CN103274059B - Feedforward torque compensation method of satellite with moved effective load - Google Patents

Abstract

The invention discloses a feedforward torque compensation method of a satellite with moved effective load. According to the feedforward torque compensation method of the satellite with the moved effective load, a feedforward torque compensation algorithm is designed on the basis of effective load movement interference analysis, compensation precision is improved through equivalent moment of force compensation, lead compensation and time calibration, and high-precision high-stability control of a complex satellite with moved effective load is achieved. The method can overcome the influence of the factors that the control period of the effective load differs from that of a compensation executing mechanism, dynamic properties differs and the theory motion law of the effective load differs from the practical motion law of the effective load, the method effectively improves the effect of the feedforward torque compensation, and enables the control stability of the satellite to be over 5*10<-4> degree/s.

Description

A kind of feedforward torque compensation method with motion capacity weight satellite

Technical field

The present invention relates to a kind of feedforward torque compensation method with motion capacity weight satellite, be specially adapted to high precision high stability degree satellite, belong to Spacecraft Attitude Control field.

Background technology

The geostationary orbit remote sensing satellites such as meteorological satellite are often with the capacity weight of rapid movement, and the GOES string of weather satellite of the such as U.S., wind and cloud No. four meteorological satellites of China etc. are all with infrared scanning radiometer and SEQUENCING VERTICAL detection instrument.Motion capacity weight relative satellite platform on satellite does rapid movement in order to meet specific region imaging requirements over the ground.The sport of capacity weight forms disturbance to satellite attitude.This disturbing influence satellite control accuracy and degree of stability, and then affect movable parts pointing accuracy and point to degree of stability, satellite is finished the work of poor quality.When the motion frequency of motion capacity weight and the flexible frequency of windsurfing close to time, windsurfing can be encouraged to resonate.Therefore, when carrying out the Attitude Control System Design of this kind of satellite, must consider to process the kinetic satellite attitude change of motion capacity weight, to meet motion capacity weight pointing accuracy and to point to degree of stability, the control accuracy meeting satellite platform and degree of stability.

For the interference of movable parts, the method that can adopt comprises the compensation of effective loading movement, feedforward torque compensation etc.Wherein comprise based on the capacity weight motion compensation of model, based on the capacity weight motion compensation of measuring based on capacity weight motion compensation.Motion compensation process is moved by capacity weight and compensates the error in pointing of satellite platform.The method can improve the pointing accuracy of movable parts, but can not improve control accuracy and the degree of stability of satellite platform.

Existing feedforward torque compensation method is according to the capacity weight characteristics of motion, and direct calculation compensation moment, does not have to consider:

(1) capacity weight is different from the control cycle compensating actuating unit;

(2) capacity weight is different from the dynamic property compensating actuating unit;

(3) capacity weight theory movement rule and actual movement rule inconsistent.

If do not consider that above-mentioned tripartite's face rings, feedforward torque compensation effect is poor, and compensation even may be caused to become interference.

Summary of the invention

Technical matters to be solved by this invention is: consider that capacity weight is different from the control cycle compensating actuating unit, dynamic property is different, simultaneously consider capacity weight theory movement rule and actual movement rule inconsistent, a kind of feedforward torque compensation method is provided, can realizes being with the high precision high stability degree of the complicated satellite of motion capacity weight to control.

The present invention includes following technical scheme:

With a feedforward torque compensation method for motion capacity weight satellite, step is as follows:

(1) according to the mode of motion of capacity weight, and consider that satellite control cycle affects, calculate the equivalent compensation moment accelerated under this mode of motion and corresponding to moderating process

(2) according to capacity weight and compensation mechanism dynamic characteristics, and because of capacity weight control cycle produced time delay different from the feedforward compensation cycle, the leading time t that Front feedback control moves relative to capacity weight is calculated _lead;

Leading time t _leadcomputing formula be $t_{\mathrm{lead}}=\frac{\arctan \left({\mathrm{\&tau;}}_{\mathrm{fc}}\mathrm{\&omega;}\right)-\arctan \left({\mathrm{\&tau;}}_y\mathrm{\&omega;}\right)}{\mathrm{\&omega;}}+t_{\mathrm{cy}},$ Wherein, τ _yfor the electromechanical time constant of capacity weight, τ _fcfor the electromechanical time constant of compensation mechanism, ω is capacity weight motion angular frequency, t _cyfor because of capacity weight control cycle produced time delay different from the feedforward compensation cycle;

(3) according to the motion parameter data under the described mode of motion of ground injection, the theoretical initial time of capacity weight acceleration and moderating process is calculated; Described motion parameter data comprises initial time, motion angle at the beginning and moving target angle; Then difference Δ T=0 correction time is made;

(4) when judging whether to receive band, target demarcation signal, is designated as (Flg, T ₀), target demarcation signal when producing described band when capacity weight moves to ad-hoc location;

If receive demarcation signal, then judge | Δ T+T _com-T ₀| whether <SynTimeLimit sets up, and SynTimeLimit is time difference threshold value, T _comfor capacity weight moves to the theoretical moment of this ad-hoc location; If | Δ T+T _com-T ₀| <SynTimeLimit, makes Δ T=T ₀-T _com, proceed to step (5); Otherwise, make Δ T remain unchanged, then proceed to step (5);

If do not received, make correction time difference Δ T remain unchanged, proceed to step (5);

(5) to will speed up or the theoretical initial time of moderating process deducts leading time t _leadafter, add difference Δ T described correction time, obtain the initial time of acceleration or deceleration compensatory control;

(6) from the initial time of acceleration or deceleration compensatory control, export compensating control signal to compensation mechanism, maintain after exporting the Δ t time and cancel the described compensating control signal of output; The equivalent compensation moment of described compensating control signal corresponding to acceleration or deceleration process determine;

(7) judge whether the motion process corresponding to described mode of motion terminates, if do not terminated, return step (4), otherwise, terminate.

Equivalent compensation moment computing formula be:

Wherein, for the capacity weight rotor inertia that ground test obtains, ε _yrfor the angular acceleration of acceleration or deceleration process under described mode of motion, t1 is capacity weight acceleration or deceleration process initial time under described mode of motion, t2 is capacity weight acceleration or deceleration process finish time under described mode of motion, Δ t is make-up time length, Δ t ≈ t2-t1 and be the integral multiple of satellite control cycle.

The present invention compared with prior art tool has the following advantages:

The present invention is on the basis that capacity weight motion artifacts is analyzed, and design feedforward torque compensation algorithm, by equivalent moment compensation, lead compensation, time calibrating, improves compensation precision, and the high precision high stability degree achieving the complicated satellite of band motion capacity weight controls.Institute of the present invention extracting method, the factors such as capacity weight is different from the compensation actuating mechanism controls cycle, dynamic property difference, capacity weight theory movement rule and actual movement rule are inconsistent can be overcome affect, effective raising feedforward torque compensation effect, makes satellite control degree of stability 5 × 10 ^-4°/more than s.

Accompanying drawing explanation

Fig. 1 is that the present invention feedovers torque compensation diagram of circuit;

Fig. 2 is quick sensing process and corresponding time relationship;

Fig. 3 is scanning process and corresponding time relationship;

Fig. 4 is detection process and corresponding time relationship;

Fig. 5 is feedforward compensation moment;

Fig. 6 is satellite three axis angular rate simulation curve when using controlled reset;

Fig. 7 is the satellite three axis angular rate simulation curve (feed forward control period of service is demarcated, do not used anticipatory control) when using feedforward torque compensation+controlled reset;

Fig. 8 is the satellite three axis angular rate simulation curve (correction of feed forward control period of service, anticipatory control) when using feedforward torque compensation+controlled reset;

Fig. 9 is the satellite three axis angular rate simulation curve (considering capacity weight motion-activated windsurfing flexible vibration) when using controlled reset;

Figure 10 is that satellite three axis angular rate simulation curve when using feedforward torque compensation+controlled reset (considers capacity weight motion-activated windsurfing flexible vibration; Feed forward control period of service is demarcated, is not used anticipatory control);

Figure 11 is that satellite three axis angular rate simulation curve when using feedforward torque compensation+controlled reset (considers capacity weight motion-activated windsurfing flexible vibration; The correction of feed forward control period of service, anticipatory control).

Detailed description of the invention

Just by reference to the accompanying drawings the present invention is described further below.

One, capacity weight typical motion rule

Two dimensional motion capacity weight can carry out north-south movement and thing motion respectively, also can move simultaneously, can produce disturbance torque when capacity weight moves to satellite X-axis (during north-south movement), Z axis (during thing motion).Consider following several typical motion rule: 1) point to fast, capacity weight kinematic mechanism can point to a target location from any one starting position in limited field, as shown in Figure 2.Rapid movement process is as follows, first in 0.5s, accelerates to 10 °/s, and then with 10 °/s speed uniform movement, finally slows down in 0.5s, and be parked in desired location.North and south, thing acceleration and deceleration rule are identical, all adopt 1/4 sinusoidal cycles.2) scan, capacity weight kinematic mechanism, with 10 °/s velocity scanning, carries out imaging to certain region, as shown in Figure 3.After East West kinematic mechanism accelerates to 10 °/s in 0.1s, with 10 °/s uniform speed scanning, after putting in place, in 0.1s, be decelerated to 0 °/s, complete the scanning in a direction; In 0.1s, oppositely accelerate to 10 °/s, then with 10 °/s velocity reversal uniform speed scanning, in 0.1s, be oppositely decelerated to 0 °/s after putting in place, complete rightabout scanning.Thing turns to period, north-south mechanism stepping 210 μ rad.And so forth, until the end of scan.East West acceleration, deceleration process adopts 1/4 sinusoidal cycles, and north-south stepping process adopts 1/2 sinusoidal cycles.3) detect, the stepping of capacity weight kinematic mechanism, sensing region is detected, as shown in Figure 4.Stepping 1792 μ rad, resident 37.4s in east-west direction mechanism 0.2s, then stepping 1792 μ rad, resident 39.2s, so circulates, until detection terminates, then north and south step further, oppositely detects.

Two, feedover torque compensation process

As shown in Figure 1, feedforward torque compensation method of the present invention comprises the steps:

(1) equivalent compensation Calculating Torque during Rotary

According to ground test, capacity weight transfer function model is

$\frac{T_y\left(s\right)}{{\mathrm{\&epsiv;}}_{\mathrm{yr}}\left(s\right)}=\frac{K_y}{{\mathrm{\&tau;}}_{y}s+1}$

Wherein, T _ys () is capacity weight moment, ε _yrfor capacity weight motion angular acceleration, τ _yfor the electromechanical time constant of capacity weight, K _yfor capacity weight is by the amplitude gain of angular acceleration to moment.

Compensating moment T _fcrelative compensation actuating unit driving voltage u _fctransfer function be

$\frac{T_{\mathrm{fc}}\left(s\right)}{u_{\mathrm{fc}}\left(s\right)}=\frac{K_{\mathrm{fc}}}{{\mathrm{\&tau;}}_{\mathrm{fc}}s+1}$

Wherein, τ _fcfor compensating actuating unit electromechanical time constant, k _fcfor compensation mechanism is by the amplitude gain of voltage to moment.

Driving voltage wherein, k _ufor the moment voltage coefficient of compensation mechanism, in the present invention, get 100.0, for equivalent compensation moment estimated valve. according to the capacity weight moment T estimated _ys () asks for, T _ys () estimated valve is designated as s (), ignores in a small amount, order then:

$\widehat{T_{\mathrm{fc}}}=-\frac{\widehat{J_y}}{\mathrm{\&Delta;t}}{\&Integral;}_{t1}^{t2}{\mathrm{\&epsiv;}}_{\mathrm{yr}}\mathrm{dt}$

Wherein, for the capacity weight rotor inertia that ground test obtains, ε _yrfor capacity weight motion angular acceleration, t1 is that capacity weight accelerates (or deceleration) initial time, t2 is for accelerating (or slow down) finish time, and Δ t is the make-up time length of corresponding t1 to t2 time period, Δ t ≈ t2-t1 and be the integral multiple of satellite control cycle.Equivalent compensation moment can calculate in advance on ground, and injects on star, and each mode of motion needs calculating two equivalent compensation moments (accelerator and moderating process).

Consider that satellite installs two capacity weights, each load has different mode of operations.Two capacity weight motion control cycles are all 0.005s, compensate actuating mechanism controls cycle (satellite control cycle) 0.032s.

Capacity weight 1, quick directing mode, the time that thing, north-south capacity weight accelerate to 10 °/s needs by 0 °/s is 0.5s, then the make-up time is a Δ t=0.48s(15 control cycle), capacity weight 1 thing, north and south rotor inertia are respectively 0.06kgm ², 0.2kgm ².Equivalent compensation moment can be calculated according to above-mentioned equivalent compensation Calculating Torque during Rotary formula and be respectively 0.0218Nm, 0.0727Nm.Capacity weight 1, scan pattern, the time that East West capacity weight accelerates to 10 °/s needs by 0 °/s is 0.1s, and north-south stepping 210 μ rad needs 0.2s, then East West make-up time length Δ t=0.096s, north-south make-up time length Δ t=0.192s; Equivalent compensation Calculating Torque during Rotary formula can calculate thing, north and south compensating moment is respectively 0.1091Nm, 0.0034Nm according to above-mentioned.

Capacity weight 2, quick directing mode, the time that thing, north-south capacity weight accelerate to 10 °/s needs by 0 °/s is 0.5s, then the make-up time is a Δ t=0.48s(15 control cycle), capacity weight 2 thing, north and south rotor inertia are respectively 0.06kgm ², 0.2kgm ², compensating moment is respectively 0.0218Nm, 0.0727Nm; Capacity weight 2, detection mode, East West stepping 1792 μ rad needs 0.2s, and north-south stepping 9135 μ rad needs 1s, then the East West make-up time is Δ t=0.192s, the north-south make-up time is Δ t=0.960s, and thing, north and south compensating moment are respectively 0.0115Nm, 0.0077Nm.

(2) leading time calculates

For first order inertial loop its delayed phase is arctan (τ ω), and wherein, τ is time constant, and ω is the angular frequency of incoming signal.

Capacity weight transfer function model is compensating moment T _fcrelative compensation mechanism driving voltage u _fctransfer function be for same incoming signal, the delayed phase of capacity weight is arctan (τ _yω), the delayed phase of compensation mechanism is arctan (τ _fcω), the time delay t that capacity weight control cycle and the difference in feedforward compensation cycle produce is considered _cy, then the phase difference of capacity weight motoring torque and feedforward compensation moment is arctan (τ _fcω)-arctan (τ _yω)+ω t _cy, Front feedback control can be asked relative to the leading time t of capacity weight actual motion _lead, $t_{\mathrm{lead}}=\frac{\arctan \left({\mathrm{\&tau;}}_{\mathrm{fc}}\mathrm{\&omega;}\right)-\arctan \left({\mathrm{\&tau;}}_y\mathrm{\&omega;}\right)}{\mathrm{\&omega;}}+t_{\mathrm{cy}}.$ Wherein, τ _y, τ _fc determines according to ground test or in-orbit identification.

Capacity weight control cycle 0.005s, the feedforward compensation cycle is 0.032s, makes t _cy=0.016s; If τ _y=0.002, τ _fc=0.1, consider that the typical motion cycle of capacity weight is at 1.0s to 2.3s, then delay time is 0.10s to 0.11s.Therefore, feedforward compensation needs to carry out lead compensation, and the desirable lead compensation time is 0.10s, also can consider that the feedforward compensation cycle is 0.032s, and getting the lead compensation time is 0.096s.

(3) according to the motion parameter data under the described mode of motion of ground injection, the theoretical initial time of capacity weight acceleration and moderating process is calculated; Described motion parameter data comprises initial time, motion angle at the beginning and moving target angle; Then difference Δ T=0 correction time is made;

(4) time calibrating

During agreement capacity weight periodic motion, move to turning position and produce timing signal.

Capacity weight, according to the regular movement of ground design, when moving to turning position, producing demarcation signal and stamping markers, being designated as (Flg, T ₀), this Signal transmissions is to computer for controlling.

Computer for controlling judges whether to receive (Flg, T ₀), if received, then judge | Δ T+T _com-T ₀| whether <SynTimeLimit sets up, and SynTimeLimit is time difference threshold value, gets 0.05s, T _comfor capacity weight moves to the theoretical moment of this ad-hoc location; If | Δ T+T _com-T ₀| <SynTimeLimit, makes Δ T=T ₀-T _com, proceed to step (5); Otherwise, make Δ T remain unchanged, then proceed to step (5);

If do not received, make correction time difference Δ T remain unchanged, proceed to step (5).

(5) to will speed up or the theoretical initial time of moderating process deducts leading time t _leadafter, add difference Δ T described correction time, obtain the initial time of acceleration or deceleration compensatory control; From the initial time of acceleration or deceleration compensatory control, export compensating control signal to compensation mechanism, maintain after exporting the Δ t time and cancel the described compensating control signal of output; The equivalent compensation moment of described compensating control signal corresponding to acceleration or deceleration process determine; .

For capacity weight 1.Use capacity weight 1 kinematic parameter, in table 1.Computer for controlling calculates the capacity weight theory movement moment: 1100.000s East West is accelerated from 0 °/s; 1100.100s East West accelerates to 10 °/s, stops accelerating, and starts with 10 °/s uniform movement; 1100.970s reduce speed now; 1101.070s be decelerated to 0 °/s; 1101.070s starts oppositely to accelerate from 0 °/s; 1101.170s accelerates to-10 °/s, stops oppositely accelerating, and starts with-10 °/s computing motion; 1102.040s reduce speed now; 1102.140s be decelerated to 0 °/s; 1102.140s start to accelerate; 1102.240s accelerates to 10 °/s, stops accelerating, and starts with 10 °/s uniform movement, the like.Wherein, at 1100.970s to 1101.170s, north-south completes a stepping; 1102.040s to 1102.240s north-south completes a stepping, the like.

During feedforward compensation, for the interference of capacity weight 1, computer for controlling is at the advanced 0.096s of 1099.904s() start to compensate, compensate satellite Z axis moment-0.1091Nm, three all after dates, putting compensating moment is zero, 1100.874s beginning Contrary compensation, due to less than control cycle, so in fact 1100.896s starts to compensate, compensate satellite Z axis moment 0.1091Nm, compensate three all after dates, putting compensating moment is zero, 1100.974s starts to compensate next time, due to less than control cycle, 1100.992s starts to continue to compensate satellite Z axis three control cycles, as shown in Figure 5.While satellite Z axis compensates, carry out satellite X-axis compensation (motion of corresponding capacity weight north-south).

Capacity weight sends commutation signal at 1101.069s, the theoretical moment 1101.070s phase ratio 0.001s then calculated with computer for controlling, 0.001s is less than 0.05s, 0.001 is used to revise following instant 1101.170s, 1102.040s, 1102.140s, 1102.240s, be modified to 1101.169s, 1102.039s, 1102.139s, 1102.239s, the like.

After feedforward moment theoretical com-pensation moment, actual compensation moment and time calibrating, moment corresponding relation is as shown in table 2.

Table 1 capacity weight 1 injecting data

Table 2 feedover the moment theoretical com-pensation moment, actual compensate moment corresponding relation after moment and time calibrating

	The theoretical moment	The actual compensation moment	Moment after time calibrating	Remarks
					Accelerate	1100.000	1099.904	/	/
At the uniform velocity	1100.100	/	/	/
					Slow down	1100.970	1100.896	/	/

Reverse acceleration	1101.070	1100.992	1101.069	Demarcate
					At the uniform velocity	1101.170	/	1101.169
Reverse deceleration	1102.040	1101.952	1102.039
					Accelerate	1102.140s	1102.048	1102.139	Do not consider this time to demarcate
At the uniform velocity	1102.240	/	1102.239
					…	…	…	…	…
Quick sensing	1605.440	…	1605.439	…
					…	…	…	…	…

(7) judge whether the motion process corresponding to described mode of motion terminates, if do not terminated, return step (4), otherwise, terminate.

Compensation effect of the present invention is see Fig. 6 to Figure 11.Known by emulation: the present invention can improve satellite control accuracy and degree of stability; Particularly during the resonance of capacity weight motion-activated windsurfing, successful.

The unspecified part of the present invention belongs to general knowledge as well known to those skilled in the art.

Claims (1)

1. the feedforward torque compensation method with motion capacity weight satellite, it is characterized in that, step is as follows:

(1) according to the mode of motion of capacity weight, and consider that satellite control cycle affects, calculate the equivalent compensation moment accelerated under this mode of motion and corresponding to moderating process

(2) according to capacity weight and compensation mechanism dynamic characteristics, and because of capacity weight control cycle produced time delay different from the feedforward compensation cycle, the leading time t that Front feedback control moves relative to capacity weight is calculated _lead;

Leading time t _leadcomputing formula be $t_{\mathrm{lead}}=\frac{\arctan \left({\mathrm{\&tau;}}_{\mathrm{fc}}\mathrm{\&omega;}\right)-\arctan \left({\mathrm{\&tau;}}_y\mathrm{\&omega;}\right)}{\mathrm{\&omega;}}+t_{\mathrm{cy}},$ Wherein, τ _yfor the electromechanical time constant of capacity weight, τ _fcfor the electromechanical time constant of compensation mechanism, ω is capacity weight motion angular frequency, t _cyfor because of capacity weight control cycle produced time delay different from the feedforward compensation cycle;

(3) according to the motion parameter data under the described mode of motion of ground injection, the theoretical initial time of capacity weight acceleration and moderating process is calculated; Described motion parameter data comprises initial time, motion angle at the beginning and moving target angle; Then difference Δ T=0 correction time is made;

(4) when judging whether to receive band, target demarcation signal, is designated as (Flg, T ₀), target demarcation signal when producing described band when capacity weight moves to ad-hoc location;

If receive demarcation signal, then judge | Δ T+T _com-T ₀| whether <SynTimeLimit sets up, and SynTimeLimit is time difference threshold value, T _comfor capacity weight moves to the theoretical moment of this ad-hoc location; If | Δ T+T _com-T ₀| <SynTimeLimit, makes Δ T=T ₀-T _com, proceed to step (5); Otherwise, make Δ T remain unchanged, then proceed to step (5);

If do not received, make correction time difference Δ T remain unchanged, proceed to step (5);

(5) to will speed up or the theoretical initial time of moderating process deducts leading time t _leadafter, add difference Δ T described correction time, obtain the initial time of acceleration or deceleration compensatory control;

(6) from the initial time of acceleration or deceleration compensatory control, export compensating control signal to compensation mechanism, maintain after exporting make-up time length Δ t and cancel the described compensating control signal of output; The equivalent compensation moment of described compensating control signal corresponding to acceleration or deceleration process determine;

(7) judge whether the motion process corresponding to described mode of motion terminates, if do not terminated, return step (4), otherwise, terminate;

Described equivalent compensation moment computing formula be:

Wherein, for the capacity weight rotor inertia that ground test obtains, ε _yrfor the angular acceleration of acceleration or deceleration process under described mode of motion, t1 is capacity weight acceleration or deceleration process initial time under described mode of motion, t2 is capacity weight acceleration or deceleration process finish time under described mode of motion, Δ t is make-up time length, Δ t ≈ t2-t1 and be the integral multiple of satellite control cycle.