A target tracking control method for photoelectric detection equipment

Abstract

The present invention discloses a target tracking control method for photoelectric detection equipment. First, based on the multi-source measurement signals provided by the photoelectric detection equipment, high-order motion information such as the angular position, angular velocity and angular acceleration of the tracked target relative to the photoelectric detection equipment in the geographic system is estimated. Then, based on the acquired target motion information, a feedforward controller is designed to achieve high-precision tracking of the target and enhance the anti-interference capability of the control system. The present invention is aimed at the target tracking requirements of the photoelectric detection equipment. While achieving high-precision target tracking, it further improves the stability and disturbance suppression capability of the control system, effectively improving the tracking performance of the photoelectric detection equipment for highly maneuverable targets in high-dynamic environments such as vehicle-mounted and airborne environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of target tracking, and in particular relates to a target tracking control method based on target high-order motion information estimation and feedforward. Background Art

[0002] The current operating environment of photoelectric detection equipment is becoming increasingly complex, and the mobility of the targets to be tracked is becoming increasingly higher, so higher requirements are also placed on the target tracking performance of photoelectric detection equipment.

[0003] Photoelectric detection equipment uses a tracking control system to achieve target pointing and tracking. The tracking control system usually adopts a dual closed-loop structure of angular position + angular velocity in the control structure. The angular position loop is the main unit for achieving target tracking. It uses the target image off-target amount as the angular position error signal of the tracked target, and ensures the effective tracking accuracy of the target through feedback control.

[0004] Specifically, high target tracking performance is reflected in the following two aspects: 1) excellent target tracking accuracy for highly maneuverable targets; 2) excellent disturbance suppression capability for the dynamic load conditions of the vehicle.

[0005] However, the target tracking technologies currently widely used in photoelectric detection systems struggle to address both of these issues. For example, traditional miss distance feedback control methods cannot eliminate tracking errors caused by miss distance delay, a lag error that is particularly critical when tracking highly maneuverable targets. While velocity feedforward technology can effectively compensate for the error caused by miss distance delay, it does not guarantee the stability and anti-interference capabilities of the tracking control system. Delay compensation technology based on the Smith predictor system can effectively improve the control system's stability margin, but it cannot specifically compensate for tracking errors caused by miss distance lag.

[0006] Therefore, there is an urgent need for a target tracking control method that can effectively compensate for the tracking error caused by the miss delay and at the same time has a high suppression capability against the disturbance caused by the dynamic environment of the vehicle. Summary of the Invention

[0007] In order to take into account both the high-precision tracking of highly maneuverable targets and the high-efficiency disturbance suppression in highly dynamic environments, the present invention provides a target tracking control method based on target high-order motion information estimation and feedforward.

[0008] The technical solution adopted by the present invention to solve the technical problem is: a target tracking control method for a photoelectric detection device, comprising the following steps:

[0009] Step S1, high-order motion information estimation: Based on the multi-source measurement signals provided by the photoelectric detection device, the high-order motion information such as the angular position, angular velocity and angular acceleration of the tracked target relative to the photoelectric detection device in the geographic frame is estimated;

[0010] According to the target image miss distance E(t-τ) at the time lag τ provided by the photoelectric detection device and the angular position Y(t) representing the inertial posture of the optical axis in the photoelectric detection device, the time axes of the two are aligned and then subjected to coordinate projection transformation to obtain the Σ N The target angular position R(t-τ) at the next lag τ is used to reconstruct the angle command signal of the tracking control system;

[0011] The target angular position R(t-τ) is used as the measurement signal of the Kalman filter, and the target relative geographic coordinate Σ is estimated after Kalman filtering. N The target angular velocity and target angular acceleration The target angular acceleration estimate Do the difference to get the target angular acceleration estimate Limiting is performed to obtain a stable target angular acceleration estimate By targeting angular acceleration This type of high-level motion information judgment further ensures angular acceleration The rate of change can adapt to the maneuverability requirements of the tracked target while avoiding frequent jitter and instability of the optical axis during target tracking. The target angular velocity estimation value and the target angular acceleration estimate with rate-limited change The high-order motion information is used for subsequent feedforward control;

[0012] Step S2, feedforward control: Based on the acquired target motion information, a feedforward controller is designed to achieve high-precision tracking of the target and enhance the anti-disturbance capability of the control system;

[0013] The angular acceleration is used to determine whether the angular acceleration exceeds the threshold, and then the angular acceleration is limited. According to the target angular velocity estimate at the time of lag τ and the estimated target angular acceleration after clipping By formula Get the angular velocity of the target at the current moment The above formula reflects the speed change caused by the target maneuverability during the lag τ time, so the obtained It plays an important role in effectively compensating for the tracking error caused by the miss lag τ;

[0014] The design is based on the transfer function Q = s + τsC p A feedforward controller, where C pis the position feedback controller of the tracking control system, s is the Laplace operator, and the control quantity generated by the feedforward controller Q can be obtained by applying the feedforward controller to the speed feedforward link. Combined with the target's angular velocity at the current moment Target tracking control based on target high-order motion information estimation and feedforward can be achieved.

[0015] Furthermore, the target angular position R(t-τ) in step S1 is obtained by the following steps:

[0016] Σ B ,Σ E and Σ N is the target surface system, the two-axis photoelectric detection equipment pitch axis coordinate system and the geographic system, θ x and θ y The target is on the target surface B The miss distance along the x and y axes, θ E is the pitch angle when the optical axis points to the target, θ N is the azimuth when the optical axis points to the target, and the optical axis is in the target surface system Σ B Vector

[0017]

[0018] According to the target surface system Σ B Projection to geographic systemΣ N Direction cosine matrix Get the optical axis in the geography department Σ N Vector

[0019]

[0020] Get the target relative geographic coordinate Σ N Altitude angle H n and azimuth A n

[0021]

[0022] The direction cosine matrix in the above coordinate projection transformation At each sampling moment, the optical axis of the photoelectric detection device is in the geographic system Σ N The attitude angle Y(t) is updated under the geographical system Σ N The attitude angle Y(t) under the condition of θ can be obtained by the attitude measurement value of the three-axis gyroscope or inertial navigation in the device. x and θ y There is a time delay of length τ, so the target relative to the geographical system Σ N Altitude angle H n and azimuth A nIt also delays the time τ, further increasing the altitude angle H before the time τ. n and azimuth A n Unification to one-dimensional direction equivalent as the goal in the geography department Σ N The angular position R(t-τ) under .

[0023] Furthermore, the state equation of the Kalman filter in step S1 adopts a uniform acceleration motion model:

[0024]

[0025] Or the current "statistical" model of the maneuvering target

[0026]

[0027]

[0028] The x2 and x3 in the formula are the target in the geographic system Σ N The estimated target angular velocity under and target angular acceleration estimate

[0029] Furthermore, in step S1, the target angular acceleration estimation value The amplitude judgment and limiting process is as follows: First, cache the angular acceleration estimate of the previous moment k-1 Where nT s =τ represents the miss delay, T s is the sampling time; then the estimated angular acceleration of the current moment k is updated Then calculate the target angular acceleration by difference Finally, determine the absolute value of angular acceleration Whether the threshold is exceeded If not, end this process; if yes, pass the threshold Get the estimated value of angular acceleration after limiting

[0030] Furthermore, the closed-loop transmission function of the system in step S2 is

[0031]

[0032] The beneficial effects of the present invention are:

[0033] The tracking control method of the present invention uses target acceleration to further accurately characterize the target maneuverability within the miss delay time, and at the same time adopts a limit on the target acceleration. The application of these high-order motion information of the target can effectively improve the tracking performance of the target, especially the highly maneuverable target.

[0034] Applying the feedforward controller of the present invention in a tracking control system can effectively improve the stability margin of the control system, so that the gain of the position feedback controller can be further increased, thereby effectively enhancing the anti-disturbance capability of the tracking control system.

[0035] The present invention includes two parts: high-order motion information estimation and feedforward control. The high-order motion information estimation estimates the target's angular position relative to the photoelectric detection device in the geographic system, as well as high-order motion information such as angular velocity and angular acceleration based on the multi-source measurement signals provided by the photoelectric detection device; the feedforward control is to design a feedforward controller based on the acquired target motion information to achieve high-precision tracking of the target and enhance the control system's anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a flow chart of the control method of the present invention;

[0037] Figure 2 It is a typical schematic diagram of the target angular position coordinate projection transformation in the geographic system;

[0038] Figure 3 This is a flow chart for determining and limiting the amplitude of the target angular acceleration;

[0039] Figure 4 This is the block diagram of a complete tracking control system based on target high-order motion information estimation and feedforward. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0041] The principle diagram of the target tracking method based on target high-order motion information estimation and feedforward disclosed by the present invention is as follows: Figure 1 As shown in the figure, it includes two parts: high-order motion information estimation and feedforward control.

[0042] The method of the present invention estimates the value of the target's high-order motion information at the time of lag τ and The angular velocity of the target at the current moment can be obtained by the following formula

[0043]

[0044] The above formula reflects the speed change caused by the target maneuverability within the lag time τ, so the obtained It plays an important role in effectively compensating for the tracking error caused by the miss lag τ.

[0045] The transfer function of the designed feedforward controller is

[0046] Q=s+τsCp (2)

[0047] In the above formula, C p is the position controller of the tracking control system, s is the Laplace operator, and the feedforward controller is applied to the speed feedforward link, so the feedforward control quantity can be obtained as

[0048]

[0049] Combined with the angular velocity of the target at the current moment obtained in step D) Target tracking control based on target high-order motion information estimation and feedforward can be achieved.

[0050] The specific implementation process is:

[0051] A, Generation of target angular position in geographic system.

[0052] At time t, according to the target image miss distance E(t-τ), and the optical axis of the photoelectric detection device in the geographic system Σ N The attitude angle Y(t) under the coordinate projection transformation is obtained by the target in the geographic system Σ N The angular position R(t-τ) under .

[0053] Taking the two-axis photoelectric detection device as an example, the coordinate projection transformation diagram is as follows Figure 2 As shown. B ,Σ E and Σ N They are target surface system, equipment pitch axis coordinate system and geographic system respectively. x and θ y The target is on the target surface B The miss distance along the x and y axes, θ E is the pitch angle when the optical axis points to the target, θ N is the azimuth when the optical axis points to the target. B The vector is

[0054]

[0055] From the target surface B Projection to geographic systemΣ N The direction cosine matrix is Optical axis in the Department of Geography N The vector is

[0056]

[0057] Therefore, the target relative to the geographical system Σ N Altitude angle H n and azimuth A n for

[0058]

[0059] The direction cosine matrix in the above coordinate projection transformation At each sampling moment, the optical axis of the photoelectric detection device is in the geographic system Σ N The attitude angle Y(t) is updated under the geographical system Σ N The attitude angle Y(t) under the condition of θ can be obtained by the attitude measurement value of the three-axis gyroscope or inertial navigation in the device. x and θ y There is a time delay of length τ, so the target relative geographic system Σ obtained by formula (6) N Altitude angle H n and azimuth A n It also delays the time τ. Further, the altitude angle H before the time τ is n and azimuth A n Unified to one-dimensional direction for expression, that is, equivalent to the goal in the geographical system Σ N The angular position R(t-τ) under .

[0060] B) Obtain the target high-order motion information estimation value. N The angular position R(t-τ) under the Kalman filter is used as the measurement signal z1(k). The Kalman filter can be used to obtain the target's position in the geographic system Σ N The optimal estimate of angular velocity and angular acceleration under and

[0061] The state equation of the Kalman filter can be used as a uniform acceleration motion model

[0062]

[0063] Or the current "statistical" model of the maneuvering target

[0064]

[0065]

[0066] The x2 and x3 in formula (7) or (8) are the target in the geographic system Σ N Estimated values ​​of angular velocity and angular acceleration under and

[0067] C) Obtain a stable target acceleration. The target angular acceleration obtained in step B) Since the filter system noise is large, its rate of change may be much greater than the actual target's maneuverability. This problem will cause the optical axis to frequently jitter and become unstable during target tracking. Differentiation to obtain the target's angular acceleration And through the diagonal acceleration Limit the amplitude to obtain a stable target angular acceleration estimate

[0068] The target angular acceleration amplitude judgment and limiting process is as follows: Figure 3 shown. Figure 3 In the example, the target angular acceleration amplitude determination and limiting process is as follows:

[0069] First, cache the angular acceleration value of the previous moment k-1 Where nT s =τ, represents the miss delay, T s is the sampling time;

[0070] Then, update the estimated angular acceleration at the current time k

[0071] Then, by taking the difference, we can calculate the angular acceleration

[0072] Finally, determine the absolute value of the angular acceleration Whether the threshold is exceeded If not, end this process; if yes, pass the threshold Get the estimated value of angular acceleration after limiting Here This is the target angular acceleration estimate for this step discrete expression of .

[0073] D) Synthesis of the current target velocity. The estimated value of the target's high-order motion information at the time lag τ obtained according to steps B) and C) and Combined with formula (1), the angular velocity of the target at the current moment can be obtained: The obtained The velocity change caused by the target maneuverability within the lag time τ is better characterized.

[0074] E) Design of feedforward controller. The above step A) obtains the target in the geographic system Σ N The angular position information R(t-τ) under the condition of τ is used to reconstruct the angle command signal of the tracking control system; and the target angular acceleration estimation value obtained in steps B) and C) is And the target angular velocity obtained in step D) High-order motion information is used for feedforward control.

[0075] The block diagram of the complete tracking control system based on target high-order motion information estimation and feedforward involved in the present invention is as follows: Figure 4 shown. Figure 4 Where E(t-τ) is the target image miss distance, which is the only target motion information that can be relied upon when the photoelectric detection equipment is tracking the target, and this signal has a time delay τ. Step A) of the present invention integrates the target image miss distance E(t-τ) and the inertial attitude angle Y(t) that characterizes the direction of the optical axis, and calculates the target angular position R(t-τ) through coordinate projection transformation. The tracking control system involved in this step uses the target angular position R(t-τ) as the equivalent command signal of the control system, C p is the position feedback controller, 1 / s is the controlled model of the tracking control system, and D(t) is the environmental disturbance to the photoelectric detection device.

[0076] exist Figure 4 Based on this, the feedforward controller Q=s+τsC is designed. p , the control quantity generated by the feedforward controller Q is The target high-order motion information estimation value obtained in steps B), C) and D) of the present invention is fully utilized. At this time, the system closed-loop function is

[0077]

[0078] In order to further compare the tracking performance, the closed-loop transmission function of the system under the traditional miss distance feedback is given.

[0079]

[0080] Comparing equations (9) and (10), we can see that:

[0081] (1) Under the feedforward controller Q designed in the present invention, the system position response (i.e., the inertial attitude angle Y(t) of the optical axis) tracks the target angular position command R better, and the system tracking accuracy is higher than that of the system under the traditional miss distance feedback.

[0082] (2) Under the feedforward controller Q designed by the present invention, the characteristic equation of the closed-loop system shown in formula (9) is It does not include the delay link that seriously restricts the stability of the system -τs , that is, the stability margin of the control system has also been improved compared with the system under traditional miss-distance feedback.

[0083] On the other hand, the disturbance rejection transfer function of the tracking control system under the feedforward controller Q designed by the present invention is shown in formula (11), and the disturbance rejection transfer function of the tracking control system under the traditional miss distance feedback is shown in formula (12).

[0084]

[0085]

[0086] Comparing equations (11) and (12), it can be seen that the characteristic equation of the closed-loop system under the technology involved in the present invention is Does not contain delay links that seriously restrict system stability -τs Therefore, the control system can set a higher position feedback controller gain, thereby reflecting a better anti-interference ability; while the tracking control system under the traditional miss distance feedback is affected by the delay link e -τs The influence of the stability margin is low, which seriously restricts the anti-interference ability of the system. It can be seen that under the technology involved in the present invention, the anti-interference ability of the tracking control system is also improved.

[0087] The present invention utilizes multi-source measurement information such as target image miss distance and gyroscope integral value to synthesize and estimate the target's high-order motion information, and further designs a feedforward controller based on this information. The entire control method improves the disturbance suppression capability while ensuring high-precision tracking performance.

[0088] The invention realizes the synthesis of the motion trajectory of the detected target and the estimation of high-order motion information such as the target angular velocity and angular acceleration. By integrating these motion information, a target tracking control method based on a new feedforward controller is proposed. This method has high target tracking performance and further improves the control system's suppression effect on disturbances.

[0089] The protection scope of the claims of the present invention is not limited to the above embodiments.

Claims

1. A target tracking control method for a photoelectric detection device, characterized in that: Includes the following steps Step S1, high-order motion information estimation: Based on the target image miss distance E(t-τ) at the time lag τ provided by the photoelectric detection device and the angular position Y(t) representing the inertial posture of the optical axis in the photoelectric detection device, the time axes of the two are aligned and then subjected to coordinate projection transformation to obtain the coordinates in the geographic system Σ N The target angular position R(t-τ) at the time of lag τ is used as the measurement signal of the Kalman filter to estimate the relative geographical coordinate Σ N The target angular velocity and target angular acceleration The target angular acceleration estimate Do the difference to get the target angular acceleration estimate Estimated target angular acceleration Limiting is performed to obtain a stable target angular acceleration estimate Step S2, feedforward control: according to the target angular velocity estimate and the estimated target angular acceleration after clipping By formula Get the angular velocity of the target at the current moment The design is based on the transfer function Q = s + τsC p A feedforward controller, where C p is the position feedback controller of the system, s is the Laplace operator, and the control quantity generated by the feedforward controller Q is obtained by applying the feedforward controller to the speed feedforward link. Combined with the target's angular velocity at the current moment Implement feedforward-based target tracking control.

2. The target tracking control method for a photoelectric detection device according to claim 1, characterized in that: The target angular position R(t-τ) in step S1 is obtained by the following steps: Σ B ,Σ E and Σ N is the target surface system, the two-axis photoelectric detection equipment pitch axis coordinate system and the geographic system, θ x and θ y Available targets on the target surface system Σ B The distance along the x and y axes is characterized by the miss distance, θ E is the pitch angle when the optical axis points to the target, θ N is the azimuth when the optical axis points to the target, and the optical axis is in the target surface system Σ B Vector According to the target surface system Σ B Projection to geographic systemΣ N Direction cosine matrix Get the optical axis in the geography department Σ N Vector Get the target relative geographic coordinate Σ N Altitude angle H n and azimuth A n Direction cosine array At each sampling moment, the optical axis of the photoelectric detection device is in the geographic system Σ N The attitude angle Y(t) is updated, and the altitude angle H before time τ is n and azimuth A n Unification to one-dimensional direction equivalent as the goal in the geography department Σ N The angular position R(t-τ) under .

3. The target tracking control method for a photoelectric detection device according to claim 1, characterized in that: The Kalman filter in step S1 adopts a uniform acceleration motion model: Or the current statistical model of the maneuvering target: The x2 and x3 in the formula are the target in the geographic system Σ N The estimated target angular velocity under and target angular acceleration estimate 4. The target tracking control method for a photoelectric detection device according to claim 1, characterized in that: In step S1, the target angular acceleration The amplitude judgment and limiting process is as follows: First, cache the angular acceleration estimate of the previous moment k-1 Where nT s =τ represents the miss delay, T s is the sampling time; then the estimated angular acceleration of the current moment k is updated Then calculate the target angular acceleration by difference Finally, determine the absolute value of angular acceleration Whether the threshold is exceeded If not, end this process; if yes, pass the threshold Get the estimated value of angular acceleration after limiting 5. The target tracking control method for a photoelectric detection device according to claim 1, characterized in that: The closed-loop transmission function of the system in step S2 is:

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