Disturbance rejection system based on frequency adaptive observation

Abstract

A disturbance suppression system based on frequency adaptive observation includes an inertial reference unit base and a platform. The platform has a laser and a sensing device. The laser emits laser light when a first motion occurs to measure a first rotation angle, and the sensing device measures a first angular velocity. A control unit obtains a first target angular velocity based on the first rotation angle and a target rotation angle. The disturbance observation unit includes a first observer that obtains a first observation frequency based on the first angular velocity and a first driving voltage; a second observer that generates a first observation angular velocity based on the first angular velocity and the first driving voltage; a control unit that generates a first angular velocity difference based on the first observation angular velocity and the first target angular velocity; a second observer that generates a first compensation angular velocity based on the first angular velocity and the first observation frequency; and a control unit that generates a second driving voltage based on the first compensation angular velocity and the first angular velocity difference. A driver drives the platform to undergo a second motion at the first target angular velocity based on the second driving voltage, and the platform rotates to the target rotation angle.

Description

Technical Field

[0001] This invention relates to the field of space laser communication and servo control, and particularly to a disturbance suppression system based on frequency adaptive observation. Background Technology

[0002] An inertial reference unit (IRU) can provide a stable reference laser relative to inertial space for a line-of-sight stabilization system. However, resonance caused by the mechanical structure of the IRU, as well as noise from external equipment, internal temperature, and inertial sensors during system operation, can all affect the accuracy of the stable reference laser output by the IRU. Currently, further optimization of the IRU's control system performance is needed. Summary of the Invention

[0003] In view of this, the main objective of the present invention is to provide a disturbance suppression system based on frequency adaptive observation, in order to at least partially solve at least one of the aforementioned technical problems, reduce rotational errors caused by external disturbance signals and internal interference signals, thereby improving the accuracy of laser output.

[0004] One embodiment of the present invention provides a disturbance suppression system based on frequency adaptive observation, comprising: an inertial reference unit including a base and a platform, the platform being connected to the base via a motor, a laser and a sensing device mounted on the platform, the laser being configured to emit laser light when the motor drives the platform to undergo a first motion, to measure a first rotation angle of the platform during the first motion based on the laser light, and the sensing device being configured to measure a first angular velocity of the platform during the first motion; a control unit configured to, in response to a second motion command, obtain a first target angular velocity required for the platform to rotate to the target rotation angle based on the first rotation angle and a target rotation angle of the second motion command; and a disturbance observation unit including: a first observer configured to obtain a second angular velocity based on the first angular velocity and a first driving voltage output by the control unit when the platform undergoes the first motion. The system comprises: a first observation frequency, which characterizes the frequency of the total disturbance signal, including external disturbance signals and internal interference signals caused by the sensing device; a second observer configured to generate a first observation angular velocity of the first motion based on the first angular velocity and the first driving voltage; a control unit generating a first angular velocity difference based on the first observation angular velocity and the first target angular velocity; the second observer generating a first compensation angular velocity for compensating the total disturbance signal based on the first angular velocity and the first observation frequency; and a control unit generating a second driving voltage for driving the platform to rotate to the first target angular velocity based on the first compensation angular velocity and the first angular velocity difference; and a driver configured to drive the motor to move the platform to a second motion at the first target angular velocity based on the second driving voltage, thereby rotating the platform to the target rotation angle.

[0005] Optionally, the disturbance suppression system further includes: an auxiliary filter connected between the disturbance observation unit and the inertial reference unit, the auxiliary filter being configured to obtain a second target angular velocity and a first disturbance angular velocity based on the first angular velocity and the first driving voltage; the second target angular velocity being characterized by the angular velocity of the driven platform rotation obtained by the control unit in response to the first motion command before the first motion occurs, and the first disturbance angular velocity being characterized by the angular velocity of the platform rotation caused by the total disturbance signal during the first motion; wherein the first observer obtains the first observation frequency based on the first disturbance angular velocity, the second observer generates the first compensation angular velocity based on the first observation frequency and the second target angular velocity, and the second observer generates the first observation angular velocity based on the second target angular velocity, the first disturbance angular velocity, and the first driving voltage.

[0006] Optionally, the control unit includes: a position loop controller configured to, after obtaining an angle difference based on the first angle and a target angle, obtain an angle drive voltage based on the angle difference to drive the platform to rotate by the angle difference; a differential tracker configured to obtain the first target angular velocity based on the angle drive voltage; and a speed loop controller configured to, after generating an adjustment angular velocity based on the first compensated angular velocity and the difference between the first angular velocity and the first angular velocity to adjust the first angular velocity to the first target angular velocity, generate the second drive voltage based on the adjustment angular velocity, so that the driver drives the platform to rotate to the target angle based on the second drive voltage.

[0007] Optionally, the auxiliary filter generates a first compensation voltage based on the first driving voltage, and the driver drives the inertial reference unit to perform the second motion based on the second driving voltage and the first compensation voltage, so that the platform rotates to the target angle.

[0008] Optionally, the first observer includes a tracking differentiator configured to obtain the first observation frequency based on the first disturbance angular velocity.

[0009] Optionally, the first observer further includes: a reset clock, configured to obtain a comparison signal based on the initial observation frequency output by the tracking differentiator when the platform undergoes a first motion; and an integrator, configured to obtain a comparison frequency based on the comparison signal, and update the frequency value of the initial observation frequency to the frequency value of the first observation frequency if the difference between the first observation frequency and the comparison frequency exceeds a preset value.

[0010] Optionally, the second observer is configured to obtain the updated first compensated angular velocity based on the second target angular velocity, the first driving voltage, and the initial rotation angle, initial observed angular velocity, and initial compensated angular velocity stored in the second observer.

[0011] Optionally, the second observer is configured to obtain the updated first disturbance angular velocity based on the second target angular velocity and the initial observation angular velocity using the resonant observation transfer function and the sinusoidal disturbance transfer function.

[0012] Optionally, the auxiliary filter is configured to obtain an angular velocity disturbance value based on the first angular velocity and the first driving voltage using a nominal model transfer function, and to obtain a first compensation voltage based on the angular velocity disturbance value using a low-pass filter.

[0013] Optionally, the auxiliary filter is configured to obtain a first interference angular velocity using the low-pass filter based on the angular velocity disturbance value, and to obtain a second target angular velocity using a high-pass filter based on the angular velocity disturbance value.

[0014] According to an embodiment of the present invention, based on the first angular velocity of the platform during its first motion and the first driving voltage output by the control unit when driving the platform during its first motion, a first observation frequency characterizing the total disturbance signal can be obtained using a first observer. Based on the first observation frequency, a first compensation angular velocity for compensating the total disturbance signal can be obtained using a second observer. A first angular velocity difference is generated using the second observer based on the first observed angular velocity of the platform during its first motion and the first target angular velocity. A second driving voltage for driving the platform to rotate to the first target angular velocity is generated using the first observer based on the first compensation angular velocity and the first angular velocity difference. Since the total disturbance signal includes external disturbance signals and internal interference signals caused by the sensing device, driving the platform to rotate using the obtained second driving voltage can reduce the rotation error caused by external disturbance signals and internal interference signals, thereby improving the accuracy of the laser output. Attached Figure Description

[0015] Figure 1 A block diagram of a disturbance suppression system provided according to an embodiment of the present invention is shown;

[0016] Figure 2 A block diagram of a disturbance suppression system according to another embodiment of the present invention is shown;

[0017] Figure 3 A block diagram of a disturbance suppression system according to another embodiment of the present invention is shown;

[0018] Figure 4 A block diagram of a first observer provided according to an embodiment of the present invention is shown;

[0019] Figure 5 A block diagram of a second observer provided according to an embodiment of the present invention is shown, in which a first observer is also shown;

[0020] Figure 6 A block diagram of an auxiliary filter provided according to an embodiment of the present invention is shown, in which an inertial reference unit is shown;

[0021] Figure 7 An experimental comparison diagram of the disturbance suppression system provided according to an embodiment of the present invention is shown.

[0022] 1. Inertial reference unit;

[0023] 11. Base

[0024] 12. Platform;

[0025] 13. Electric motor;

[0026] 14. Laser;

[0027] 15. Sensing devices;

[0028] 151. MHD angular velocity sensor;

[0029] 152. MEMS gyroscope;

[0030] 16. Flexible hinge;

[0031] 2. Control unit;

[0032] 21. Position loop controller;

[0033] 22. Differential tracker;

[0034] 23. Speed ​​loop controller;

[0035] 3. Disturbance observation unit;

[0036] 31. First Observer;

[0037] 311. Tracking Differentiator;

[0038] 312. Reset the clock;

[0039] 313. Integral Observer;

[0040] 32. Second observer;

[0041] 4. Driver;

[0042] 5. Auxiliary filter. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0044] When designing a disturbance suppression system, disturbance suppression can be achieved through disturbance observation, thereby improving the bandwidth and robustness of the system and ultimately enhancing its disturbance suppression performance. The applicant has discovered that external disturbances generated by the periodic motion of carrier components can be characterized as sinusoidal disturbances. Noise from the sensors on inertial reference unit 1 limits the bandwidth and order of observations. Therefore, the design of the disturbance suppression system can be based on suppressing sinusoidal disturbances and sensor noise.

[0045] Figure 1 A block diagram of a disturbance suppression system provided according to an embodiment of the present invention is shown.

[0046] like Figure 1As shown, this invention provides a disturbance suppression system based on frequency adaptive observation. The disturbance suppression system includes an inertial reference unit 1, a control unit 2, a disturbance observation unit 3, and a driver 4. The inertial reference unit 1 includes a base 11 and a platform 12. The driver 4 can be a linear driver. The platform 12 is connected to the base 11 via a motor 13, which can be a voice coil motor. The base 11 can be mounted on a carrier. The platform 12 and the base 11 can be connected by a flexible hinge 16. The motor 13, together with the flexible hinge 16, provides two degrees of freedom for the platform 12 around the base 11. A laser 14 and a sensing device 15 are mounted on the platform 12. The laser 14 is configured to emit laser light when the motor 13 drives the platform 12 to undergo a first motion, so as to measure the first rotation angle θ of the platform 12 during the first motion based on the laser light. CCD The sensing device 15 is configured to measure the first angular velocity ω of the platform 12 during its first motion. m Control unit 2 is configured to respond to a second motion command, based on a first rotation angle θ. CCD The target rotation angle θ of the second motion command r The platform 12 is rotated to the target rotation angle θ. r The first target angular velocity required.

[0047] According to an embodiment of the present invention, before the first motion occurs, the drive motor 13 can be used to control the platform 12 to be stationary relative to inertial space, with a rotation angle of zero degrees relative to inertial space, for reference in subsequent measurements. Specifically, external disturbance signals are transmitted to the platform via the base 11 and the flexible hinge 16. The low stiffness of the flexible hinge 16 can eliminate most of the high-frequency disturbances. The remaining low-frequency disturbances are measured by the sensing device 15 on the platform 12 and transmitted to the host computer. The host computer can generate a corresponding drive voltage based on the angular velocity and angular position signals fed back by the sensing device 15. After the mechanical resonance is eliminated by the notch filter, the driver 4 causes the motor 13 to generate a driving torque opposite to the external disturbance signal, thereby keeping the platform 12 stationary relative to inertial space with a rotation angle of zero degrees relative to inertial space.

[0048] The sensing device 15 may include an MHD angular velocity sensor 151 and a MEMS gyroscope 152, which can be used to measure the high-frequency angular velocity of the platform 12 relative to inertial space and the low-frequency angular velocity of the platform 12 relative to inertial space, respectively. The first angular velocity can be obtained by fusing the low-frequency and high-frequency angular velocities. The first rotation angle can be obtained using a CCD camera. Specifically, after the laser is emitted onto the CCD camera, the first rotation angle can be obtained by the amount of light spot deviation.

[0049] The first angular velocity can be the angular velocity of the platform relative to inertial space after the platform 12 undergoes its first motion. The first rotation angle can be the rotation angle of the platform relative to inertial space after the platform 12 undergoes its first motion. The target rotation angle can be the expected rotation angle after the second motion occurs. The disturbance observation unit 3 and the control unit 2 can form a control loop to coordinate the control of the platform rotation. Using the first angular velocity, the control unit 2 and the second observer 32 can form a stable control structure with a closed-loop angular velocity loop. Using the first rotation angle, the control unit 2 can form a tracking control structure with a closed-loop angular position loop.

[0050] According to an embodiment of the present invention, the internal disturbance signal and the external disturbance signal present in the inertial reference unit 1 can be used as the total disturbance signal to establish the state-space equation of the inertial reference unit 1. The state-space equation of the inertial reference unit 1 can be expressed as follows:

[0051]

[0052] in,

[0053] in, It can be expressed as a differential equation of the state vector x. x1=∫ωdt, where x1 can represent the angular displacement of inertial reference unit 1, ω can represent the angular velocity of inertial reference unit 1, and t can represent the rotation time of inertial reference unit 1. x2=ω, where x2 can represent the angular velocity of inertial reference unit 1. x3=f, where x3 can represent the system disturbance signal, i.e., the total disturbance frequency of inertial reference unit 1. The total disturbance frequency can include the disturbance frequencies generated by external disturbance signals and internal interference signals caused by sensing device 15. a0, a1, and b0 can be represented as parameters of inertial reference unit 1, and a0, a1, and b0 can be known constants. h can be the differential of the total disturbance signal. u can be the voltage that drives the inertial reference unit 1 to move using the driver 4.

[0054] Furthermore, such as Figure 1 As shown, the disturbance observation unit 3 includes a first observer 31 and a second observer 32. The first observer 31 is configured to observe the first angular velocity ω. m The first observation frequency f is obtained by the first driving voltage u output by the control unit 2 when the platform 12 undergoes the first movement. i First observation frequency f i This can be characterized as the frequency of the total disturbance signal. The total disturbance signal includes external disturbance signals and internal interference signals caused by the sensing device 15. The first observer 31 can be a frequency observer. The second observer 32 can be a generalized extended state observer. The first driving voltage u can be the voltage output by the control unit 2 to control the rotation of the motor 13 when the platform 12 undergoes its first movement.

[0055] Furthermore, the second observer 32 is configured to measure the first angular velocity ω. m The first observed angular velocity z2 is generated by the first driving voltage u and the first target angular velocity. The control unit 2 generates a first angular velocity difference based on the first observed angular velocity z2 and the first target angular velocity. The second observer 32 generates a first angular velocity difference based on the first angular velocity ω. m and the first observation frequency f i A first compensation angular velocity z3 is generated to compensate for the total disturbance signal. The control unit 2 generates a second driving voltage u based on the first compensation angular velocity z3 and the first angular velocity difference to drive the platform 12 to rotate to the first target angular velocity. b The first observed angular velocity can be characterized as the observed angular velocity of platform 12 when the first motion occurs.

[0056] Furthermore, driver 4 is configured to operate according to the second drive voltage u b The drive motor 13 drives the platform 12 to undergo a second motion at the first target angular velocity, causing the platform 12 to rotate to the target angle.

[0057] According to an embodiment of the present invention, based on the first angular velocity of the platform 12 when it undergoes the first motion and the first driving voltage output by the control unit 2 when it drives the platform 12 to undergo the first motion, a first observation frequency characterizing the total disturbance signal can be obtained using the first observer 31. Based on the first observation frequency, a first compensation angular velocity for compensating the total disturbance signal can be obtained using the second observer 32. The second observer 32 generates a first angular velocity difference based on the first observed angular velocity of the platform 12 when it undergoes the first motion and the first target angular velocity. The first observer 31 generates a second driving voltage for driving the platform 12 to rotate to the first target angular velocity based on the first compensation angular velocity and the first angular velocity difference. Since the total disturbance signal includes external disturbance signals and internal interference signals caused by the sensing device 15, driving the platform 12 to rotate using the obtained second driving voltage can reduce the rotation error caused by external disturbance signals and internal interference signals, thereby improving the accuracy of the laser output by the laser 14.

[0058] Figure 2 A block diagram of a disturbance suppression system according to another embodiment of the present invention is shown.

[0059] like Figure 2 As shown, according to an embodiment of the present invention, the disturbance suppression system further includes an auxiliary filter 5. The auxiliary filter 5 is connected between the disturbance observation unit 3 and the inertial reference unit 1. The auxiliary filter 5 is configured to adjust according to the first angular velocity ω. m The second target angular velocity ω' and the first disturbance angular velocity ω' are obtained from the first driving voltage u. dThe second target angular velocity ω' represents the angular velocity of the driven platform 12 before the first motion, obtained by the control unit 2 in response to the first motion command. In other words, the second target angular velocity ω' can be represented as the angular velocity of the platform 12 during the first motion without external disturbance signals or internal interference signals. That is, the second target angular velocity can be expressed as the angular velocity x2 in the state-space equation of the inertial reference unit 1. The first disturbance angular velocity is represented as the angular velocity of the platform 12 caused by the total disturbance signal during the first motion. The first disturbance angular velocity ω' d It can be expressed as the angular velocity corresponding to the system disturbance x3 in the state-space equation of inertial reference unit 1.

[0060] According to an embodiment of the present invention, the first observer 31 is based on the first disturbance angular velocity ω' d The first observation frequency f is obtained i The second observer 32 is based on the first observation frequency f. i The second target angular velocity ω' generates a first compensation angular velocity z3. The second observer 32 generates a first compensation angular velocity z3 based on the second target angular velocity ω' and the first disturbance angular velocity ω'. d The first observed angular velocity z2 is generated by the first driving voltage u.

[0061] Figure 3 A block diagram of a disturbance suppression system according to another embodiment of the present invention is shown.

[0062] like Figure 3 As shown, according to an embodiment of the present invention, the control unit 2 includes a position loop controller 21, a differential tracker 22, and a speed loop controller 23. The position loop controller 21 is configured to, according to a first rotation angle θ CCD and target turning angle θ r After obtaining the angle difference e1, the angle driving voltage u1 used to drive the platform 12 to rotate is obtained based on the angle difference e1. The angle difference can be represented as the difference between the first angle and the target angle. The angle driving voltage can be used to drive the motor 13 to rotate under the condition of no external disturbance signals and internal interference signals, so that the platform 12 can rotate by the angle difference, that is, it can rotate to the target angle. The position loop controller 21 can be a proportional-integral (PI) controller, which can have a faster angular velocity response and will not enhance high-frequency noise.

[0063] like Figure 3 As shown, when inertial reference unit 1 is working, an external input will be used to rotate to the target rotation angle θ. r The second motion command is to turn the first angle θ CCD After being transmitted to control unit 2, control unit 2 controls the first rotation angle θ. CCD and target turning angle θ rAfter subtraction, the rotation angle difference e1 used to control the rotation angle position can be obtained. After the rotation angle difference e1 is amplified by the position loop controller 21, the rotation angle drive voltage u1 used to drive the platform 12 to rotate is obtained, thereby enabling the laser emitted by the inertial reference unit 1 to rotate to the target rotation angle θ. r .

[0064] Furthermore, due to the presence of external disturbance signal θ b At that time, using only the position loop controller 21 is not enough to suppress external disturbance signals θ b The effect on the rotation angle driving voltage u1 is that the laser emitted by the inertial reference unit 1 cannot be accurately rotated to the target rotation angle θ. r The rotation angle θ of the laser emitted by inertial reference unit 1 to the target can be improved by adding a closed-loop angular velocity control loop. r The accuracy.

[0065] According to an embodiment of the present invention, the differential tracker 22 obtains a first target angular velocity based on the rotational drive voltage. The speed loop controller 23 is configured to generate an adjustment angular velocity based on the adjustment angular velocity to adjust the first angular velocity to the first target angular velocity, after generating an adjustment angular velocity based on the first compensated angular velocity and the first angular velocity difference, and then generate a second drive voltage based on the adjustment angular velocity, so that the driver 4 drives the platform 12 to rotate to the target rotational angle based on the second drive voltage. The angular velocity difference caused by external disturbance signals and internal interference signals can be compensated by adjusting the angular velocity.

[0066] like Figure 3 As shown in the embodiment of the present invention, when the IRU system is working, the rotation drive voltage u1 is differentiated by the differential tracker 22 to obtain the first target angular velocity v1. The first target angular velocity v1 is then subtracted from the first observed angular velocity z2, which is the first observed angular velocity x2 of the inertial reference unit 1 obtained by the second observer 32, to obtain the first angular velocity difference e2 for the control platform to reach the first observed angular velocity z2.

[0067] Furthermore, due to the external disturbance signal θ b The internal disturbance signal causes a certain error in the first angular velocity difference e2. The second angular velocity difference e′2 can be obtained by subtracting the first compensated angular velocity z3 (characterized by the system disturbance signal x3 obtained from the second observer 32) from the proportional gain of the first angular velocity difference e′2, thus obtaining the second driving voltage u used to control the rotation of motor 13 by the second angular velocity difference e′2. b Second driving voltage u bAfter subtracting the first compensation voltage u' output from the auxiliary filter 5, it is input to the driver 4 in the form of voltage. The driver 4 controls the voice coil motor of the inertial reference unit 1 to generate a response speed and displacement, driving the platform 12 to rotate to the target angle, thereby achieving the suppression of external disturbances and the tracking of the input signal.

[0068] According to an embodiment of the present invention, after model identification of the inertial reference unit 1, a velocity loop controller 23 can be designed based on the identification results, thereby ensuring disturbance suppression capability while reducing the impact of angular velocity loop gyroscope drift on the control loop. The velocity loop controller 23 can be represented as follows:

[0069]

[0070] Among them, C v (s) can be characterized as a speed loop controller 23, K vn p1 and p2 can be characterized as the gain of the adjustable velocity loop controller 23, p1 and p2 can be characterized as the poles of the angular velocity loop identification model of the inertial reference unit 1, and s can be represented as the complex variable of the velocity loop controller transfer function.

[0071] Figure 4 A block diagram of a first observer provided according to an embodiment of the present invention is shown.

[0072] like Figure 4 As shown, according to an embodiment of the present invention, the first observer 31 includes a tracking differentiator 311. The tracking differentiator 311 is configured to obtain a first observation frequency based on a first disturbance angular velocity. According to an embodiment of the present invention, the tracking differentiator 311 measures the first disturbance angular velocity ω' d After differentiation, the differential value can be obtained. Based on the first disturbance angular velocity ω' d and differential value The first observation frequency f can be obtained. i .

[0073] like Figure 4 As shown, according to an embodiment of the present invention, the first observer 31 further includes a reset clock 312 and an integrator 313. The reset clock 312 is configured to obtain a comparison signal based on the initial observation frequency output by the tracking differentiator 311 when the platform 12 undergoes a first motion. The integrator 313 is configured to obtain a comparison frequency based on the comparison signal, and update the frequency value of the initial observation frequency to the frequency value of the first observation frequency if the difference between the first observation frequency and the comparison frequency exceeds a preset value.

[0074] According to an embodiment of the present invention, the reset clock 312 can obtain a comparison signal based on the initial observation frequency output by the tracking differentiator 311 when the platform 12 undergoes its first motion. The comparison signal can then be processed by the integrator 313 to obtain the comparison frequency f. id By comparing the frequency f output by the integrator 313 id The first observation frequency f output by the first observer 31 i The system compares the first observation frequency with the comparison frequency to determine if the difference exceeds a preset value. If the difference exceeds the preset value, a reset command is sent to the integrator 313 to update the initial observation frequency to the first observation frequency. If the difference does not exceed the preset value, the first observation frequency f is reset. i After the change filter is applied, the output is sent to the second observer 32.

[0075] According to an embodiment of the present invention, the frequency of the total disturbance signal of the inertial reference unit 1 can be estimated in real time by setting a first observer 31. The first observation frequency output by the first observer 31 can be expressed as follows:

[0076]

[0077] In the formula, f i Let ω′ be the first observation frequency. d This can be expressed as the first disturbance angular velocity. This can be expressed as the differential of the first disturbance angular velocity. In |f id -f i If |≤ε, the frequency is considered unchanged; when |f id -f i |>ε, indicating a change in frequency. ε can be represented as a preset value.

[0078] According to an embodiment of the present invention, the second observer 32 is configured to obtain an updated first compensated angular velocity based on the second target angular velocity, the first driving voltage, and the initial rotation angle, initial observed angular velocity, and initial compensated angular velocity stored in the second observer 32.

[0079] According to an embodiment of the present invention, the second observer 32 is configured to obtain the updated first disturbance angular velocity based on the second target angular velocity and the initial observation angular velocity using the resonant observation transfer function and the sinusoidal disturbance transfer function.

[0080] According to an embodiment of the present invention, after obtaining the first observation frequency using the first observer 31, a second observer 32 with frequency adaptation can be designed to enhance the disturbance suppression capability of the total disturbance signal, thereby improving the stability accuracy of the inertial reference unit 1. The frequency-adaptive second observer 32 can be represented as follows:

[0081]

[0082] Where H(s)=H rf (s)+H υf (s);

[0083] in, The values ​​of x1, x2, and x3 in formula (2) can be used as the observations. β1, β2, and β3 are the gains of the second observer 32, and their values ​​can be determined with the stability of the disturbance suppression system as a constraint. rf (s) represents the resonant observation transfer function of inertial reference cell 1, which can be used for the resonance of inertial reference cell 1, H vf (s) represents the sinusoidal perturbation transfer function of inertial reference cell 1, and can be used to represent the sinusoidal perturbation of inertial reference cell 1. rf and k vf They can be represented as H respectively rf (s) and H vf The gain of (s). ω rf This can be expressed as the resonant frequency of inertial reference unit 1, ω. vf This can be expressed as the first observation frequency, ξ, of the output of the first observer 31. vf It can be represented as a damping term and can be used to increase the bandwidth of the control loop.

[0084] Figure 5 A block diagram of a second observer provided according to an embodiment of the present invention is shown, in which a first observer is also shown.

[0085] like Figure 5 As shown in the embodiment of the present invention, after integrating the second target angular velocity ω', the observed value z1 of the angular displacement corresponding to the second target angular velocity ω' can be obtained, and the angular displacement observed value z'1 collected at the previous sampling time is updated to the angular displacement observed value z1.

[0086] According to an embodiment of the present invention, the value of the first driving voltage u multiplied by the gain b0 is related to the first angular velocity ω. m The value after multiplying by gain β2, the value after multiplying the observed angular displacement z'1 at the previous sampling time by gain -a0, the value after multiplying the observed angular velocity z'2 at the previous sampling time by gain -2ω0, and the observed total disturbance z'3 at the previous sampling time are added together and then integrated to obtain the updated observed angular velocity z2, which is the first observed angular velocity.

[0087] According to an embodiment of the present invention, the change in angular velocity is obtained by subtracting the observed value z'2 of the angular velocity at the previous sampling time from the second target angular velocity ω'. This change in angular velocity is then processed by a gain β3 to generate an intermediate value. The intermediate value is then integrated into a first output value, and the intermediate value is further processed by the resonant observation transfer function H of the inertial reference unit 1. rf The second output value and intermediate value after (s) are the same as the first observation frequency f. i The sinusoidal perturbation transfer function H after passing through inertial reference cell 1 vf After adding the third output value after (s), we can obtain the updated observation value of the total disturbance z3, which is the first compensated angular velocity.

[0088] According to an embodiment of the present invention, the auxiliary filter 5 generates a first compensation voltage based on the first driving voltage, and the driver 4 drives the inertial reference unit 1 to perform a second motion based on the second driving voltage and the first compensation voltage, so that the platform 12 rotates to the target rotation angle.

[0089] According to an embodiment of the present invention, the auxiliary filter 5 is configured to obtain an angular velocity disturbance value based on a first angular velocity and a first driving voltage using a nominal model transfer function, and to obtain a first compensation voltage based on the angular velocity disturbance value using a low-pass filter.

[0090] According to an embodiment of the present invention, the auxiliary filter 5 is configured to obtain a first interference angular velocity based on the angular velocity disturbance value using a low-pass filter, and to obtain a second target angular velocity based on the angular velocity disturbance value using a high-pass filter.

[0091] like Figure 3 As shown, according to an embodiment of the present invention, when the base 11 is subjected to an external disturbance signal θ b Afterwards, through the passive transmission characteristics of the flexible hinge 16 of the inertial reference unit 1, the external disturbance signal θ b The high-frequency components are attenuated, and the residual angular perturbation transmitted to inertial reference cell 1 is θ. d After differentiation, the external disturbance signal θ b The angular velocity caused by the disturbance transmitted to platform 12 can be expressed as the disturbance angular velocity ω. d Disturbance angular velocity ω d The actual angular velocity ω of platform 12 is obtained by superimposing the angular velocity of platform 12 driven by the voice coil motor. k Actual angular velocity ω k The measured value of the angular velocity of platform 12, i.e., the first angular velocity ω, is obtained by the sensor device 15. m First angular velocity ω m After separation by auxiliary filter 5, the second target angular velocity ω' and the first interference angular velocity ω' can be obtained. d First disturbance angular velocity ω' dAfter passing through the first observer 31, the angular velocity ω' of the first disturbance can be obtained. d The corresponding first observation frequency f i The second observer 32 operates based on the first observation frequency f. i From the second target angular velocity ω', we can obtain the observed values ​​of the second target angular velocity ω' and the system disturbance x3, namely the first observed angular velocity z2 and the first compensated angular velocity z3. The first observed angular velocity z2 and the first compensated angular velocity z3 are used as feedback quantities and subtracted by the control unit 2 to obtain the second angular velocity difference e'2. The second driving voltage u is generated using the second angular velocity difference e'2. b The control platform 12 rotates, thereby enabling closed-loop control of angular velocity.

[0092] According to an embodiment of the present invention, the auxiliary filter 5 may include a low-pass filter. The low-pass filter can be used to separate external disturbance signals received by the inertial reference unit 1 from internal interference signals caused by the sensing device 15. Specifically, the following transfer function can be established:

[0093]

[0094]

[0095] Among them, G n (s) is the nominal model transfer function of the controlled object in the closed loop of the angular velocity loop. The controlled object can be an inertial reference element. G v Hω' is the transfer function of the controlled object in the closed-loop angular velocity loop, where the controlled object can be an inertial reference element. Q(s) is a low-pass filter. d ω d The transfer function of the first angular velocity input to auxiliary filter 5 to separate the external disturbance signal is Hω'. n The first angular velocity is input to the auxiliary filter 5, and the output transfer function is obtained after filtering out high-frequency noise. By setting the auxiliary filter 5, the high-frequency noise in the closed loop of the angular velocity loop can be reduced, and the design bandwidth of the second observer 32 can be increased, thereby improving the observation accuracy of the first observer 31.

[0096] Figure 6 A block diagram of an auxiliary filter provided according to an embodiment of the present invention is shown, in which an inertial reference unit is illustrated.

[0097] like Figure 6 As shown, according to an embodiment of the present invention, the actual angular velocity ω of the platform 12 rotation is... k After measurement by sensor 15, sensor noise n is added to obtain the measured value of the angular velocity of platform 12, i.e., the first angular velocity ω. m The first driving voltage u is transmitted via the nominal model transfer function G.n (s) After processing, via the first angular velocity ω m Subtracting this gives the angular velocity disturbance value. angular velocity disturbance value Then, through the inverse of the nominal model transfer function G... n (s) -1 After passing through the low-pass filter Q(s), the first compensation voltage u′ is obtained, which is fed back to the first driving voltage u. This allows the controlled object in the auxiliary filter 5 to behave as the nominal model within the cutoff frequency of the low-pass filter. Angular velocity disturbance value After passing through a low-pass filter Q(s) and damping ξ Q Afterwards, high-frequency noise can be filtered out, thus obtaining the angular velocity caused by the total disturbance, i.e., the first disturbance angular velocity ω′. d Angular velocity disturbance value After passing through the high-pass filter 1-Q(s), the high-frequency disturbance value can be obtained, which is then analyzed by the first angular velocity ω. m After subtracting, we can obtain the second target angular velocity ω′ after filtering out high-frequency noise.

[0098] Figure 7 An experimental comparison diagram of the disturbance suppression system provided according to an embodiment of the present invention is shown.

[0099] According to an embodiment of the present invention, the following is an experimental verification scheme for the embodiment of the present invention.

[0100] First, a voice coil motor can be installed between the base and platform of the inertial reference unit (IRU), and the RMU is used to control the platform's rotation. The IRU is then mounted on a vibration table to simulate external interference signals. A MEMS gyroscope and an MHD angular velocity sensor are used to collaboratively measure the platform's angular velocity relative to inertial space, i.e., the first angular velocity. A laser interferometer is used to measure the platform's angular displacement, i.e., the first rotation angle. A Dspace-micro labox controller is used to acquire the first rotation angle and the first angular velocity, with the sampling frequency set to 1250Hz.

[0101] Then, sinusoidal disturbance signals of 1Hz, 10Hz, and 50Hz were input using a vibration table. By identifying the disturbance suppression system, it was determined that the system has a mechanical resonance of approximately 35Hz. The existing dual-loop feedback control A and extended state observer B, along with the disturbance suppression system C of this application, were used to estimate and suppress the input disturbance. The root mean square of the residual error after disturbance suppression for the three control methods at different disturbance frequencies is shown in the figure. Figure 7 As shown. The root mean square error of the disturbance suppression system of this application is small; therefore, the disturbance suppression system of this application has a better suppression effect.

[0102] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A frequency-adaptive observation-based disturbance rejection system, characterized by, include: An inertial reference unit includes a base and a platform, the platform being connected to the base via a motor, a laser and a sensing device being mounted on the platform, the laser being configured to emit a laser when the motor drives the platform to undergo a first motion, so as to measure a first rotation angle of the platform during the first motion based on the laser, and the sensing device being configured to measure a first angular velocity of the platform during the first motion. The control unit is configured to, in response to a second motion command, obtain a first target angular velocity required for the platform to rotate to the target angle based on the first angle and the target angle of the second motion command; The disturbance observation unit includes: A first observer is configured to obtain a first observation frequency based on the first angular velocity and the first drive voltage output by the control unit when the platform undergoes a first motion. The first observation frequency characterizes the frequency of the total disturbance signal, which includes external disturbance signals and internal interference signals caused by the sensing device. The second observer is configured to generate a first observed angular velocity of the first motion based on the first angular velocity and the first driving voltage; the control unit generates a first angular velocity difference based on the first observed angular velocity and the first target angular velocity; the second observer generates a first compensated angular velocity for compensating the total disturbance signal based on the first angular velocity and the first observation frequency; and the control unit generates a second driving voltage for driving the platform to rotate to the first target angular velocity based on the first compensated angular velocity and the first angular velocity difference. The driver is configured to drive the motor to move the platform at a first target angular velocity according to the second drive voltage, thereby causing the platform to rotate to the target angle.

2. The perturbation suppression system of claim 1, wherein, Also includes: An auxiliary filter is connected between the disturbance observation unit and the inertial reference unit. The auxiliary filter is configured to obtain a second target angular velocity and a first disturbance angular velocity based on the first angular velocity and the first driving voltage. The second target angular velocity is characterized by the angular velocity of the driven platform rotation obtained by the control unit in response to the first motion command before the first motion occurs. The first disturbance angular velocity is characterized by the angular velocity of the platform rotation caused by the total disturbance signal during the first motion. Wherein, the first observer obtains the first observation frequency based on the first interference angular velocity, the second observer generates the first compensation angular velocity based on the first observation frequency and the second target angular velocity, and the second observer generates the first observation angular velocity based on the second target angular velocity, the first interference angular velocity and the first driving voltage.

3. The disturbance suppression system according to claim 2, characterized in that, The control unit includes: The position loop controller is configured to, after obtaining the angle difference based on the first angle and the target angle, obtain an angle drive voltage based on the angle difference to drive the platform to rotate by the angle difference; The differential tracker obtains the first target angular velocity based on the rotational drive voltage; The speed loop controller is configured to generate an adjustment angular velocity based on the adjustment angular velocity after generating an adjustment angular velocity for adjusting the first angular velocity to the first target angular velocity according to the first compensated angular velocity and the first angular velocity difference, so that the driver drives the platform to rotate to the target rotation angle based on the second drive voltage.

4. The disturbance suppression system according to claim 2, characterized in that, The auxiliary filter generates a first compensation voltage based on the first driving voltage, and the driver drives the inertial reference unit to perform the second motion based on the second driving voltage and the first compensation voltage, so that the platform rotates to the target rotation angle.

5. The disturbance suppression system according to claim 3, characterized in that, The first observer includes: The tracking differentiator is configured to obtain the first observation frequency based on the first disturbance angular velocity.

6. The disturbance suppression system according to claim 5, characterized in that, The first observer also includes: The clock is reset and configured to obtain a comparison signal based on the initial observation frequency output by the tracking differentiator when the platform undergoes its first motion; An integrator is configured to obtain a comparison frequency based on the comparison signal, and update the frequency value of the initial observation frequency to the frequency value of the first observation frequency if the difference between the first observation frequency and the comparison frequency exceeds a preset value.

7. The disturbance suppression system according to claim 3, characterized in that, The second observer is configured to obtain the updated first compensated angular velocity based on the second target angular velocity, the first driving voltage, and the initial rotation angle, initial observed angular velocity, and initial compensated angular velocity stored in the second observer.

8. The disturbance suppression system according to claim 7, characterized in that, The second observer is configured to obtain the updated first disturbance angular velocity based on the second target angular velocity and the initial observation angular velocity, using the resonant observation transfer function and the sinusoidal disturbance transfer function.

9. The disturbance suppression system according to claim 3, characterized in that, The auxiliary filter is configured to obtain an angular velocity disturbance value based on the first angular velocity and the first driving voltage using a nominal model transfer function, and to obtain a first compensation voltage based on the angular velocity disturbance value using a low-pass filter.

10. The disturbance suppression system according to claim 9, characterized in that, The auxiliary filter is configured to obtain a first interference angular velocity using the low-pass filter based on the angular velocity disturbance value, and to obtain a second target angular velocity using the high-pass filter based on the angular velocity disturbance value.

Images