CN-122020973-A - Parachute six-degree-of-freedom mathematical model construction method for Mars landing

CN122020973ACN 122020973 ACN122020973 ACN 122020973ACN-122020973-A

Abstract

The invention discloses a method for constructing a six-degree-of-freedom mathematical model of a parachute for mars landing. The method comprises the steps of establishing a Mars atmospheric environment parameter model, initializing a density function, a gravity acceleration function and a temperature function of Mars atmosphere, taking tail end height, speed and attack angle data of a Mars entering section as input to obtain initial state parameters, executing active disturbance rejection control on a flight track of the entering section based on the initial state parameters, carrying out drag acceleration tracking control on corrected parachute opening point state data, establishing a Mars earth surface inertial coordinate system and a parachute system body coordinate system, utilizing the parachute opening point state data to construct a fire transformation matrix, determining attitude angles and speed components of the system based on the transformation matrix to obtain a coordinate system initialization result, and utilizing a parachute-aircraft system with additional quality items to establish a six-degree-of-freedom dynamics model based on the coordinate system initialization result. The invention solves the technical problem of inaccurate landing of Mars.

Inventors

XIA YUANQING
SUN ZHONGQI
ZHAI DIHUA
ZHAN YUFENG
DAI LI
DAI JUAN
WU CHUGE
CUI PINGYUAN
YAN LIPING
LI YIRAN
Shen Ganghui
GAO HAN
CUI BING
YU DONGDONG
ZHANG SHUHUA
YOU LIJIE
ZHANG YUAN
YANG HONGJIU

Assignees

中原工学院
北京理工大学

Dates

Publication Date: 20260512
Application Date: 20251230

Claims (10)

1. The method for constructing the six-degree-of-freedom mathematical model of the parachute for the mars landing is characterized by comprising the following steps of: establishing a Mars atmospheric environment parameter model, initializing a density function, a gravity acceleration function and a temperature function of Mars atmosphere, and obtaining initial state parameters by taking the tail end height, speed and attack angle data of a Mars entering section as input; Executing an active disturbance rejection control algorithm based on the initial state parameters, carrying out drag acceleration tracking control on the flight track of the entering section, and outputting corrected open umbrella point state data; Establishing a Mars earth surface inertial coordinate system and a parachute system body coordinate system, constructing a transformation matrix between the Mars earth surface inertial coordinate system and the parachute system body coordinate system by using the parachute opening point state data, and determining attitude angles and speed components of the system based on the transformation matrix to obtain a coordinate system initialization result; based on the coordinate system initialization result, a six-degree-of-freedom dynamics model is established by utilizing a parachute-aircraft system with additional quality items.
2. The method of claim 1, wherein modeling the atmospheric environment parameters of the spark comprises: Acquiring a Mars atmospheric density distribution function, and calculating gravity acceleration according to the Mars radius and the earth surface gravity constant to obtain an atmospheric density and gravity acceleration coupling parameter set; And matching the coupling parameter set with the input initial height, and calculating a local atmospheric characteristic parameter set of the Mars entering section, wherein the local atmospheric characteristic parameter set comprises local density, pressure and temperature.
3. The method of claim 1, wherein executing an active disturbance rejection control algorithm based on the initial state parameters, performing drag acceleration tracking control on the flight trajectory of the incoming segment, and outputting corrected open umbrella point status data, comprises: Based on the initial state parameters, estimating the total disturbance in real time by using an extended state observer; the total disturbance is utilized to compensate unknown disturbance, so that the dragging acceleration tracks the reference dragging acceleration, and real-time track deviation is obtained; and calculating the updated opening point height, speed and attitude angle based on the real-time track deviation to obtain corrected opening point state data.
4. The method of claim 1, wherein establishing a Mars earth surface inertial coordinate system and a parachute system body coordinate system, and constructing a transformation matrix between the Mars earth surface inertial coordinate system and the parachute system body coordinate system using the parachute opening state data comprises: determining an origin based on the Mars earth surface right below the umbrella opening point, determining a Z axis based on the Mars center direction, determining an X axis based on the initial flight direction, determining a Y axis according to a right-hand rule, and establishing an inertial coordinate system of the Mars earth surface; determining an origin based on a parachute-aircraft system centroid, determining an X-axis based on a system instantaneous motion direction, determining a Z-axis based on a direction along a main parachute symmetry axis, and establishing a parachute system body coordinate system; And establishing a coordinate transformation matrix between the Mars earth surface inertial coordinate system and the parachute system body coordinate system by using the parachute opening point state data, wherein the coordinate transformation matrix meets the compound rotation relation of the triaxial rotation sequence.
5. The method of claim 1, wherein establishing a six degree of freedom dynamics model with the parachute-aerial vehicle system of additional mass terms based on the coordinate system initialization result comprises: correcting the calculation error of the additional mass by using a time self-adaptive damping correction coefficient to obtain an equivalent additional mass term, and constructing a translational mechanics equation based on the equivalent additional mass term; Based on the positional relationship between aerodynamic force components and the mass center of the parachute relative to the mass center of the system, calculating aerodynamic moments in roll, pitch and yaw directions, and establishing an angular motion equation by combining the rotational inertia of the system; the six-degree-of-freedom dynamics model comprises a translational mechanics equation and an angular movement equation.
6. The method of claim 5, wherein correcting the additional mass calculation error using the time-adaptive damping correction factor to obtain an equivalent additional mass term, and constructing a translational mechanics equation based on the equivalent additional mass term, comprises: calculating local atmospheric density at the unfolding height of the parachute based on the Mars atmospheric environment parameter model, and constructing a basic additional mass model of the system according to the parachute reference area coefficient; Constructing the equivalent additional quality item which changes along with time by utilizing a time self-adaptive damping correction coefficient, wherein the equivalent additional quality item is used for representing the transient influence of unsteady airflow in the spark rarefied atmosphere on a parachute system; And superposing the aircraft mass, the parachute mass and the equivalent additional mass item to obtain the total equivalent mass of the parachute-aircraft system, and establishing the translational mechanics equation under the parachute system body coordinate system based on the total equivalent mass.
7. A method for controlling spark landing, comprising: determining a movement characteristic of the aircraft based on the method of any one of claims 1 to 6; controlling the aircraft spark landing based on the motion characteristics.
8. A six-degree-of-freedom model building system for a parachute for the landing of a Mars, comprising: The model building module is configured to build a Mars atmospheric environment parameter model, initialize a density function, a gravity acceleration function and a temperature function of Mars atmosphere, and input end height, speed and attack angle data of a Mars entering section to obtain initial state parameters; The state determining module is configured to execute an active disturbance rejection control algorithm based on the initial state parameters, carry out drag acceleration tracking control on the flight track of the entering section and output corrected open point state data; The transformation module is configured to establish a Mars earth surface inertial coordinate system and a parachute system body coordinate system, construct a transformation matrix between the Mars earth surface inertial coordinate system and the parachute system body coordinate system by utilizing the parachute opening state data, and determine attitude angles and speed components of the system based on the transformation matrix to obtain a coordinate system initialization result; a build module configured to build a six degree of freedom dynamics model using the parachute-aerial vehicle system of additional quality items based on the coordinate system initialization result.
9. A computer device is characterized by comprising a memory and a processor, The memory stores a computer program; the processor being operative to execute a computer program stored in the memory, the computer program when run causes the processor to perform the method of any one of claims 1 to 6.
10. A computer program product comprising a computer program, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any of claims 1 to 6.

Description

Parachute six-degree-of-freedom mathematical model construction method for Mars landing Technical Field The invention relates to the field, in particular to a parachute six-degree-of-freedom mathematical model construction method for mars landing. Background The Mars Entry, descent and landing (Entry, DESCENT AND LANDING, EDL) process is a critical stage in the Mars detection mission, where the parachute system plays a central role in the aircraft deceleration and steady descent process. In order to analyze and verify the motion characteristics of a parachute-aircraft system in a Mars atmosphere environment, a corresponding kinetic mathematical model is generally required to be established to describe the speed, attitude and position change condition of the system in a descent stage. In the prior art, the modeling method for the Mars parachute system is mostly based on simplified dynamics assumption, and usually adopts a three-degree-of-freedom or quasi-static model, or ignores aerodynamic unsteady effect and additional mass change in six-degree-of-freedom modeling, so that the real dynamics of translational and rotational coupling in the parachute unfolding and descending processes are difficult to comprehensively reflect. On the other hand, mars atmosphere has the characteristics of low density, large scale height, rapid change of pneumatic environment along with the height and the like, when the parachute moves in the thin atmosphere, the acceleration effect of surrounding air flow can introduce obvious unsteady additional mass and damping change, and the existing six-degree-of-freedom model is generally subjected to approximate treatment by adopting constant additional mass or experience damping coefficient, so that the simulation precision is insufficient in the transient stage of the parachute unfolding and the gesture oscillation process. In addition, the partial modeling method does not effectively correct the end state of the entering section, directly uses the calculation result of the entering track as the initial condition of parachute opening, and easily transmits the disturbance error of the entering section to the parachute descent model, thereby influencing the overall simulation stability and reliability. Therefore, there is a need for a parachute system mathematical model construction method capable of combining the atmospheric environmental characteristics of a Mars, considering the disturbance correction of an entering section, and describing the coupling effect of translational motion and angular motion under a six-degree-of-freedom frame simultaneously, so as to improve the accuracy and stability of dynamic simulation of the Mars entering and landing process. Disclosure of Invention The embodiment of the invention provides a method and a system for constructing a six-degree-of-freedom mathematical model of a parachute for mars landing, which are used for at least solving the technical problem of mars. According to one aspect of the embodiment of the invention, a six-degree-of-freedom mathematical model construction method for a Mars landing is provided, and comprises the steps of establishing a Mars atmospheric environment parameter model, initializing a density function, a gravity acceleration function and a temperature function of Mars atmosphere, taking tail end height, speed and attack angle data of a Mars entering section as input to obtain initial state parameters, executing an active disturbance rejection control algorithm based on the initial state parameters, carrying out drag acceleration tracking control on a flight track of the entering section, outputting corrected parachute opening state data, establishing a Mars earth surface inertia coordinate system and a parachute system body coordinate system, utilizing the parachute opening state data to construct a transformation matrix between the Mars earth surface inertia coordinate system and the parachute system body coordinate system, determining attitude angles and speed components of a system based on the transformation matrix to obtain a coordinate system initialization result, and establishing a six-degree-of-freedom dynamic model by utilizing a parachute-aircraft system with additional quality items based on the coordinate system initialization result. According to another aspect of the embodiment of the invention, a system for constructing a six-degree-of-freedom parachute mathematical model for mars landing is further provided, which comprises a model construction module, a state determination module, a transformation module and a construction module, wherein the model construction module is configured to construct a mars atmospheric environment parameter model, initialize a density function, a gravity acceleration function and a temperature function of the mars atmosphere, input end height, speed and attack angle data of a mars entering section to obtain initial state parameters, the state determination module is conf