CN107300861A - A kind of spacecraft dynamics distributed computing method - Google Patents

Abstract

The invention discloses a distributed computing method for spacecraft dynamics, which belongs to the technical field of control and simulation. This method uses a distributed computing strategy to distribute the dynamics simulation work of multiple spacecraft in different simulation computers. Each simulation computer only performs dynamic calculations for one spacecraft, and then through the data exchange between different simulation computers Obtain the dynamic data of other spacecraft and complete the multi-spacecraft joint simulation test task. The invention solves the disadvantages of insufficient simulation computer computing ability and repeated modeling encountered in the centralized simulation of multi-objective dynamics (such as spacecraft formation flight) in the existing centralized simulation technology, and improves the calculation efficiency of simulation.

Description

A Distributed Computing Method for Spacecraft Dynamics

technical field

The invention relates to a distributed computing method for spacecraft dynamics, in particular to a distributed computing method for joint simulation of multi-objective dynamics, which belongs to the technical field of control and simulation.

Background technique

For the design and verification of the spacecraft GNC system, the spacecraft dynamics simulation is an indispensable link and runs through the whole project. It simulates the space environment of the spacecraft and the orbit and attitude movement of the spacecraft, and provides a mathematical simulation environment for the design of the spacecraft control system. Based on the attitude information and sensor information generated by the dynamics simulation system, the control system calculates the control information and feeds it back to the dynamics simulation system, thereby verifying the effectiveness of the control system.

When the spacecraft is performing ground physics simulation experiments, the requirements for dynamic calculation efficiency are very strict, and all dynamic calculations and sensor excitation work need to be completed within one control cycle. However, since there is no distributed computing method at present, the spacecraft dynamics simulation is to establish a specific dynamics simulation model for the task, and all the dynamics calculations are centralized on the same simulation computer. When it is necessary to conduct a joint test on multiple spacecraft (such as missions such as spacecraft formation flight), it is difficult to complete the test with the current dynamics simulation method. The problems encountered are mainly as follows:

1) Due to the different number and types of spacecraft involved in different missions and different formation configurations, the same spacecraft may be modeled repeatedly in different simulation missions, and the dynamic model or simulation calculation structure needs to be redesigned.

2) Due to the limited computing power of a single simulation computer, when there are many spacecraft that need to be simulated simultaneously, it will inevitably lead to the inability to complete the simulation calculation tasks of multiple spacecraft within the same control cycle.

Contents of the invention

The technical problem solved by the invention is to overcome the deficiencies of the prior art, provide a distributed computing method for spacecraft dynamics, and solve the problem of dynamic distributed computing in joint simulation of multiple spacecraft.

The technical scheme of the present invention is: a kind of spacecraft dynamics distributed calculation method, the steps are as follows:

(1) Arrange each spacecraft model that needs to be simulated at the same time on its own simulation computer, select one simulation computer as the simulation computer, and the spacecraft arranged on it as the spacecraft;

(2) On each simulation computer, initialize the physical parameters of the spacecraft in its own layout and other spacecraft in the co-simulation, where the physical parameters to be initialized for the spacecraft in its own layout include mass, moment of inertia, position of center of mass, sailboard Flexible model, docking interface location, actuator and sensor installation location, other spacecraft physical parameters for co-simulation include center of mass location, relative navigation sensor installation location, moment of inertia, mass;

(3) T simulation time, the simulation computer obtains the dynamic data of other spacecraft other than the spacecraft T-1 simulation time through data exchange, and performs extended calculations on the obtained dynamic data of other spacecraft to obtain other spacecraft T -1 Kinetic parameters at the moment of simulation;

(4) Use the dynamic data of other spacecraft T-1 simulation time, the dynamic parameters calculated by extension, and the dynamic data of this spacecraft T-1 simulation time to solve the relative navigation between multiple spacecraft, and get The relative relationship between the spacecraft and other spacecraft at T-1 simulation time;

(5) Using the dynamic data of the spacecraft T-1 simulation time and the relative relationship with other spacecraft obtained in step (4), calculate the relative navigation sensor and the non-relative navigation sensor of the spacecraft at the T-1 simulation time. Incentive data of the device;

(6) According to the relative relationship between the spacecraft and other spacecraft obtained in step (4), judge the docking state of the spacecraft and other spacecraft;

(7) Calculate the dynamic data of the spacecraft T simulation time according to the docking state;

(8) Output the dynamic data of the spacecraft at T simulation time to other spacecraft according to the communication protocol, and realize the distributed calculation of multi-objective dynamics joint simulation at T simulation time.

In described step (3), this simulation computer obtains the structure of other spacecraft T-1 simulation time dynamics data as follows:

{

spacecraft number;

time system;

Spacecraft inertial frame position;

Spacecraft inertial frame velocity;

Spacecraft inertial frame acceleration;

Attitude quaternion of spacecraft inertial frame;

The angular velocity of the spacecraft's own system relative to the inertial system is projected on the own system;

The angular acceleration of the spacecraft body system relative to the inertial system is projected on the body system;

Spacecraft specific acceleration;

spacecraft flight status;

}.

In the step (6), when the relative relationship between the spacecraft and other spacecraft satisfies any of the following, it is determined that the spacecraft is docked with other spacecraft:

① The relative distance between the spacecraft and the flight direction of other spacecraft is equal to 0;

② The relative distance between the spacecraft and other spacecraft in the flight direction is equal to 0, and the relative attitude angle is less than 1 degree.

The realization method of described step (7) is as follows:

(4.1) If the spacecraft is not docked with other spacecraft, use the physical parameters of the spacecraft to directly calculate the dynamic data of the spacecraft at T simulation time;

(4.2) If the spacecraft is docked with other spacecraft, it is judged whether the spacecraft is the master spacecraft. If it is the master spacecraft, the physical parameters of the docked assembly are used to directly calculate the T simulation time of the spacecraft Kinetic data, otherwise enter step (4.3);

(4.3) According to the flight state of the spacecraft in the dynamic data of other spacecraft T-1 simulation time, determine the main control spacecraft in other spacecraft, extrapolate the dynamic data of the main control spacecraft T-1 simulation time, and get The dynamic parameters of the main control spacecraft at T simulation time, enter step (4.4);

(4.4) According to the relative relationship between the spacecraft and the master spacecraft, calculate the dynamic data of the spacecraft T simulation time.

In the described step (4.1), the method for calculating the dynamics data of this spacecraft T simulation moment is as follows:

(5.1) Calculate the sailboard rotation angle of the spacecraft according to the sailboard control command at T simulation time, and calculate the spacecraft T Deflection moments and plumes at the moment of simulation;

(5.2) Calculate the specific force acceleration of the spacecraft T simulation time according to the control force, moment, environmental disturbance force, disturbance moment, flexure moment and plume received by the spacecraft T simulation time;

(5.3) According to the physical parameters and the specific force acceleration of the spacecraft T simulation moment, the numerical integration algorithm is used to calculate the position, velocity and acceleration of the spacecraft T simulation moment under the inertial system;

(5.4) Utilize the torque and physical parameters received by the spacecraft T at the simulation moment, and iteratively calculate the attitude quaternion to obtain the attitude of the spacecraft T at the simulation moment;

(5.5) Update the simulation time;

(5.6) According to the position of the inertial system at the simulation time of the spacecraft T, the number of orbits is obtained;

(5.7) Calculate the attitude rotation matrix of the spacecraft system relative to the orbital system and inertial system from the inertial system position and attitude solution at the simulation time of the spacecraft T, and calculate the attitude angular velocity of the spacecraft T simulation time;

(5.8) After conversion, the attitude and attitude angular velocity of the inertial system and the orbital system at the simulation time of the spacecraft T are obtained.

In the described step (4.2), the method for calculating the dynamic data of this spacecraft T simulation moment is as follows:

(6.1) Calculate the sailboard rotation angle of the assembly after docking according to the sailboard control command at T simulation time, and calculate the assembly T simulation according to the sailboard rotation angle and the control force, torque, environmental disturbance force, and disturbance torque received by the assembly T simulation time The moment of flexure and plume;

(6.2) Calculate the specific force acceleration of the combination T at the simulation moment according to the control force, moment, environmental disturbance force, disturbance moment, flexural moment and plume received by the combination T at the simulation moment;

(6.3) According to the physical parameters and the specific force acceleration of the assembly T at the simulation moment, the numerical integration algorithm is used to calculate the position, velocity and acceleration of the assembly T under the inertial system at the simulation moment;

(6.4) Utilize the torque and physical parameters received by the assembly T at the simulation moment, iteratively calculate the attitude quaternion, and obtain the attitude of the assembly T at the simulation moment;

(6.5) Update the simulation time;

(6.6) Obtain the number of 6 tracks according to the position of the inertial system at the simulation time of the assembly T;

(6.7) Calculate the attitude rotation matrix of the spacecraft system relative to the orbital system and inertial system from the inertial system position and attitude solution at the simulation time of the assembly T, and calculate the attitude angular velocity of the assembly T at the simulation time;

(6.8) After conversion, the attitude and attitude angular velocity of the inertial system and the orbital system of the combination T are obtained, and the attitude and attitude angular velocity of the inertial system and the orbital system of the combination are the attitude and attitude of the inertial system and the orbital system of the spacecraft. Attitude angular velocity.

The advantage of the present invention compared with prior art is:

1) Each simulation computer only performs simulation calculations for a single spacecraft dynamics, which improves the calculation efficiency of the simulation and fundamentally solves the situation that the simulation calculation task cannot be completed within one control cycle due to the limitation of the calculation capacity of a single computer occur.

2) For the same spacecraft, it only needs to establish a dynamic model once, which fundamentally solves the problem of high development cost and cycle time caused by the need to repeatedly establish simulation models for different missions or formation configurations in existing dynamic simulation systems. long question.

Description of drawings

Fig. 1 is a running sequence diagram of the present invention.

detailed description

A spacecraft dynamics distributed computing method proposed by the invention can be used to complete multi-spacecraft joint simulation.

In this method, each spacecraft model that needs to be simulated at the same time is first laid out on its own simulation computer.

Each simulation computer only performs dynamic calculation for one spacecraft, and different simulation computers obtain dynamic data of other spacecraft through data exchange, and then complete the distributed joint calculation of multi-spacecraft dynamics. As shown in Figure 1, the dynamic calculation of each simulation computer includes the following steps:

(1) Power initialization

Initialize the physical parameters of the spacecraft (referred to as the spacecraft) in its own layout. The physical parameters include mass, moment of inertia, center of mass position, sailboard flexible model, docking port position (only for rendezvous and docking functions), sensor installation, Actuator characteristics. And initialize the physical parameters of other spacecraft that will be co-simulated, including the position of the center of mass, the installation position of the relative navigation sensor, the moment of inertia, and the mass. For subsequent relative navigation calculations and dynamic calculations in docking mode.

In the following, the relative navigation calculation between multiple spacecraft is performed using the relative data at T-1 time.

(2) Obtain other spacecraft dynamics data

In order to complete the co-simulation of multi-spacecraft dynamics, it is necessary to obtain the dynamic data of other spacecraft. According to the data exchange agreement, the simulation computer obtains the dynamic data of T-1 simulation time of other spacecrafts other than the spacecraft, mainly including the position, velocity, attitude and other information of the inertial system. The obtained dynamic data of other spacecraft is extended and calculated to obtain parameters such as the orbital number, attitude rotation matrix, and orbital angular velocity of other spacecraft T-1 at the simulation time, which can be used for subsequent relative navigation calculations or one-step extrapolation.

(3) Calculate the relative relationship between the spacecraft at time T-1

Using the dynamic data of other spacecraft at T-1 simulation time, the dynamic parameters calculated by extension, and the dynamic data of this spacecraft at T-1 time obtained by the current simulation computer, calculate the relationship between the spacecraft at T-1 simulation time and Relative information such as relative position and relative attitude among other spacecraft.

(4) Sensor excitation

Using the dynamic data of the spacecraft and the calculation result of step (3), calculate the T-1 simulation time, the excitation data (theoretical output value) of the relative navigation sensors such as the relative radar of the spacecraft, and the gyroscope, star sensitivity and other non-contact sensors. Relative to the excitation data of the navigation sensor (theoretical output value).

(5) Docking status judgment

According to the relative relationship between the own spacecraft and other spacecraft obtained in step (3), judge the docking state of the own spacecraft and other spacecraft at T-1 simulation time.

When the relative relationship between the spacecraft and other spacecraft satisfies any of the following, it is determined that the spacecraft is docked with other spacecraft:

① The relative distance between the spacecraft and the flight direction of other spacecraft is equal to 0;

② The relative distance between the spacecraft and other spacecraft in the flight direction is equal to 0, and the relative attitude angle is less than 1 degree.

In actual operation, other docking judgment principles can also be set according to specific project requirements, not limited to the above two.

Next, the simulation computer calls different dynamics calculation branches according to the judgment result of step (5). If the docking is not completed, go to step (6), otherwise go to step (7) and start to solve the dynamics of the spacecraft T simulation time Learning data:

(6) In single spacecraft mode (docking not completed): use the physical parameters of the spacecraft to calculate the dynamic data of the spacecraft T simulation time, turn to (8).

The method of calculating the dynamic data of the spacecraft T simulation time is as follows:

1) Calculate the sailboard rotation angle of the spacecraft according to the sailboard control command at the simulation time T, and calculate the deflection angle at the simulation time T according to the sailboard rotation angle and the control force, torque, environmental disturbance force, and disturbance torque received by the spacecraft at the simulation time T. Sexual moments and plumes;

2) Calculate the specific force acceleration at T simulation time according to the control force, moment, environmental disturbance force, disturbance moment, flexure moment and plume received by the spacecraft at T simulation time;

3) Using the physical parameters and specific force acceleration of the spacecraft at the simulation time T, the numerical integration algorithm (such as the Runge-Kutta method) is used to calculate the position, velocity and acceleration of the spacecraft in the inertial system at the simulation time T;

4) Using the torque and physical parameters received by the spacecraft at the simulation time T, iteratively calculate the attitude quaternion to obtain the attitude of the spacecraft at the simulation time T;

5) Update the simulation time and the corresponding Julian day time;

6) According to the position of the inertial system of the spacecraft at T simulation time, the number of orbits is obtained;

7) Calculate the attitude rotation matrix of the spacecraft system relative to the orbital system and inertial system from the position and attitude of the spacecraft's inertial system at the simulation time T, and calculate the attitude angular velocity of the spacecraft at the simulation time T;

8) After conversion, the attitude and attitude angular velocity of the spacecraft's inertial system and orbital system at T simulation time are obtained.

(7) The docking mode has been formed,

1) If the spacecraft is a follower spacecraft (non-actively controlled spacecraft), extrapolate the dynamic data of the master spacecraft obtained in step (2) at time T-1 to obtain the Dynamic parameters, obtain the dynamic data of this spacecraft T simulation moment according to the relative position, relative attitude etc. that step (3) obtains afterwards;

2) If the spacecraft is the main control spacecraft, the orbit dynamics and attitude dynamics of the spacecraft are calculated using the physical parameters of the docked assembly to obtain the dynamic data of the spacecraft at T simulation time.

The implementation method of step 2) is similar to the calculation method when the docking is not completed, except that the physical parameters of the spacecraft need to be replaced with the physical parameters of the docked assembly, and finally the attitude and attitude angular velocity of the assembly are solved, which is the The attitude of the device and the attitude angular velocity.

(8) The simulation computer outputs the dynamic data of the spacecraft T simulation time to other spacecraft according to the communication protocol to complete the data exchange.

After the above steps are completed, the current simulation computer has completed all the work of the distributed dynamics calculation at the T simulation time. When the T+1 simulation time arrives, repeat steps (2) to (8).

It should be noted that if only a single spacecraft needs to be simulated for dynamics, it is only necessary to perform the above steps (1), (4) and (6) in sequence.

In order to complete the multi-spacecraft distributed relative navigation calculation, and complete the spacecraft relative position and attitude calculation in the docking mode, the present invention provides the minimum dynamic data structure that needs to be exchanged between each simulation computer as follows:

{

spacecraft number;

time system;

Spacecraft inertial frame position;

Spacecraft inertial frame velocity;

Spacecraft inertial frame acceleration;

Attitude quaternion of spacecraft inertial frame;

The angular velocity of the spacecraft's own system relative to the inertial system is projected on the own system;

The angular acceleration of the spacecraft body system relative to the inertial system is projected on the body system;

Spacecraft specific acceleration;

spacecraft flight status;

}

Among them, the spacecraft number is used to represent the dynamic data of the spacecraft, the time system such as Julian day, etc., and the flight status of the spacecraft refers to whether the docking is completed, whether it is the main control aircraft, etc.

In the present invention, the distributed computing strategy is used to distribute the dynamics simulation work of multiple spacecraft in different simulation computers. Data exchange obtains the dynamic data of other spacecraft, and completes the multi-spacecraft joint simulation test task.

The invention can solve the dynamic calculation task of multiple spacecraft through distributed calculation, and can complete the simulation of two working modes of rendezvous and docking and non-rendezvous and docking spacecraft.

The method of the present invention can also be applied to non-aerospace fields such as industrial automation (such as multi-robot joint control) to realize multi-objective dynamic distributed simulation calculation.

The invention solves the disadvantages of insufficient simulation computer computing ability and repeated modeling encountered in the centralized simulation of multi-objective dynamics (such as spacecraft formation flight) in the existing centralized simulation technology, and improves the calculation efficiency of simulation.

The content that is not described in detail in the description of the present invention belongs to the well-known technology of those skilled in the art.

Claims (6)

1. a kind of spacecraft dynamics distributed computing method, it is characterised in that step is as follows：

(1) each spacecraft model for needing emulation simultaneously is laid out on respective simulation computer respectively, selects one to imitate Genuine computer is as this simulation computer, and the spacecraft being laid out thereon is used as this spacecraft；

(2) on every simulation computer, other spacecraft physical parameters of spacecraft and associative simulation to own layout Initialized, the spacecraft physical parameter to be initialized of wherein own layout include quality, rotary inertia, centroid position, Windsurfing Flexible Model about Ecology, docking port position, executing agency and sensor installation site, other spacecraft physical parameters of associative simulation Including centroid position, Relative Navigation sensor installation site, rotary inertia, quality；

(3) T emulates the moment, when this simulation computer obtains other spacecraft T-1 emulation beyond this spacecraft by data exchange The dynamics data at quarter, and calculating is extended to other spacecraft dynamics data of acquisition, obtain other spacecraft T-1 and imitate The kinetic parameter at true moment；

(4) kinetic parameter that other spacecraft T-1 emulate the dynamics data at moment, extension is calculated, and this boat are utilized Its device T-1 emulates the dynamics data at moment, and Relative Navigation is resolved between carrying out many spacecrafts, obtains carving copy space flight during T-1 emulation Relativeness between device and other spacecrafts；

(5) the relative pass between other spacecrafts obtained using this spacecraft T-1 emulation moment dynamics data, step (4) System, the excited data of carving copy spacecraft Relative Navigation sensor and non-Relative Navigation sensor when calculating T-1 emulation；

(6) relativeness between this spacecraft and other spacecrafts for being obtained according to step (4), judges this spacecraft and other boats The mated condition of its device；

(7) dynamics data that this spacecraft T emulates the moment is calculated according to mated condition；

(8) dynamics data that this spacecraft T is emulated to the moment is exported to other spacecrafts according to communications protocol, realizes that T is emulated The Distributed Calculation of moment multiple target Dynamic Co-Simulation.

2. a kind of spacecraft dynamics distributed computing method according to claim 1, it is characterised in that the step (3) in, the structure that this simulation computer obtains other spacecraft T-1 emulation moment dynamics datas is as follows：

{

Spacecraft is numbered；

Time system；

Spacecraft inertial system position；

Spacecraft inertial system speed；

Spacecraft inertial system acceleration；

Spacecraft inertial system attitude quaternion；

Spacecraft body series are projected relative to the angular speed of inertial system in body series；

Spacecraft body series are projected relative to the angular acceleration of inertial system in body series；

Spacecraft specific force acceleration；

Spacecraft flight state；

}。

3. a kind of spacecraft dynamics distributed computing method according to claim 1, it is characterised in that the step (6) in when this spacecraft and other spacecraft relativenesses meet it is following any one when, judge this spacecraft and other space flight Device is to connecting：

1. this spacecraft is equal to 0 with other spacecraft flight directions relative distance；

2. this spacecraft is equal to 0 with other spacecraft flight directions relative distance, and relative attitude angle is less than 1 degree.

4. a kind of spacecraft dynamics distributed computing method according to claim 1, it is characterised in that the step (7) implementation method is as follows：

(4.1) if on this spacecraft and other spacecrafts are undocked, this boat is directly calculated using this spacecraft physical parameter Its device T emulates the dynamics data at moment；

(4.2) if whether in this spacecraft and other spacecraft launching sites, it is master control spacecraft to judge this spacecraft, if Master control spacecraft, then directly calculate the dynamics data that this spacecraft T emulates the moment using the physical parameter of assembly after docking, Otherwise step (4.3) is entered；

(4.3) the spacecraft flight state in moment dynamics data is emulated according to other spacecraft T-1, determines other spacecrafts In master control spacecraft, by master control spacecraft T-1 emulate the moment dynamics data extrapolate, obtain T emulation moment master control spacecraft Kinetic parameter, into step (4.4)；

(4.4) according to the relativeness between this spacecraft and master control spacecraft, the dynamics number that this spacecraft T emulates the moment is calculated According to.

5. a kind of spacecraft dynamics distributed computing method according to claim 4, it is characterised in that the step (4.1) method that this spacecraft T emulation moment dynamics datas are calculated in is as follows：

(5.1) the windsurfing corner that moment windsurfing control instruction calculates this spacecraft is emulated according to T, according to windsurfing corner and this boat Controling power, torque that its device T emulation moment is subject to, environmental disturbances power, disturbance torque calculate scratching for this spacecraft T emulation moment Property torque and plume；

(5.2) controling power, the torque being subject to according to this spacecraft T emulation moment, environmental disturbances power, disturbance torque, flex torque And plume, calculate the specific force acceleration that this spacecraft T emulates the moment；

(5.3) physical parameter and specific force acceleration at moment are emulated according to this spacecraft T, this boat is calculated using numerical integration algorithm Its device T emulates position, speed and acceleration of the moment under inertial system；

(5.4) torque and physical parameter being subject to using this spacecraft T emulation moment, calculating is iterated to attitude quaternion, Obtain this spacecraft T emulation moment postures；

(5.5) simulation time is updated；

(5.6) moment inertial system position is emulated according to this spacecraft T and obtains the radical of track 6；

(5.7) moment inertial system position, attitude algorithm are emulated by this spacecraft T and goes out spacecraft body series relative to track system, used Property system posture spin matrix, and calculate obtain this spacecraft T emulate the moment attitude angular velocity；

(5.8) by conversion, this spacecraft T emulation moment inertial systems and the posture and attitude angular velocity of track system are obtained.

6. a kind of spacecraft dynamics distributed computing method according to claim 4, it is characterised in that the step (4.2) method that this spacecraft T emulation moment dynamics datas are calculated in is as follows：

(6.1) the windsurfing corner that moment windsurfing control instruction calculates assembly after docking is emulated according to T, according to windsurfing corner and Controling power, torque that the assembly T emulation moment is subject to, environmental disturbances power, disturbance torque calculate scratching for assembly T emulation moment Property torque and plume；

(6.2) the moment controling power, the torque that are subject to are emulated according to assembly T, environmental disturbances power, disturbance torque, flex torque and Plume, calculates the specific force acceleration that assembly T emulates the moment；

(6.3) physical parameter and specific force acceleration at moment are emulated according to assembly T, assembly is calculated using numerical integration algorithm T emulates position, speed and acceleration of the moment under inertial system；

(6.4) torque and physical parameter being subject to using the assembly T emulation moment, calculating is iterated to attitude quaternion, is obtained Moment posture is emulated to assembly T；

(6.5) simulation time is updated；

(6.6) moment inertial system position is emulated according to assembly T and obtains the radical of track 6；

(6.7) moment inertial system position, attitude algorithm are emulated by assembly T and goes out spacecraft body series relative to track system, inertia The posture spin matrix of system, and calculate the attitude angular velocity for obtaining the assembly T emulation moment；

(6.8) by conversion, assembly T emulation moment inertial systems and the posture and attitude angular velocity of track system, described group are obtained Fit inertial system and the posture and attitude angular velocity of track system are this spacecraft inertial system and the posture and attitude angle of track system Speed.