CN113639946A

CN113639946A - Method for determining mechanism bumping and vibrating conditions during movement of patrol device

Info

Publication number: CN113639946A
Application number: CN202110928297.8A
Authority: CN
Inventors: 党兆龙; 陈百超; 彭松; 潘冬; 邹猛
Original assignee: Jilin University; Beijing Institute of Spacecraft System Engineering
Current assignee: Jilin University; Beijing Institute of Spacecraft System Engineering
Priority date: 2021-08-13
Filing date: 2021-08-13
Publication date: 2021-11-12
Anticipated expiration: 2041-08-13
Also published as: CN113639946B

Abstract

The invention discloses a method for determining a mechanism bumping and vibrating condition when a patrol device moves, which comprises the following steps: determining an unevenness parameter according to the landing area range of the patrol instrument and the statistical characteristics of the surface topography of the planet; determining the maximum amplitude of the patrol instrument during bumping and vibration according to the obstacle crossing height index of the patrol instrument and by combining the wheel layout characteristics of the patrol instrument and the gravitational acceleration of the surface of a planet; and determining the fundamental frequency of the bumping vibration according to the contact length of the wheels of the patrol device or the unevenness of the ground and the moving speed. The invention can determine the bumping environment of the patrol instrument in the moving process and provide test conditions for developing the research and test of an organization.

Description

Method for determining mechanism bumping and vibrating conditions during movement of patrol device

Technical Field

The invention belongs to the field of deep space exploration, and particularly relates to a method for determining a mechanism bumping and vibrating condition when a patrol device moves.

Background

When the patrol instrument moves on the surface of a planet (moon and mars), the mechanism on the patrol instrument is in a vibration state due to the complexity of the terrain on the surface of the planet and the soil environment, so that the bumping phenomenon is generated. The occurrence of the pitching phenomenon comes from two aspects: on one hand, the surface of the planet is distributed with impact pits, stones and other unstructured landforms; another aspect is the mobile device nature of the rover. The two components act together to transfer uneven terrain on the surface of the planet to the vehicle body through the wheels and the suspension, and then to a mechanism arranged on the vehicle body.

The topography of the surface of the planet can be divided into features such as slopes, impact pits, rocks and the like; for a specific detection task, the landform and landform characteristics of a landing area are generally concerned, and high-resolution landform data of the landing area can be obtained through remote sensing and other means; for the case of lack of landform data of the landing zone, the landform characteristics of the similar area can be used for approximation.

1) Lunar and Mars surface topography:

the lunar surface terrain is divided into a lunar sea area and a high land area; the moon sea is divided into flat moon sea and rugged moon sea; typical features of lunar terrain are impact pits, slopes, and rocks. The distribution of the impact pits is described by the diameter of the impact pits and the number of the impact pits larger than the diameter; the slope is divided into areas such as flat moons, rugged moons and high lands for description, and a numerical relation curve between a slope base line and the average slope is obtained. The rock also obtains corresponding rock diameter and rock number curve larger than the diameter according to the difference of the distribution area; these are obtained by processing the obtained graphic data in a certain range and can be used as the preliminary basis for developing the research of the landing zone; with the development of the lunar orbit detection technology, a lunar high-precision topographic map is obtained, and topographic analysis of a landing zone can be carried out according to the lunar high-precision topographic map; the traditional power spectrum-based terrain statistical distribution is not used, and high-precision lunar terrain data are directly used.

Taking the lunar surface unevenness as an example, the typical lunar surface unevenness statistical property is shown in fig. 1, and as can be seen from fig. 1, the lunar surface unevenness can be divided into three areas, namely, flat moon (Smooth Mare), rugged moon (Rough Mare), and high land (Rough Upland/hummocky Upland); also shown in fig. 1 are the unevenness of two terrains (Grass Runway and Bonita lavaFlow, Ariz) on the earth.

Compared with lunar terrain, more stones are distributed on the surface of the mars; the distribution of the stones on the surface of the spark is generally exemplified by the number of the occupied areas of the stones; for example, NASA has a statistical distribution of rocks around Pathfinder patrollers with a mean surrounding stone distribution of 18.7%, a minimum of 6.7%, and a maximum of 44.9%.

The topographic features of the surfaces of the moon and the mars are input conditions of jolting and vibration when the development patrol device moves, so that a surface digital elevation model needs to be established according to typical features such as impact pits, stones, slopes and the like.

2) The moving performance of the patrol device is as follows:

when the patrol device moves on the surface of the planet, certain moving capacity is required to be achieved, and a patrol detection task is achieved; the moving capability generally comprises moving speed, obstacle crossing height, maneuvering capability, climbing capability and the like; due to the restriction of the resources of the patrol device, the items of the mobility are required in an independent mode, so that the waste of the resources caused by the overlapping requirements is avoided; for example, the obstacle crossing height index generally refers to the obstacle crossing height on the horizontal ground, and no special requirement is imposed on the obstacle crossing capability on a slope; taking the three-number or four-number Chang E patrol device in China as an example, the moving device adopts a passive main rocker arm and an auxiliary rocker arm plus 6 wheels which are independently driven.

The moving speed is 200m/h, the obstacle crossing height is 200mm, and the maneuvering capability has the pivot steering and the steering between the marching (the steering radius is not more than 1.5 m); the climbing capability is not lower than 20 degrees; when the patrol instrument turns and climbs on the surface of the planet, the surface is flat, so that the mechanism on the patrol instrument cannot shake; only in the obstacle crossing process, the processes of the wheels encountering obstacles, rolling up the obstacles, leaving the obstacles and the like exist, so that the height of wheel axles of the wheels is changed, and the height of a vehicle body is further changed; the shape of the obstacle is shown in fig. 2 to 4, taking a step as an example, and the obstacle crossing process is shown in fig. 2.

Disclosure of Invention

The invention aims to provide a method for determining a mechanism bumping and vibrating condition when a patrol device moves.

A method for determining a mechanism bumping vibration condition when a tour device moves comprises the following steps:

1) the vibration amplitude is based on the obstacle crossing capability of the inspection tour; determining the height of the wheel during obstacle crossing as the maximum amplitude of the bumping vibration according to the obstacle crossing height index of the patrol device and by combining the wheel layout characteristics of the patrol device and the gravity acceleration of the surface of a planet, thereby determining the amplitude of the bumping vibration condition;

2) the fundamental frequency characteristic is based on the contact length and the moving speed of the wheel of the rover; the contact length of the wheel of the patrol instrument is comprehensively determined according to the weight of the patrol instrument on the surface of the planet, the pressure bearing characteristic of the star soil, the width and the diameter D of the wheel and the topographic factors of the surface of the planet.

3) And determining the fundamental frequency condition of the bumping vibration according to the surface unevenness parameter of the planet of the patrolling device and the moving speed of the patrolling device.

The invention has the beneficial effects that:

by adopting the determination method, the maximum amplitude of the patrol instrument during bumping and vibrating can be determined according to the obstacle crossing height index of the patrol instrument and by combining the wheel layout characteristics of the patrol instrument and the gravity acceleration of the surface of a planet; determining the fundamental frequency during bumping and vibration according to the contact length and the moving speed of the wheels of the patrol device; according to the two conditions, the bump test condition in the development process of the patrol instrument mechanism can be determined, and the test condition is created for detecting whether the mechanism meets the requirement of the movement of the star surface of the patrol instrument.

Drawings

FIG. 1 is a graph of statistical characteristics of lunar surface irregularities;

FIG. 2 is a schematic view of the traversing device traveling on level ground during the traversing process;

FIG. 3 is a schematic diagram of the crossing of the steps on the front wheels of the inspection device in the obstacle crossing process of the inspection device;

fig. 4 is a schematic diagram of the obstacle crossing process of the patrolling device, wherein the front wheels and the middle wheels of the patrolling device go up the steps.

Detailed Description

1) determining an unevenness parameter according to the landing area range of the patrol instrument and the statistical characteristics of the surface topography of the planet;

2) and determining the amplitude condition of the bumping vibration according to the obstacle crossing index of the patrol instrument and the surface gravity acceleration of the target planet required to run by the patrol instrument.

The obstacle crossing height of the patrol instrument is H, and the gravity acceleration of the surface of the planet is g_pThe total number of wheels is 2 n. The patrol bump occurs when the patrol crosses an obstacle, and the maximum bump occurs when two wheels on the same side cross the obstacle. For example, a rover has 6 wheels, 3 wheels on one side, and a primary and secondary rocker arm suspension is used. The distances between the front wheels and the middle wheels and between the middle wheels and the rear wheels are equal. The maximum jounce amplitude of the rover then occurs when either the two front wheels or the two rear wheels cross the obstacle; the maximum bump amplitude calculation formula of the patrol instrument vehicle body is as follows:

in the ground test, the equivalent amplitude of the pitching vibration is as follows:

for a Mars rover, for example, the gravitational acceleration of the Mars surface is

The obstacle crossing height is 300mm, and the equivalent amplitude of the pitching vibration is 75 mm.

The contact length of the wheel of the patrol instrument is comprehensively determined according to the weight of the patrol instrument on the surface of the planet, the pressure bearing characteristic of the star soil, the width and the diameter D of the wheel, the topography of the surface of the planet and other factors. The wheel-to-ground contact length L of the rover wheel can be estimated according to 2/3 of the wheel radius. The moving speed v is the maximum speed of the rover on the horizontal shape of the surface of the planet.

Where λ is the wavelength of the Mars surface topography, and is a value of 1/4 that is close to the contact length based on the surface roughness of the planet.

For example, in the case of a Mars rover, the wheel radius of a Mars vehicle is 150mm, and the maximum speed v on a horizontal terrain with a Mars surface is 200m/h 0.05 m/s. The wheel soil contact length is about 0.1m, then f 2 Hz.

Claims

1. A method for determining a mechanism bumping vibration condition when a tour device moves is characterized by comprising the following steps: the method comprises the following steps:

2) the fundamental frequency characteristic is based on the contact length and the moving speed of the wheel of the rover; the contact length of the wheel of the patrol instrument is comprehensively determined according to the weight of the patrol instrument on the surface of the planet, the pressure bearing characteristic of the star soil, the width and the diameter D of the wheel and the topographic factors of the surface of the planet;

2. The method for determining the mechanism pitching vibration condition during the movement of a patrol instrument according to claim 1, wherein: the obstacle crossing height of the patrolling device is H, and the gravity acceleration of the surface of the planet is g_pThe total number of wheels is 2 n; the patrol device jounces when the patrol device crosses an obstacle, the maximum jounce occurs when two wheels on the same side cross the obstacle, and when the patrol device is provided with 6 wheels, and the number of the wheels on one side is 3, a main rocker arm suspension and an auxiliary rocker arm suspension are adopted; the distances between the front wheels and the middle wheels and between the middle wheels and the rear wheels are equal, so that the maximum bump amplitude of the patrol instrument body is calculated when the two front wheels or the two rear wheels cross the obstacleThe formula is as follows:

3. the method for determining the mechanism pitching vibration condition during the movement of a patrol instrument according to claim 1, wherein: the wheel soil contact length L of the patrolling device wheel is estimated according to 2/3 of the wheel radius; the moving speed v is the maximum speed of the patrol device on the horizontal shape of the surface of the planet;

where λ is the wavelength of the Mars surface topography, which is a value 1/4 where the surface roughness of the planet takes on a near contact length.