Three-axis holder control system based on flight platform linear acceleration compensation

Abstract

The utility model relates to a three-axis holder control system based on flight platform linear acceleration compensation. The three-axis holder control system comprises a stable frame structure assembly used for realizing pitching, rolling or yawing; the sensor assembly is used for realizing permanent magnet synchronous motor driving and angle feedback of the holder structure; the driving assembly is arranged on the stable frame structure assembly and used for driving the stable frame structure assembly to rotate; and the control circuit assembly is used for controlling the stable frame structure assembly to move. According to the three-axis holder, a pitching-rolling-yawing three-axis structural form is adopted, a three-axis motor is driven through attitude and speed closed-loop control of a servo control system to compensate disturbance torque, transmitted to the load camera frame due to disturbance of a mounting unmanned aerial vehicle platform, of the load camera frame, and therefore three-axis self-stabilization of the system is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of unmanned aerial vehicles, in particular to a three-axis gimbal control system based on linear acceleration compensation of a flight platform. Background Art

[0002] With the widespread application of drones in aerial photography, security monitoring, and mapping, higher requirements are placed on the stability and precision control of drone-mounted equipment. Traditional drone gimbal control systems have problems such as insufficient stability in complex environments and limited attitude control accuracy. In particular, when the drone carrier is continuously maneuvering, the linear acceleration or deceleration of the drone carrier will cause the three-axis acceleration value in the attitude sensor to seriously deviate from the gravity field acceleration value, resulting in inaccurate attitude data after fusion.

[0003] Therefore, it is crucial to provide a control system that improves stability and attitude control accuracy. Utility Model Content

[0004] In view of this, the utility model proposes a three-axis gimbal control system based on flight platform linear acceleration compensation, aiming to solve the problems existing in the prior art.

[0005] Specifically, the utility model provides a three-axis gimbal control system based on flight platform linear acceleration compensation, comprising:

[0006] Stable frame components for achieving pitch, roll or yaw;

[0007] Sensor components for realizing angle feedback of permanent magnet synchronous motor drive and pan-tilt structure;

[0008] A driving assembly disposed on the stable frame structure assembly for driving the stable frame structure assembly to rotate;

[0009] and a control circuit assembly for controlling the movement of the stabilizing frame structure assembly.

[0010] Based on the above solution, the stable frame structure assembly includes an azimuth axis, a roll axis and a pitch axis which are perpendicular to each other.

[0011] Based on the above solution, the stable frame structure assembly also includes:

[0012] An azimuth frame for rotating 360° around the azimuth axis, a roll frame arranged on the azimuth frame for performing rolling flight actions around the roll axis, and a pitch load frame arranged inside the roll frame for rotating around the pitch axis.

[0013] Based on the above solution, the sensor assembly includes:

[0014] An IMU attitude sensor disposed on the pitch load frame for acquiring attitude data;

[0015] Magnetic encoders for position detection are respectively arranged on the azimuth axis, the roll axis and the pitch axis;

[0016] and a photoelectric load arranged inside the pitch load frame for collecting image information.

[0017] Based on the above scheme, the driving assembly includes an azimuth motor arranged on the azimuth axis for driving the azimuth axis to rotate, a roll motor arranged on the roll axis for driving the roll axis to rotate, and a pitch motor arranged on the pitch axis for driving the pitch axis to rotate.

[0018] Based on the above scheme, the control circuit component includes a communication interface for obtaining the linear acceleration of the mounting platform, a microcontroller circuit arranged in the pitch load frame for attitude solution and three-axis stabilization control algorithm, a motor drive circuit for driving the drive component according to a trigger signal, and a conductive slip ring for realizing electrical connection between the azimuth motor and the azimuth frame.

[0019] The controller of the utility model obtains the spatial three-axis angular velocity and three-axis angular acceleration of the load camera frame through the IMU attitude sensor, and calculates the attitude angle of the load camera frame by integrating the linear acceleration compensation of the flight platform. Then, the attitude and speed closed-loop control of the servo control system drives the three-axis motor to compensate for the disturbance torque transmitted to the load camera frame by the disturbance of the mounted drone platform, thereby realizing the three-axis self-stabilization of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limiting of the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0021] Figure 1 Schematic diagram of a three-axis gimbal control system based on flight platform linear acceleration compensation in Example 1;

[0022] Figure 2 It is a structural schematic diagram of a three-axis gimbal control system based on flight platform linear acceleration compensation in Example 1;

[0023] Figure 3 This is a block diagram of the three-closed-loop control mode of the self-stabilizing servo control of the three-axis gimbal control system in Example 1. DETAILED DESCRIPTION

[0024] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments in the present utility model and the features in the embodiments can be combined with each other. The present utility model will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] Example 1

[0026] like Figure 1-2 As shown, a three-axis gimbal control system based on linear acceleration compensation of a flight platform includes a stable frame structure component 1 for realizing pitch, roll or yaw, a sensor component 2 for realizing permanent magnet synchronous motor drive and angle feedback of the gimbal structure, a control circuit component 4 for controlling the movement of the stable frame structure component 1, and a drive component 3 arranged on the stable frame structure component 1 for driving the stable frame structure component 1 to rotate.

[0027] Among them, the stable frame structure component 1 includes an azimuth axis 1-1, a roll axis 1-2 and a pitch axis 1-3 which are perpendicular to each other; it also includes: an azimuth frame 1-4 for 360° rotation around the azimuth axis 1-1, a roll frame 1-5 arranged on the azimuth frame 1-4 for rolling flight action around the roll axis 1-2, and a pitch load frame 1-6 arranged inside the roll frame 1-5 for rotating around the pitch axis 1-3. That is, from the inside to the outside, they are the pitch load frame 1-6, the roll frame 1-5 and the azimuth frame 1-4, and the structural size is compact and reasonable. The structural frame is made of aviation aluminum material, and the shell of the non-load-bearing parts is made of engineering plastic material, which can reduce the weight as much as possible while ensuring the structural strength.

[0028] The sensor assembly 2 includes an IMU attitude sensor 2-1 arranged on the pitch load frame 1-6 for acquiring attitude data, a magnetic encoder 2-2 respectively arranged on the azimuth axis 1-1, the roll axis 1-2 and the pitch axis 1-3 for position detection, and an optoelectronic load 2-3 arranged inside the pitch load frame 1-6 for collecting image information. A magnetic encoder 2-2 is installed on each of the three axes to realize the angle feedback of the permanent magnet synchronous motor drive and the gimbal structure; the IMU attitude sensor 2-1 and the optoelectronic load 2-3 are installed on the pitch load frame 1-6 to realize the measurement of the three-axis angular velocity and acceleration of the pitch load frame 1-6.

[0029] The driving assembly 3 includes an azimuth motor 3-1 arranged on the azimuth axis 1-1 for driving the azimuth axis 1-1 to rotate, a roll motor 3-2 arranged on the roll axis 1-2 for driving the roll axis 1-2 to rotate, and a pitch motor 3-3 arranged on the pitch axis 1-3 for driving the pitch axis 1-3 to rotate. Specifically, the driving assembly 3 adopts a brushless motor direct drive mode, and is composed of three brushless DC servo motors. The brushless motor direct drive mode can reduce the motor size and ensure the system stiffness and response speed.

[0030] The control circuit assembly 4 includes a communication interface for obtaining the linear acceleration of the mounting platform, a microcontroller circuit 4-2, a motor drive circuit 4-3, and a conductive slip ring 4-4 ​​for realizing the electrical connection between the azimuth motor 3-1 and the azimuth frame 1-4. Among them, the microcontroller circuit 4-2 obtains the real-time information of the IMU attitude sensor 2-1 and the magnetic encoder 2-2 and the linear acceleration data of the mounting platform through the communication interface. The microcontroller circuit 4-2 controls the motor drive circuit 4-3 to realize the control of the motors on the three axes, and drives the motors on the three axes to compensate for the spatial disturbance through the FOC control algorithm. The microcontroller circuit 4-2 obtains the real-time information of the 6-axis IMU attitude sensor 2-1, the magnetic encoder 2-2 and the linear acceleration data of the mounting platform through the communication interface. The motor drive circuit 4-3 in the three-axis gimbal control module is connected to the three-axis motor, and drives the three-axis motor to compensate for the spatial disturbance through FOC control.

[0031] like Figure 3 As shown, the self-stabilizing control algorithm of the three-axis gimbal control system adopts the PID cascade control mode, and the structure of the PID cascade control is position loop + speed loop + current loop. First, input the given parameters of the attitude position. When the system is running, the attitude data fed back after the IMU attitude sensor 2-1 data fusion is obtained and the difference is made between the given attitude position, and the result is sent to the position controller; the output of the position controller is subtracted from the speed feedback, and the result is sent to the speed controller; the output signal of the speed controller is subtracted from the current feedback, and the result is sent to the current controller, and the output of the current controller is sent to the motor drive circuit.

[0032] Example 2

[0033] A method for solving attitude calculation adopts the system in Example 1. On the basis of Example 1, a communication interface is used to input the linear motion acceleration of the platform into a microcontroller circuit to compensate the acceleration value collected by a three-axis accelerometer, eliminate the coupling superposition between the three-axis accelerometer and the gravity field caused by the linear acceleration of the carrier, and then a data fusion algorithm is performed to solve the high-precision attitude angle.

[0034] The attitude solution of this system adopts the strategy of flight platform acceleration compensation, uses the communication interface to obtain the linear acceleration of the flight platform, and then compensates the three-axis acceleration data in the IMU attitude sensor 2-1 to offset the motion acceleration in the three-axis accelerometer.

[0035] The acceleration compensation algorithm is as follows:

[0036] The linear acceleration of the aircraft based on the northeast sky coordinate system obtained from the aircraft: a=[ax1,ay1,az1]

[0037] Convert the northeast celestial coordinates from the outer frame to the inner pitch frame in sequence. The conversion process is as follows:

[0038] The three-axis attitude is defined as the yaw angle ψ, which rotates around the z-axis. The roll angle φ, which rotates around the x-axis θ, and which rotates around the y-axis. The coordinate system conversion is as follows:

[0039]

[0040] The above rotation matrix is ​​used to transform the aircraft linear acceleration based on the northeast sky coordinate system to the camera device coordinate system. The three-axis accelerometer subtracts the three-axis linear acceleration converted to the device coordinate system to obtain the compensated three-axis acceleration data.

[0041] The data of the three-axis accelerometer and three-axis gyroscope in the compensated IMU attitude sensor are then input into the microcontroller circuit to solve the attitude angle of the pitch frame through the data fusion algorithm, and then the cascade PID control algorithm is applied to output the control motion compensation for platform disturbance isolation, and then the control motion compensator is used to isolate the platform disturbance, thereby maintaining the spatial stability of the payload camera assembly.

[0042] The utility model uses a high-precision attitude sensor to obtain the inertial space angular velocity and angular acceleration of the load camera component in real time, inputs them into the microcontroller circuit and combines them with the linear acceleration of the mounting platform obtained by the external communication interface of the pan-tilt head, uses an advanced attitude solution method to solve the high-precision attitude angle of the load camera component, and inputs the solved attitude angle into the pan-tilt head servo control system for motion compensation. The imaging system has high stability, high overall system control accuracy, good stabilization effect, and fast response speed.

Claims

1. A three-axis gimbal control system based on flight platform linear acceleration compensation, characterized in that: include: A stabilizing frame structure assembly (1) for achieving pitch, roll or yaw; A sensor assembly (2) for realizing the angle feedback of the permanent magnet synchronous motor drive and the pan-tilt structure; A driving assembly (3) disposed on the stabilizing frame structure assembly (1) and used for driving the stabilizing frame structure assembly (1) to rotate; and a control circuit component (4) for controlling the movement of the stabilizing frame structure component (1).

2. The three-axis gimbal control system based on flight platform linear acceleration compensation according to claim 1, characterized in that: The stable frame structure component (1) comprises an azimuth axis (1-1), a rolling axis (1-2) and a pitch axis (1-3) which are perpendicular to each other.

3. The three-axis gimbal control system based on flight platform linear acceleration compensation according to claim 2, characterized in that: The stable frame structure assembly (1) further comprises: An azimuth frame (1-4) for rotating 360 degrees around the azimuth axis (1-1), a roll frame (1-5) arranged on the azimuth frame (1-4) for performing a rolling flight action around a roll axis (1-2), and a pitch load frame (1-6) arranged inside the roll frame (1-5) for rotating around a pitch axis (1-3).

4. The three-axis gimbal control system based on flight platform linear acceleration compensation according to claim 3, characterized in that: The sensor assembly (2) comprises: An IMU attitude sensor (2-1) arranged on the pitch load frame (1-6) for acquiring attitude data; Magnetic encoders (2-2) for position detection are respectively arranged on the azimuth axis (1-1), the roll axis (1-2) and the pitch axis (1-3); and a photoelectric load (2-3) arranged inside the pitch load frame (1-6) for collecting image information.

5. The three-axis gimbal control system based on flight platform linear acceleration compensation according to claim 2, characterized in that: The driving assembly (3) comprises an azimuth motor (3-1) arranged on the azimuth axis (1-1) for driving the azimuth axis (1-1) to rotate, a roll motor (3-2) arranged on the roll axis (1-2) for driving the roll axis (1-2) to rotate, and a pitch motor (3-3) arranged on the pitch axis (1-3) for driving the pitch axis (1-3) to rotate.

6. The three-axis gimbal control system based on flight platform linear acceleration compensation according to claim 3, characterized in that: The control circuit component (4) comprises a communication interface for acquiring the linear acceleration of the mounting platform, a microcontroller circuit (4-2) arranged in a pitch load frame (1-6) for attitude resolution and a three-axis image stabilization control algorithm, a motor drive circuit (4-3) for driving the drive component (3) according to a trigger signal, and a conductive slip ring (4-4) for realizing electrical connection between the azimuth motor (3-1) and the azimuth frame (1-4).

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