阅读说明：本技术 一种用于软着陆障碍探测的复杂月表模拟场及验证方法 (Complex lunar surface simulation field for soft landing obstacle detection and verification method ) 是由 谢欢 魏超 童小华 许雄 叶真 刘世杰 金雁敏 冯永玖 王超 柳思聪 陈鹏 肖 于 2021-08-31 设计创作，主要内容包括：本发明涉及一种用于软着陆障碍探测的复杂月表模拟场及验证方法,用于构建月表地形地貌特征,并可动态调整特征分布结构,该模拟场包括固化的用于模拟软着陆安全着陆区的平坦区域,该平坦区域上设有可移动石块、不同尺寸的坑体和斜坡区,所述坑体设有坑唇和顶盖,通过坑体的顶盖和可移动石块动态变换模拟场地形,从而来模拟多种月表平地、洼地、月坑、石块的地形特征和月表弱反射率障碍探测环境；所述验证方法包括获取基准地形数据、获取激光器成像点云数据、误差校验以及精度评定。与现有技术相比,本发明为深空探测软着陆过程的多种着陆区快速建模与障碍物识别提供支撑。(The invention relates to a complex lunar surface simulation field and a verification method for soft landing obstacle detection, which are used for constructing lunar surface topographic and topographic features and dynamically adjusting a feature distribution structure, wherein the simulation field comprises a solidified flat area for simulating a soft landing safe landing area, movable stones, pit bodies with different sizes and a slope area are arranged on the flat area, the pit bodies are provided with pit lips and a top cover, and the terrain of the simulation field is dynamically changed through the top cover of the pit bodies and the movable stones, so that the topographic features of various lunar surfaces, the pits, the lunar pits and stones and a lunar surface weak reflectivity obstacle detection environment are simulated; the verification method comprises the steps of obtaining reference topographic data, obtaining laser imaging point cloud data, checking errors and evaluating precision. Compared with the prior art, the method provides support for rapid modeling and obstacle identification of various landing areas in the deep space exploration soft landing process.)

1. A complex lunar surface simulation field for soft landing obstacle detection is characterized by being used for constructing lunar surface topographic and topographic features and dynamically adjusting feature distribution structures, and comprising a solidified flat area for simulating a soft landing safe landing area, wherein a movable stone block, pit bodies with different sizes and a slope area are arranged on the flat area, the pit bodies are provided with pit lips and a top cover, and the terrain of the simulation field is dynamically changed through the top cover of the pit bodies and the movable stone block, so that various lunar surface flat lands, hollow lands, lunar pits, the topographic features of the stone block and lunar surface weak reflectivity obstacle detection environments are simulated.

2. The complex lunar surface simulation field for soft landing obstacle detection as claimed in claim 1, wherein the flat area is cured with a set proportion of concrete.

3. The complex lunar surface simulation field for soft landing obstacle detection as claimed in claim 2, wherein the flat area surface is coated with a coating for simulating a lunar soil weak reflectivity environment; the coating comprises mixed crushed stone with set particle size and paint with set gray level.

4. The complex lunar surface simulation field for soft landing obstacle detection as claimed in claim 1, wherein the pit body comprises circular pit bodies and annular lip pits with different diameters and depths, and is used for simulating pit body obstacles of the complex lunar surface in equal proportion.

5. The complex lunar surface simulation field for soft landing obstacle detection as claimed in claim 4, wherein the roof of the pit body is randomly built on the pit body with a diameter larger than a set value.

6. The complex lunar surface simulation field for soft landing obstacle detection as claimed in claim 5, wherein the top cover of the pit body is detachable and the balance degree of the pit body meets the set requirement.

7. The complex lunar surface simulation field for soft landing obstacle detection as claimed in claim 1, wherein the slope region is a plurality of groups of continuous slopes with fixed slopes, and a plurality of pit bodies with different sizes are arranged on the slope surface of the slope and used for simulating a slope region of complex terrain.

8. The complex lunar surface simulation field for soft landing obstacle detection according to claim 1, characterized in that a depression having an elevation lower than the base plane, a plurality of unequally sized moon pits being distributed in the area, enabling the simulation of a lunar surface complex terrain depression.

9. A complex lunar surface simulation field for soft landing obstacle detection as claimed in claim 1, wherein the stones are of unequal size and have geometrical characteristics according to geometrical characteristic data of the stones on the lunar surface for simulating small stone obstacles protruding on the lunar surface; the stones are randomly distributed in the simulation field; wherein the stone is a differentiated granite stone.

10. A verification method of a complex lunar surface simulation field for soft landing obstacle detection based on claim 1, wherein a laser is vertically suspended above the simulation field center for imaging along the direction of the main imaging optical axis, and the verification method comprises the following steps:

step S1: acquiring reference topographic data, and scanning and imaging the simulation field by using a three-dimensional scanner to acquire three-dimensional topographic data;

step S2: acquiring laser imaging point cloud, scanning and imaging an analog field by using a laser to be calibrated, acquiring point cloud data of the point cloud, and segmenting and extracting;

step S3: error checking, namely checking the laser three-dimensional imaging error by using the existing simulated field obstacle parameters and three-dimensional terrain data;

step S4: and (4) precision evaluation, namely comparing and analyzing the correction value with a reference value, and evaluating the imaging quality precision.

Technical Field

The invention relates to the field of design of lunar surface simulation fields, in particular to a complex lunar surface simulation field for soft landing obstacle detection and a verification method.

Background

Landing detection, sampling return and manned landing are inevitable trends of future deep space detection, and safe landing of the detector is a precondition for smooth implementation of the detector. Aiming at the irreproducibility of the landing process, a three-dimensional laser imaging system of a multi-beam linear array detection technology is selected for the deep space detection landing scheme in China to carry out obstacle fine detection and safe landing point selection, and the premise is that the three-dimensional imaging distance measurement level precision is high in credibility.

The lunar topography reflects the high and low form and space distribution characteristics of the lunar surface, and the lunar land, the lunar sea, the impact pit and the like form a control frame of a lunar topography system. The impact crater is the most obvious characteristic of the lunar surface and is formed by the impact of extraterrestrial celestial bodies and meteorites; the moon land area is relatively bright, the relief is large, and the density of impact pits is large. The laser radar can directly obtain a three-dimensional image of the surface of a target, and is suitable for a deep space exploration landing task in special environments with complex terrain, weak illumination or no illumination and the like.

Due to the limitation of a complex imaging structure and a system hardware technology, the development of a three-dimensional laser imaging system of a multi-beam linear array detection technology is a very complex system engineering, the three-dimensional imaging process has errors such as distance measurement and angle measurement, and in the development process of prototype and prototype at each stage, multiple ground experiments are required to be carried out to verify the precision of each key parameter so as to improve the laser three-dimensional imaging quality and improve the detection precision of the landing zone obstacle and the reliability of safety zone selection, thereby ensuring the smooth development of the deep space detection engineering.

Disclosure of Invention

The present invention is directed to overcoming the above-mentioned drawbacks of the prior art and providing a complex lunar surface simulation field and verification method for soft landing obstacle detection.

The purpose of the invention can be realized by the following technical scheme:

according to a first aspect of the present invention, there is provided a complex lunar surface simulation field for soft landing obstacle detection for constructing lunar surface topographic features and dynamically adjusting feature distribution structures, the simulation field comprising a solidified flat area for simulating a soft landing safe landing zone, the flat area being provided with a movable stone block, a pit body of different size and a sloped area, the pit body being provided with a pit lip and a top cover, the simulation field topography being dynamically transformed by the top cover of the pit body and the movable stone block, thereby simulating a variety of lunar surface terrains, depressions, lunar pits, topographic features of the stone block and lunar surface weak reflectivity obstacle detection environments.

Preferably, the flat area is formed by curing concrete with a set proportion.

Preferably, the flat area surface is coated with a coating for simulating a lunar soil weak reflectivity environment; the coating comprises mixed crushed stone with set particle size and paint with set gray level.

Preferably, the pit body comprises a circular pit body and an annular lip pit with different diameters and depths, and is used for simulating the obstacle of the pit body of a complex lunar surface in equal proportion.

Preferably, the roof of the pit body is randomly constructed on the pit body having a diameter greater than a set value.

Preferably, the top cover of the pit body can be detached, and the balance degree of the pit body meets the set requirement.

Preferably, the slope region is a plurality of groups of continuous slopes with fixed slopes, and a plurality of pit bodies with different sizes are arranged on the slope surface of the slope and used for simulating a slope region of a complex terrain.

Preferably, the depression is lower in elevation than the base plane, and a plurality of unequally sized moon pits are distributed in the area, so that simulation of the depression area of the complex terrain on the lunar surface is realized.

Preferably, the stones are of different sizes, and the geometrical characteristics of the stones are based on the geometrical characteristic data of the stones on the surface of the moon, so as to simulate small stone barriers protruding on the lunar surface; the stones are randomly distributed in the simulation field; wherein the stone is a differentiated granite stone.

According to a second aspect of the present invention, there is provided a verification method for a complex lunar surface simulation field for soft landing obstacle detection based on the above-mentioned, a laser is vertically suspended above the simulation field center for imaging along the imaging main optical axis direction, the verification method comprises the following steps:

step S1: acquiring reference topographic data, and scanning and imaging the simulation field by using a three-dimensional scanner to acquire three-dimensional topographic data;

step S2: acquiring laser imaging point cloud, scanning and imaging an analog field by using a laser to be calibrated, acquiring point cloud data of the point cloud, and segmenting and extracting;

step S3: error checking, namely checking the laser three-dimensional imaging error by using the existing simulated field obstacle parameters and three-dimensional terrain data;

step S4: and (4) precision evaluation, namely comparing and analyzing the correction value with a reference value, and evaluating the imaging quality precision.

Compared with the prior art, the invention has the following advantages:

1) the invention provides a complex lunar surface simulation field for ground verification of soft landing obstacle detection, which is designed and built based on geometrical characteristic data of lunar surface flat ground, depression, moon pits, stones and the like, wherein the simulation field comprises pit bodies, slopes, low-lying areas, stones and the like for simulating lunar surface topographic features in proportion;

2) the invention designs and builds a simulation field shape adjusting structure of a multi-size moon pool top cover and movable stones, and realizes rapid adjustment and simulation of different lunar surface landform characteristics according to a lander obstacle detection ground verification scheme;

3) the geometric characteristic data in the invention is derived from actual data of real satellite landing detection, and reflects real complex lunar surface landforms.

Drawings

FIG. 1 is a schematic view of a complex lunar surface simulation field for soft landing obstacle detection in accordance with an embodiment;

FIG. 2 is a flow chart of a verification method for a complex lunar surface simulation field according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.

The invention provides a complex lunar surface simulation field for ground verification of soft landing obstacle detection, which mainly comprises the following steps: 1) typical geometric characteristic data of actual lunar surface flat ground, depression, moon pit, stone and the like of the landing areas designed by ChangE No. three, No. four and No. five are integrated, and a 60-meter multiplied by 60-meter full-element characteristic simulation field of lunar surface landform and landform in equal proportion is designed and built; 2) designing and building a simulation field shape adjusting structure of a multi-size moon pool top cover and movable stones, and realizing rapid adjustment and simulation of different lunar surface topographic features according to a lander obstacle detection ground verification scheme; 3) mixing the crushed stone with a specific particle size and a specific gray coating, and simulating a lunar soil weak reflectivity environment during lunar surface obstacle detection on the ground; 4) suspending the laser above the simulation field, and carrying out obstacle detection capability verification and imaging quality precision analysis in the simulation soft landing process. Next, the following examples are given.

The embodiment adopts a multi-laser detection multi-beam three-dimensional imaging system. The area of a built complex lunar surface simulation field is 3600 square meters, the laser scanner is arranged above the center of the simulation field along the direction of an imaging main optical axis, obstacles such as simulation field moon pits, slopes, low-lying areas and stones are scanned and imaged, and quality error calibration analysis of laser three-dimensional imaging is carried out, as shown in figure 1. The design process of the complex lunar surface landform simulation field is described in detail below.

1. Design of complex lunar surface landform simulation field

The invention discloses a complex lunar surface landform simulation field, which is the key for developing soft landing obstacle detection ground verification, and aims at solving the problems of sparse spacing of multi-beam laser three-dimensional imaging points and difficult identification and verification of small-size obstacles. The specific design scheme is as follows:

1.1 the area of the simulation field is 60 multiplied by 60 meters, a foundation plane is formed by concrete curing in a specific proportion, a flat area which accords with the size of the lander is designed, and a soft landing safety landing area is simulated; designing circular pit bodies and annular pit lips with different diameters based on the geometric characteristic data of moon surface moon pits of the landing areas designed by ChangE's III, IV and V, and realizing equal-proportion simulation of the moon pit obstacles with complex lunar surface landform;

1.2 designing a mountain-shaped slope area to simulate a lunar surface complex terrain, designing and constructing 3 groups of continuous slopes with fixed slopes, and designing a plurality of lunar pits with unequal sizes to be distributed on a slope surface to realize comprehensive simulation of slope body obstacles and pit body obstacles; designing a depression with an elevation lower than that of a base plane, and distributing a plurality of moon pits with different sizes in the area to realize the simulation of a low depression area of a lunar surface complex terrain;

1.3, mixing the crushed stone with the specific particle size and the specific gray paint to realize the ground simulation of the lunar soil weak reflectivity environment in lunar surface obstacle detection.

2 dynamic adjustment structure design for lunar surface landform

The invention designs and constructs a simulated field terrain changing structure of a plurality of sizes of pit body top covers and movable stones, and can rapidly and dynamically simulate different lunar surface terrain features. The specific scheme is designed as follows:

2.1 selecting a plurality of moon pits with larger diameters in the range of simulating field flat ground, designing and building a detachable pit body top cover with high balance degree, and utilizing specific gray paint to enable the pit body top cover to be consistent with the reflectivity of the simulating field;

2.2 designing a plurality of weathered granite stones with different sizes based on geometric characteristic data of the stones on the surface of the moon, and simulating small raised stone obstacles on the moon surface; designing a plurality of stones with different sizes to be randomly distributed in the simulation field based on the flat land and depression distribution of the simulation field and the range of a preset safe landing area;

2.3 in order to solve the simulation and verification of the space distribution form of various lunar surface obstacles in the same field, the invention discloses a method for covering various pit bodies and quickly placing stones in a simulation field, and realizes the simulation of various lunar surface topographic features by the combination of the number of lunar pits and stones and the change of the flat land range.

3 Soft landing obstacle detection ground verification scheme based on complex lunar surface simulation field

Considering calibration parameter correlation among system parameters and between system and external elements, and combining the comprehensive influence of typical lunar surface obstacles such as a moon pit, a stone block, a depression, a slope and the like on multi-beam laser three-dimensional imaging, designing a method for vertically suspending a laser above the center of a simulation field to image along the direction of an imaging main optical axis, wherein the ground verification scheme for detecting soft landing obstacles based on the complex lunar surface simulation field is as follows:

and S1, acquiring reference terrain data: scanning and imaging the simulation field by using a high-precision three-dimensional scanner to obtain high-precision three-dimensional terrain data;

s2, acquiring laser imaging point cloud: scanning and imaging the analog field by using a laser to be calibrated to obtain point cloud data of the analog field, and segmenting and extracting the point cloud data;

s3, error checking: checking and correcting the laser three-dimensional imaging error by using the existing simulated field obstacle parameters and the high-precision three-dimensional terrain data;

s4, precision assessment: and comparing and analyzing the correction value with the reference value, and evaluating the imaging quality precision.

The invention provides a design method of a complex lunar surface simulation field for ground verification of soft landing obstacle detection, which is characterized in that a simulation field for simulating lunar surface topographic features such as a pit body, a slope, a low-lying area and stones is designed and built on the basis of geometrical feature data such as lunar surface flat ground, a depression, a moon pit and stones, a weak-reflectivity lunar soil environment is simulated by mixing specific-granularity broken stones and specific gray-scale paint, a simulation field topographic dynamic adjustment structure of a plurality of sizes of moon pit top covers and movable stones is designed and built, and the influence of the complex lunar surface environment on laser three-dimensional imaging quality and obstacle detection in a soft landing process is simulated. The invention can improve the quality precision and the obstacle detection capability of laser three-dimensional imaging and can provide support for the safe soft landing of the deep space detection lander.

While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.