CN103345149A - Dynamically tuned gyroscope servo control loop - Google Patents

Abstract

The invention discloses a dynamically tuned gyroscope servo control loop which is composed of a gyroscope gauge outfit, a torquer and a controller. The controller is composed of a second-order integration element, a differentiation element, a low-pass filter and the like. For the transfer function of the controller, two integration elements are used by the dynamically tuned gyroscope servo control loop for the first time so that a system becomes a II-type system. By means of the second-order integration element, errors relevant to constant disturbance torque can be eliminated, so that the stability precision of a servo loop system is improved. The differentiation element is used for increasing the gain and phase margin of a low-frequency stage, unconditionally stabilizing the system and improving the robust stability of parameters. The low-pass filter is used for eliminating high-frequency noise.

Description

A kind of dynamically tuned gyro, DTG servo control loop

Technical field

The present invention relates to a kind of servo control loop of strap-down inertial measurement unit, relate in particular to a kind of dynamically tuned gyro, DTG servo control loop, be mainly used in the Aeronautics and Astronautics field of high precision angular velocity measurement.

Background technology

Dynamically tuned gyro, DTG is a kind of two degree-of-freedom gyro that the high speed rotor is constituted the supporting of universal joint formula with flexible member.Under tuning rotating speed, the dynamic force moment of gimbal has been offset the elastic restraint moment of flexible support, makes gyrorotor become free free rotor, therefore is called dynamically tuned gyro, DTG.Moving accent gyroscope and the carrier used in the strapdown system are connected, and the angular motion of carrier will directly be added on the gyroscope.Because the moving accent gyroscope of open-circuit condition is only limited in small angle range and works, the therefore gyroscope of using in strapdown system must be delivered to corresponding torquer by balanced loop again with its output, makes gyroscope work in closed circuit state.Under this condition, torquer applies moment to rotor, order about rotor and follow the tracks of the housing motion, gyrostatic error angle remains near zero, and the electric current by being transported to torquer (or voltage, pulsed frequency) is measured carrier around the angular velocity of gyro output axis.Domestic existing moving accent gyroscope servo control loop is type 0 system, and namely system does not contain integral element.Though this system is applied, along with the demand of high precision angular velocity measurement is more and more urgent, launch the controller design of transferring the gyroscope servo loop to moving again in different model.

The major defect of former type 0 system is that low-band gain is not high, the system stiffness deficiency, and the open-loop transfer function of establishing the gyroscope servo loop is G (s), then the relative error of systematic survey is

In the bandwidth range of system, the amplitude of open-loop transfer function is more big, and measuring accuracy is more high.For realizing the measurement high-precision requirement of gyroscope servo loop, the open loop enlargement factor of system should be greater than 150dB, for guaranteeing the robust stability of gyroscope servo-drive system, the bandwidth of gyroscope servo-drive system should be no more than 200rad/s, requiring the gyroscope servo-drive system simultaneously is a unconditional stability system, namely the phase place of open-loop transfer function in bandwidth with interior all more than-180 °.But present gyroscope servo loop can not satisfy accuracy requirement.

Summary of the invention

Technology of the present invention is dealt with problems: overcome the deficiencies in the prior art, a kind of dynamically tuned gyro, DTG servo control loop is provided, improved robust stability and the stable state accuracy of servo control loop.

Technical solution of the present invention: a kind of dynamically tuned gyro, DTG servo control loop,

The present invention's advantage compared with prior art is as follows:

(1) the present invention proposes to adopt 2 integral elements first, makes servo-control system become an II type system, adopts second order integral element can eliminate the error relevant with normal value rate of change of angular, thereby improves the stable state accuracy of servo loop system.

(2) the present invention redesigns the controller of servo control loop first, adopt second order integral element and differentiation element, system-gain is brought up to more than the 200dB, compare existing dynamically tuned gyro, DTG servo control loop low-band gain and have only problem about 100dB, the present invention can guarantee that servo-control system is a unconditional stability system, has improved the stability of system when closure.

(3) if adopt the method for pole-zero cancellation to need the parameter of accurate known each accelerometer gauge outfit, be unfavorable for batch requirement of producing, the controller of the present invention's design then can guarantee system to the robust stability of gauge outfit parameter, is conducive to batch product of instrument.

Description of drawings

Fig. 1 is existing 0 type servo control loop open loop frequency characteristic synoptic diagram;

Fig. 2 is realization schematic diagram of the present invention;

Fig. 3 is II type servo control loop open loop frequency characteristic synoptic diagram of the present invention.

Embodiment

Dynamically tuned gyro, DTG is made up of critical pieces such as CD-ROM drive motor, supporting system, angular transducer, gyroscopic couple device, gyrorotor, seal casinghousings.CD-ROM drive motor drives supporting system by driving shaft and gyrorotor rotates with constant angular velocity, guarantees tuning rotating speed and angular momentum that gyro has to be needed.When instrumentation, flexibly mounted positive moment of elasticity can be balanced the power bounce-back property moment of the vibratory movement generation of ring fully and offset, and makes gyrorotor become free free rotor.Angular transducer is used for converting the relative instrument housing of gyrorotor to corresponding voltage signal around the corner of two quadrature output shafts.Torquer is the device that gyrorotor is applied moment.Gyrorotor is the inertial mass that produces angular momentum H, be made up of the permanent-magnetic clamp of flywheel, torquer, movable plate electrode and the angle bridle of sensor, so gyrorotor is again the ingredient of torquer, sensor and angle bridle.

Moving accent gyroscope and the carrier used in the strapdown system are connected, and the angular motion of carrier will directly be added on the gyroscope.Because the moving accent gyroscope of open-circuit condition is only limited in small angle range and works, the therefore gyroscope of using in strapdown system must be delivered to corresponding torquer by balanced loop again with its output, makes gyroscope work in closed circuit state.Under this condition, torquer applies moment to rotor, order about rotor and follow the tracks of the housing motion, gyrostatic error angle remains near zero, and the electric current by being transported to torquer (or voltage, pulsed frequency) is measured carrier around the angular velocity of gyro output axis.

The gyrostatic gauge outfit transport function of moving accent comprises two parts: (1) gauge outfit output-transfer function

Described the frequency field mathematical relation between carrier angular velocity and the gyroscope angular transducer, wherein, H is the gyroscope angular momentum, and λ is the cross damping moment coefficient; (2) gauge outfit precession transport function

The frequency field mathematical relation that is applied between epitrochanterian moment and the angular velocity has been described.The controller can guarantee that system is a unconditional stability system at present, be that the phase place of low-frequency range is all more than-180 °, system bandwidth is 200rad/s, satisfy the requirement of robust stability, as shown in Figure 1, but because system has only about 100dB in the gain of low-frequency range, be difficult to satisfy strap-down inertial measurement unit to the requirement of angular velocity high-acruracy survey.Therefore, need controller of redesign to make servo loop to improve the gain of system.

Controller of the present invention is made up of second order integral element, differentiation element, low-pass filter etc., and 2 integral elements make system become an II type system, can eliminate the error relevant with normal value disturbance torque, thereby improves the stable state accuracy of servo loop system; Differentiation element is in order to realize improving low-band gain and phase margin, unconditional stability system and parameter robust stability, and low-pass filter is in order to eliminate high frequency noise.The servo loop of the present invention design as shown in Figure 2, K wherein _p, K _tBe respectively the amplification coefficient of angular transducer and torquer, C (s) is the transport function of servo loop controller.The present invention has redesigned the transport function of controller, make gyroscope servo loop system zero limit all at the robust stability of RHP with the raising parameter, and to make gyroscope servo loop system be thereby that the stability when closed has been guaranteed in unconditional stability, adopts second order integral element to improve stable state accuracy simultaneously.

The servo loop controller transfer function of the present invention's design is:

Wherein, K is the enlargement factor of controller, T ₁, T ₂Be the time constant of controller Mid Frequency,

Be the transport function of low-pass filter in the controller, ξ is the ratio of damping of low-pass filter, T ₃Be the time constant of low-pass filter, T ₁With the time constant approximately equal of gyroscope gauge outfit, T ₂S+1 is the transport function of differentiation element in the controller,

Be the transport function of second order integral element, T ₃＜T ₂＜T ₁

Used gyroscope servo loop does not comprise integral element at present

Will there be an error relevant with normal value disturbance torque in system.The present invention proposes to adopt two integral elements first in controller, namely

Can eliminate the error term relevant with normal value disturbance torque, improve the stable state accuracy of system.

Because the imperfection of manufacturing process makes the numerical value of this limit not unique, for guaranteeing the robust stability of system when parameter changes, zero limit is all in RHP in the controller of the present invention's design.For guaranteeing that system is the unconditional stability system, namely in bandwidth with interior phase place all more than-180 °, adopt second order integral element to improve stable state accuracy.Adopt behind this controller gyroscope servo loop open-loop transfer function Bode diagram as shown in Figure 3.As can be seen, the open loop enlargement factor of system is greater than 200dB, and the bandwidth of system is approximate identical with former design, is no more than 200rad/s, and phase place in bandwidth with interior all more than-180 °, satisfy the design objective requirement.

The present invention not detailed description is technology as well known to those skilled in the art.

Claims (1)

1. dynamically tuned gyro, DTG servo control loop, by sensor, torquer and controller are formed, when carrier has the angular velocity input, thereby the relative gyrowheel of gyroscope housing departs from an angle produces deviation signal, sensor detects this deviation signal, controller converts the detected deviation signal of sensor to electric signal, electric signal after controller will be changed feeds back to torquer, producing trimming moment by torquer makes gyrowheel rotate to eliminate above-mentioned deviation signal again, the output of controller is as gyrostatic output the most at last, it is characterized in that: described controller is by second order integral element, differentiation element and low-pass filter are formed, and the transport function C of controller (s) is: $C\left(s\right)=\frac{K(T_{1}s+1)(T_{2}s+1)}{s^2(T_3^2{s}^2+2\mathrm{\ξ}{T}_{3}s+1)},$

Wherein, K is the enlargement factor of controller, T ₁, T ₂Be the time constant of controller Mid Frequency,

Be the transport function of low-pass filter in the controller, ξ is the ratio of damping of low-pass filter, T ₃Be the time constant of low-pass filter, T ₂S+1 is the transport function of differentiation element, Be the transport function of second order integral element, T ₃＜T ₂＜T ₁

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