
(vii) means for modifying said second summation signal by a factor which changes inversely relative to said air speed,
(viii) a first servo motor driven by an electrical power source through a first power switch and connected to drive said elevator, said servo motor having a control winding with first and second terminals,
(ix) means for applying said modified first and second summation signals as the inputs to said first and second terminals, respectively, of said first servo motor,
(b) a second system including:
(i) a second longitudinal cyclic command sensor,
(ii) a second collective pitch position sensor,
(iii) a second air speed sensor,
(iv) means for combining the outputs of said second sensors to produce a third summation signal,
(v) means for modifying said third summation signal by a factor which changes inversely relative to said air speed,
(vi) means for combining the outputs of said second sensors to produce a fourth summation signal,
(vii) means for modifying said fourth summation signal by a factor which varies inversely relative to said air speed,
(viii) a second servo motor driven by an electrical power source through a second power switch and connected to drive said elevator, said servo motor having a control winding with first and second terminals, and
(ix) means for applying said modified first and second summation signals as the inputs to said first and second terminals, respectively, of said second servo motor.

17 more elements

Dependencies are inferred from the claim text.

Electrically controlled elevator

Life of this patent

Electrically controlled elevator

Life of this patent

Abstract

Claims30