A high-precision dynamic compensation algorithm for gravity disturbance torque in a dumbbell-shaped satellite simulator

Abstract

This invention discloses a high-precision dynamic compensation algorithm for gravity disturbance torque of a dumbbell-shaped satellite simulator, relating to the field of spacecraft ground zero-gravity simulation experiments. Based on a high-precision dynamic compensation system for gravity disturbance torque of a dumbbell-shaped satellite simulator, a camera field-of-view coordinate system and a simulator body coordinate system are established. A control torque for the dumbbell-shaped simulator is established in the camera field-of-view coordinate system, and the three-axis attitude of the dumbbell-shaped simulator is maintained and controlled. The gravity disturbance torque is calculated in real time and dynamically compensated. The dynamic compensation algorithm provided by this invention can continuously and automatically calculate the compensation torque and obtain the movement distance of the counterweight, performing real-time compensation for the gravity disturbance torque, ensuring that the simulator's center of mass coincides with the center of the ball bearing, greatly improving the accuracy and reliability of spacecraft ground micro-low gravity simulation experiments.

Description

Technical Field

[0001] This invention relates to the field of zero-gravity simulation experiments on spacecraft, and in particular to a high-precision dynamic compensation algorithm for gravity disturbance torque of a dumbbell-shaped satellite simulator. Background Technology

[0002] Air flotation, a typical technology for simulating microgravity on the ground for spacecraft, offers advantages such as high simulation accuracy, short production cycle, and convenient maintenance through point force compensation. Ground-based zero-gravity simulation tests of spacecraft based on air flotation can effectively ensure the reliability of spacecraft operation in space, greatly improving the cost-effectiveness of spacecraft research and development.

[0003] As a typical example of air-bearing technology in spacecraft ground-based zero-gravity experiments, the dumbbell-shaped simulator can achieve a zero-gravity simulation environment in space using high-pressure air bearings and multi-control ball bearings. However, the degree of gravity compensation is closely related to the degree of coincidence between the center of the ball and the simulator's center of mass. Therefore, during the test preparation stage, it is often necessary to adjust the center of mass by adding counterweights to reduce gravitational torque interference and achieve a balancing effect. This process is often done manually, resulting in low balancing efficiency and an inability to guarantee accuracy.

[0004] Therefore, a high-precision dynamic compensation algorithm for gravity interference torque of a dumbbell-shaped satellite simulator is urgently needed to solve the above problems. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a high-precision dynamic compensation algorithm for the gravity disturbance torque of a dumbbell-shaped satellite simulator. This algorithm continuously and automatically calculates the compensation torque and obtains the movement distance of the counterweight, performing real-time compensation for the gravity disturbance torque to ensure that the simulator's center of mass is highly aligned with the center of the ball bearing. The algorithm includes the following steps:

[0006] S1: Establish the camera field of view coordinate system and simulator body coordinate system based on the high-precision dynamic compensation system for gravity interference torque of dumbbell-shaped satellite simulator;

[0007] S2: Establish the control torque of the dumbbell-shaped simulator in the camera's field of view coordinate system and maintain control over the three-axis attitude of the dumbbell-shaped simulator;

[0008] S3: Calculates the gravitational disturbance torque in real time and performs dynamic compensation for the gravitational disturbance torque.

[0009] Preferably, the specific steps of S1 are as follows:

[0010] S101: Obtain the field of view information of several external visual measurement cameras, analyze the field of view information of the cameras and establish a camera field of view coordinate system T(O; X, Y, Z). The camera field of view coordinate system takes any position within the field of view of the camera as the origin O, the vertical direction of the platform as the vertical axis Y, and the overlapping surface of the upper surface of the platform as the plane XOZ. The camera field of view coordinate system is used to describe the three directional positions (X, Y, Z) of the dumbbell simulator and the Euler angles (U, V, W) of the dumbbell simulator's corresponding three directional attitudes.

[0011] S102: Establish the body coordinate system T(O) on the dumbbell-shaped simulator. b ;X b ,Y b Z b The body coordinate system is used to describe the three directional positions (X, Y, F, Z) of the dumbbell-shaped simulator. b ,Y b Z b ) and three orientation angles (U) b V b W b The body coordinate system has its origin O at the center of the ball bearing. b Z is the direction parallel to the boom. b The Z axis b The axis points to Z. b In the positive direction of flywheel torque, X b axis and Y b The axes point to X respectively b Xiang and Y b In the positive direction of flywheel torque;

[0012] The body coordinate system T(O) b ;X b ,Y b Z b The three-axis directions of the camera coincide with the three-axis directions of the camera's field of view coordinate system T(O; X, Y, Z).

[0013] Preferably, the specific steps of S2 are as follows:

[0014] S201: With the three axes of the camera's field of view coordinate system fixed, the change in the Euler angles (U, V, W) corresponding to the XYZ axes in the camera's field of view coordinate system is defined as (ΔU, ΔV, ΔW), and the corresponding Euler angular rate is defined as (ω). U ,ω V ,ω W );

[0015] S202: Based on the principle of proportional-derivative control, the control laws in the three directions are restricted to obtain the expressions for the control laws in the three directions;

[0016] S203: Based on the attitude angles (U, V, W) and control torque T of the dumbbell-shaped simulator in the current camera field of view coordinate system. x T y T z The control torque in the body coordinate system is obtained;

[0017] S204: By adjusting the control parameters Achieve stable control of the three-axis posture of the dumbbell-shaped simulator within a certain accuracy range.

[0018] Preferably, the expressions for the control laws in the three directions in S202 are as follows:

[0019]

[0020] Among them, T x T y T z These are the control torques for the x-axis, y-axis, and z-axis, respectively. These are adjustable control parameters.

[0021] Preferably, the control torque in the body coordinate system in S203 is as follows:

[0022]

[0023] in, These are the rotation matrices of the camera's field-of-view coordinate system around the X-axis and the Z-axis, respectively;

[0024] in,

[0025] Preferably, the specific content of the real-time calculation of the gravitational disturbance torque in S3 is as follows:

[0026] The dumbbell-shaped simulator is controlled and stabilized using a triple orthogonal reaction flywheel.

[0027] The gravitational disturbance torque is calculated to obtain the gravitational disturbance torque;

[0028] The expression for the torque of the gravitational disturbance force is:

[0029]

[0030] Preferably, the specific steps for dynamically compensating for the gravitational disturbance torque in S3 are as follows:

[0031] S301: Based on the distance the three mass blocks need to move in the positive direction to compensate for the gravitational disturbance torque in the body coordinates and the weight of the mass blocks, the expression for the compensation torque in the body coordinates is obtained.

[0032] S302: In the dumbbell-shaped simulator's body coordinate system, apply the compensation torque. With gravitational disturbance torque Equal in magnitude but opposite in direction, we obtain the target system of equations to be solved.

[0033] S303: Solve the system of equations for the target to obtain the required distance the mass block needs to move in the body coordinates;

[0034] S304: The calculated required movement distance ΔX of the mass block in the body coordinate system. b ΔY b ΔZ b The stepper motor is driven to move the mass block to a relative position, completing one compensation cycle.

[0035] S305: During the test preparation phase, this process is repeated until the control torque approaches 0.

[0036] Preferably, the expression for the compensation torque in body coordinates in S301 is:

[0037]

[0038] in, The following are the representations of the gravity of the mass block in body coordinates along the three axes:

[0039]

[0040] in,

[0041] In the above formula, They represent Components in the three axes of the body coordinate system They represent Components in the three axes of the body coordinate system They represent Components along the three axes in the body coordinate system. M x M y M z Let g be the mass of the mass block driven by the stepper motor along the three axes in the camera's field of view coordinate system, and g be the local gravitational acceleration. Let be the rotation matrix of the camera's field-of-view coordinate system about the Y-axis. These are the rotation matrices of the camera's field-of-view coordinate system around the X-axis and the Z-axis, respectively.

[0042] Preferably, in S302, the expression for the target system of equations to be solved is:

[0043]

[0044] Preferably, the expression for the required movement distance of the mass block in the body coordinate system in S303 is:

[0045]

[0046] In summary, the high-precision dynamic compensation algorithm for gravity disturbance torque of a dumbbell-shaped satellite simulator of the present invention, compared with traditional technology, controls the simulator to maintain the desired posture by designing a control torque, obtains the compensation torque based on the control torque feedback, and calculates the adjustment distance of the counterweight in real time. It can continuously and automatically calculate the compensation torque and adjust the movement distance of the counterweight to compensate for gravity disturbance torque in real time, so that the center of mass of the simulator is highly coincident with the center of the ball bearing, thus achieving the purpose of high-precision dynamic compensation.

[0047] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the satellite simulator components of the present invention;

[0049] Figure 2 This is a front view of the satellite simulator components of the present invention;

[0050] Figure 3 This diagram illustrates the steps of a high-precision dynamic compensation algorithm for gravity interference torque in a dumbbell-shaped satellite simulator according to the present invention.

[0051] Figure label:

[0052] 1. Reaction flywheel; 2. Linear module; 3. Stepper motor; 4. Mass block; 5. Guide rail; 6. Lead screw; 7. Ball bearing; 8. Ball socket. Detailed Implementation

[0053] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application.

[0054] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0055] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0056] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0057] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0058] like Figure 1 and Figure 2 As shown in the figure, the hardware part involved in the high-precision dynamic compensation algorithm for gravity interference torque of a dumbbell-shaped satellite simulator in this application is as follows: the dumbbell-shaped satellite simulator is the part above the ball socket 8 in the figure. The ball socket 8 cooperates with the ball bearing 7 to realize the air buoyancy zero gravity simulation of three-degree-of-freedom attitude.

[0059] The simulator's body coordinate system, the positive direction of the linear module's driven mass motion, and the positive direction of the reaction flywheel torque are all marked in the figure. The simulator's initial body coordinate system and the camera's field-of-view coordinate system are aligned in three axes. The linear module 2 can drive the mass block 4 to move using the stepper motor 3.

[0060] like Figure 3 As shown, the present invention provides a high-precision dynamic compensation algorithm for gravity interference torque of a dumbbell-shaped satellite simulator, including the following steps: S1, establishing the camera field of view coordinate system and the simulator body coordinate system based on the high-precision dynamic compensation system for gravity interference torque of the dumbbell-shaped satellite simulator.

[0061] S1 also involves the following: acquiring camera field-of-view information composed of several external visual measurement cameras; analyzing the camera field-of-view information and establishing a camera field-of-view coordinate system T(O; X, Y, Z); and establishing a body coordinate system T(O) on a dumbbell-shaped simulator. b ;X b ,Y b Z b ).

[0062] The camera field-of-view coordinate system takes any position within the camera's field of view as the origin O, the vertical direction of the platform as the vertical axis Y, and the overlapping surface of the upper surface of the platform as the plane XOZ.

[0063] The camera field-of-view coordinate system is used to describe the three-directional positions (X, Y, Z) of the dumbbell simulator and the Euler angles (U, V, W) of the dumbbell simulator's corresponding three-directional attitudes.

[0064] Furthermore, the body coordinate system is used to describe the three directional positions (X, Y, F, Z) of the dumbbell-shaped simulator. b ,Y b Z b ) and three orientation angles (U) b V bW b The body coordinate system has its origin O at the center of the ball bearing. b Z is the direction parallel to the boom. b The Z axis b The axis points to Z. b In the positive direction of flywheel torque, X b axis and Y b The axes point to X respectively b Xiang and Y b In the positive direction of flywheel torque.

[0065] In addition, it is important to note the body coordinate system T(O) b ;X b ,Y b Z b The three-axis directions of the camera coincide with the three-axis directions of the camera's field of view coordinate system T(O; X, Y, Z).

[0066] S2, establish the control torque of the dumbbell-shaped simulator in the camera's field of view coordinate system and maintain control over the three-axis attitude of the dumbbell-shaped simulator.

[0067] Specifically, this can be understood as follows: with the three axes of the camera's field of view coordinate system fixed, the change in the Euler angles (U, V, W) corresponding to the XYZ axes in the camera's field of view coordinate system is defined as (ΔU, ΔV, ΔW), and the corresponding Euler angular rate is defined as (ω). U ,ω V ,ω W ).

[0068] Based on the principle of proportional-derivative control, the control laws in the three directions are constrained to obtain the expressions for the control laws in the three directions.

[0069] The expressions for the control laws in the three directions are as follows:

[0070]

[0071] Among them, T x T y T z These are the control torques for the x-axis, y-axis, and z-axis, respectively. These are adjustable control parameters.

[0072] Based on the attitude angles (U, V, W) and control torque T of the dumbbell-shaped simulator in the current camera field of view coordinate system x T y T z The control torque in the body coordinate system is obtained.

[0073] The control torque in the body coordinate system is as follows:

[0074]

[0075] in, These are the rotation matrices of the camera's field-of-view coordinate system around the X-axis and the Z-axis, respectively;

[0076] in,

[0077] It is understandable that by adjusting the control parameters Achieve stable control of the three-axis posture of the dumbbell-shaped simulator within a certain accuracy range.

[0078] Finally, the gravitational disturbance torque is calculated in real time and dynamically compensated for.

[0079] It is understandable that the control torque required by the three orthogonal reaction flywheels is in the opposite direction to the control torque mentioned above.

[0080] After the dumbbell-shaped simulator reaches a stable attitude under the control of three orthogonal reaction flywheels, in the simulator's body coordinate system, the gravitational disturbance torque is approximately equal in magnitude and opposite in direction to the control torque in the system, and approximately consistent with the torque of the reaction flywheels. Specifically, the real-time calculation of the gravitational disturbance torque can be achieved by first controlling the dumbbell-shaped simulator with the three orthogonal reaction flywheels until a stable attitude is reached, and then calculating the gravitational disturbance torque.

[0081] The expression for the torque of the gravitational disturbance force is:

[0082] In addition, dynamic compensation for the gravitational disturbance torque is required. Specifically, the expression for the compensation torque in the body coordinates is obtained by first determining the distance the three mass blocks need to move in the positive direction to compensate for the gravitational disturbance torque and the weight of the mass blocks in the body coordinates.

[0083] Secondly, in the body coordinate system of the dumbbell-shaped simulator, the compensation torque is... With gravitational disturbance torque With equal magnitudes and opposite directions, we obtain the target system of equations to be solved.

[0084] Finally, the required movement distance of the mass block in the body coordinate system is obtained by solving the system of equations for the target.

[0085] Based on the calculated required movement distance ΔX of the mass block in the body coordinate system b ΔY b ΔZ b It can drive a stepper motor to move the mass block to a relative position and complete one compensation. During the test preparation stage, this process is repeated until the control torque is close to 0.

[0086] Understandably, the installation requirements for the three orthogonally arranged stepper motors are parallel to and aligned with the positive direction of the torque of the three orthogonal reaction flywheels. In the camera's field-of-view coordinate system, the masses of the mass blocks driven by the stepper motors along the three axes are M... x M y M z .

[0087] In the dumbbell-shaped simulator's body coordinate system, the distances that the three mass blocks need to move in the positive direction to compensate for the gravitational disturbance torque are ΔX, respectively. b ΔY b ΔZ b The weight of the mass block in this system can be expressed as follows:

[0088] in, It can also be expressed as follows:

[0089]

[0090] in,

[0091] according to The definition can be obtained The specific representation of all components is given in the above formula. They represent Components in the three axes of the body coordinate system They represent Components in the three axes of the body coordinate system They represent Components along the three axes in the body coordinate system. M x M y M z Let g be the mass of the mass block driven by the stepper motor along the three axes in the camera's field of view coordinate system, and g be the local gravitational acceleration. Let be the rotation matrix of the camera's field-of-view coordinate system about the Y-axis. These are the rotation matrices of the camera's field-of-view coordinate system around the X-axis and the Z-axis, respectively.

[0092] In addition, in the dumbbell-shaped simulator's body coordinate system, the distance the three mass blocks move is required to exactly compensate for the gravitational disturbance torque. Therefore, based on the representation of the moving distance and the gravity of the mass blocks in this system, the expression for the compensation torque in the body coordinate system can be expressed as:

[0093]

[0094] Therefore, we can obtain a set of objective equations to be solved.

[0095] By combining the solution results of the gravitational disturbance torque, the required movement distance of the mass block in the body coordinate system can be obtained by solving the system of equations for the target. The expression for the movement distance is as follows:

[0096]

[0097] During the test preparation phase, this process is repeated until the control torque approaches zero, achieving a centroid balancing effect. During the test phase, it is repeated according to the control cycle to achieve high-precision dynamic compensation.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-precision dynamic compensation algorithm for gravity disturbance torque in a dumbbell-shaped satellite simulator, characterized in that, Includes the following steps: S1: Establish the camera field-of-view coordinate system and the simulator body coordinate system based on the high-precision dynamic compensation system for gravity interference torque of the dumbbell-shaped satellite simulator; S2: Establish the control torque for the dumbbell-shaped simulator in the camera's field of view coordinate system and maintain control over the three-axis attitude of the dumbbell-shaped simulator; the specific steps of S2 are as follows: S201: With the three axes of the camera's field of view coordinate system fixed, the change in the Euler angles (U, V, W) corresponding to the XYZ axes in the camera's field of view coordinate system is defined as (ΔU, ΔV, ΔW), and the corresponding Euler angular rate is defined as (ω). U ,ω V ,ω W ); S202: Based on the principle of proportional-derivative control, the control laws in the three directions are restricted to obtain the expressions for the control laws in the three directions; S203: Based on the attitude angles (U, V, W) and control torque T of the dumbbell-shaped simulator in the current camera field of view coordinate system. x T y T z The control torque in the body coordinate system is obtained; S204: By adjusting the control parameters Achieve stable control of the three-axis posture of the dumbbell-shaped simulator within a certain accuracy range; S3: Real-time calculation of gravitational disturbance torque and dynamic compensation of gravitational disturbance torque. The specific steps of S3 are as follows: S301: Based on the distance the three mass blocks need to move in the positive direction to compensate for the gravitational disturbance torque in the body coordinates and the weight of the mass blocks, the expression for the compensation torque in the body coordinates is obtained. S302: In the dumbbell-shaped simulator's body coordinate system, apply the compensation torque. With gravitational disturbance torque Equal in magnitude but opposite in direction, we obtain the target system of equations to be solved. S303: Solve the system of equations for the target to obtain the required distance the mass block needs to move in the body coordinates; S304: The calculated required movement distance ΔX of the mass block in the body coordinate system. b ΔY b ΔZ b The stepper motor is driven to move the mass block to a relative position, completing one compensation cycle. S305: During the test preparation phase, this process is repeated until the control torque approaches 0.

2. The high-precision dynamic compensation algorithm for gravity interference torque of a dumbbell-shaped satellite simulator according to claim 1, characterized in that, The specific steps of S1 are as follows: S101: Obtain the field of view information of several external visual measurement cameras, analyze the field of view information of the cameras and establish a camera field of view coordinate system T(O; X, Y, Z). The camera field of view coordinate system takes any position within the field of view of the camera as the origin O, the vertical direction of the platform as the vertical axis Y, and the overlapping surface of the upper surface of the platform as the plane XOZ. The camera field of view coordinate system is used to describe the three directional positions (X, Y, Z) of the dumbbell simulator and the Euler angles (U, V, W) of the dumbbell simulator's corresponding three directional attitudes. S102: Establish the body coordinate system T(O) on the dumbbell-shaped simulator. b ;X b ,Y b Z b The body coordinate system is used to describe the three directional positions (X, Y, F, Z) of the dumbbell-shaped simulator. b ,Y b Z b ) and three orientation angles (U) b V b W b The body coordinate system has its origin O at the center of the ball bearing. b Z is the direction parallel to the boom. b The axis, the Z b The axis points to Z. b In the positive direction of flywheel torque, X b axis and Y b The axes point to X respectively b Xiang and Y b In the positive direction of flywheel torque; The body coordinate system T(O) b ;X b ,Y b Z b The three-axis directions of the camera coincide with the three-axis directions of the camera's field of view coordinate system T(O; X, Y, Z).

3. The high-precision dynamic compensation algorithm for gravity interference torque of a dumbbell-shaped satellite simulator according to claim 1, characterized in that, The expressions for the control laws in the three directions of S202 are as follows: Among them, T x T y T z These are the control torques for the x-axis, y-axis, and z-axis, respectively. These are adjustable control parameters.

4. The high-precision dynamic compensation algorithm for gravity interference torque of a dumbbell-shaped satellite simulator according to claim 1, characterized in that, The control torque in the body coordinate system of S203 is as follows: in, in, These are the rotation matrices of the camera's field-of-view coordinate system around the X-axis and the Z-axis, respectively.

5. The high-precision dynamic compensation algorithm for gravity interference torque of a dumbbell-shaped satellite simulator according to claim 1, characterized in that, The specific details of real-time calculation of gravitational disturbance torque in S3 are as follows: The dumbbell-shaped simulator is controlled and stabilized using a triple orthogonal reaction flywheel. The gravitational disturbance torque is calculated to obtain the gravitational disturbance torque; The expression for the torque of the gravitational disturbance force is:

6. The high-precision dynamic compensation algorithm for gravity interference torque of a dumbbell-shaped satellite simulator according to claim 1, characterized in that, The expression for the compensating torque in body coordinates in S301 is: in, The following are the representations of the gravity of the mass block in body coordinates along the three axes: in, In the above formula They represent Components in the three axes of the body coordinate system They represent Components in the three axes of the body coordinate system They represent The components of the three axes in the body coordinate system, M x M y M z Let g be the mass of the mass block driven by the stepper motor along the three axes in the camera's field of view coordinate system, and g be the local gravitational acceleration. Let be the rotation matrix of the camera's field-of-view coordinate system about the Y-axis. These are the rotation matrices of the camera's field-of-view coordinate system around the X-axis and the Z-axis, respectively.

7. The high-precision dynamic compensation algorithm for gravity interference torque of a dumbbell-shaped satellite simulator according to claim 6, characterized in that, In S302, the expression for the objective system of equations to be solved is:

8. The high-precision dynamic compensation algorithm for gravity interference torque of a dumbbell-shaped satellite simulator according to claim 7, characterized in that, The expression for the required distance the mass block needs to move in the body coordinate system in S303 is:

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