Antenna array servo system cooperative control method based on dynamic performance index

Abstract

The invention discloses an antenna array servo system cooperative control method based on a dynamic performance index, and the method comprises the steps: constructing an antenna array servo control system which comprises a control unit, a controlled antenna array, an execution mechanism, a feedback measurement unit, and a disturbance measurement unit; according to the model of each antenna unit in the antenna array servo control system, establishing a state-space equation of a controlled antenna array from an input signal and a disturbance measurement signal of an execution mechanism to system pointing position output; a cooperative control performance index function of the antenna array servo control system is obtained according to the receiving power pattern of each antenna unit, and a control unit obtains a cooperative control quantity according to a measurement signal and a control strategy based on the performance index function; and transmitting the cooperative control quantity to each execution mechanism of the controlled antenna array to realize cooperative control of the antenna array servo control system. According to the cooperative control method, the antenna pointing precision and the performance of the correlator are remarkably optimized.

Description

Technical Field

[0001] The present invention relates to the field of automatic control, and in particular to a collaborative control method of an antenna array servo system based on dynamic performance indicators. Background Art

[0002] With the rapid development of fields such as communications, remote sensing, and radio astronomy, antennas, as core components for signal reception and transmission, play a vital role in aerospace, national defense, and space science. To improve signal transmission efficiency, antennas require high radio gain and operating frequency. However, as antenna aperture increases, costs also increase, while improvements in sensitivity and resolution are gradually reaching a bottleneck. Consequently, research in radio telescopes has gradually shifted from single, large-aperture antennas to multi-antenna arrays. Combining multiple, smaller antennas not only reduces costs but also significantly improves system sensitivity and resolution.

[0003] Multi-antenna arrays offer advantages in sensitivity and resolution, but because they are often deployed in open areas, they are susceptible to external disturbances such as gusts and temperature changes, which can cause vibration and deformation in the antenna structure, reducing the antenna's pointing accuracy. This is especially true when the antenna array servo control system is tracking a non-cooperative moving target or in the presence of unfavorable conditions such as gusts of wind. The pointing accuracy of a single antenna will be significantly affected by external influences, resulting in a significant loss in accuracy, which in turn affects the pointing accuracy of the entire antenna array. Therefore, developing a collaborative servo control method for antenna arrays, whereby individual antennas optimize their local loop command strategy by fusing multiple information from local and neighboring antennas, can compensate for this loss in antenna array pointing accuracy and improve both the array's pointing accuracy and anti-interference capabilities. This is a pressing technical challenge. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, an object of the present invention is to provide a collaborative control method for an antenna array servo system based on dynamic performance indicators.

[0005] Aiming at the situation where the antenna array is affected by wind disturbance with correlation, the present invention conducts research and analysis based on the signal processing mechanism of the antenna array connected by a correlator, summarizes and extracts the key performance indicators of the antenna array servo control, and carries out research on the collaborative control of the antenna array servo control system. The collaborative control method significantly optimizes the antenna pointing accuracy and correlator performance.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A collaborative control method for an antenna array servo system based on dynamic performance indicators comprises the following steps:

[0008] Constructing an antenna array servo control system, the antenna array servo control system comprising a control unit, a controlled antenna array, an actuator, a feedback measurement unit, and a disturbance measurement unit;

[0009] Based on the model of each antenna unit in the antenna array servo control system, the state space equation of the controlled antenna array from the input signal of the actuator and the disturbance measurement signal to the system pointing position output is established;

[0010] According to the received power pattern of each antenna unit, a collaborative control performance index function of the antenna array servo control system is obtained, and the control unit obtains a collaborative control amount according to the measurement signal and the control strategy based on the performance index function;

[0011] The coordinated control quantity is transmitted to each actuator of the controlled antenna array to realize the coordinated control of the antenna array servo control system.

[0012] Furthermore, the antenna array servo control system includes:

[0013] The controlled antenna array includes multiple antenna units. The multiple antenna units are located in the same area and are subjected to correlated wind gust disturbances. The antenna units are connected using correlators.

[0014] The actuator is a servo motor of the antenna unit;

[0015] The feedback measurement unit is a servo motor encoder on the antenna shaft, which is used to measure the actual pointing position of the antenna;

[0016] The disturbance measurement unit is an inertial navigation sensor installed on the main reflector of the antenna, which is used to measure the vibration velocity of the main reflector of the antenna caused by wind disturbance;

[0017] The control unit is used to set the pointing position control instructions, collect sensor data from each antenna unit, and calculate and send control quantities.

[0018] Furthermore, the state space equation for establishing the controlled antenna array from the input signal of the actuator and the disturbance measurement signal to the system pointing position output is specifically:

[0019] The state space equation of the i-th antenna element in the controlled antenna array is expressed as:

[0020] x i (k+1)=A i x i (k)+B i u i (k)+E i d i (k)

[0021] θ i (k) = Ci x i (k)

[0022] Where x i (k) is the system state quantity of the i-th antenna unit, u i (k) is the actuator control input of the i-th antenna unit, d i (k) is the disturbance input signal measured by the inertial navigation sensor of the i-th antenna unit, θ i (k) is the actual pointing position of the antenna measured by the servo motor encoder of the i-th antenna unit, k represents the k-th sampling moment, A i 、B i 、C i and E i is the parameter matrix of the i-th antenna element;

[0023] The state space equations of each antenna unit together constitute the state space equations of the antenna array servo control system.

[0024] Furthermore, the state space equations of each antenna unit together constitute the state space equation of the antenna array servo control system:

[0025] x(k+1)=Ax(k)+Bu(k)+Ed(k)

[0026] θ(k)=Cx(k)

[0027] Where, is the system state quantity of the antenna array, is the servo control input of the antenna array, is the disturbance received by the antenna array, is the pointing position of the antenna array, A=diag(A i )、B=diag(B i )、C=diag(C i )、E=diag(E i ) is the model parameter matrix of the antenna array, and num is the number of antenna elements in the antenna array.

[0028] Furthermore, the gust disturbances received are correlated, specifically:

[0029] By calculating the measured values of the disturbance signal received by each antenna unit, the correlation is expressed as a covariance matrix:

[0030] Q d =(q ij ) num×num

[0031] Where q ijis the covariance of the disturbance signal measurement values of the i-th and j-th antenna elements, and num is the number of antenna elements in the antenna array.

[0032] Furthermore, according to the received power pattern of each antenna, the coordinated control performance index function of the antenna array servo control system is obtained, which is specifically:

[0033] According to the antenna receiving power pattern and the correlator output calculation formula, the coordinated control performance index function of the antenna array servo system is obtained;

[0034]

[0035] Where, and the antenna unit pointing position θ i The relationship between (k) is Where θ is the direction of the signal source, θ i (k) is the pointing direction of the i-th antenna unit, ε is the second-order derivative of the directional pattern of the i-th antenna unit at the center point, ρ i is an adjustable parameter, u i (k) is the actuator control input of the i-th antenna unit, and k represents the k-th sampling time.

[0036] Further, the control unit includes a forward channel controller and an LQG controller;

[0037] The forward channel controller adopts a PI controller, which outputs the forward channel control amount according to the deviation between the antenna command signal and the servo motor encoder measurement signal;

[0038] The LOG controller includes a Kalman filter and a quadratic optimal state feedback, and outputs a state feedback control quantity according to the actuator control input and the servo motor encoder measurement signal;

[0039] The forward channel control quantity and the state feedback control quantity are superimposed and output to the servo motor as the system control quantity.

[0040] Furthermore, the Kalman filter includes a system model and a noise model. The system model adopts the model of the antenna array servo control system. The noise model includes process noise covariance Q and measurement noise covariance R. The process noise covariance Q is obtained through the covariance matrix of wind disturbance.

[0041] Furthermore, the quadratic optimal state feedback is designed using the performance index function in the antenna array servo system, and the state feedback control quantity is calculated according to the system state observation value output by the Kalman filter.

[0042] Furthermore, each antenna unit is a two-degree-of-freedom parabolic antenna.

[0043] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0044] (1) This paper analyzes the processing mechanism of the measurement signal of the antenna array servo control system in the working state, extracts the key performance indicators of the antenna array servo control, analyzes the impact of wind disturbance on the pointing direction of the antenna array from the perspective of control, and provides theoretical support for performance evaluation and controller design.

[0045] (2) This paper studies the coordinated control of antenna array servo control systems, focusing on servo control performance indicators. Based on a design method combining a forward channel controller and a linear quadratic Gaussian (LQG) controller, the collaborative controller for the antenna array servo control system is designed. Compared with existing methods of independently controlling each antenna unit in antenna array servo control systems, this method provides higher accuracy in compensating for pointing deviations caused by wind disturbances, effectively improving the pointing accuracy of the antenna array.

[0046] (3) The present invention integrates the independent antenna units in the antenna array into an integrated antenna array servo control system. By integrating multiple information from local and neighboring antennas, the local loop command strategy is optimized to achieve better servo control results. This solution is easy to implement and inexpensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the process of the present invention;

[0048] Figure 2 Schematic diagram of the collaborative control structure of the present invention;

[0049] Figure 3 The received power pattern and fitting diagram of the antenna unit of the present invention;

[0050] Figures 4(a) and 4(b) are schematic diagrams of two antenna units of an antenna array servo control system being subjected to correlated wind disturbances;

[0051] Figure 5(a) and Figure 5(b) are comparison diagrams of the simulated tracking errors of the antenna array servo control system with cooperative control and independent control. DETAILED DESCRIPTION

[0052] The present invention will be further described in detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

[0053] Example

[0054] like Figure 1 As shown, a collaborative control method for an antenna array servo system based on dynamic performance indicators includes the following steps:

[0055] S1. Construct an antenna array servo control system. The system includes a control unit, a controlled antenna array, an actuator, a feedback measurement unit, and a disturbance measurement unit. When the antenna array servo control system is running, the system pointing position signal and the disturbance measurement signal are collected.

[0056] Further explanation:

[0057] The controlled antenna array includes multiple antenna units located in the same area. The gust disturbances they experience are correlated. The two antenna units connected by a correlator are the most basic components of the antenna array system. The azimuth and elevation axes of the two-degree-of-freedom parabolic antenna are similar, and the actuators are the servo motors of the antenna units.

[0058] The feedback measurement unit is a servo motor encoder on the antenna shaft, which is used to measure the actual pointing position of the antenna;

[0059] The disturbance measurement unit is an inertial navigation sensor installed on the main reflector of the antenna, which is used to measure the vibration velocity of the main reflector of the antenna caused by wind disturbance;

[0060] The control unit uses a forward channel controller and an LQG controller to set the pointing position control instructions, collect sensor data from each antenna unit, and calculate and send control quantities.

[0061] The forward channel controller in the control unit uses a PI controller, outputting a forward channel control variable based on the deviation between the antenna command signal and the servo motor encoder measurement signal. The LQG controller, designed using a Kalman filter and quadratic optimal state feedback, outputs a state feedback control variable based on the actuator control input and the servo motor encoder measurement signal. The forward channel control variable and the state feedback control variable are superimposed and output to the servo motor.

[0062] S2. Based on the model of each antenna unit in the antenna array servo control system, establish the state space equation of the controlled antenna array from the input signal of the actuator and the disturbance measurement signal to the system pointing position output;

[0063] The model of each unit is determined according to the specific antenna model, and the specific parameters of different models are different.

[0064] In this embodiment, two identical antenna unit models are selected as components of the antenna array, and their state space equations are:

[0065] x1(k+1)=A1x1(k)+B1u1(k)+E1d1(k)

[0066] θ1(k)=C1x1(k)

[0067] x2(k+1)=A2x2(k)+B2u2(k)+E2d2(k)

[0068] θ2(k)=C2x2(k)

[0069] Where x1(k) and x2(k) are the system state variables of the two antenna units, u1(k) and u2(k) are the actuator control inputs of the two antenna units, d1(k) and d2(k) are the disturbance input signals measured by the inertial navigation sensors of the two antenna units, θ1(k) and θ2(k) are the actual pointing positions measured by the encoders of the servo motors of the two antennas, and k represents the kth sampling time.

[0070] The specific model parameter matrix of the two antennas is:

[0071]

[0072] The models of the two antenna units constitute the model of the antenna array servo control system, and its state space equation is:

[0073] x(k+1)=Ax(k)+Bu(k)+Ed(k)

[0074] θ(k)=Cx(k)

[0075] Where, is the system state quantity of the antenna array, is the servo control input of the antenna array, is the disturbance received by the antenna array, is the pointing position of the antenna array, A=diag(A1,A2), B=diag(B1,B2), C=diag(C1,C2), E=diag(E1,E2) is the model parameter matrix of the antenna array.

[0076] The state space equations of each antenna unit together constitute the state space equation of the antenna array servo control system:

[0077] x(k+1)=Ax(k)+Bu(k)+Ed(k)

[0078] θ(k)=Cx(k)

[0079] Where, is the system state quantity of the antenna array, is the servo control input of the antenna array, is the disturbance received by the antenna array, is the pointing position of the antenna array, A=diag(A i )、B=diag(B i )、C=diag(C i )、E=diag(E i) is the model parameter matrix of the antenna array, and num is the number of antenna elements in the antenna array.

[0080] S3. Obtaining a collaborative control performance index function of the antenna array servo control system based on the received power pattern of each antenna unit, and obtaining a collaborative control amount based on the measurement signal and a control strategy based on the performance index function;

[0081] The wind disturbances received by each antenna element in the antenna array are correlated. By calculating the measured values of the disturbance signals received by each antenna element, this correlation is expressed as a covariance matrix:

[0082] Q d =(q ij ) num×num

[0083] Where q ij is the covariance of the disturbance signal measurement values of the i-th and j-th antenna elements, and num is the number of antenna elements in the antenna array.

[0084] By simulating the disturbance signal measurements of the two antenna elements, the correlation is expressed as a covariance matrix:

[0085]

[0086] like Figure 3 As shown, the received power pattern of an antenna is a symmetrical graph showing how the relative field strength of the radiation field at a certain distance from the antenna varies with direction. In this embodiment, the two antennas have the same model and therefore have the same received power pattern. Considering that the center point of the antenna generally does not deviate significantly from the target radio source during operation, a second-order linear fit is performed at the center of the pattern using a Taylor expansion, resulting in the received power pattern fitting function for the two antenna elements:

[0087]

[0088] Where, represents the angle at which the two antenna elements deviate from the center of the pattern, and ε1=ε2=0.125 is the fitting coefficient of the received power patterns of the two antennas.

[0089] Substituting the received power pattern fitting function of the two antenna units into the servo control performance index function, and selecting the adjustable parameter ρ1 = ρ2 = 80, the controller design index, i.e., the servo control performance index function, is obtained as follows:

[0090]

[0091] The collaborative control strategy of the antenna array system consists of two parts: the forward channel controller and the LQG controller. The specific parameters of the controller are designed based on the servo control performance indicator function. When the antenna array is in operation, it calculates according to the measurement data and the collaborative control structure and outputs the control quantity.

[0092] The forward channel controller uses a PI controller, which outputs the forward channel control quantity according to the deviation between the antenna command signal and the servo motor encoder measurement signal. In this embodiment, the parameters of the PI controller are K P =12 and K I =0.8.

[0093] The Kalman filter of the LQG controller includes a system model and a noise model. The system model adopts the model of the antenna array servo control system. The noise model includes the process noise covariance Q and the measurement noise covariance R. The process noise covariance Q is obtained through the covariance matrix of the wind disturbance:

[0094] Q=EQ d E T

[0095] According to the simulated measurement noise of the two antenna encoders r1=r2=0.01, the measurement noise covariance R is obtained as follows:

[0096] R=diag(r1,r2)

[0097] The quadratic optimal state feedback of the LQG controller is designed based on the performance index function in the antenna array servo system. The state feedback controller is obtained by solving the discrete Riccati equation. The state feedback controller outputs the state feedback control quantity according to the system state estimated by the Kalman filter.

[0098] The output control quantity of the forward channel controller is superimposed on the state feedback control quantity of the LQG controller, and the superimposed control quantity is input to the servo motor of each antenna unit of the antenna array to realize the coordinated control of the antenna array servo control system. The superimposed control quantity is expressed as:

[0099] u(k)=u c (k)+u f (k)

[0100] Where u c (k) is the output control variable of the forward channel PI controller; u f (k) is the state feedback control quantity of the LQG controller, and u(k) is the control quantity input by the actuator.

[0101] S4. The control unit generates a coordinated control variable based on the measurement signals of each antenna unit of the antenna array and transmits it to the actuator of each antenna unit for coordinated control. In this embodiment, when the two antennas are subjected to correlated wind disturbances as shown in Figures 4(a) and 4(b) and the azimuth axis command signal is 0°, the tracking error of the antenna array servo control system under coordinated control is simulated, and the PI controller used in the actual antenna system is used as an independent control for comparison to verify the effectiveness of the coordinated control. The comparison diagrams of the simulation results are shown in Figures 5(a) and 5(b). The coordinated control can effectively suppress the impact of wind disturbances.

[0102] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A collaborative control method for an antenna array servo system based on dynamic performance indicators, characterized in that: The steps include: Constructing an antenna array servo control system, the antenna array servo control system comprising a control unit, a controlled antenna array, an actuator, a feedback measurement unit, and a disturbance measurement unit; Based on the model of each antenna unit in the antenna array servo control system, the state space equation of the controlled antenna array from the input signal of the actuator and the disturbance measurement signal to the system pointing position output is established; According to the received power pattern of each antenna unit, a collaborative control performance index function of the antenna array servo control system is obtained, and the control unit obtains a collaborative control amount according to the measurement signal and the control strategy based on the performance index function; The coordinated control quantity is transmitted to each actuator of the controlled antenna array to realize the coordinated control of the antenna array servo control system.

2. The antenna array servo system collaborative control method according to claim 1, characterized in that: The antenna array servo control system comprises: The controlled antenna array includes multiple antenna units. The multiple antenna units are located in the same area and are subjected to correlated wind gust disturbances. The antenna units are connected using correlators. The actuator is a servo motor of the antenna unit; The feedback measurement unit is a servo motor encoder on the antenna shaft, which is used to measure the actual pointing position of the antenna; The disturbance measurement unit is an inertial navigation sensor installed on the main reflector of the antenna, which is used to measure the vibration velocity of the main reflector of the antenna caused by wind disturbance; The control unit is used to set the pointing position control instructions, collect sensor data from each antenna unit, and calculate and send control quantities.

3. The antenna array servo system collaborative control method according to claim 2, characterized in that: The state space equation for establishing the controlled antenna array from the input signal of the actuator and the disturbance measurement signal to the system pointing position output is specifically: The state space equation of the i-th antenna element is expressed as: x i (k+1)=A i x i (k)+B i u i (k)+E i d i (k) i i (k)=C i x i (k) Where x i (k) is the system state quantity of the i-th antenna unit, u i (k) is the actuator control input of the i-th antenna unit, d i (k) is the disturbance input signal measured by the inertial navigation sensor of the i-th antenna unit, θ i (k) is the actual pointing position of the antenna measured by the servo motor encoder of the i-th antenna unit, k represents the k-th sampling moment, A i 、B i 、C i and E i is the parameter matrix of the i-th antenna element; The state space equations of each antenna unit together constitute the state space equations of the antenna array servo control system.

4. The antenna array servo system collaborative control method according to claim 3, characterized in that: The state space equations of each antenna unit together constitute the state space equation of the antenna array servo control system: x(k+1)=Ax(k)+Bu(k)+Ed(k) θ(k)=Cx(k) Where, is the system state quantity of the antenna array, is the servo control input of the antenna array, is the disturbance received by the antenna array, is the pointing position of the antenna array, A=diag(A i )、B=diag(B i )、C=diag(C i )、E=diag(E i ) is the model parameter matrix of the antenna array, and num is the number of antenna elements in the antenna array.

5. The antenna array servo system collaborative control method according to claim 2, characterized in that: The gust disturbances are correlated, specifically: By calculating the measured values of the disturbance signal received by each antenna unit, the correlation is expressed as a covariance matrix: Q d =(q ij ) num×num Where q ij is the covariance of the disturbance signal measurement values of the i-th and j-th antenna elements, and num is the number of antenna elements in the antenna array.

6. The antenna array servo system collaborative control method according to any one of claims 1 to 5, characterized in that: According to the received power pattern of each antenna, the coordinated control performance index function of the antenna array servo control system is obtained, which is specifically: According to the antenna receiving power pattern and the correlator output calculation formula, the coordinated control performance index function of the antenna array servo system is obtained; Where, and the antenna unit pointing position θ i The relationship between (k) is Where θ is the direction of the signal source, θ i (k) is the pointing direction of the i-th antenna unit, ε is the second-order derivative of the directional pattern of the i-th antenna unit at the center point, ρ i is an adjustable parameter, u i (k) is the actuator control input of the i-th antenna unit, and k represents the k-th sampling time.

7. The antenna array servo system collaborative control method according to claim 1, characterized in that: The control unit includes a forward channel controller and an LQG controller; The forward channel controller adopts a PI controller, which outputs the forward channel control amount according to the deviation between the antenna command signal and the servo motor encoder measurement signal; The LOG controller includes a Kalman filter and a quadratic optimal state feedback, and outputs a state feedback control quantity according to the actuator control input and the servo motor encoder measurement signal; The forward channel control quantity and the state feedback control quantity are superimposed and output to the servo motor as the system control quantity.

8. The antenna array servo system collaborative control method according to claim 7, characterized in that: The Kalman filter includes a system model and a noise model. The system model adopts the model of the antenna array servo control system. The noise model includes process noise covariance Q and measurement noise covariance R. The process noise covariance Q is obtained through the covariance matrix of wind disturbance.

9. The antenna array servo system collaborative control method according to claim 8, characterized in that: The quadratic optimal state feedback is designed using the performance index function in the antenna array servo system, and the state feedback control quantity is calculated according to the system state observation value output by the Kalman filter.

10. The antenna array servo system collaborative control method according to claim 2, characterized in that: Each antenna unit is a two-degree-of-freedom parabolic antenna.

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