A three-axis attitude stabilization control method for underactuated spacecraft considering multi-sensitive axis avoidance

Abstract

The present invention discloses a three-axis attitude stabilization control method for underactuated spacecraft that considers multi-sensitive axis avoidance. The method comprises: establishing an attitude dynamics model and constraint description equations for the underactuated spacecraft based on a two-flywheel configuration; establishing a trajectory guidance potential function based on the attitude dynamics model and constraint equations; and designing a three-axis stabilization control law for the underactuated spacecraft based on the guidance potential function. The proposed method can achieve three-axis stabilization control for underactuated spacecraft. Compared to existing underactuated control methods, it can effectively avoid multiple risk orientations within the attitude space during a mission. The method has a low computational complexity and can be used for three-axis attitude stabilization control of spacecraft with only two flywheel torque inputs.

Description

Technical Field

[0001] The present invention belongs to the field of motion planning and control, and in particular relates to a three-axis attitude stabilization control method for an underactuated spacecraft considering multi-sensitive axis avoidance. Background Art

[0002] During on-orbit operations, spacecraft must perform numerous maneuvering, tracking, and other control tasks to switch between different configurations. Many motion constraints exist within spacecraft attitude control tasks. For example, to prevent direct sunlight from impacting the lens of an onboard infrared telescope, the infrared telescope must point at an angle of at least 60° to the sun. To ensure a good measurement range for the solar sensor, the angle between the sensor and the sun must be less than 120°. Furthermore, spacecraft attitude control tasks are also affected by actuator failures. When an actuator fails and is partially damaged, the input control dimension may be reduced, rendering the spacecraft control system underactuated. To ensure spacecraft payload safety and mission completion, it is necessary to consider attitude control methods that satisfy both spatial pointing constraints and underactuated constraints.

[0003] In related technology, the Chinese patent application "An Optimization Method for Underactuated Reaction Wheel Configuration" (CN111762342A) optimizes the installation positions of two reaction wheels based on attitude errors and underactuated Euler axes. While this patent's technical solution achieves an optimized configuration of the flywheel actuators of an underactuated spacecraft, it fails to address the stability control issues of the underactuated spacecraft and cannot achieve three-axis attitude stabilization of the underactuated spacecraft.

[0004] In related technology, the Chinese patent application "A Three-Axis Attitude Stabilization Control Method for Underactuated Spacecraft" (CN103336528A) organizes the underactuated spacecraft system into a Brockett double-integral system and utilizes linear system methods to derive a state feedback control law for the underactuated spacecraft. While this patent's technical solution achieves three-axis stabilization control for an underactuated spacecraft, it does not derive the underactuated spacecraft's dynamic equations and does not derive a control law for the actual input torque.

[0005] In related technologies, the paper "Potential Function-Based Attitude Maneuvering Control of Dual Flywheel Spacecraft" proposes a feedback control method for underactuated spacecraft based on the potential function method. However, the paper does not establish tight constraints on the underactuated Euler axes, nor does it consider the issue of avoiding space risk orientation.

[0006] In related technologies, the papers "Anti-unwinding attitude control of spacecraft with forbidden pointing constraints" and "Saturated attitude control for rigid spacecraft under attitude constraints" both proposed attitude avoidance control methods based on potential function methods. However, the stabilization controllers proposed in these papers lack the ability to handle underactuated actuator failures.

[0007] While relevant technologies have made considerable progress in underactuated control and attitude avoidance, they fail to consider the simultaneous occurrence of both constraints. While the probability of a spacecraft underactuation due to a fault is low, it can still occur in actual space missions. In the event of a control underactuation failure, if the backup underactuated controller fails to account for the spatial pointing constraint, the spacecraft could be in danger of damaging its critical payload. With the increasing cost of spacecraft, an effective control method that can simultaneously address both constraints and ensure spacecraft safety is needed. Summary of the Invention

[0008] In view of this, the present invention provides a three-axis attitude stabilization control method for an under-actuated spacecraft taking into account multi-sensitive axis avoidance, which is used to solve the three-axis attitude stabilization control problem of an under-actuated spacecraft under multiple spatial pointing constraints. It can achieve three-axis attitude stabilization with only two-axis control torque input, and effectively avoid multiple risk directions in the attitude space.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] The present invention provides a three-axis attitude stabilization control method for an underactuated spacecraft considering multi-sensitive axis avoidance, comprising:

[0011] S1: Establish the attitude dynamics model and constraint description equations of the underactuated spacecraft based on the two-flywheel configuration;

[0012] S2: Establishing the trajectory guidance potential function according to the posture dynamics model and constraint equations;

[0013] S3: Design a three-axis stabilization control law for an underactuated spacecraft based on a guided potential function.

[0014] In one possible implementation, the posture dynamics model is established based on the zero initial angular momentum assumption:

[0015]

[0016]

[0017] in, is the error quaternion, q e Represents Q e The vector part, q e4 Indicates Q e The scalar part of is the angular velocity quaternion, ω is the attitude angular velocity; is the control law to be designed, h w is the torque of the reaction flywheel; J is the inertia matrix; for any quaternion Operator (·) * have Operators express:

[0018]

[0019] Among them, I3 is the 3D unit matrix, and there is:

[0020]

[0021] in, is the desired attitude quaternion, q d Indicates Q d The vector part, q d4 Indicates Q d scalar part; Q = [q T ,q4] T is the attitude quaternion, q represents the vector part of Q, and q4 represents the scalar part of Q.

[0022] In a possible implementation, the constraint description equation includes a constraint equation for describing the avoidance of an under-actuated Euler axis:

[0023] Q T M uw Q>0

[0024] in,

[0025]

[0026] C=[q d4 I3-S(q d )-q d ]

[0027] θ a is the control parameter of the design; for any x∈R 3 , the operator S(·) has:

[0028]

[0029] a wu is the underactuated Euler axis direction vector, and satisfies:

[0030]

[0031] in,

[0032]

[0033]

[0034] Among them, h w1 , h w2 represents the angular momentum direction vector of the two flywheels.

[0035] In a possible implementation, the constraint description equation further includes a constraint equation for risk avoidance:

[0036]

[0037] in,

[0038]

[0039] represents the constraint matrix of the jth pointing constraint on the i-th sensitive axis, σ i Represents the direction vector of the i-th sensitive axis, Represents the direction vector of the j-th pointing constraint about the i-th sensitive axis; I4 is a 4-dimensional unit matrix.

[0040] In a possible implementation, the guiding potential function is:

[0041] V=V a +V r

[0042] in,

[0043]

[0044]

[0045] α, β, χ, ε are control parameters.

[0046] In a possible implementation, the three-axis stability control law is:

[0047]

[0048] in,

[0049]

[0050] Among them, λ and g are the control parameters to be designed.

[0051] Beneficial effects:

[0052] The method disclosed in this paper can achieve three-axis stabilization control for underactuated spacecraft, requiring minimal computational effort. It can be used for three-axis attitude stabilization control of spacecraft with only two flywheel outputs. Compared to existing underactuated control methods, this method can effectively mitigate multiple risk orientations within the attitude space during a mission, providing a safe backup control solution for reliable on-orbit operation of spacecraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A flowchart of a three-axis attitude stabilization control method for an underactuated spacecraft considering multi-sensitive axis avoidance is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only for illustration and are not intended to limit the present application.

[0055] The embodiment of the present invention provides a three-axis attitude stabilization control method for an underactuated spacecraft considering multi-sensitive axis avoidance, such as Figure 1 As shown, the following steps are included:

[0056] S1: Establish the attitude dynamics model and constraint description equations of the underactuated spacecraft based on the two-flywheel configuration;

[0057] S2: Establishing the trajectory guidance potential function according to the posture dynamics model and constraint equations;

[0058] S3: Design a three-axis stabilization control law for an underactuated spacecraft based on a guided potential function.

[0059] Wherein, the S1 includes:

[0060] Step S11, establishing the attitude dynamics equation based on the zero initial angular momentum assumption:

[0061]

[0062]

[0063] in, is the error quaternion, q e Indicates Q e The vector part, q e4 Indicates Q e The scalar part of is the angular velocity quaternion, ω is the attitude angular velocity; is the control law to be designed, hw is the torque of the reaction flywheel; J is the inertia matrix; for any quaternion Operator (·) * have Operators express:

[0064]

[0065] And there are:

[0066]

[0067] in, is the desired attitude quaternion, q d Indicates Q d The vector part, q d4 Indicates Q d scalar part; Q = [q T ,q4] T is the attitude quaternion, q represents the vector part of Q, and q4 represents the scalar part of Q.

[0068] Step S12: To avoid under-actuated Euler axes, establish a constraint description equation for the posture:

[0069] Q T M uw Q>0

[0070] in,

[0071]

[0072] C=[q d4 I3-S(q d )-q d ]

[0073] Among them, θ a is the control parameter of the design; for any x∈R 3 , the operator S(·) has:

[0074]

[0075] Among them, a wu is the underactuated Euler axis direction vector, and satisfies:

[0076]

[0077] in,

[0078]

[0079]

[0080] Among them, h w1 , h w2 represents the angular momentum direction vector of the two flywheels.

[0081] Step S13: Establish a constraint equation for the posture in order to avoid risk:

[0082]

[0083] in,

[0084]

[0085] in, represents the constraint matrix of the jth pointing constraint on the i-th sensitive axis, σ i Represents the direction vector of the i-th sensitive axis, It represents the direction vector of the j-th pointing constraint about the i-th sensitive axis, and I3 is a 4-dimensional unit matrix.

[0086] The S2 includes:

[0087] The guiding potential function is: V = V a +V r

[0088] in,

[0089]

[0090]

[0091] Among them, α, β, χ, and ε are control parameters.

[0092] The S3 includes:

[0093]

[0094] in,

[0095]

[0096] Among them, λ and g are adjustable control parameters.

[0097] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A three-axis attitude stabilization control method for an underactuated spacecraft considering multi-sensitive axis avoidance, characterized in that: The following steps are involved: S1: Establish the attitude dynamics model and constraint description equations of the underactuated spacecraft based on the two-flywheel configuration; S2: Establishing the guidance potential function of the trajectory according to the posture dynamics model and constraint description equations; The constraint description equations include constraint equations for avoiding under-actuated Euler axes: ； in, ; ； ； ； ； in, , represents the angular momentum direction vectors of the two flywheels; is the attitude quaternion, express The vector part of express The scalar part of ; the superscript T indicates the transpose of the matrix; is a 3D unit matrix; is the control parameter to be designed; Quaternion representing the desired attitude The vector part of Quaternion representing the desired attitude The scalar part of is the inertia matrix; For any , operator have: ； The guiding potential function is: ; in, ; Representing error quaternion The scalar part of ； in, , , , is the control parameter; Representing error quaternion The vector part of The constraint matrix representing the j-th pointing constraint of the i-th sensitive axis; S3: Design a three-axis stabilization control law for an underactuated spacecraft based on a guided potential function.

2. The three-axis attitude stabilization control method for an underactuated spacecraft considering multi-sensitive axis avoidance according to claim 1, characterized in that: In S1, the dynamic model is established based on zero initial angular momentum: ； ； in, is the error quaternion, is the angular velocity quaternion, is the attitude angular velocity; To design the control law, is the torque of the reaction flywheel.

3. The three-axis attitude stabilization control method for an underactuated spacecraft considering multi-sensitive axis avoidance according to claim 1, characterized in that: In the S1, ; in, is the desired attitude quaternion, for any quaternion , , operator have , operator express: 。 4. The three-axis attitude stabilization control method for an underactuated spacecraft considering multi-sensitive axis avoidance according to claim 1, characterized in that: The constraint description equation also includes a constraint equation for risk avoidance: ； in, ; in, Represents the direction vector of the i-th sensitive axis, Represents the direction vector of the jth pointing constraint about the i-th sensitive axis; is a 4-dimensional unit matrix.

5. The three-axis attitude stabilization control method for an underactuated spacecraft considering multi-sensitive axis avoidance according to claim 1, characterized in that: The three-axis stability control law is: ； in, ； in, , is an adjustable control parameter.

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