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There are many types of rate gyroscopes, the three most commonly used

Feb 08, 2019

(1) torsion rod type rate gyroscope: when the aircraft speed around the input axis of the gyroscope has angular velocity, the beginning of the instantaneous rate gyroscope shell forced the rotor to follow the rotation, equivalent to the input shaft to apply an external torque.According to the precession principle of the gyroscope (see gyroscope), along the output shaft of the rate gyroscope, gyroscopic torque will be generated to precess the rotor around the output shaft, causing torsion of the torsion bar, and then an additional elastic torque will be generated along the output shaft.Similarly, under the action of elastic torque, the rotor will precess around the input shaft. When its precession angular velocity is equal to the angular velocity of the aircraft, the shell will no longer exert torque on the rotor, so the rotor will no longer precess around the output shaft, and the torsion rod will no longer continue to twist.The precession angular velocity of the rotor around the input shaft is proportional to the applied torque.At this time, the precession angular velocity is equal to the angular velocity of the aircraft, so the elastic moment is proportional to the angular velocity of the aircraft.While the elastic moment is proportional to the rotation Angle of the torsion bar, so the rotation Angle of the rotor around the output shaft (that is, the signal output by the Angle sensor) is proportional to the angular velocity of the aircraft.Dampers are used to suppress oscillations during rotation.Torsion rod type rate gyroscope is widely used in aircraft attitude control because of its simple structure.Its disadvantage is that the rotor will deviate from the zero when the output, so that the output cross-coupling error.The larger the input angular velocity, the larger the error, and therefore the accuracy is not very high.

(2) feedback type rate gyroscope: in order to make up for the shortcomings of the torsion rod type rate gyroscope, the output signal of the Angle sensor can be amplified and fed back to the torquer on the output shaft to form a loop, with the electric spring instead of the torsion rod, as long as the gain of the loop is large enough to make the rotor always keep near zero.The current flowing into the torquer is proportional to the input angular velocity and can be used as the output of the instrument.

(3) integrating gyroscope: take out the torsion rod (or spring) of the rate gyroscope and only retain the damper to become the integrating gyroscope.When the aircraft has angular velocity around the input axis of the integrating gyroscope, the initial condition is the same as that of the rate gyroscope, and the rotor precession around the output axis.The damping moment generated by the damper causes the rotor to precession around the input axis.Since the damping torque is proportional to the angular velocity, the rotor continues to rotate around the output shaft (no torsion bar constraint), and its speed is proportional to the angular velocity of the aircraft. Therefore, the Angle sensor on the output shaft outputs a signal proportional to the rotation Angle of the aircraft.Since the input is angular velocity and the output is Angle signal, it is called integral gyroscope.It is widely used in inertial navigation.

(4) fiber optic gyroscope: mainly include interferometric, resonance and stimulated brillouin scattering, are based on the Sagnac effect, i.e., when a ring light path in inertial space around the vertical axis in the plane of the Yu Guanglu turns, the spread of the light path opposite two columns of light will be the optical path difference due to inertia movement, leading to the interference of two beams of coherent light waves.The phase difference corresponding to the optical path difference is intrinsically related to the rotation Angle rate. The rotation Angle rate can be determined by detecting and demodulating the interference light intensity signal.

Semi-Liquid Floating Gyro(Substitute of Honeywell liquid floating gyro)

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