阅读说明：本技术 一种基于太阳翼驱动控制的火星环绕器在线角动量管理方法 (Mars surrounding device online angular momentum management method based on solar wing drive control ) 是由 张玉花 王卫华 施桂国 唐文国 吴梦璇 周誌元 于 2020-04-30 设计创作，主要内容包括：本发明公开了一种基于太阳翼驱动控制的火星环绕器在线角动量管理方法,其方法为：基于探测器姿态动力学模型,分析动量轮控制力矩、太阳翼光压力矩、重力梯度力矩及喷气力矩的作用过程,建立动量轮累积模型；根据太阳翼光压力矩的作用过程,基于太阳翼一维驱动能力约束,联合喷气控制力矩共同实现动量轮的动量管理。本发明针对深空探测任务中采用长期对日姿态基准航行的探测器,采用基于太阳翼角度为控制量,整器角动量为目标量的闭环控制方法,降低喷气卸载频次1/2以上,提高整器寿命。(The invention discloses a Mars surround online angular momentum management method based on solar wing drive control, which comprises the following steps: analyzing the action processes of momentum wheel control moment, solar wing light pressure moment, gravity gradient moment and jet moment based on a detector attitude dynamics model, and establishing a momentum wheel accumulation model; and the momentum management of the momentum wheel is realized jointly by combining the jet control torque based on the one-dimensional driving capability constraint of the solar wing according to the action process of the solar wing light pressure torque. The invention aims at the detector adopting long-term sun attitude reference navigation in a deep space exploration task, adopts a closed-loop control method based on the sun wing angle as a control quantity and the angular momentum of the whole device as a target quantity, reduces the air injection unloading frequency by more than 1/2, and prolongs the service life of the whole device.)

1. The Mars surrounding device online angular momentum management method based on solar wing drive control is characterized in that in an on-orbit flight process, the two wing drive capability of a solar wing is utilized, through asynchronous drive, sun-receiving and sun-exposing surfaces of the solar wing are different, light pressure torque is generated, and momentum of a whole device is managed, and the angular momentum management method comprises the following steps:

analyzing the action processes of momentum wheel control moment, solar wing light pressure moment, gravity gradient moment and jet moment based on a detector attitude dynamics model, and establishing a momentum wheel accumulation model;

according to the action process of the solar wing light pressure moment, based on solar wing one-dimensional driving capability constraint, the momentum management of the momentum wheel is realized jointly by combining the jet control moment, and the specific method comprises the following steps:

according to the momentum wheel accumulation model and the sunlight pressure moment model, the one-dimensional driving angle of the solar wing is used as a control quantity,

wherein β is the driving angle of the sun wing, K_pIs the coefficient of the proportional term, K_iIs an integral term coefficient;

the air injection unloading is adopted for large-scale unloading protection, and a hysteresis unloading strategy is adopted:

wherein, T_onoffA thruster jet signal is given, 0 is off, -1 is negative jet, and 1 is positive jet; h is_cAngular momentum of any of the three axes, h_n1For the upper threshold value of the angular momentum of the jet unloading, h_n2Is the lower threshold value of the jet unloading angular momentum.

2. The Mars surround online angular momentum management method based on solar wing drive control as claimed in claim 1, wherein for a detector with momentum wheel as an actuator, an attitude dynamics model is established as follows:

wherein J is a matrix of 3 × 3, representing the moment of inertia of the probe body;is a representation of the angular velocity of the probe relative to the inertial system under the system;

3. The Mars surround machine on-line angular momentum management method based on solar wing driving control as claimed in claim 2,

sunlight pressure moment:

wherein, I₀Is the solar radiation constant, c is the speed of light, A is the area of the solar wing cell piece, psi is the included angle between the normal vector of the solar wing cell surface and the sun vector,

4. The Mars surround machine on-line angular momentum management method based on solar wing driving control as claimed in claim 3,

gravity gradient moment:

wherein mu is a gravitational constant of a central celestial body, R is the distance from the detector to the gravitational center,

5. The Mars circulator online angular momentum management method based on solar wing drive control as claimed in claim 4, wherein the jet torque is as follows:

in the formulaIs the vector of the centroid of the detector to the nozzle mounting point,the product of the direction and magnitude of the thrust generated for the thruster.

6. The Mars surround machine on-line angular momentum management method based on solar wing driving control as claimed in claim 5,

the momentum wheel accumulation model is:

wherein the jet torqueThe moment is actively controlled; light pressure moment

Technical Field

The invention relates to a Mars detection attitude control technology, in particular to an online angular momentum management method suitable for Mars detection.

Background

China will launch Mars detectors in 2020, and the conventional three-step flow of 'winding', 'falling' and 'patrolling' is realized at one time. After the detector escapes from the earth, the detector cannot adopt magnetic control unloading like a near earth satellite, so the existing deep space detectors adopting a momentum wheel control mode all adopt jet unloading. The main constraints of the deep space probe adopting the jet unloading include two aspects: on the one hand, fuel is consumed, and the fuel loading is limited under the existing carrying constraint, so that the consumption of the fuel directly influences the service life of the whole device; and on the other hand, the air injection unloading directly influences the orbit determination strategy and the orbit determination precision of the ground orbit determination.

The management of the foreign deep space probe on the angular momentum mainly comprises two aspects: on one hand, the flight process adopts a jet three-axis stable control mode, and the process does not involve the work of a momentum wheel, so that the angular momentum management directly adopts a jet offset scheme; on the other hand, the flight process adopts a spin control mode, the scheme carries out angular momentum exchange through the body coupling of the three shafts of the detector, and the unloading frequency can be reduced for a single shaft. The scheme is not applicable to a detector with high-precision and stable ground requirement, and in order to ensure high-precision ground pointing (pointing precision is 0.05 degrees), a momentum wheel is required to be used as an actuating mechanism for three-axis stable control.

Disclosure of Invention

The technical problem solved by the invention is as follows: the method overcomes the defects of the prior art, and provides an online angular momentum management method suitable for Mars detection.

The technical scheme of the invention is as follows:

the utility model provides a mars surround ware online angular momentum management method based on sun wing drive control, in the flight process of the orbit, utilizes the both wings driving ability of sun wing, through asynchronous drive, makes sun wing's the face of shining different to sunshine, produces the light pressure moment, manages the whole ware momentum, and the step of this angular momentum management method includes:

analyzing the action processes of momentum wheel control moment, solar wing light pressure moment, gravity gradient moment and jet moment based on a detector attitude dynamics model, and establishing a momentum wheel accumulation model;

according to the action process of the solar wing light pressure moment, based on solar wing one-dimensional driving capability constraint, the momentum management of the momentum wheel is realized jointly by combining the jet control moment, and the specific method comprises the following steps:

according to the momentum wheel accumulation model and the sunlight pressure moment model, the one-dimensional driving angle of the solar wing is used as a control quantity,

wherein β is the driving angle of the sun wing, K_pIs the coefficient of the proportional term, K_iIs an integral term coefficient;

the air injection unloading is adopted for large-scale unloading protection, and a hysteresis unloading strategy is adopted:

wherein, T_onoffA thruster jet signal is given, 0 is off, -1 is negative jet, and 1 is positive jet; h is_cAngular momentum of any of the three axes, h_n1For the upper threshold value of the angular momentum of the jet unloading, h_n2Is the lower threshold value of the jet unloading angular momentum.

Preferably, for a detector with a momentum wheel as an actuating mechanism, establishing an attitude dynamics model as follows:

wherein J is a matrix of 3 × 3, representing the moment of inertia of the probe body;is a representation of the angular velocity of the probe relative to the inertial system under the system;

is composed ofThe high-order terms of (a) are,

the angular momentum is controlled for the three axes generated by the momentum wheel,a three-axis control moment generated for the momentum wheel;a jet torque generated for the jet;

the light pressure moment is generated for the sunlight pressure;

is the gravity gradient moment under the action of the gravity of the central celestial body.

Preferably, the solar pressure torque:

wherein, I₀Is the solar radiation constant, c is the speed of light, A is the area of the solar wing cell piece, psi is the included angle between the normal vector of the solar wing cell surface and the sun vector,

is a normal vector of the solar wing battery surface,

is a plane intersection vector formed by the surface of the solar wing battery, the normal line and the sun vector, C_rsIs the diffuse reflection coefficient of the solar wing, C_rdIs the specular reflection coefficient of the solar wing,the pressure center vector from the center of the solar wing to the center of mass of the body under the system is obtained.

Preferably, the gravity gradient moment:

wherein mu is a gravitational constant of a central celestial body, R is the distance from the detector to the gravitational center,j is a matrix of 3 × 3 for the sagittal diameter of gravity center to the surround, representing the moment of inertia of the probe body.

Preferably, the air injection torque:

in the formulaIs the vector of the centroid of the detector to the nozzle mounting point,the product of the direction and magnitude of the thrust generated for the thruster.

Preferably, the momentum wheel accumulation model is:

wherein the jet torqueThe moment is actively controlled; light pressure momentChanging the included angle between the sun vector and the normal of the cell surface by one-dimensional drivingAdjusting; moment of gravity gradientGenerated by coupling the inertia of the detector with the gravity vector of the central celestial body under the system.

Compared with the prior art, the invention has the beneficial effects that:

(1) aiming at the detector adopting long-term sun attitude reference navigation in a deep space detection task, the invention adopts a closed-loop control method based on the sun wing angle as a control quantity and the angular momentum of the whole device as a target quantity, reduces the air injection unloading frequency by more than 1/2 and prolongs the service life of the whole device;

(2) the Mars detector with + X sun-facing reference, positive and negative Y solar wings and one-dimensional driving capability around Y is taken as an example, and the Mars detector can be applied to other attitude references in subsequent deep space tasks or solar wings with two-dimensional driving capability in an extensible manner;

(3) the invention adopts the combination of solar wing driving feedback and air injection to carry out angular momentum management, carries out integral angular momentum unloading control in a layered manner, is suitable for different stages, mainly adopts sunlight pressure interference in the round-of-the-sun flying stage, and can completely counteract the interference based on a solar wing driving feedback control strategy; the control capability of the whole device is also ensured due to the protection of air injection unloading in the flying around the mars;

(4) the method provides reference significance for angular momentum management of a subsequent deep space detector, starts with interference and controllability, realizes on-orbit autonomous optimization management of angular momentum, and improves subsequent deep space detection capability.

Drawings

FIG. 1 is a flow chart of the method of the present invention;

FIG. 2 is a schematic view of the installation and rotation polarity of the solar wing according to the present invention;

FIG. 3 is a schematic view of the moment of light pressure generated by the incident of the sun according to the present invention.

Detailed Description

The invention is further illustrated by the following examples.

The invention takes the + X-day-to-Z constraint ground-to-ground reference as an example analysis, and the reference is defined as: the + X axis of the detector body points to the sun, the Y axis is perpendicular to the sun-ground plane, the Z axis meets the right-hand rule, and the-Z axis is located on one side of the earth. The detector is provided with two solar wings which are respectively arranged in the positive direction and the negative direction of the body and have one-dimensional driving capability around the Y axis. Meanwhile, the solar wing is provided with an attitude control thruster, so that control moment in three axial directions can be independently generated. Aiming at the above configuration detector, the zero momentum management of the detector momentum wheel system is realized by utilizing the coupling control of the solar wing drive and the jet. The method comprises the following specific steps:

in the on-line angular momentum management method for the Mars surround device based on solar wing drive control, in the process of on-orbit flight, the two wing drive capability of a solar wing is utilized, and through asynchronous drive, the sun-receiving and sun-exposure surfaces of the solar wing are different, so that the light pressure moment is generated, and the momentum of the whole device is managed, as shown in figure 1, the angular momentum management method comprises the following steps:

analyzing the action processes of momentum wheel control moment, solar wing light pressure moment, gravity gradient moment and jet moment based on a detector attitude dynamics model, and establishing a momentum wheel accumulation model;

according to the action process of the solar wing light pressure moment, based on solar wing one-dimensional driving capability constraint, the momentum management of the momentum wheel is realized jointly by combining the jet control moment, and the specific method comprises the following steps:

according to the momentum wheel accumulation model and the sunlight pressure moment model, the one-dimensional driving angle of the solar wing is used as a control quantity,

wherein β is the driving angle of the sun wing, K_pIs the coefficient of the proportional term, K_iIs an integral term coefficient;

the air injection unloading is adopted for large-scale unloading protection, and a hysteresis unloading strategy is adopted:

wherein, T_onoffA thruster jet signal is given, 0 is off, -1 is negative jet, and 1 is positive jet; h is_cIn three axes ofOf any axis of angular momentum, h_n1For the upper threshold value of the angular momentum of the jet unloading, h_n2Is the lower threshold value of the jet unloading angular momentum.

Aiming at a detector with a momentum wheel as an actuating mechanism, establishing an attitude dynamics model as follows:

wherein J is a matrix of 3 × 3, representing the moment of inertia of the probe body;is a representation of the angular velocity of the probe relative to the inertial system under the system;

is composed of

The high-order terms of (a) are,

the angular momentum is controlled for the three axes generated by the momentum wheel,a three-axis control moment generated for the momentum wheel;a jet torque generated for the jet;

the light pressure moment is generated for the sunlight pressure;

is the gravity gradient moment under the action of the gravity of the central celestial body.

As shown in fig. 2 and 3, the sunlight pressure moment:

wherein, I₀Is the solar radiation constant, c is the speed of light, A is the area of the solar wing cell piece, psi is the included angle between the normal vector of the solar wing cell surface and the sun vector,is a normal vector of the solar wing battery surface,

is a plane intersection vector formed by the surface of the solar wing battery, the normal line and the sun vector, C_rsIs the diffuse reflection coefficient of the solar wing, C_rdIs the specular reflection coefficient of the solar wing,the pressure center vector from the center of the solar wing to the center of mass of the body under the system is obtained.

Gravity gradient moment:

wherein mu is a gravitational constant of a central celestial body, R is the distance from the detector to the gravitational center,j is a matrix of 3 × 3 for the sagittal diameter of gravity center to the surround, representing the moment of inertia of the probe body.

Air injection torque:

in the formula

Is the vector of the centroid of the detector to the nozzle mounting point,

the product of the direction and magnitude of the thrust generated for the thruster.

The momentum wheel accumulation model is:

wherein the jet torque

The moment is actively controlled; light pressure momentChanging the included angle between the sun vector and the normal of the battery surface through one-dimensional driving to adjust; moment of gravity gradientGenerated by coupling the inertia of the detector with the gravity vector of the central celestial body under the system.

For example, a mars detection configuration is adopted, two solar wings are arranged, the two solar wings are arranged in the positive Y direction and the negative Y direction and can rotate around the Y axis in one dimension, the rotation range is 0-360 degrees, the normal line of the solar wing corresponding to 0 degree points to-Z, the normal line of the solar wing corresponding to 270 degrees points to + X, and the angle of the solar wing is 270 degrees in a long-term flight state. The area of the single wing solar wing is 20m2, and the deviation of the center of mass is 10 m. And setting an angular momentum unloading threshold of 5Nms, and unloading once in about 15 days during the cruising process.

A closed-loop driving angular momentum management scheme based on the solar wing is adopted, the angular driving amplitude limit of the solar wing is set to be 250-290 degrees, the angular momentum unloading threshold is set to be 5Nms, and the air injection unloading is required once in about 40 days in the cruising process. The unload frequency is reduced by more than 1/2 compared to not performing the angular momentum management scheme.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.