Electro-chemical dual-mode propulsion system for on-orbit service and control method thereof

Abstract

The application discloses a chemical and electric dual-mode propulsion system for on-orbit service and a control method thereof. The system comprises a chemical propulsion subsystem, an electric propulsion subsystem, an energy and control management module, wherein the chemical propulsion subsystem and the electric propulsion subsystem are arranged in parallel and are electrically connected to the energy and control management module respectively. The energy and control management module generates a thrust command, allocates power and controls the two types of propulsion subsystems in a coordinated manner. The control method constructs a dual-mode coordinated thrust model and a propulsion mode continuous spectrum evolution model, jointly optimizes chemical propulsion input, electric propulsion input and mode weight parameters under multiple constraint conditions, and realizes adaptive adjustment of the propulsion mode according to the on-orbit service task demand.

Description

Technical Field

[0001] This invention relates to the field of spacecraft on-orbit servicing technology, and in particular to a chemical-electric dual-mode propulsion system and its control method for on-orbit servicing. Background Technology

[0002] With the development of aerospace technology, on-orbit servicing missions have gradually become an important support for the long-term stable operation of space infrastructure. On-orbit servicing spacecraft typically need to have the following capabilities: 1) the ability to maneuver across orbits or over a wide range of orbits to achieve rapid arrival at the servicing target; 2) the ability to perform high-precision, low-disturbance relative motion control when approaching the target spacecraft; and 3) the ability to achieve comprehensive and coordinated control of energy, attitude, orbit, and structural loads throughout the mission.

[0003] Most existing servicing spacecraft employ a single type of propulsion. While chemical propulsion systems offer high thrust and fast response, they suffer from low efficiency and high energy consumption, making them unsuitable for long-term precision control. Electric propulsion systems, on the other hand, boast high efficiency and specific impulse, but their low thrust and limited maneuverability make them ill-suited for rapid orbital transfers. In complex servicing missions, a single propulsion mode cannot simultaneously achieve both all-domain maneuverability and precise approach control. Furthermore, existing dual-propulsion systems are mostly simply configured side-by-side, lacking thruster layout optimization, coordinated propulsion mode control, and integrated design methods under multiple constraints tailored to the characteristics of servicing missions, thus limiting system efficiency and control accuracy.

[0004] Therefore, it is urgent to improve and update spacecraft propulsion technology, and propose a chemical-electric dual-mode propulsion system and its control method for on-orbit service missions to solve the problems existing in the current technology. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a chemical-electric dual-mode propulsion system and its control method for on-orbit service.

[0006] The objective of this invention is achieved through the following technical solution: To achieve the above objective, this invention provides the following technical solution: a chemical-electric dual-mode propulsion system for on-orbit service, the system comprising: The chemical propulsion subsystem is used to provide thrust for spacecraft to perform large-scale orbital maneuvers. The electric propulsion subsystem is used to provide thrust for precise relative motion control during spacecraft servicing. The energy and control management module is used for the coordinated scheduling of the chemical propulsion subsystem and the electric propulsion subsystem.

[0007] Furthermore, the energy and control management module uses a dual-modal thrust collaborative synthesis model to implement propulsion control for the spacecraft, synthesizing the propulsion vector by combining the input vectors of the chemical propulsion subsystem and the electric propulsion subsystem through an installation matrix and weighting coefficients.

[0008] Furthermore, the weighting coefficients include chemical propulsion weighting coefficients. and electric propulsion weighting coefficient : ; Assign functions to the adaptive modes as follows: ; in, , and These are the spacecraft's position, velocity, and acceleration vectors, respectively. and These are the desired position and velocity vectors, respectively. , and These are the normalized threshold parameters for the corresponding terms, and the orbital maneuver transfer speed increment is a finite value.

[0009] Furthermore, the energy and control management module optimizes propulsion control based on the following dual-modal cooperative performance index function: ; In the formula, For state error, Let be the spacecraft state vector. Let be the desired state vector. and These are the control input vectors for chemical propulsion and electric propulsion, respectively. Here is the state error weight matrix. and These are the energy consumption weight matrices for chemical propulsion and electric propulsion, respectively. For reference weighting coefficients, These are the modal adjustment weighting coefficients.

[0010] Furthermore, the propulsion system is controlled under the following multiple constraints: ; In the formula, and These are the mapping matrices for chemical thrust and electric thrust, respectively. and These are the maximum permissible chemical thrust and the maximum permissible electric thrust, respectively. and These are the power of the electric propulsion subsystem and the maximum available power, respectively. The target spacecraft's position vector. For a safe distance, For attitude angular velocity, This represents the upper limit of the attitude angular velocity.

[0011] According to another aspect of the specification, a control method for the system is also provided, which constructs a multi-stage unified propulsion control optimization model through a single-stage dual-modal cooperative performance index function, and performs integrated control of the orbit transfer stage, approach stage, and on-orbit service operation stage. The specific optimization model is as follows: In the formula, For the first Phase spacecraft state vector, and The first Stage chemical propulsion and electric propulsion control input vectors, For the joint control input vector, For the first Stage-based dual-modal cooperative performance index function, To control the smoothing weight matrix, The total number of phases for in-orbit service missions.

[0012] Furthermore, the control method also includes control via a continuous spectrum control space, specifically: The chemical propulsion subsystem and the electric propulsion subsystem are uniformly mapped into a continuous propulsion mode control space. The combined thrust of the spacecraft is constructed through the propulsion mode distribution function. The dynamic migration behavior of chemical propulsion and electric propulsion in the continuous mode space is constructed using the propulsion mode distribution function, and the evolution model is obtained. Under the constraints of the propulsion mode evolution dynamics model, the propulsion mode distribution function is used as the control object. The extreme value of the three-field coupled variational objective functional of propulsion-orbit-on-orbit service mission is solved to obtain the optimal propulsion mode distribution function. This function is then mapped to the actual control input of the chemical propulsion subsystem and the electric propulsion subsystem, thereby realizing the coordinated optimal control of the dual-mode propulsion system.

[0013] Furthermore, the process of mapping the chemical propulsion subsystem and the electric propulsion subsystem into a unified propulsion mode continuous spectrum control space, and constructing the spacecraft's composite thrust through the propulsion mode distribution function, includes: ; In the formula, To advance the modal continuous spectrum variables, when When corresponding to the pure electric propulsion mode, when The time corresponds to a purely chemical propulsion mode; To advance the modal distribution function and satisfy the normalization condition: ; This is the thrust density function for the corresponding mode.

[0014] Furthermore, the construction of the dynamic migration behavior of chemical propulsion and electric propulsion in continuous mode space using the propulsion mode distribution function includes: ; In the formula, To advance the mode migration velocity function in the continuous spectrum space, For spacecraft status The driving propulsion mode source term function.

[0015] Furthermore, the extreme value solution is performed on the three-field coupled variational objective functional of the propulsion-orbit-on-orbit servicing mission: ; In the formula, These are performance indicators for orbital motion and attitude control. To advance the energy term of modal distribution and its smoothness, For indicators related to on-orbit service missions, To determine the desired state for performing on-orbit servicing tasks; by solving the optimal propulsion mode distribution function. This is then mapped to the actual control inputs of the chemical propulsion subsystem and the electric propulsion subsystem, achieving coordinated optimal control of the dual-mode propulsion system.

[0016] The beneficial effects of this invention are: 1. This invention achieves continuous coordinated control of chemical propulsion and electric propulsion during mission execution, avoiding the problem of discontinuous switching between traditional dual-mode propulsion methods.

[0017] 2. This invention enables the propulsion mode to adaptively evolve with the spacecraft's state and on-orbit service requirements, thereby improving energy efficiency and relative motion control accuracy.

[0018] 3. This invention achieves optimal control of the propulsion system throughout the entire on-orbit service mission through multi-stage unified optimization and multi-constraint collaborative control, thereby reducing energy redundancy. Attached Figure Description

[0019] Figure 1 This is an external view of the chemical-electric dual-mode propulsion system of the present invention; Figure 2 This is a schematic diagram of the component installation layout of the chemical-electric dual-mode propulsion system of this invention. Figure 3 This is a schematic diagram of the installation layout of the present invention's chemical and electric dual-mode propulsion system on a satellite. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figure 1-3 This invention provides a technical solution: a chemical-electric dual-mode propulsion system and its control method for on-orbit service, wherein the propulsion system and its control method include: The chemical propulsion subsystem consists of four chemical thrusters, 10-1, 10-2, 10-3 and 10-4, each with a thrust of 20N, used to enable the spacecraft to perform large-scale orbital maneuvers. The electric propulsion subsystem, namely Hall electric propulsion component 9, has a thrust range of 0.1N to 0.2N and is used to achieve precise relative motion control during the spacecraft's on-orbit servicing process; The Energy and Control Management module coordinates and controls the chemical propulsion subsystem and the electric propulsion subsystem. This module implements propulsion control for the spacecraft based on the following dual-mode thrust coordination synthesis model: (1) In the formula, For spacecraft at all times The combined thrust vector, and These are the control input vectors for chemical propulsion and electric propulsion, respectively. and These are the installation direction matrices for chemical thrusters and electric thrusters, respectively. and The weighting coefficients for chemical propulsion and electric propulsion are respectively, satisfying... It is used to achieve coordinated control of chemical propulsion and electric propulsion when spacecraft are performing on-orbit servicing missions.

[0023] Weighting coefficients for chemical propulsion and electric propulsion and Determined through adaptive allocation: (2) In the formula, Assign functions to the adaptive modes as follows: (3) In the formula, , and These are the spacecraft's position, velocity, and acceleration vectors, respectively, obtained by measurements from the onboard navigation system. and These are the desired position and velocity vectors, respectively. , and These are the normalized threshold parameters for the corresponding terms, and the orbital maneuver transfer velocity increment. Less than .

[0024] The energy and control management module optimizes propulsion control based on the following dual-modal cooperative performance index function: (4) In the formula, For state error, Let be the spacecraft state vector. Let be the desired state vector. Here is the state error weight matrix. and These are the energy consumption weight matrices for chemical propulsion and electric propulsion, respectively. These are the modal adjustment weighting coefficients. For reference weighting coefficients, select them as follows: (5) The following multi-constraint system control is constructed: (6) In the formula, and These are the mapping matrices for chemical thrust and electric thrust, respectively. and These are the maximum permissible chemical thrust and the maximum permissible electric thrust, respectively. and These are the power of the electric propulsion subsystem and the maximum available power, respectively. The target spacecraft's position vector can be obtained through orbit prediction models or onboard measurement systems. For a safe distance, For attitude angular velocity, This represents the upper limit of the attitude angular velocity.

[0025] A multi-stage unified propulsion control optimization model is constructed using a dual-modal collaborative performance index function. The energy and control management module performs integrated control over the orbit transfer phase, approach phase, and on-orbit service operation phase. The constructed optimization model is as follows: (7) In the formula, For the first Phase spacecraft state vector, and The first Stage chemical propulsion and electric propulsion control input vectors, For the joint control input vector, For the first Stage performance index function, To control the smoothing weight matrix, The total number of phases for in-orbit service missions.

[0026] The chemical propulsion subsystem and the electric propulsion subsystem are mapped to a continuous spectrum control space of propulsion modes, and the spacecraft's composite thrust is constructed through the propulsion mode distribution function. The composite thrust generated by propulsion control is generalized to the following form: (8) In the formula, To advance the modal continuous spectrum variables, when When corresponding to the pure electric propulsion mode, when The time corresponds to a purely chemical propulsion mode; To advance the modal distribution function and satisfy the normalization condition: In this embodiment, we take ,in It is a symbolic function; Let be the thrust density function corresponding to the mode. The continuous propulsion mode expression in this formula is an equivalent generalization of the discrete propulsion system above. When the propulsion mode distribution function ϕ(t,α) degenerates into a discrete distribution, it can be reduced to the thrust synthesis model in (1).

[0027] By constructing within the control space of the propulsion modal continuum A dynamic evolution model is used to describe the dynamic migration behavior of chemical propulsion and electric propulsion in continuous modal space. The evolution model is constructed as follows: (9) In the formula, To advance the mode migration velocity function in the continuous spectrum space, For spacecraft status The driving propulsion mode source term function.

[0028] Under the constraints of the propulsion modal evolution dynamics model, the propulsion modal distribution function is used. To control the object, we solve for the extrema of the following three-field coupled variational objective functional of the propulsion-orbit-on-orbit servicing mission: (10) In the formula, These are performance indicators for orbital motion and attitude control. To advance the energy term of modal distribution and its smoothness, For indicators related to on-orbit service missions, To determine the desired state for performing on-orbit servicing tasks; by solving the optimal propulsion mode distribution function. This is then mapped to the actual control inputs of the chemical propulsion subsystem and the electric propulsion subsystem, achieving coordinated optimal control of the dual-mode propulsion system.

[0029] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

[0030] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this application. This application is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A chemical-electric dual-mode propulsion system for on-orbit service, characterized in that, The system includes: The chemical propulsion subsystem is used to provide thrust for spacecraft to perform large-scale orbital maneuvers. The electric propulsion subsystem is used to provide thrust for precise relative motion control during spacecraft servicing. The energy and control management module is used for the coordinated scheduling of the chemical propulsion subsystem and the electric propulsion subsystem.

2. The chemical-electric dual-mode propulsion system for on-orbit service according to claim 1, characterized in that, The energy and control management module uses a dual-mode thrust collaborative synthesis model to implement propulsion control for the spacecraft, synthesizing the propulsion vector by combining the input vectors of the chemical propulsion subsystem and the electric propulsion subsystem through an installation matrix and weighting coefficients.

3. The chemical-electric dual-mode propulsion system for on-orbit service according to claim 2, characterized in that, The weighting coefficients include the chemical propulsion weighting coefficient. and electric propulsion weighting coefficient : ； Assign functions to the adaptive modes as follows: ； in, , and These are the spacecraft's position, velocity, and acceleration vectors, respectively. and These are the desired position and velocity vectors, respectively. , and These are the normalized threshold parameters for the corresponding terms, and the orbital maneuver transfer speed increment is a finite value.

4. The chemical-electric dual-mode propulsion system for on-orbit service according to claim 1, characterized in that, The energy and control management module optimizes propulsion control based on the following dual-modal cooperative performance index function: ； In the formula, For state error, Let be the spacecraft state vector. Let be the desired state vector. and These are the control input vectors for chemical propulsion and electric propulsion, respectively. Here is the state error weight matrix. and These are the energy consumption weight matrices for chemical propulsion and electric propulsion, respectively. For reference weighting coefficients, These are the modal adjustment weighting coefficients.

5. A chemical-electric dual-mode propulsion system for on-orbit service according to claim 4, characterized in that, The propulsion system control is performed under the following multiple constraints: ； In the formula, and These are the mapping matrices for chemical thrust and electric thrust, respectively. and These are the maximum permissible chemical thrust and the maximum permissible electric thrust, respectively. and These are the power of the electric propulsion subsystem and the maximum available power, respectively. The target spacecraft's position vector. For a safe distance, For attitude angular velocity, This represents the upper limit of the attitude angular velocity.

6. A control method for the system according to any one of claims 1-5, characterized in that, A multi-stage unified propulsion control optimization model is constructed using a single-stage dual-modal cooperative performance index function to achieve integrated control of the orbit transfer phase, approach phase, and on-orbit service operation phase. The specific optimization model is as follows: In the formula, For the first Phase spacecraft state vector, and The first Stage chemical propulsion and electric propulsion control input vectors, For the joint control input vector, For the first Stage-based dual-modal cooperative performance index function, To control the smoothing weight matrix, The total number of phases for in-orbit service missions.

7. The control method according to claim 6, characterized in that, The control method also includes control through a continuous spectrum control space, specifically: The chemical propulsion subsystem and the electric propulsion subsystem are uniformly mapped into a continuous propulsion mode control space. The combined thrust of the spacecraft is constructed through the propulsion mode distribution function. The dynamic migration behavior of chemical propulsion and electric propulsion in the continuous mode space is constructed using the propulsion mode distribution function, and the evolution model is obtained. Under the constraints of the propulsion mode evolution dynamics model, the propulsion mode distribution function is used as the control object. The extreme value of the three-field coupled variational objective functional of propulsion-orbit-on-orbit service mission is solved to obtain the optimal propulsion mode distribution function. This function is then mapped to the actual control input of the chemical propulsion subsystem and the electric propulsion subsystem, thereby realizing the coordinated optimal control of the dual-mode propulsion system.

8. The control method according to claim 7, characterized in that, The process of mapping the chemical propulsion subsystem and the electric propulsion subsystem into a propulsion mode continuous spectrum control space, and constructing the spacecraft's composite thrust through the propulsion mode distribution function, includes: ； In the formula, To advance modal continuous spectrum variables, when When corresponding to the pure electric propulsion mode, when The time corresponds to a purely chemical propulsion mode; To advance the modal distribution function and satisfy the normalization condition: ; This is the thrust density function for the corresponding mode.

9. The control method according to claim 8, characterized in that, The method of constructing the dynamic migration behavior of chemical propulsion and electric propulsion in continuous mode space using the propulsion mode distribution function includes: ； In the formula, To advance the mode migration velocity function in the continuous spectrum space, For spacecraft status The driving propulsion mode source term function.

10. The control method according to claim 9, characterized in that, The extreme value solution is obtained for the three-field coupled variational objective functional of the propulsion-orbit-on-orbit service mission: ； In the formula, These are performance indicators for orbital motion and attitude control. To advance the energy term of modal distribution and its smoothness, For indicators related to on-orbit service missions, The desired state for performing on-orbit servicing tasks; By solving the optimal propulsion mode distribution function This is then mapped to the actual control inputs of the chemical propulsion subsystem and the electric propulsion subsystem, achieving coordinated optimal control of the dual-mode propulsion system.

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