A method for compensating the rotational inertia of a three-axis stabilized platform based on a mechanical model

Abstract

The application discloses a kind of three-axis stable platform rotation inertia compensation method based on mechanics model, to platform body axis angle β zk , inner frame axis angle β yk , platform body to x p , y p , z p Axis of rotation inertia Inner frame to axis of rotation inertia Outer frame to axis of rotation inertia As the input information of decoupling link, the compensation value of rotation inertia is obtained by solving through mechanics model, is compensated to outer ring axis stabilization loop, compensates the servo control loop gain variation caused by the change of frame system rotation inertia.The application first gives the mechanics model between frame angular acceleration and total moment of force on frame axis, is used to compensate the gain of outer ring servo control loop when inner ring axis is large angle, guarantees the stable margin of servo control loop when platform frame system is at any position in inner ring.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of three-axis stable platform based on the inertia compensation method of mechanical model, belong to inertial navigation field. BACKGROUND

[0002] With the increasing demand of vehicle maneuvering orbit transfer flight, it is required that the inertial navigation system realizes accurate navigation and guidance under large maneuvering and high dynamic conditions. When the vehicle is to be maneuvered for orbit transfer flight, large attitude angle may occur in the inner ring shaft of the three-axis stable platform. Under such conditions, it is required that the platform servo control loop still maintains sufficient stability margin and reliability.

[0003] Since the three-axis stable platform adopts a frame structure, when the position of the frame structure changes, the rotational inertia of the frame structure will change, thereby causing the gain of the platform servo control loop to change. The change of the gain of the servo control loop will further affect the reliability and control accuracy.

[0004] In order to reduce the change of the gain of the servo control loop caused by the change of the rotational inertia of the frame, at present, the three-axis stable platform mainly works within the range of ±45° of the inner ring. The change of the rotational inertia of the frame caused by the small angle of the inner ring is within the controllable range. The existing measures can only meet the requirements of the vehicle with limited maneuvering attitude, and it is difficult to meet the requirements of the vehicle with large maneuvering motion. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a three-axis stable platform based on the inertia compensation method of mechanical model, which can effectively improve the stability and reliability of the vehicle under large maneuvering conditions when the inner ring shaft works at a large angle.

[0006] The technical solution of the present application is:

[0007] A three-axis stable platform based on the inertia compensation method of mechanical model, the three-axis stable platform includes a base, an outer frame, an inner frame and a platform body, corresponding base body coordinate system x b y b z b , outer frame body coordinate system inner frame body coordinate system and platform body coordinate system x p y p z p ; the z p axis of the platform body coordinate system coincides with the axis of the inner frame body coordinate system, the axis of the inner frame body coordinate system coincides with the Coincident axes, outer frame body coordinate system x-axis and base body coordinate system b Axis coincidence;

[0008] The rotational inertia compensation method based on the mechanical model for the three-axis stabilization platform is implemented as follows:

[0009] The coordinates of the three-axis stabilized platform relative to the platform body coordinate system x were measured. p y p z p Moment of inertia of the shaft Inner frame coordinate system to inner frame body coordinate system Moment of inertia of the shaft outer frame coordinate system of outer frame body Moment of inertia of the shaft

[0010] The relative rotation angles of the three-axis stabilized platform were measured, including the outer frame axis of the base around the outer frame body coordinate system. The angle β of the shaft rotation xk The outer frame around the inner frame axis in the coordinate system of the inner frame body. The angle β of the shaft rotation yk The inner frame revolves around the z-axis of the platform in the platform's coordinate system. p The angle β of the shaft rotation zk ;

[0011] Calculate the rotational inertia gain compensation value of the outer frame shaft. The calculation formula is as follows:

[0012]

[0013] J xx For coupling to the rotation of the platform shaft and the inner frame shaft during rotation The principal moment of inertia of the shaft.

[0014] Preferably, the coordinate system x of the three-axis stabilized platform relative to the platform body coordinate system is measured by the following method. p y p z p Moment of inertia of the shaft Inner frame coordinate system to inner frame body coordinate system Moment of inertia of the shaft outer frame coordinate system of outer frame body Moment of inertia of the shaft

[0015]

[0016] After assembling the platform, a moment of inertia testing device was used to test the moment of inertia of the platform in three directions using the torsion method. After assembling the inner frame, a moment of inertia testing device was used to test the moment of inertia of the inner frame in three directions using the torsion method. After assembling the outer frame, a moment of inertia testing device was used to test the moment of inertia of the outer frame using the torsion method.

[0017] Preferably, the outer frame axis of the base around the outer frame body coordinate system is measured by the following method. The angle β of the shaft rotation xk The outer frame around the inner frame axis in the coordinate system of the inner frame body. The angle β of the shaft rotation yk The inner frame revolves around the z-axis of the platform in the platform's coordinate system. p The angle β of the shaft rotation zk :

[0018] On the outer frame axis An angle sensor is installed on the shaft to measure the angle around the base. The angle β of the shaft rotation xk ; on the inner frame axis An angle sensor is installed on the shaft to measure the angle of the outer frame around the shaft. The angle β of the shaft rotation yk ; on the z-axis of the platform p A sensor mounted on the shaft measures the inner frame around the z-axis. p The angle β of the shaft rotation zk .

[0019] Preferred,

[0020] Preferably, the base body coordinate system x b y b z b , outer frame body coordinate system Inner frame body coordinate system and the platform's body coordinate system x p y p z p The origins of the four coordinate systems coincide.

[0021] Preferably, the coordinate transformation matrix from the platform body coordinate system to the inner frame body coordinate system.

[0022]

[0023] Preferably, the coordinate transformation matrix from the inner frame body coordinate system to the outer frame body coordinate system.

[0024]

[0025] The advantages of this invention compared to the prior art are as follows:

[0026] (1) The present invention provides a rotational inertia compensation method for a three-axis stabilizing platform based on a mechanical model, which can compensate for the gain changes of the platform axis and the inner frame axis at any angle, especially the inner ring at a large angle.

[0027] (2) The present invention provides a rotational inertia compensation method for a three-axis stabilized platform based on a mechanical model. The inner frame can work at any large angle when it is not singular, which increases the reliability of the carrier's large maneuver flight. Attached Figure Description

[0028] Figure 1 This is a schematic diagram showing the relationship between the four coordinates in a three-axis stabilized platform.

[0029] Figure 2 This is a schematic diagram illustrating the change in rotational inertia of the outer frame shaft based on the mechanical model of the present invention.

[0030] Figure 3 This is a flowchart of a rotational inertia compensation method for a three-axis stabilization platform based on a mechanical model, according to the present invention. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments:

[0032] The triaxial stabilization platform of this invention utilizes a rotational inertia compensation method based on a mechanical model, which obtains rotational inertia information of the frame system: the platform relative to x... p y p z p Moment of inertia of the shaft Inner frame for x p1 y p1 z p1 Moment of inertia of the shaft outer frame moment of inertia of the axis and the platform's platform axis angle β zk Inner ring axis angle β yk As input information for the compensation process, the change in rotational inertia is calculated using a mechanical model to achieve the gain compensation value for the servo control loop.

[0033] This invention is based on a three-axis stabilization platform system, which includes a base, an outer frame, an inner frame, and a platform. The coordinate system of the three-axis stabilization platform is defined as follows: Figure 1 The diagram shown illustrates the relationship between the coordinate systems of the various frames of the three-axis platform. The corresponding base body coordinate system x... b y b z b , outer frame body coordinate system Inner frame body coordinate system and the platform's body coordinate system x p y p z p The origins of the four coordinate systems coincide, and the z-axis of the platform's body coordinate system is... p The coordinate system of the axis and the inner frame body With the axes coinciding, the y-axis of the inner frame's body coordinate system... p1 The coordinate system of the axis and the outer frame body Coincident axes, outer frame body coordinate system x-axis and base body coordinate system b The axis coincides with the axis. Specifically, the base, outer frame, and inner frame revolve around the axis z of the platform. p Turn through β zk Corners, base and outer frame around the inner frame axis Turn through β yk Angle, base around the outer frame axis Turn through β xk horn.

[0034] Platform against x p y p z p Moment of inertia of the shaft Inner frame Moment of inertia of the shaft outer frame Moment of inertia of the shaft

[0035]

[0036] J xx For coupling to the rotation of the platform shaft and the inner frame shaft during rotation Principal moment of inertia of the shaft, J yy For coupling to the rotation of the platform shaft and the inner frame shaft during rotation Principal moment of inertia of the shaft, J xy For coupling to the rotation of the platform shaft and the inner frame shaft during rotation The product of the rotational inertia of the shaft, J yx For coupling to the rotation of the platform shaft and the inner frame shaft during rotation The product of the rotational inertia of the shaft, J xz For coupling to the rotation of the platform shaft and the inner frame shaft during rotation The product of rotational inertia of the shaft.

[0037] The specific implementation process is as follows: based on the principle of linear superposition of mechanical motion, there is...

[0038]

[0039] In the formula, L p , M represents the momentum on each frame axis of the platform.p , These represent the total torque acting on the three supporting shafts.

[0040] According to the momentum theorem, the torque vector equation of the frustum axis is established as follows:

[0041]

[0042] Let be the torque in the z-direction of the platform.

[0043] The moment vector equations for the internal frame are established as follows:

[0044]

[0045] in,

[0046] The calculated equations for the moment-frame angular acceleration along the inner frame axis are as follows:

[0047]

[0048] Let be the torque in the y-direction of the inner frame. These represent the angular velocities of the inner frame in the x, y, and z directions, respectively. These are the angular velocities of the platform in the x, y, and z directions, respectively. The base, outer frame, and inner frame are arranged around the axis z of the platform. p angular velocity of rotation. These are the angular accelerations in the x and y directions of the inner frame, respectively.

[0049] The moment vector equations for the outer frame are established as follows:

[0050]

[0051] in,

[0052] The calculated equations for the moment-angle acceleration along the outer frame axis are as follows:

[0053]

[0054] The torque in the x-direction of the outer frame. These are the angular velocities of the outer frame in the x, y, and z directions, respectively. The base, outer frame, and inner frame are arranged around the axis z of the platform. p angular acceleration of rotation. These are the angular accelerations in the x and y directions of the inner frame, respectively. The base and outer frame are about the axis of the inner frame. angular acceleration of rotation. The base and outer frame are about the axis of the inner frame. Rotational angular velocity.

[0055] Ignore and Irrelevant minor quantities yield the torque-angular acceleration equations for the three frame axes as follows.

[0056]

[0057] Based on the above dynamic model, the rotational inertia gain compensation value of the outer frame shaft is calculated. The specific calculation formula is as follows:

[0058]

[0059] Figure 3 This is a schematic diagram illustrating the change in rotational inertia of the outer frame shaft based on the mechanical model of the present invention.

[0060] Based on the above principles, such as Figure 2 The processing flowchart shown below illustrates the following steps in implementing this invention:

[0061] (1) The x-axis of the three-axis stabilized platform was measured. p y p z p Moment of inertia of the shaft Inner frame for x p1 y p1 z p1 Moment of inertia of the shaft outer frame Moment of inertia of the shaft

[0062] (2) The relative rotation angles of the three-axis stabilized platform system were measured, including: the base's rotation around the outer frame's body coordinate system. The angle β of the shaft rotation xk The outer frame around the inner frame's body coordinate system The angle β of the shaft rotation yk The z-coordinate of the inner frame around the body coordinate system of the platform p The angle β of the shaft rotation zk ;

[0063] (3) Calculate the rotational inertia gain compensation value of the outer frame shaft. The specific calculation formula is as follows:

[0064]

[0065] in, This is the gain compensation value for the rotational inertia of the outer frame shaft.

[0066] The above-mentioned triaxial stabilization platform's rotational inertia compensation method based on a mechanical model: In step (1), the rotational inertia of the platform relative to x is measured using the following method. p y p z p Moment of inertia of the shaft Inner frame for x p y p z p Moment of inertia of the shaft outer frame Moment of inertia of the shaft

[0067] After assembling the platform body, a moment of inertia testing device was used to test the moment of inertia of the platform body in three directions using the torsion method. After assembling the inner ring section, a moment of inertia testing device was used to test the moment of inertia of the inner ring in three directions using the torsion method. After assembling the outer ring section, a moment of inertia testing device was used to test the torsion of the outer ring frame. Moment of inertia of the shaft

[0068] The above-mentioned triaxial stabilization platform uses a mechanical model-based method for compensating for rotational inertia: In step (2), the moment of inertia of the base around the outer frame body coordinate system is measured using the following method. The angle β of the shaft rotation xk The outer frame around the inner frame's body coordinate system The angle β of the shaft rotation yk The z-coordinate of the inner frame around the body coordinate system of the platform p The angle β of the shaft rotation zk :

[0069] In the outer frame An angle sensor is installed on the shaft to measure the coordinates of the base around the outer frame body. The angle β of the shaft rotation xk ; within the inner frame An angle sensor is mounted on the shaft to measure the coordinates of the outer frame around the inner frame body. The angle β of the shaft rotation yk ; in Taiwan p A sensor mounted on the axis measures the z-axis of the inner frame around the body coordinate system of the stage. p The angle β of the shaft rotation zk .

[0070] This invention provides for the first time a mechanical model relating the absolute angular acceleration of the frame to the total torque on the frame axis. This model is used to compensate for the gain of the servo control loop of the outer frame axis when the inner frame axis is at a large angle, ensuring the stability margin of the servo control loop of the platform frame system at any position of the inner frame.

[0071] Example 1:

[0072] In this embodiment, the calculation formula of the present invention is used to calculate the moment of inertia compensation, and the following conditions are set: the base is in the coordinate system of the outer frame. The angle β of the shaft rotation xk =0°; outer frame around inner frame coordinate system The angle β of the shaft rotation yk =0°; Inner frame around the table coordinate system z p The angle β of the shaft rotation zk =0°

[0073] According to the calculation formula provided by the present invention: This principal inertia is the outer frame axis when the frame system is at zero position. The principal inertia in the direction, at which point the gain of the servo loop when it is at zero position is K.

[0074] Example 2:

[0075] In this embodiment, the calculation formula of the present invention is used to calculate the moment of inertia compensation, and the following conditions are set: the base is in the coordinate system of the outer frame. The angle β of the shaft rotation xk =0°, outer frame around inner frame coordinate system The angle β of the shaft rotation yk =70°; Inner frame around the table coordinate system z p The angle β of the shaft rotation zk =0°

[0076] According to the calculation formula provided by the present invention: This is equivalent to the gain of the servo control loop becoming

[0077] The calculation results above show that when the position of the inner frame axis changes, the rotational inertia of the frame platform in the direction of the outer frame axis is strongly correlated with the position of the inner frame axis. The gain of the servo control loop must be compensated for the rotational inertia based on the mechanical model. Otherwise, the increase in the gain of the servo control loop will lead to a decrease in the stability margin, which will affect the stability and reliability of the system.

[0078] When the inner frame axis angle rotates from 0° to 70°, the servo control loop gain increases by 1.736 times. This is based on the gain compensation value for the moment of inertia. The calculation formula is as follows: Applying this gain compensation value to the servo control loop can eliminate the gain variation in the servo control loop caused by the change in the inner frame axis.

[0079] The above two embodiments can verify the correctness and rationality of the rotational inertia compensation method based on the mechanical model of the present invention.

[0080] The above description is only one specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

[0081] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for compensating the rotational inertia of a three-axis stabilized platform based on a mechanical model, characterized in that: The three-axis stabilized platform includes a base, an outer frame, an inner frame, and a platform body, with the corresponding base body coordinate system x... b y b z b , outer frame body coordinate system Inner frame body coordinate system and the platform's body coordinate system x p y p z p The z-coordinate of the platform's body coordinate system p The coordinate system of the axis and the inner frame body Coincident axes, inner frame body coordinate system The coordinate system of the axis and the outer frame body Coincident axes, outer frame body coordinate system x-axis and base body coordinate system b Axis coincidence; The rotational inertia compensation method based on the mechanical model for the three-axis stabilization platform is implemented as follows: The coordinates of the three-axis stabilized platform relative to the platform body coordinate system x were measured. p y p z p Moment of inertia of the shaft Inner frame coordinate system to inner frame body coordinate system Moment of inertia of the shaft outer frame coordinate system of outer frame body Moment of inertia of the shaft The relative rotation angles of the three-axis stabilized platform were measured, including the outer frame axis of the base around the outer frame body coordinate system. The angle β of the shaft rotation xk The outer frame around the inner frame axis in the coordinate system of the inner frame body. The angle β of the shaft rotation yk The inner frame revolves around the z-axis of the platform in the platform's coordinate system. p The angle β of the shaft rotation zk ; Calculate the rotational inertia gain compensation value of the outer frame shaft. The calculation formula is as follows: J xx For coupling to the rotation of the platform shaft and the inner frame shaft during rotation The principal moment of inertia of the shaft; Base body coordinate system x b y b z b , outer frame body coordinate system Inner frame body coordinate system and the platform's body coordinate system x p y p z p The origins of the four coordinate systems coincide.

2. The method for compensating the rotational inertia of a three-axis stabilized platform based on a mechanical model according to claim 1, characterized in that: The coordinate system x of the three-axis stabilized platform relative to the platform body coordinate system was measured using the following method. p y p z p Moment of inertia of the shaft Inner frame coordinate system to inner frame body coordinate system Moment of inertia of the shaft outer frame coordinate system of outer frame body Moment of inertia of the shaft After assembling the platform, a moment of inertia testing device was used to test the moment of inertia of the platform in three directions using the torsion method. After assembling the inner frame, a moment of inertia testing device was used to test the moment of inertia of the inner frame in three directions using the torsion method. After assembling the outer frame, a moment of inertia testing device was used to test the moment of inertia of the outer frame using the torsion method.

3. The method for compensating the rotational inertia of a three-axis stabilized platform based on a mechanical model according to claim 1, characterized in that: The outer frame axis of the base around the outer frame body coordinate system is measured using the following method. The angle β of the shaft rotation xk The outer frame around the inner frame axis in the coordinate system of the inner frame body. The angle β of the shaft rotation yk The inner frame revolves around the z-axis of the platform in the platform's coordinate system. p The angle β of the shaft rotation zk : On the outer frame axis An angle sensor is installed on the shaft to measure the angle around the base. The angle β of the shaft rotation xk ; on the inner frame axis An angle sensor is installed on the shaft to measure the angle of the outer frame around the shaft. The angle β of the shaft rotation yk ; on the z-axis of the platform p A sensor mounted on the shaft measures the inner frame around the z-axis. p The angle β of the shaft rotation zk .

4. The method for compensating the moment of inertia of a three-axis stabilized platform based on a mechanical model according to claim 1, characterized in that:

5. The method for compensating the rotational inertia of a three-axis stabilized platform based on a mechanical model according to claim 1, characterized in that: Coordinate transformation matrix from platform body coordinate system to inner frame body coordinate system 6. The method for compensating the moment of inertia of a three-axis stabilized platform based on a mechanical model according to claim 1, characterized in that: Coordinate transformation matrix from inner frame body coordinate system to outer frame body coordinate system

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