Bird monitoring holder control method and system

Abstract

The invention discloses a bird monitoring holder control method and system, and the method comprises the steps: building a detection system coordinate system comprising a holder body, a pitching frame and an azimuth frame, determining the conversion relation of all coordinate systems, obtaining the angular velocity and angular acceleration of the azimuth frame of the holder, and driving the holder. The system utilizes a gyroscope and an angular displacement sensor to construct a four-loop three-closed-loop control architecture, namely a current loop, a gyroscope stabilizing loop and a target tracking and attitude locking control loop. A tracking mode, a locking mode or an angular rate stabilizing mode can be switched according to instructions, and all loops work cooperatively in different modes, for example, a current loop stabilizes current, and a gyro stabilizing ring inhibits interference. The bird target can be locked through the image processing system, the miss distance is calculated and fed back for control, and accurate tracking is achieved. The problems that a traditional bird monitoring holder is low in control precision, poor in interference resistance and insufficient in driving and servo control are solved, and the high-precision and real-time tracking and monitoring requirements for birds in the complex environment are met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of bird monitoring, and particularly relates to a bird monitoring cloud control method and system. BACKGROUND

[0002] In the field of modern bird research and ecological protection, behavior monitoring and environmental observation of birds are crucial. As a key device for realizing remote and precise monitoring, the control technology of bird monitoring cloud is of great concern.

[0003] Early bird monitoring cloud control methods are relatively simple, mostly using open-loop control, which is difficult to cope with complex environmental disturbances and rapid bird movements, resulting in low monitoring accuracy. With the development of sensor technology, some cloud platforms have introduced simple feedback control, such as relying only on single position feedback, which has improved control accuracy to some extent, but still has deficiencies in dynamic target tracking and posture stability.

[0004] In recent years, with the progress of computer vision and image processing technology, bird monitoring cloud has begun to have target recognition and tracking functions. However, existing cloud control methods still have room for improvement in handling multi-coordinate system conversion, accurate angular velocity and angular acceleration calculation, and building efficient and stable control architecture. For example, in complex outdoor environments, the cloud platform may be subject to wind resistance, vibration and other disturbances, resulting in decreased accuracy of target tracking, making it difficult to meet the needs of long-term, high-precision monitoring of bird behavior.

[0005] At the same time, the traditional permanent magnet DC torque motor driving control method has limitations in efficiency and response speed, and cannot quickly and accurately adjust according to the motion state of the cloud platform. Moreover, the performance of the servo controller also affects the control accuracy and stability of the entire cloud platform system, and the existing controller has limited ability to handle non-linear and uncertain factors, making it difficult to achieve real-time and accurate tracking of bird targets. SUMMARY

[0006] Therefore, the present application provides a bird monitoring cloud control method and system to solve the problems of low accuracy, poor anti-interference, insufficient motor driving and servo control in bird monitoring cloud control, and to meet the needs of high-precision, real-time tracking and monitoring of birds in complex environments.

[0007] To achieve the above purpose, the present application provides the following technical solution: a bird monitoring cloud control method, comprising the following steps:

[0008] A detection system coordinate system is established, the detection system coordinate system comprises a pedestal coordinate system, a pitch frame coordinate system and an azimuth frame coordinate system, a conversion relationship between the pedestal coordinate system, the pitch frame coordinate system and the azimuth frame coordinate system is obtained, and angular velocity and angular acceleration of the azimuth frame of the holder relative to the detection system coordinate system are determined;

[0009] The azimuth frame of the holder is driven according to the angular velocity and the angular acceleration of the azimuth frame of the holder relative to the detection system coordinate system, a three-closed-loop control architecture comprising a current loop, a gyro-stabilized loop control loop, a target tracking control loop and a posture locking control loop is constructed by using a gyroscope as an angular velocity feedback element and an angular displacement sensor as a position feedback element;

[0010] According to the control instruction, a tracking mode, a locking mode or an angular rate stabilization mode in an open-loop state is switched, the target tracking control loop is closed in the tracking mode, the posture locking control loop is closed in the locking mode, and in the angular rate stabilization mode, the current loop takes the current Hall sensor as a current detection element to form a negative feedback of the current, and the gyro-stabilized loop control loop suppresses the interference angular rate on the rotating shaft;

[0011] The bird target in the monitoring field of view of the holder is locked by the image processing system, the off-target amount of the bird target is fed to the servo controller, the control calculation of the target tracking control loop is performed, and the control calculation result of the target tracking control loop is brought into the gyro-stabilized loop control loop, so that the tracking of the bird target is realized.

[0012] As a preferred scheme of the bird monitoring holder control method, in the process of obtaining the conversion relationship between the pedestal coordinate system, the pitch frame coordinate system and the azimuth frame coordinate system:

[0013] When the pitch frame rotates relative to the pedestal coordinate system around the Oz axis, the conversion relationship between the pedestal coordinate system and the pitch frame coordinate system is represented by a coordinate transformation matrix R(z, a):

[0014]

[0015] When the azimuth frame of the holder rotates relative to the pitch frame coordinate system around the axis, the conversion relationship between the azimuth coordinate system and the pitch frame coordinate system is represented by a coordinate transformation matrix R(y o , β):

[0016]

[0017] In the formula, a is the angle of rotation of the pitch frame relative to the pedestal coordinate system around the Oz axis; β is the angle of rotation of the azimuth frame of the holder relative to the pitch frame coordinate system around the axis.

[0018] As the preferred solution of the bird monitoring gimbal control method, the angular velocity and angular acceleration of the gimbal azimuth frame relative to the coordinate system of the detection system are determined in the process of:

[0019] When the pitch frame rotates around the Oz t axis relative to the coordinate system of the base body by an angle α, the angular velocity of the pitch frame is

[0020] When the gimbal azimuth frame rotates around the Oy o axis relative to the coordinate system of the pitch frame by an angle β, the angular velocity of the gimbal azimuth frame is

[0021] The angular velocity of the gimbal azimuth frame relative to the coordinate system of the detection system is obtained by synthesis:

[0022]

[0023] In the formula, w m : the angular velocity of the gimbal azimuth frame relative to the coordinate system of the detection system; w mm : the angular velocity of the gimbal azimuth frame around the Oy o axis relative to the coordinate system of the pitch frame; R(y o , β): the coordinate transformation matrix when the gimbal azimuth frame rotates around the Oy o axis relative to the coordinate system of the pitch frame by an angle β; ω o : the angular velocity of the pitch frame around the Oz t axis relative to the coordinate system of the base body; : the angular velocity of the pitch frame around the Oz t axis relative to the coordinate system of the base body, the first derivative of α with respect to time; : the angular velocity of the gimbal azimuth frame around the Oy o axis relative to the coordinate system of the pitch frame, the first derivative of β with respect to time; T: indicates the matrix transpose.

[0024] As the preferred solution of the bird monitoring gimbal control method, when the pitch frame rotates around the Oz t axis relative to the coordinate system of the base body by an angle α, the angular acceleration of the pitch frame is

[0025] When the gimbal azimuth frame rotates around the Oy o axis relative to the coordinate system of the pitch frame by an angle β, the angular acceleration of the gimbal azimuth frame is

[0026] The angular acceleration of the gimbal azimuth frame relative to the coordinate system of the detection system is:

[0027]

[0028] In the formula, Angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system; Gimbal azimuth frame rotation axis Oy o Angular acceleration relative to the pitch frame coordinate system; Coordinate transformation matrix R(y) o The derivative of β with respect to time; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular acceleration of the axis of rotation relative to the frustum coordinate system, ω o The first derivative with respect to time; Pitch frame around Oz t The angular acceleration of the axis relative to the frustum coordinate system, and the second derivative of α with respect to time; Gimbal azimuth frame rotation axis Oy o The second derivative of β with respect to time is the angular acceleration relative to the pitch frame coordinate system.

[0029] As a preferred solution for bird monitoring pan-tilt control, a permanent magnet DC torque motor is used to drive the pan-tilt azimuth frame according to the angular velocity and angular acceleration of the pan-tilt azimuth frame relative to the coordinate system of the detection system.

[0030] The voltage balance equation of the permanent magnet DC torque motor is:

[0031]

[0032] The electromagnetic torque of the permanent magnet DC torque motor:

[0033] M a =C m i a

[0034] The back electromotive force of the permanent magnet DC torque motor:

[0035] E=C e ω

[0036] The transfer function model of the permanent magnet DC torque motor is as follows:

[0037]

[0038] In the formula, U a : The average value of the DC voltage applied between the two phase windings; L a The equivalent inductance of the two phases of the electric motor; Motor armature circuit current i a Rate of change over time; R a : Equivalent resistance of two phases of the motor; i a: Armature circuit current of the motor; E a : Back electromotive force of the motor; M a : Electromagnetic torque of the motor; C m : Torque coefficient of the motor; G(s): Transfer function of the motor, where s is the Laplace operator used to convert differential equations in the time domain into algebraic equations in the complex frequency domain; J m : Moment of inertia of the motor; J L : Moment of inertia of the load.

[0039] As a preferred embodiment of the bird monitoring PTZ control method, the servo controller includes a tracking differentiator, an extended state observer, and a nonlinear state error feedback control law;

[0040] The formula for arranging the transition process and extracting the differential signal using the tracking differentiator is:

[0041]

[0042] In the formula, e1(t): tracking error, which is the difference between u1(t) and u0(t);

[0043] u1(t), u2(t): Tracking the internal variables of the differentiator, where u2(t) is the input signal; Let u1(t) be the derivative of u1(t) with respect to time.

[0044] u0(t): The quantity calculated by the function fhan(u1(t),u2(t),r,h);

[0045] r: Fast factor, used to affect the response speed of the tracking differentiator;

[0046] h: Filter factor, which plays a role in filtering the signal;

[0047] The extended state observer estimates the state of the controlled object and the total disturbance based on the output and input control signals of the controlled object, using the following formula:

[0048]

[0049] In the formula, e2(t): system error, which is the difference between the output y(t) and z1(t) of the controlled object;

[0050] Let z1(t), z2(t), and z3(t) be the time derivatives of the state variables z1(t), z2(t), and z3(t) estimated by the extended state observer, respectively.

[0051] β1, β2, β3: Observer parameters used to adjust the performance of the extended state observer;

[0052] sgn(e(t)): The sign function, which outputs the corresponding sign value based on the sign of e(t);

[0053] b0: A coefficient that is used in the calculation of terms related to the input control signal u(t) in the formula;

[0054] The control law is calculated using the following formula:

[0055]

[0056] In the formula, u(t): the final control quantity, which is the signal output by the system used to control the controlled object;

[0057] The proportional gain and derivative gain parameters are used to adjust the proportional and derivative action strength of the control law;

[0058] α1, α2: Nonlinear factors that affect the nonlinear characteristics of the control law;

[0059] δ1, δ2: Filtering parameters;

[0060] fal: Nonlinear function.

[0061] The present invention also provides a bird monitoring pan-tilt control system, comprising:

[0062] The coordinate system establishment module is used to establish the detection system coordinate system, which includes the platform coordinate system, the pitch frame coordinate system, and the azimuth frame coordinate system. It obtains the transformation relationship between the platform coordinate system, the pitch frame coordinate system, and the azimuth frame coordinate system, and determines the angular velocity and angular acceleration of the gimbal azimuth frame relative to the detection system coordinate system.

[0063] The drive control module is used to drive the gimbal orientation frame according to the angular velocity and angular acceleration of the gimbal orientation frame relative to the coordinate system of the detection system. It uses a gyroscope as an angular velocity feedback element and an angular displacement sensor as a position feedback element to construct a three-closed-loop control architecture including a current loop, a gyroscope stabilization loop control loop, a target tracking control loop and an attitude locking control loop.

[0064] The mode switching module is used to switch between tracking mode, locking mode, or angular rate stabilization mode in open loop state according to control commands. In the tracking mode, the target tracking control loop is closed; in the locking mode, the attitude locking control loop is closed; in the angular rate stabilization mode, the current loop uses a current Hall sensor as the current detection element to form negative current feedback; and the gyro stabilization loop control loop suppresses the interference angular rate on the rotation axis.

[0065] The target tracking module is used to lock onto bird targets in the field of view of the pan-tilt-zoom (PTZ) camera through the image processing system, transmit the bird target miss distance to the servo controller, execute the control calculation of the target tracking control loop, and input the control calculation result of the target tracking control loop into the gyroscope stabilization loop control loop to achieve bird target tracking.

[0066] As a preferred solution for a bird monitoring pan-tilt control system, in the coordinate system establishment module, when the pitch frame rotates around the Oz axis relative to the platform coordinate system, the transformation relationship between the platform coordinate system and the pitch frame coordinate system is represented by the coordinate transformation matrix R(z,α):

[0067]

[0068] When the gimbal's azimuth frame rotates about its axis relative to the pitch frame coordinate system, the transformation relationship between the azimuth and pitch frame coordinate systems is achieved through the coordinate transformation matrix R(y). o ,β) means:

[0069]

[0070] In the formula, α is the angle of rotation of the pitch frame about the Oz axis relative to the platform coordinate system; β is the angle of rotation of the gimbal azimuth frame about the axis relative to the pitch frame coordinate system.

[0071] In the coordinate system establishment module, when the pitch frame revolves around Oz t When the axis rotates by an angle α relative to the table coordinate system, the angular velocity of the pitch frame

[0072] When the gimbal's orientation frame revolves around Oy o When the axis rotates by an angle β relative to the pitch frame coordinate system, the angular velocity of the gimbal's azimuth frame is...

[0073] The synthesized angular velocity of the gimbal's orientation frame relative to the detection system's coordinate system is as follows:

[0074]

[0075] In the formula, w m : Angular velocity of the gimbal's orientation frame relative to the detection system's coordinate system; w mm : Gimbal azimuth frame around axis Oy o Angular velocity of rotation relative to the pitch frame coordinate system; R(y o ,β): Azimuth frame about axis Oy o The coordinate transformation matrix relative to the pitch frame coordinate system when rotated by an angle β; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular velocity of the axis relative to the frustum coordinate system, and the first derivative of α with respect to time; Gimbal azimuth frame rotation axis Oy o Angular velocity of rotation relative to the pitch frame coordinate system, β: first derivative of time; T: denotes matrix transpose;

[0076] In the coordinate system establishment module, when the pitch frame revolves around Oz t When the axis rotates by an angle α relative to the table coordinate system, the angular acceleration of the pitch frame is:

[0077] When the gimbal's orientation frame revolves around Oy o When the axis rotates by an angle β relative to the pitch frame coordinate system, the angular acceleration of the gimbal's azimuth frame is...

[0078] The angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system is:

[0079]

[0080] In the formula, Angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system; Gimbal azimuth frame rotation axis Oy o Angular acceleration relative to the pitch frame coordinate system; R(y o ,β): Coordinate transformation matrix R(y o The derivative of β with respect to time; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular acceleration of the axis of rotation relative to the frustum coordinate system, ω o The first derivative with respect to time; Pitch frame around Oz t The angular acceleration of the axis relative to the frustum coordinate system, and the second derivative of α with respect to time; Gimbal azimuth frame rotation axis Oy o The second derivative of β with respect to time is the angular acceleration relative to the pitch frame coordinate system.

[0081] As a preferred solution for the bird monitoring PTZ control system, the drive control module uses a permanent magnet DC torque motor to drive the PTZ orientation frame according to the angular velocity and angular acceleration of the PTZ orientation frame relative to the coordinate system of the detection system.

[0082] The voltage balance equation of the permanent magnet DC torque motor is:

[0083]

[0084] The electromagnetic torque of the permanent magnet DC torque motor:

[0085] M a =C m i a

[0086] The back electromotive force of the permanent magnet DC torque motor:

[0087] E=C e ω

[0088] The transfer function model of the permanent magnet DC torque motor is as follows:

[0089]

[0090] In the formula, U a : The average value of the DC voltage applied between the two phase windings; L a The equivalent inductance of the two phases of the electric motor; Motor armature circuit current i a Rate of change over time; R a : Equivalent resistance of two phases of the motor; i a : Armature circuit current of the motor; E a : Back electromotive force of the motor; M a : Electromagnetic torque of the motor; C m : Torque coefficient of the motor; G(s): Transfer function of the motor, where s is the Laplace operator used to convert differential equations in the time domain into algebraic equations in the complex frequency domain; J m : Moment of inertia of the motor; J L The moment of inertia of the load;

[0091] In the target tracking module, the servo controller includes a tracking differentiator, an extended state observer, and a nonlinear state error feedback control law;

[0092] The formula for arranging the transition process and extracting the differential signal using the tracking differentiator is:

[0093]

[0094] In the formula, e1(t): tracking error, which is the difference between u1(t) and u0(t);

[0095] u1(t), u2(t): Tracking the internal variables of the differentiator, where u2(t) is the input signal; Let u1(t) be the derivative of u1(t) with respect to time.

[0096] u0(t): The quantity calculated by the function fhan(u1(t),u2(t),r,h);

[0097] r: Fast factor, used to affect the response speed of the tracking differentiator;

[0098] h: Filter factor, which plays a role in filtering the signal;

[0099] The extended state observer estimates the state of the controlled object and the total disturbance based on the output and input control signals of the controlled object, using the following formula:

[0100]

[0101] In the formula, e2(t): system error, which is the difference between the output y(t) and z1(t) of the controlled object;

[0102] Let z1(t), z2(t), and z3(t) be the time derivatives of the state variables z1(t), z2(t), and z3(t) estimated by the extended state observer, respectively.

[0103] β1, β2, β3: Observer parameters used to adjust the performance of the extended state observer;

[0104] sgn(e(t)): The sign function, which outputs the corresponding sign value based on the sign of e(t);

[0105] b0: A coefficient that is used in the calculation of terms related to the input control signal u(t) in the formula;

[0106] The control law is calculated using the following formula:

[0107]

[0108] In the formula, u(t): the final control quantity, which is the signal output by the system used to control the controlled object;

[0109] The proportional gain and derivative gain parameters are used to adjust the proportional and derivative action strength of the control law;

[0110] α1, α2: Nonlinear factors that affect the nonlinear characteristics of the control law;

[0111] δ1, δ2: Filtering parameters;

[0112] fal: Nonlinear function.

[0113] The beneficial effects of this invention are as follows:

[0114] First, improve tracking accuracy: By establishing a coordinate system for the detection system and obtaining the transformation relationship between the coordinate systems, the angular velocity and angular acceleration of the pan-tilt frame are accurately determined. Combined with a three-closed-loop control architecture, the image processing system is used to lock onto the bird target, achieving precise tracking and ensuring that the bird target is always in the center of the monitoring camera's field of view, effectively improving the tracking accuracy of the bird target.

[0115] Second, enhance anti-interference capability: The gyroscope serves as the angular velocity feedback element, and the angular displacement sensor serves as the position feedback element. Together with the current loop negative feedback and the gyroscope stabilization loop, it suppresses interference angular rates and can still operate stably in complex environments, reducing the impact of external interference on PTZ control and ensuring the stability and reliability of monitoring.

[0116] Third, it enables flexible mode switching: it can switch between tracking, locking, or angular rate stabilization modes according to control commands to meet the needs of different monitoring scenarios, such as tracking birds in flight and locking the attitude when specific observation needs are required, thus enhancing the flexibility and adaptability of gimbal control. Attached Figure Description

[0117] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0118] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0119] Figure 1 This is a schematic diagram of the bird monitoring PTZ control method provided in an embodiment of the present invention;

[0120] Figure 2 This is a schematic diagram of the three-closed-loop design of the bird monitoring PTZ control method provided in an embodiment of the present invention;

[0121] Figure 3 This is a block diagram illustrating the principle of the bird monitoring PTZ control method provided in an embodiment of the present invention.

[0122] Figure 4 This is a schematic diagram of the coordinate system in the bird monitoring pan-tilt control method provided in this embodiment of the invention;

[0123] Figure 5 Ox in the bird monitoring pan-tilt control method provided in the embodiments of the present invention o y o z o Schematic diagram of rotation around the Oz axis by an angle α;

[0124] Figure 6 In the bird monitoring pan-tilt control method provided in the embodiments of the present invention, y o Axis around Ox o y o z o Schematic diagram of rotation angle β;

[0125] Figure 7 This is a schematic diagram illustrating the relationship between control voltage and the controlled object in the bird monitoring PTZ control method provided in this embodiment of the invention;

[0126] Figure 8 The mathematical model of the motor in the bird monitoring PTZ control method provided in this embodiment of the invention;

[0127] Figure 9 This is the structure of a second-order active disturbance rejection controller in the bird monitoring PTZ control method provided in this embodiment of the invention;

[0128] Figure 10 This is a schematic diagram of the bird monitoring PTZ control system architecture provided in an embodiment of the present invention. Detailed Implementation

[0129] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0130] Example 1

[0131] See Figure 1 Embodiment 1 of the present invention provides a bird monitoring pan-tilt control method, comprising the following steps:

[0132] S1. Establish the detection system coordinate system, which includes the platform coordinate system, the pitch frame coordinate system, and the azimuth frame coordinate system. Obtain the transformation relationship between the platform coordinate system, the pitch frame coordinate system, and the azimuth frame coordinate system, and determine the angular velocity and angular acceleration of the gimbal azimuth frame relative to the detection system coordinate system.

[0133] S2. Drive the gimbal orientation frame according to the angular velocity and angular acceleration of the gimbal orientation frame relative to the coordinate system of the detection system. Use the gyroscope as the angular velocity feedback element and the angular displacement sensor as the position feedback element to construct a three-closed-loop control architecture including a current loop, a gyroscope stabilization loop control loop, a target tracking control loop and an attitude locking control loop.

[0134] S3. Switch between tracking mode, locking mode or angular rate stabilization mode in open loop state according to control command. Close the target tracking control loop in tracking mode, close the attitude locking control loop in locking mode, and in angular rate stabilization mode, the current loop uses the current Hall sensor as the current detection element to form negative current feedback. The gyroscope stabilization loop control loop suppresses the interference angular rate on the rotation axis.

[0135] S4. The image processing system locks the bird target in the field of view of the pan-tilt unit, sends the bird target miss distance to the servo controller, executes the control calculation of the target tracking control loop, and brings the control calculation result of the target tracking control loop into the gyroscope stabilization loop control loop to realize the tracking of the bird target.

[0136] In this embodiment, the gimbal employs a high-precision servo motor and an angle encoder, and incorporates MEMS detachment for closed-loop motion control, enabling more stable target tracking. The monitoring module detects the bird target's position in real time, controls the gimbal turntable to keep the bird target always centered in the monitoring camera's field of view, and simultaneously activates a laser to deter birds, ensuring timely removal even during bird movement, thus improving the real-time performance of bird deterrence.

[0137] See Figure 2 The gimbal control system design employs second-order nonlinear function control. A friction torque model of the system is established, and the resulting object model is integrated into the established control mathematical model. PID parameter adjustment is then performed to match indicators such as isolation and bandwidth. Here, ω(t) represents the angular velocity signal input to the detection system, θ(t) represents the deflection angle signal input to the detection system, and M... f For the disturbance torque, ω dLet θ be the angular rate of disturbance transmitted from the aircraft motion to the stabilized platform, and θ be the angle of deflection of the platform frame axis. The input to the control system is the pitch or yaw angle of the detection system, and the output is the motor rotation angle θ. First, the pitch or yaw angle is converted into the motor speed ω(t) through calculations of the detection system's dynamic equations and coordinate system transformation. The motor speed is controlled by a three-loop active disturbance rejection controller to achieve high stability margin and strong anti-interference capability. The three closed loops are the innermost current loop, the middle gyro stabilization loop control loop, and the outermost target tracking and attitude locking control loop. The controller switches between tracking mode and locking mode according to instructions. In tracking mode, the target tracking loop is closed; in locking mode, the attitude locking loop is closed; and in open-loop mode, it is in angular rate stabilization mode.

[0138] The adoption of a three-loop cascade control scheme—position-velocity-current—ensures the reliability and robustness of the detection system's stable control under complex operating environments. The position loop, the outer loop of the servo control system, aims to ensure zero steady-state error in position following and determines the accuracy of target position tracking control. The velocity loop, the inner loop, determines the speed at which the line of sight moves from the current position to the target position, playing a crucial role in the system's speed and stability; therefore, the velocity loop holds a significant position in the servo system.

[0139] Specifically, the current loop improves torque stiffness and reduces unstable control caused by current instability. The current loop uses a Hall effect sensor as the current detection element, forming negative feedback to prevent sudden changes in motor current. The gyro stabilization loop suppresses interference angular velocities on the rotation axis, ensuring the optical axis of the photoelectric load on the stabilizing platform remains stable in inertial space. The target tracking control loop, introduced based on the gyro stabilization loop, uses the image processing system to lock the target in the field of view and sends the target miss distance to the servo controller. It then performs tracking loop control calculations, inputs the results into the gyro stabilization loop, drives the motor to rotate the photoelectric load, and performs target tracking motion, keeping the target always centered in the field of view. The attitude locking control loop adjusts the platform's attitude angles according to the control commands input to the stabilizing platform, locking the two frame axes of the platform to specific angles to achieve zero-angle platform frame angles or enter a protection state.

[0140] Based on the method of platform stabilization, stabilization platforms can be divided into two primary stabilization platforms: platform-based stabilization and mirror-based stabilization, as well as a secondary stabilization platform consisting of a platform and a mirror. Among these, the primary gyroscope-stabilized platform has been widely used. It employs a ring-frame system as the optical platform for a photoelectric sensor. A gyroscope is placed on the platform to measure its motion. Changes in the gyroscope's sensitive attitude angle are amplified and then drive a torque motor in the ring-frame. This torque motor drives the platform to keep the photoelectric sensor's line of sight stable.

[0141] SeeFigure 3 The detection system employs a two-axis, single-stage gyroscope stabilization method. It primarily consists of a velocity loop composed of rate gyroscopes and a position loop integrated with the information processing system. A current loop, which improves motor response, is included within the velocity loop. A ring frame system serves as the optical platform for the photoelectric sensor. Gyroscopes are placed on the platform to measure its motion. Changes in the gyroscope's sensitive attitude angle are amplified and drive a torque motor on the ring frame. This torque motor drives the platform, stabilizing the photoelectric sensor's line of sight, thus achieving stabilization and search functions. Once a target is locked, the information processing system provides a target position deviation signal. The position controller converts this into a velocity command, which is output to the velocity loop, driving the photoelectric sensor's line of sight to follow the target's movement, thereby achieving the tracking function.

[0142] See Figure 4 , Figure 5 and Figure 6 In one possible embodiment, during step S1, when obtaining the transformation relationship between the platform coordinate system, the pitch frame coordinate system, and the azimuth frame coordinate system:

[0143] When the pitch frame rotates about the Oz axis relative to the table coordinate system, the transformation relationship between the table coordinate system and the pitch frame coordinate system is represented by the coordinate transformation matrix R(z,α):

[0144]

[0145] When the gimbal's azimuth frame rotates about its axis relative to the pitch frame coordinate system, the transformation relationship between the azimuth and pitch frame coordinate systems is achieved through the coordinate transformation matrix R(y). o ,β) means:

[0146]

[0147] In the formula, α is the angle of rotation of the pitch frame around the Oz axis relative to the platform coordinate system; β is the angle of rotation of the gimbal azimuth frame around the axis relative to the pitch frame coordinate system.

[0148] As a preferred method for controlling a bird monitoring pan-tilt unit, the process of determining the angular velocity and angular acceleration of the pan-tilt unit's orientation frame relative to the coordinate system of the detection system includes:

[0149] When the pitch frame rotates around Oz t When the axis rotates by an angle α relative to the table coordinate system, the angular velocity of the pitch frame

[0150] When the gimbal's orientation frame revolves around Oy o When the axis rotates by an angle β relative to the pitch frame coordinate system, the angular velocity of the gimbal's azimuth frame is...

[0151] The synthesized angular velocity of the gimbal's orientation frame relative to the detection system's coordinate system is as follows:

[0152]

[0153] In the formula, w m : Angular velocity of the gimbal's orientation frame relative to the detection system's coordinate system; w mm : Gimbal azimuth frame around axis Oy o Angular velocity of rotation relative to the pitch frame coordinate system; R(y o ,β): Azimuth frame about axis Oy o The coordinate transformation matrix relative to the pitch frame coordinate system when rotated by an angle β; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular velocity of the axis relative to the frustum coordinate system, and the first derivative of α with respect to time; Gimbal azimuth frame rotation axis Oy o β is the first derivative of β with respect to time, representing the angular velocity of rotation relative to the pitch frame coordinate system; T: denotes matrix transpose.

[0154] As a preferred solution for bird monitoring pan-tilt control methods, when the pitch frame rotates around Oz t When the axis rotates by an angle α relative to the table coordinate system, the angular acceleration of the pitch frame is:

[0155] When the gimbal's orientation frame revolves around Oy o When the axis rotates by an angle β relative to the pitch frame coordinate system, the angular acceleration of the gimbal's azimuth frame is...

[0156] The angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system is:

[0157]

[0158] In the formula, Angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system; Gimbal azimuth frame rotation axis Oy o Angular acceleration relative to the pitch frame coordinate system; Coordinate transformation matrix R(y) o The derivative of β with respect to time; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular acceleration of the axis of rotation relative to the frustum coordinate system, ω o The first derivative with respect to time; Pitch frame around Oz t The angular acceleration of the axis relative to the frustum coordinate system, and the second derivative of α with respect to time; Gimbal azimuth frame rotation axis Oy o The second derivative of β with respect to time is the angular acceleration relative to the pitch frame coordinate system.

[0159] See Figure 7 and Figure 8 In one possible embodiment, a permanent magnet DC torque motor is used to drive the gimbal azimuth frame according to the angular velocity and angular acceleration of the gimbal azimuth frame relative to the coordinate system of the detection system.

[0160] The voltage balance equation of the permanent magnet DC torque motor is:

[0161]

[0162] The electromagnetic torque of the permanent magnet DC torque motor:

[0163] M a =C m i a (t)

[0164] The back electromotive force of the permanent magnet DC torque motor:

[0165] E=C e ω

[0166] The transfer function model of the permanent magnet DC torque motor is as follows:

[0167]

[0168] In the formula, U a : The average value of the DC voltage applied between the two phase windings; L a The equivalent inductance of the two phases of the electric motor; Motor armature circuit current i a Rate of change over time; R a : Equivalent resistance of two phases of the motor; i a : Armature circuit current of the motor; E a : Back electromotive force of the motor; M a : Electromagnetic torque of the motor; C m : Torque coefficient of the motor; G(s): Transfer function of the motor, where s is the Laplace operator used to convert differential equations in the time domain into algebraic equations in the complex frequency domain; J m : Moment of inertia of the motor; J L : Moment of inertia of the load.

[0169] Specifically, a permanent magnet DC torque motor is a device that converts electrical energy into mechanical energy, and its operation is based on the principle of electromagnetic induction. Inside the motor, permanent magnets generate a fixed magnetic field. When current passes through the armature windings, it interacts with this magnetic field to generate an electromagnetic force, which in turn forms an electromagnetic torque that drives the motor shaft to rotate.

[0170] During motor operation, the applied voltage needs to overcome various potentials and resistance voltage drops. The average DC voltage U applied between the two phase windings... a One part is used to resist the induced electromotive force generated by the inductor, that is (where L) a It is the two-phase equivalent inductance of the electric motor. It is the armature circuit current i of the motor. a (Rate of change with respect to time); a portion is used to overcome the voltage drop caused by the winding resistance, i.e., R a i a (R a i is the equivalent resistance of the two phases of the motor. a (This is the armature circuit current of the motor); another part is used to balance the back electromotive force E generated when the motor rotates.

[0171] According to Ampere's law, a current-carrying conductor in a magnetic field experiences an electromagnetic force. In a permanent magnet DC torque motor, the armature current i a The electromagnetic torque M is generated by the interaction of the magnetic field produced by the permanent magnet. a It is proportional to the armature current, and the proportionality constant is the torque coefficient C of the motor. m M a =C m i a This electromagnetic torque is used to drive the movement of the motor and the connected load (such as the gimbal azimuth frame).

[0172] When a motor rotates, the armature winding cuts magnetic lines of force in the magnetic field, generating an induced electromotive force (EMF) according to the law of electromagnetic induction. This EMF is in the opposite direction to the applied voltage and is called the back EMF, E. The magnitude of the back EMF is directly proportional to the motor's rotational speed and also related to the motor's structural parameters. In a permanent magnet DC torque motor, the back EMF can be expressed as a function of parameters such as the motor's rotational speed.

[0173] A transfer function is a mathematical model that describes the relationship between the input and output of a system in the complex frequency domain. It incorporates the voltage balance equations of the motor, the electromagnetic torque equations, and the moment of inertia (J) of the motor and load. m J is the moment of inertia of the motor. lBy considering factors such as the load's moment of inertia, and through Laplace transform (where s is the Laplace operator used to convert differential equations in the time domain into algebraic equations in the complex frequency domain), the transfer function model of the permanent magnet DC torque motor can be obtained. The model describes the control relationship between the control voltage and the controlled object (the gimbal orientation frame). By analyzing the transfer function, the dynamic performance of the motor (such as response speed and stability) can be studied, and a corresponding control system can be designed. Thus, based on the angular velocity and angular acceleration of the gimbal orientation frame relative to the coordinate system of the detection system, the permanent magnet DC torque motor can be precisely controlled to drive the gimbal orientation frame.

[0174] See Figure 9 In one possible embodiment, the servo controller includes a tracking differentiator, an extended state observer, and a nonlinear state error feedback control law;

[0175] The formula for arranging the transition process and extracting the differential signal using the tracking differentiator is:

[0176]

[0177] In the formula, e1(t): tracking error, which is the difference between u1(t) and u0(t); u1(t) and u2(t): internal variables of the tracking differentiator, where u2(t) is the input signal; The derivative of u1(t) with respect to time is given by: u0(t): a quantity calculated by the function fhan(u1(t),u2(t),r,h); r: a fast factor used to affect the response speed of the tracking differentiator; h: a filtering factor used to filter the signal.

[0178] Specifically, the formula e1(t) = u1(t) - u0(t) is used to calculate the tracking error e1(t), which reflects the difference between the internal variable u1(t) of the tracking differentiator and the quantity u0(t) calculated by the function fhan. This error value can be used for subsequent evaluation and adjustment of the system tracking performance. This indicates that the time derivative of the internal variable u1(t) of the tracking differentiator is equal to the input signal u2(t). Through this relationship, the tracking differentiator can extract information similar to the derivative from the input signal u2(t), thereby obtaining the trend of signal change. This is crucial for predicting the future state of the system and making control adjustments in advance. For example, when a gimbal tracks a bird target, it can predict its movement trend based on the derivative information of the target's position signal. In u0(t) = fhan(u1(t), u2(t), r, h), the fhan function calculates u0(t) based on the internal variable u1(t) of the tracking differentiator, the input signal u2(t), and the fast factor r and the filter factor h. The larger the fast factor r, the faster the tracking speed, enabling the system to respond quickly to changes in the input signal. The filter factor h filters the signal, removing high-frequency noise interference, making the generated u0(t) a smooth transition signal, avoiding overshoot or oscillation caused by sudden changes in the input signal, and ensuring that the system smoothly tracks the given input value.

[0179] Among them, the extended state observer estimates the state of the controlled object and the total disturbance based on the output and input control signals of the controlled object, as shown in the following formula:

[0180]

[0181] In the formula, e2(t): system error, which is the difference between the output y(t) and z1(t) of the controlled object; β1, β2, β3: β1, β2, β3: observer parameters used to adjust the performance of the extended state observer; sgn(e(t)): sign function, outputting the sign value according to the positive or negative sign of e(t); b0: a coefficient used in the formula to calculate terms related to the input control signal u(t).

[0182] Specifically, The system error e2(t) is determined, which is the difference between the actual output y(t) of the controlled object and the state variables estimated by the extended state observer. The difference between the estimated and actual values ​​reflects the degree of deviation between the observer's estimate and the actual value, and is an important basis for subsequent adjustments to the estimated state. and The state variables estimated by the extended state observer were calculated respectively. The derivatives with respect to time. These derivatives are calculated by combining the system error e(t), observer parameters β1, β2, β3, the sign function sgn(e(t)), the input control signal u(t), and the coefficient b0. Through this calculation method, the observer can dynamically update the estimated values ​​of the controlled object's state variables based on the current system error and the input signal, making them as close as possible to the actual state. Observer parameters β1, β2, and β3 are used to adjust the performance of the extended state observer, such as adjusting the estimation speed and accuracy; the sign function sgn(e(t)) adjusts its calculation direction according to the sign of the system error e(t) to better adapt to system changes; the coefficient b0 participates in the calculation related to the input control signal u(t), enabling the observer to consider the influence of the control signal on the system state, thereby more accurately estimating the controlled object's state and the total disturbance.

[0183] The formula for calculating the control law using the nonlinear state error feedback control law is:

[0184]

[0185] In the formula, u(t): the final control quantity, which is the signal output by the system used to control the controlled object; Proportional gain and derivative gain parameters are used to adjust the proportional and derivative action strength of the control law; α1, α2: nonlinear factors that affect the nonlinear characteristics of the control law; δ1, δ2: filter parameters; fal: nonlinear function.

[0186] Specifically, and Two error quantities, e1(t) and e2(t), are calculated, reflecting the intermediate control quantity u0(t) and the state variables estimated by the extended state observer, respectively. The differences between them, and the two state variables estimated by the extended state observer. and The differences between them. These error quantities are the basis for calculating the control rate. The two error quantities e1(t) and e2(t) are processed using the nonlinear function fal, combined with the proportional gain and differential gain parameters. The intermediate control quantity u0(t) is calculated using nonlinear factors α1 and α2 and filter parameters δ1 and δ2. The proportional and derivative gain parameters are used to adjust the proportional and derivative action strengths of the control law to balance the system's response speed and stability; the nonlinear factors affect the nonlinear characteristics of the control law, enabling the system to better cope with complex nonlinear situations; the filter parameters act as filters, reducing the noise influence in the error signal. Finally, The final control quantity u(t) is obtained and output to the controlled object to adjust its behavior so that it can operate in the expected way, thereby achieving effective control of the system.

[0187] A simulation test was conducted at a medium-sized airport, assuming the airport runway is 3000 meters long and 60 meters wide, and there is a wetland around the airport that attracts a large number of birds. Multiple monitoring points were set up at both ends and sides of the runway, and the bird monitoring pan-tilt control system of this invention was installed.

[0188] (I) Bird Motion Data Simulation

[0189] Simulate a bird taking off from a wetland northeast of the airport and flying towards the runway. At t=0, the bird's initial position is 1000 meters from the runway edge and 50 meters above it; its trajectory can be approximated as a downward-sloping straight line. The initial angular velocity signals w(t) acquired by the detection system are 0.1 rad / s (horizontal direction) and 0.05 rad / s (vertical direction), the deflection angle signals θ(t) are 10° horizontally and 5° vertically, the disturbance torque M is 0.01 N·m, the disturbance angular rate ωd transmitted from the aircraft to the stabilizing platform is 0.005 rad / s, and the initial deflection angles α=0° and β=0° of the platform frame axis.

[0190] (II) Control Process Simulation

[0191] 1. Coordinate Transformation and Motion Analysis: Based on the established coordinate system, the changes in the bird's position and motion parameters in different coordinate systems are calculated. Transformations are performed between the platform coordinate system, the pitch frame coordinate system, and the azimuth frame coordinate system to determine the angular velocity and angular acceleration of the azimuth frame relative to the detection system coordinate system. For example, after 1 second, the change in the angular velocity of the azimuth frame is calculated using the coordinate transformation formula, providing data for subsequent control command generation.

[0192] 2. Control Command Generation: The collected angle data is converted into a motor speed signal through calculations using the dynamic equations of the detection system and coordinate system transformation. A three-loop active disturbance rejection controller (ADRC) is used to generate motor control commands. For example, the current loop controls the motor based on the voltage balance equation and electromagnetic torque formula of the DC torque motor. Each part of the ADRC operates according to the set parameters. Assume the ADRC parameters are: tracking differentiator fast factor r = 3.1, filter factor h = 0.001; extended state observer parameters β1 = 1000, β2 = 16000, β3 = 800000, disturbance compensation factor b0 = 2; nonlinear state error feedback control law parameters β11 = 40, β12 = 0.8, α1 = 0.5, α2 = 0.25, δ = 0.05.

[0193] 3. Bird Tracking and Repelling Execution: The motor drives the gimbal to rotate according to control commands, tracking the bird target. At t=3 seconds, the gimbal successfully stabilizes the bird's position in the center of the monitoring camera's field of view. At this time, the multi-shape laser is activated, selecting a fan-shaped laser beam to scare the bird away. Calculations show that within 3-5 seconds, the bird changes its flight direction, moves away from the runway, and is successfully driven away.

[0194] Test data

[0195] A month-long trial was conducted at the airport to compare the effects of installing the system using the method of this invention before and after installation, as well as with traditional bird deterrence methods.

[0196] (I) Statistics on the number of bird invasions

[0197] 1. Before the installation of the system of this invention: On average, birds invaded the airport runway and surrounding dangerous areas 15 times per day.

[0198] 2. After installing the system of this invention: the average number of bird intrusions per day is reduced to 5.

[0199] 3. Comparison of traditional bird deterrence methods (such as sound deterrence, scarecrow deterrence, etc.) with the same period: The average number of bird intrusions per day was 10.

[0200] (II) Comparison of Bird Repelling Success Rates

[0201] 1. This invention achieves a 90% success rate in repelling invasive birds. Among the successfully repelled birds, 80% changed their flight direction and moved away from the airport after the first laser irradiation; 10% were repelled after 2-3 laser irradiations; and the remaining 10% were repelled under alternating irradiation with lasers of various shapes.

[0202] 2. Traditional bird deterrence methods: The success rate is only 60%. Among them, the effectiveness of sound deterrence decreases significantly after birds become accustomed to it, and it is ineffective for about 40% of birds; scarecrows are not very effective for some large birds, and can only deter about 30% of large birds.

[0203] (III) Flight Delay Statistics

[0204] 1. Before the installation of the system of this invention: the average monthly flight delays caused by bird intrusions were 20 hours.

[0205] 2. After installing the system of this invention: the average monthly flight delays caused by bird intrusions are reduced to 5 hours.

[0206] 3. Traditional bird control methods: Flight delays caused by bird intrusion average 12 hours per month.

[0207] The above examples and experimental data demonstrate that the bird monitoring PTZ control method and system of the present invention can effectively reduce the number of bird intrusions, improve the success rate of bird deterrence, reduce flight delays caused by bird problems, and ensure the flight safety and normal operation of the airport in airport scenarios.

[0208] Example 2

[0209] See Figure 10 Embodiment 2 of the present invention also provides a bird monitoring pan-tilt control system, comprising:

[0210] The coordinate system establishment module 001 is used to establish the detection system coordinate system, which includes the platform coordinate system, the pitch frame coordinate system and the azimuth frame coordinate system. It obtains the transformation relationship between the platform coordinate system, the pitch frame coordinate system and the azimuth frame coordinate system, and determines the angular velocity and angular acceleration of the gimbal azimuth frame relative to the detection system coordinate system.

[0211] The drive control module 002 is used to drive the gimbal orientation frame according to the angular velocity and angular acceleration of the gimbal orientation frame relative to the coordinate system of the detection system. It uses a gyroscope as an angular velocity feedback element and an angular displacement sensor as a position feedback element to construct a three-closed-loop control architecture including a current loop, a gyroscope stabilization loop control loop, a target tracking control loop and an attitude locking control loop.

[0212] The mode switching module 003 is used to switch between tracking mode, locking mode or angular rate stabilization mode in open loop state according to control commands. In the tracking mode, the target tracking control loop is closed. In the locking mode, the attitude locking control loop is closed. In the angular rate stabilization mode, the current loop uses the current Hall sensor as the current detection element to form negative current feedback. The gyroscope stabilization loop control loop suppresses the interference angular rate on the rotation axis.

[0213] The target tracking module 004 is used to lock the bird target in the field of view of the pan-tilt unit through the image processing system, send the bird target miss distance to the servo controller, execute the control calculation of the target tracking control loop, and bring the control calculation result of the target tracking control loop into the gyroscope stabilization loop control loop to realize the tracking of the bird target.

[0214] In this embodiment, in the coordinate system establishment module 001, when the pitch frame rotates about the Oz axis relative to the stage coordinate system, the transformation relationship between the stage coordinate system and the pitch frame coordinate system is represented by the coordinate transformation matrix R(z,α):

[0215]

[0216] When the gimbal's azimuth frame rotates about its axis relative to the pitch frame coordinate system, the transformation relationship between the azimuth and pitch frame coordinate systems is achieved through the coordinate transformation matrix R(y). o ,β) means:

[0217]

[0218] In the formula, α is the angle of rotation of the pitch frame about the Oz axis relative to the platform coordinate system; β is the angle of rotation of the gimbal azimuth frame about the axis relative to the pitch frame coordinate system.

[0219] In the coordinate system establishment module 001, when the pitch frame rotates around Oz t When the axis rotates by an angle α relative to the table coordinate system, the angular velocity of the pitch frame

[0220] When the gimbal's orientation frame revolves around Oy o When the axis rotates by an angle β relative to the pitch frame coordinate system, the angular velocity of the gimbal's azimuth frame is...

[0221] The synthesized angular velocity of the gimbal's orientation frame relative to the detection system's coordinate system is as follows:

[0222]

[0223] In the formula, w m : Angular velocity of the gimbal's orientation frame relative to the detection system's coordinate system; w mm : Gimbal azimuth frame around axis Oy o Angular velocity of rotation relative to the pitch frame coordinate system; R(y o ,β): Azimuth frame about axis Oy o The coordinate transformation matrix relative to the pitch frame coordinate system when rotated by an angle β; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular velocity of the axis relative to the frustum coordinate system, and the first derivative of α with respect to time; Gimbal azimuth frame rotation axis Oy o Angular velocity of rotation relative to the pitch frame coordinate system, β: first derivative of time; T: denotes matrix transpose;

[0224] In the coordinate system establishment module 001, when the pitch frame rotates around Oz t When the axis rotates by an angle α relative to the table coordinate system, the angular acceleration of the pitch frame is:

[0225] When the gimbal's orientation frame revolves around Oy oWhen the axis rotates by an angle β relative to the pitch frame coordinate system, the angular acceleration of the gimbal's azimuth frame is...

[0226] The angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system is:

[0227]

[0228] In the formula, Angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system; Gimbal azimuth frame rotation axis Oy o Angular acceleration relative to the pitch frame coordinate system; Coordinate transformation matrix R(y) o The derivative of β with respect to time; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular acceleration of the axis of rotation relative to the frustum coordinate system, ω o The first derivative with respect to time; Pitch frame around Oz t The angular acceleration of the axis relative to the frustum coordinate system, and the second derivative of α with respect to time; Gimbal azimuth frame rotation axis Oy o The second derivative of β with respect to time is the angular acceleration relative to the pitch frame coordinate system.

[0229] In this embodiment, the drive control module 002 uses a permanent magnet DC torque motor to drive the gimbal orientation frame according to the angular velocity and angular acceleration of the gimbal orientation frame relative to the coordinate system of the detection system.

[0230] The voltage balance equation of the permanent magnet DC torque motor is:

[0231]

[0232] The electromagnetic torque of the permanent magnet DC torque motor:

[0233] M a =C m i a

[0234] The back electromotive force of the permanent magnet DC torque motor:

[0235] E=C e ω

[0236] The transfer function model of the permanent magnet DC torque motor is as follows:

[0237]

[0238] In the formula, U a : The average value of the DC voltage applied between the two phase windings; L a The equivalent inductance of the two phases of the electric motor; Motor armature circuit current i a Rate of change over time; R a : Equivalent resistance of two phases of the motor; i a : Armature circuit current of the motor; E a : Back electromotive force of the motor; M a : Electromagnetic torque of the motor; C m : Torque coefficient of the motor; G(s): Transfer function of the motor, where s is the Laplace operator used to convert differential equations in the time domain into algebraic equations in the complex frequency domain; J m : Moment of inertia of the motor; J L The moment of inertia of the load;

[0239] In the target tracking module 004, the servo controller includes a tracking differentiator, an extended state observer, and a nonlinear state error feedback control law;

[0240] The formula for arranging the transition process and extracting the differential signal using the tracking differentiator is:

[0241]

[0242] In the formula, e1(t): tracking error, which is the difference between u1(t) and u0(t);

[0243] u1(t), u2(t): Tracking the internal variables of the differentiator, where u2(t) is the input signal; Let u1(t) be the derivative of u1(t) with respect to time.

[0244] u0(t): The quantity calculated by the function fhan(u1(t),u2(t),r,h);

[0245] r: Fast factor, used to affect the response speed of the tracking differentiator;

[0246] h: Filter factor, which plays a role in filtering the signal;

[0247] The extended state observer estimates the state of the controlled object and the total disturbance based on the output and input control signals of the controlled object, using the following formula:

[0248]

[0249] In the formula, e2(t): system error, which is the difference between the output y(t) and z1(t) of the controlled object;

[0250] Let z1(t), z2(t), and z3(t) be the time derivatives of the state variables z1(t), z2(t), and z3(t) estimated by the extended state observer, respectively.

[0251] β1, β2, β3: Observer parameters used to adjust the performance of the extended state observer;

[0252] sgn(e(t)): The sign function, which outputs the corresponding sign value based on the sign of e(t);

[0253] b0: A coefficient that is used in the calculation of terms related to the input control signal u(t) in the formula;

[0254] The control law is calculated using the following formula:

[0255]

[0256] In the formula, u(t): the final control quantity, which is the signal output by the system used to control the controlled object;

[0257] The proportional gain and derivative gain parameters are used to adjust the proportional and derivative action strength of the control law;

[0258] α1, α2: Nonlinear factors that affect the nonlinear characteristics of the control law;

[0259] δ1, δ2: Filtering parameters;

[0260] fal: Nonlinear function.

[0261] It should be noted that the information interaction and execution process between the modules of the above system are based on the same concept as the method embodiment in Embodiment 1 of this application, and the resulting technical effects are the same as those in the method embodiment of this application. For details, please refer to the description in the method embodiment shown above in this application, and it will not be repeated here.

[0262] Example 3

[0263] Embodiment 3 of the present invention provides a non-transitory computer-readable storage medium storing program code for a bird monitoring pan-tilt control method. The program code includes instructions for executing the bird monitoring pan-tilt control method of Embodiment 1 or any possible implementation thereof.

[0264] Computer-readable storage media can be any available medium that a computer can access, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives, SSDs).

[0265] Example 4

[0266] Embodiment 4 of the present invention provides an electronic device, including: a memory and a processor;

[0267] The processor and the memory communicate with each other via a bus; the memory stores program instructions that can be executed by the processor, and the processor can execute the bird monitoring PTZ control method of Embodiment 1 or any possible implementation thereof by calling the program instructions.

[0268] Specifically, a processor can be implemented in hardware or software. When implemented in hardware, the processor can be a logic circuit, an integrated circuit, etc. When implemented in software, the processor can be a general-purpose processor that reads software code stored in memory. This memory can be integrated into the processor or located outside the processor and exist independently.

[0269] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0270] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0271] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for controlling a bird monitoring pan-tilt unit, characterized in that, Includes the following steps: Establish a detection system coordinate system, which includes a platform coordinate system, a pitch frame coordinate system, and an azimuth frame coordinate system. Obtain the transformation relationship between the platform coordinate system, the pitch frame coordinate system, and the azimuth frame coordinate system, and determine the angular velocity and angular acceleration of the gimbal azimuth frame relative to the detection system coordinate system. The gimbal orientation frame is driven by the angular velocity and angular acceleration of the gimbal orientation frame relative to the coordinate system of the detection system. A three-closed-loop control architecture is constructed, which includes a current loop, a gyroscope stabilization loop control loop, a target tracking control loop, and an attitude locking control loop, using a gyroscope as an angular velocity feedback element and an angular displacement sensor as a position feedback element. According to the control command, the tracking mode, locking mode or angular rate stabilization mode in open loop state are switched. In the tracking mode, the target tracking control loop is closed. In the locking mode, the attitude locking control loop is closed. In the angular rate stabilization mode, the current loop uses the current Hall sensor as the current detection element to form negative current feedback. The gyroscope stabilization loop control loop suppresses the interference angular rate on the rotation axis. The image processing system locks onto the bird target in the pan-tilt-zoom (PTZ) monitoring field of view, sends the bird target miss distance to the servo controller, executes the control calculation of the target tracking control loop, and inputs the control calculation result of the target tracking control loop into the gyroscope stabilization loop control loop to achieve bird target tracking.

2. The bird monitoring pan-tilt control method according to claim 1, characterized in that, During the process of obtaining the transformation relationship between the platform coordinate system, the pitch frame coordinate system, and the azimuth frame coordinate system: When the pitch frame rotates about the Oz axis relative to the table coordinate system, the transformation relationship between the table coordinate system and the pitch frame coordinate system is represented by the coordinate transformation matrix R(z,α): When the gimbal's azimuth frame rotates about its axis relative to the pitch frame coordinate system, the transformation relationship between the azimuth and pitch frame coordinate systems is achieved through the coordinate transformation matrix R(y). o ,β) means: In the formula, α is the angle of rotation of the pitch frame around the Oz axis relative to the platform coordinate system; β is the angle of rotation of the gimbal azimuth frame around the axis relative to the pitch frame coordinate system.

3. The bird monitoring pan-tilt control method according to claim 2, characterized in that, In determining the angular velocity and angular acceleration of the gimbal's orientation frame relative to the coordinate system of the detection system: When the pitch frame rotates around Oz t When the axis rotates by an angle α relative to the table coordinate system, the angular velocity of the pitch frame When the gimbal's orientation frame revolves around Oy o When the axis rotates by an angle β relative to the pitch frame coordinate system, the angular velocity of the gimbal's azimuth frame is... The synthesized angular velocity of the gimbal's orientation frame relative to the detection system's coordinate system is as follows: In the formula, w m : Angular velocity of the gimbal's orientation frame relative to the detection system's coordinate system; w mm : Gimbal orientation frame around axis Oy o Angular velocity of rotation relative to the pitch frame coordinate system; R(y o ,β): Azimuth frame about axis Oy o The coordinate transformation matrix relative to the pitch frame coordinate system when rotated by an angle β; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular velocity of the axis relative to the frustum coordinate system, and the first derivative of α with respect to time; Gimbal azimuth frame rotation axis Oy o β is the first derivative of β with respect to time, representing the angular velocity of rotation relative to the pitch frame coordinate system; T: denotes matrix transpose.

4. The bird monitoring pan-tilt control method according to claim 3, characterized in that, When the pitch frame rotates around Oz t When the axis rotates by an angle α relative to the table coordinate system, the angular acceleration of the pitch frame is: When the gimbal's orientation frame revolves around Oy o When the axis rotates by an angle β relative to the pitch frame coordinate system, the angular acceleration of the gimbal's azimuth frame is... The angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system is: In the formula, Angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system; Gimbal azimuth frame rotation around axis Oy o Angular acceleration relative to the pitch frame coordinate system; Coordinate transformation matrix R(y) o The derivative of β with respect to time; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular acceleration of the axis of rotation relative to the frustum coordinate system, ω o The first derivative with respect to time; Pitch frame around Oz t The angular acceleration of the axis relative to the frustum coordinate system, and the second derivative of α with respect to time; Gimbal azimuth frame rotation around axis Oy o The second derivative of β with respect to time is the angular acceleration relative to the pitch frame coordinate system.

5. The bird monitoring pan-tilt control method according to claim 1, characterized in that, A permanent magnet DC torque motor is used to drive the gimbal azimuth frame according to the angular velocity and angular acceleration of the gimbal azimuth frame relative to the coordinate system of the detection system; The voltage balance equation of the permanent magnet DC torque motor is: The electromagnetic torque of the permanent magnet DC torque motor: M a =C m i a The back electromotive force of the permanent magnet DC torque motor: EC e ω The transfer function model of the permanent magnet DC torque motor is as follows: In the formula, U a : The average value of the DC voltage applied between the two phase windings; L a The equivalent inductance of the two phases of the electric motor; Motor armature circuit current i a Rate of change over time; R a : Equivalent resistance of two phases of the motor; i a : Armature circuit current of the motor; E a : Back electromotive force of the motor; M a : Electromagnetic torque of the motor; C m : Torque coefficient of the motor; G(s): Transfer function of the motor, where s is the Laplace operator used to convert differential equations in the time domain into algebraic equations in the complex frequency domain; J m : Moment of inertia of the motor; J L : Moment of inertia of the load.

6. The bird monitoring pan-tilt control method according to claim 1, characterized in that, The servo controller includes a tracking differentiator, an extended state observer, and a nonlinear state error feedback control law; The formula for arranging the transition process and extracting the differential signal using the tracking differentiator is: In the formula, e1(t): tracking error, which is the difference between u1(t) and u0(t); u1(t), u2(t): Tracking the internal variables of the differentiator, where u2(t) is the input signal; Let u1(t) be the derivative of u1(t) with respect to time. u0(t): The quantity calculated by the function fhan(u1(t),u2(t),r,h); r: Fast factor, used to affect the response speed of the tracking differentiator; h: Filter factor, which plays a role in filtering the signal; The extended state observer estimates the state of the controlled object and the total disturbance based on the output and input control signals of the controlled object, using the following formula: In the formula, e2(t): system error, which is the difference between the output y(t) and z1(t) of the controlled object; Let z1(t), z2(t), and z3(t) be the time derivatives of the state variables z1(t), z2(t), and z3(t) estimated by the extended state observer, respectively. β1, β2, β3: Observer parameters used to adjust the performance of the extended state observer; sgn(e(t)): The sign function, which outputs the sign value according to the sign of e(t); b0: A coefficient that is used in the calculation of terms related to the input control signal u(t) in the formula; The control law is calculated using the following formula: In the formula, u(t): the final control quantity, which is the signal output by the system used to control the controlled object; The proportional gain and derivative gain parameters are used to adjust the proportional and derivative action strength of the control law; α1, α2: Nonlinear factors that affect the nonlinear characteristics of the control law; δ1, δ2: Filtering parameters; fal: Nonlinear function.

7. A bird monitoring pan-tilt control system, characterized in that, include: The coordinate system establishment module is used to establish the detection system coordinate system, which includes the platform coordinate system, the pitch frame coordinate system, and the azimuth frame coordinate system. It obtains the transformation relationship between the platform coordinate system, the pitch frame coordinate system, and the azimuth frame coordinate system, and determines the angular velocity and angular acceleration of the gimbal azimuth frame relative to the detection system coordinate system. The drive control module is used to drive the gimbal orientation frame according to the angular velocity and angular acceleration of the gimbal orientation frame relative to the coordinate system of the detection system. It uses a gyroscope as an angular velocity feedback element and an angular displacement sensor as a position feedback element to construct a three-closed-loop control architecture including a current loop, a gyroscope stabilization loop control loop, a target tracking control loop and an attitude locking control loop. The mode switching module is used to switch between tracking mode, locking mode, or angular rate stabilization mode in open loop state according to control commands. In the tracking mode, the target tracking control loop is closed; in the locking mode, the attitude locking control loop is closed; in the angular rate stabilization mode, the current loop uses a current Hall sensor as the current detection element to form negative current feedback; and the gyro stabilization loop control loop suppresses the interference angular rate on the rotation axis. The target tracking module is used to lock onto bird targets in the field of view of the pan-tilt-zoom (PTZ) camera through the image processing system, transmit the bird target miss distance to the servo controller, execute the control calculation of the target tracking control loop, and input the control calculation result of the target tracking control loop into the gyroscope stabilization loop control loop to achieve bird target tracking.

8. A bird monitoring pan-tilt control system according to claim 7, characterized in that, In the coordinate system establishment module, when the pitch frame rotates about the Oz axis relative to the stage coordinate system, the transformation relationship between the stage coordinate system and the pitch frame coordinate system is represented by the coordinate transformation matrix R(z,α): When the gimbal's azimuth frame rotates about its axis relative to the pitch frame coordinate system, the transformation relationship between the azimuth and pitch frame coordinate systems is achieved through the coordinate transformation matrix R(y). o ,β) means: In the formula, α is the angle of rotation of the pitch frame about the Oz axis relative to the platform coordinate system; β is the angle of rotation of the gimbal azimuth frame about the axis relative to the pitch frame coordinate system. In the coordinate system establishment module, when the pitch frame revolves around Oz t When the axis rotates by an angle α relative to the table coordinate system, the angular velocity of the pitch frame When the gimbal's orientation frame revolves around Oy o When the axis rotates by an angle β relative to the pitch frame coordinate system, the angular velocity of the gimbal's azimuth frame is... The synthesized angular velocity of the gimbal's orientation frame relative to the detection system's coordinate system is as follows: In the formula, w m : Angular velocity of the gimbal's orientation frame relative to the detection system's coordinate system; w mm : Gimbal orientation frame around axis Oy o Angular velocity of rotation relative to the pitch frame coordinate system; R(y o ,β): Azimuth frame about axis Oy o The coordinate transformation matrix relative to the pitch frame coordinate system when rotated by an angle β; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular velocity of the axis relative to the frustum coordinate system, and the first derivative of α with respect to time; Gimbal azimuth frame rotation around axis Oy o Angular velocity of rotation relative to the pitch frame coordinate system, β: first derivative of time; T: denotes matrix transpose; In the coordinate system establishment module, when the pitch frame revolves around Oz t When the axis rotates by an angle α relative to the table coordinate system, the angular acceleration of the pitch frame is: When the gimbal's orientation frame revolves around Oy o When the axis rotates by an angle β relative to the pitch frame coordinate system, the angular acceleration of the gimbal's azimuth frame is... The angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system is: In the formula, Angular acceleration of the gimbal's orientation frame relative to the detection system's coordinate system; Gimbal azimuth frame rotation around axis Oy o Angular acceleration relative to the pitch frame coordinate system; Coordinate transformation matrix R(y) o The derivative of β with respect to time; ω o : Pitch frame around Oz t The angular velocity of the axis relative to the table coordinate system; Pitch frame around Oz t The angular acceleration of the axis of rotation relative to the frustum coordinate system, ω o The first derivative with respect to time; Pitch frame around Oz t The angular acceleration of the axis relative to the frustum coordinate system, and the second derivative of α with respect to time; Gimbal azimuth frame rotation around axis Oy o The second derivative of β with respect to time is the angular acceleration relative to the pitch frame coordinate system.

9. A bird monitoring pan-tilt control system according to claim 8, characterized in that, In the drive control module, a permanent magnet DC torque motor is used to drive the gimbal azimuth frame according to the angular velocity and angular acceleration of the gimbal azimuth frame relative to the coordinate system of the detection system. The voltage balance equation of the permanent magnet DC torque motor is: The electromagnetic torque of the permanent magnet DC torque motor: M a =C m i a The back electromotive force of the permanent magnet DC torque motor: E=C e oh The transfer function model of the permanent magnet DC torque motor is as follows: In the formula, U a : The average value of the DC voltage applied between the two phase windings; L a The equivalent inductance of the two phases of the electric motor; Motor armature circuit current i a Rate of change over time; R a : Equivalent resistance of two phases of the motor; i a : Armature circuit current of the motor; E a : Back electromotive force of the motor; M a : Electromagnetic torque of the motor; C m : Torque coefficient of the motor; G(s): Transfer function of the motor, where s is the Laplace operator used to convert differential equations in the time domain into algebraic equations in the complex frequency domain; J m : Moment of inertia of the motor; J L : Moment of inertia of the load.

10. A bird monitoring pan-tilt control system according to claim 8, characterized in that, In the target tracking module, the servo controller includes a tracking differentiator, an extended state observer, and a nonlinear state error feedback control law; The formula for arranging the transition process and extracting the differential signal using the tracking differentiator is: In the formula, e1(t): tracking error, which is the difference between u1(t) and u0(t); u1(t), u2(t): Tracking the internal variables of the differentiator, where u2(t) is the input signal; Let u1(t) be the derivative of u1(t) with respect to time. u0(t): The quantity calculated by the function fhan(u1(t),u2(t),r,h); r: Fast factor, used to affect the response speed of the tracking differentiator; h: Filter factor, which plays a role in filtering the signal; The extended state observer estimates the state of the controlled object and the total disturbance based on the output and input control signals of the controlled object, using the following formula: In the formula, e2(t): system error, which is the difference between the output y(t) and z1(t) of the controlled object; Let z1(t), z2(t), and z3(t) be the time derivatives of the state variables z1(t), z2(t), and z3(t) estimated by the extended state observer, respectively. β1, β2, β3: Observer parameters used to adjust the performance of the extended state observer; sgn(e(t)): The sign function, which outputs the sign value according to the sign of e(t); b0: A coefficient that is used in the calculation of terms related to the input control signal u(t) in the formula; The control law is calculated using the following formula: In the formula, u(t): the final control quantity, which is the signal output by the system used to control the controlled object; The proportional gain and derivative gain parameters are used to adjust the proportional and derivative action strength of the control law; α1, α2: Nonlinear factors that affect the nonlinear characteristics of the control law; δ1, δ2: Filtering parameters; fal: Nonlinear function.

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