Mars exploration landing platform structure with complex and heavy loads

Abstract

A Mars exploration landing platform structure that withstands complex and large loads has a Mars rover interface on the top surface of the top plate, and rear-buried connecting seats for connecting to the reinforcing beam in the back cover are arranged at the four corners; four diagonal brace brackets are installed on the back of the top plate, and the position of one end of the diagonal brace bracket connected to the top plate corresponds to the position of the rear-buried connecting seat; side panels are installed between adjacent diagonal brace brackets, and the side panels form the side surfaces of an inverted trapezoidal quadrangular pyramid, and the diagonal brace brackets are located at the edge positions of the quadrangular pyramid; landing buffer mechanism interfaces are respectively arranged on the four side edges, and buffer corner boxes are installed inside the side panels at the interface positions; partitions are installed at the buffer corner box positions for transmitting force to the bottom plate, and the three sides of the partitions are respectively connected to the bottom plate, the side plates, and the top plate, and the fourth side is suspended, and an auxiliary support corner box is installed at the junction of the suspended side and the top plate; the interior of the inverted trapezoidal quadrangular pyramid is used to install an engine and a tank, and the bottom plate is connected to the side edges and the diagonal brace brackets; a bracket positioning seat is installed on the diagonal brace bracket for connecting to the large bottom interface.

Description

Technical Field

[0001] The present invention belongs to the field of spacecraft structure, and invents and designs a landing platform structure, which is particularly suitable for landing structures with multiple force transmission paths, large load levels, high interface precision requirements, and used for landing on planets such as Mars. Background Art

[0002] With the rapid development of aerospace technology, my country's exploration of the universe has gradually moved from near-Earth space to deep space. In the field of deep space planetary exploration, in addition to longer space flight distances, spacecraft also have to face more complex space environment factors, such as a wider temperature change environment, more charged particle irradiation conditions, etc. In addition to space flight exploration research, in the process of conducting different planetary explorations, it is also necessary to face different atmospheric environments, different gravity fields, temperature field environments, etc. These factors are all influencing factors that need to be considered in the design of deep space planetary exploration spacecraft.

[0003] During the Mars landing and exploration process, the landing platform structure with the performance of stable landing with a payload is the main load-bearing structure in the Mars probe. This product is located in the middle of the entire structure, connected to the back cover on the top and the large bottom on the bottom, and carries the main payload equipment - the Mars rover. The landing platform structure will experience the environmental conditions of Earth launch, in-orbit flight, interstellar flight, re-entry into the atmosphere on Mars, and landing on the surface of Mars as the Mars probe completes the process. Its ability to withstand multiple environmental loads is something that previous spacecraft did not have. This performance requirement brings great design difficulty to the design of the Mars landing platform structure.

[0004] In order to fully meet the support requirements of the payload equipment on the Mars lander and achieve the goals of smooth launch, reliable flight, safe landing, and release of the rover, a Mars landing platform structure with multiple force transmission paths, large load levels, and high interface precision was invented. Summary of the invention

[0005] The technical problem solved by the present invention is to overcome the deficiencies of the prior art and provide a Mars exploration landing platform structure capable of bearing complex and large loads.

[0006] The solution of the present invention is: a Mars exploration landing platform structure that bears complex and large loads, used to connect the back cover and the large bottom of the landing rover, including a top plate, a bottom plate, four side plates, four diagonal support brackets, and four partitions;

[0007] A rover interface is provided on the top surface of the top plate, and rear-buried connecting seats for connecting to the reinforcing beam in the back cover are provided at the four corners, and four diagonal brace brackets are installed on the back of the top plate, and the position of one end of the diagonal brace bracket connected to the top plate corresponds to the position of the rear-buried connecting seat, and side panels are installed between adjacent diagonal brace brackets, and the side panels form the side surfaces of an inverted trapezoidal quadrangular pyramid, and the diagonal brace bracket is located at the edge position of the inverted trapezoidal quadrangular pyramid; landing buffer mechanism interfaces are respectively provided on the four side edges, and buffer corner boxes are installed inside the side panels at the interface positions, and the buffer corner boxes transmit force to the top plate or the bottom plate; wherein a partition is installed at the buffer corner box position for transmitting force to the bottom plate, and the three sides of the partition are respectively connected to the bottom plate, the side plates and the top plate, and the fourth side is suspended, and an auxiliary support corner box is installed at the junction of the suspended side and the top plate; the interior of the inverted trapezoidal quadrangular pyramid is used to install an engine and a tank, and the bottom plate is connected to the side edges and the diagonal brace bracket; a bracket positioning seat is installed on the diagonal brace bracket for connecting with the large bottom interface.

[0008] Preferably, a reinforcing beam is provided inside the top plate at the position of the buffer corner box installed at the junction of the above-mentioned suspended edge and the top plate; and an annular reinforcing beam is provided inside the top plate at the position of the Mars rover interface.

[0009] Preferably, the diagonal brace bracket is a multi-rib bracket with a triangular side surface, and the end face of the bracket placed between the bottom plate and the two side plates is a non-hollow structure. A protruding cone for installing the bracket positioning seat is arranged inwardly on this surface, and flanges for connecting with the side edges are arranged on both sides of this surface, and the flanges are used to diffuse stress; a connecting frame is arranged between the two triangular side surfaces, and the part where the triangular side surface is connected to the top plate, the side edge and the bottom plate is a continuous structure, and the triangular side surface and the end face connected to the top plate are hollowed out on the basis of meeting the structural strength requirements.

[0010] Preferably, a reinforcing beam is embedded in the portion where the side panel is connected to the flange.

[0011] Preferably, the position of the bracket positioning seat on the diagonal support bracket is required to be lower than half the height of the edge of the inverted trapezoidal quadrangular pyramid.

[0012] Preferably, the bracket positioning seat is a symmetrical structure with a center hole, the upper end surface of the center hole is the mounting surface of the large bottom, the outer ring of the mounting surface is provided with a flange structure, the lower end surface of the center hole is provided with a flange plate for connecting to the diagonal support bracket, reinforcing ribs are provided between the above-mentioned flange structure and the flange plate, an annular cavity is provided between the lower end surface of the center hole and the flange plate, and support ribs consistent with the position of the reinforcing ribs are provided inside the annular cavity.

[0013] Preferably, the flatness of the protruding frustum of the four diagonal brace brackets is not higher than 0.15 mm. Taking the mounting surface of any bracket positioning seat mounted on the diagonal brace bracket as a reference, the remaining bracket positioning seats are adjusted to ensure that the flatness of the four mounting surfaces is not higher than 0.1 mm.

[0014] Preferably, the rear embedded connection seat is a symmetrical structure with a central hole, the upper end surface is an annular cone for bearing shear load, at least four bosses are evenly distributed around the annular cone for supporting and connecting the reinforcing beam in the back cover, and a lug interface is arranged on the flange below the boss in the same position as the boss, which is used to realize the screw connection with the embedded parts inside the top plate; a reinforcing rib is arranged at a position consistent with the boss below the flange, and the reinforcing rib is connected to the flange on the lower surface. A vent hole is arranged outward from the central hole of the rear embedded connection seat.

[0015] Preferably, the buffer angle box that transmits force to the base plate is called the main buffer angle box, which is composed of three mutually perpendicular surfaces. A cylindrical connecting port is arranged in the surface for connecting with the interface of the landing buffer mechanism, and the cylindrical connecting port is connected to the two vertical surfaces through reinforcing ribs; the sum of the areas of the above three mutually perpendicular surfaces must be at least greater than five times the sum of the end surface areas of all the cylindrical connecting ports.

[0016] Preferably, the partition is a skin-and-honeycomb core structure, and a fan-shaped carbon skin reinforcement layer is added to the outer side of the end surface that is bonded to the corresponding buffer corner box, and the thickness of the reinforcement layer is more than three times the thickness of the skin.

[0017] Preferably, the buffer angle box that transmits force to the top plate is called an auxiliary buffer angle box, which consists of two end faces at a certain angle to each other. A cylindrical connecting port is set in the surface for connecting to the interface of the landing buffer mechanism, and the cylindrical connecting port is connected to the two end faces through reinforcing ribs; the sum of the areas of the two end faces must be at least greater than five times the sum of the end face areas of all the cylindrical connecting ports.

[0018] Preferably, an avoidance hole for the engine and the tank is provided on the bottom plate, and a carbon cloth reinforcement area is provided around the avoidance hole, and the width of the carbon cloth reinforcement area is not less than 25 mm, and the thickness is not less than 2 mm.

[0019] The beneficial effects of the present invention compared with the prior art are:

[0020] ①Achieve the design goals of extremely high load-bearing capacity and multiple load-bearing capacity.

[0021] During the landing process of the Mars Lander, the landing platform structure is subjected to a parachute load of 190kN, which is an extremely demanding interface load. The maximum landing load borne by the landing platform structure during landing consists of two parts, including a landing impact load of 31kN and a bending moment load of 1700Nm. This is a combined complex load condition of multiple loads and is also the most difficult key technical problem. The inverted trapezoidal four-sided pyramid configuration combined with the locally reinforced support structure design at the key interface ensures that the landing platform structure can safely withstand the above loads. The verification results show that the safety margin of the landing platform structure is 3.9, which is greater than the design specification requirement of 0.25, effectively ensuring the safe use of the landing platform structure.

[0022] ② Realize the complex bearing space configuration design with multiple bearing interface requirements.

[0023] The landing platform structure is the intermediate structure that connects the upper and lower parts of the Mars lander. The landing platform structure is connected to the back cover at the top and the large bottom at the bottom. The Mars rover (the largest and most important payload in the rover) is loaded on the top of the landing platform structure. Four sets of landing legs are installed on the four sides of the lower end of the cone. Each set of landing legs has three interfaces. Four sets of tanks are hung on the lower end of the landing platform. The configuration characteristics of the landing platform structure are that there are many types of interfaces and complex spatial orientation. The configuration design of the inverted trapezoidal quadrangular cone realizes effective support with a large top and a small bottom. Four sets of landing leg (i.e., landing buffer mechanism) support positions are designed on the four sides of the cone under the landing platform structure for installing the landing legs to ensure the strong support of the landing legs. The landing platform supports the Mars rover on the top.

[0024] ③ Through local strengthening technology, the problems of uneven load distribution and insufficient local strength of brittle composite interfaces can be effectively solved.

[0025] On top of the landing platform structure, the Mars rover, the largest load-bearing device, is supported. Its installation interface on the top plate is subject to concentrated loads, and local reinforcement is achieved by embedding annular reinforcement beams to ensure the local support strength of the top plate. For the landing impact load on the landing platform structure caused by the recoil of the landing legs, an embedded C-shaped beam is designed at the main supporting bulkhead position, and main and auxiliary buffer support corner boxes are added on both sides of the bulkhead to achieve the effect of load dispersion support. Such reinforcement methods effectively ensure load sharing and eliminate the problem of insufficient local strength of brittle composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of the lander, showing the alignment relationship between the main structures;

[0027] Figure 2This is a schematic diagram of the landing platform structure assembly equipment. The figure shows the spatial assembly relationship of various load equipment on the landing platform structure. a. Schematic diagram of the landing platform structure assembly equipment b. Schematic diagram of the tank under the landing platform structure;

[0028] Figure 3 The figure is a schematic diagram of the landing platform structure, which shows the composition of the landing platform structure and the spatial relationship between the various parts, and indicates the interfaces of the main load equipment. a. Schematic diagram of the structural state and load-bearing interface of the +X end, schematic diagram of the structural state and load-bearing interface of the -X end, schematic diagram of the structural state and load-bearing interface of the -X end after the bottom plate and part of the side plate are removed;

[0029] Figure 4 It is a schematic diagram of the back cover interface on the landing platform structure, and the figure shows the schematic diagram of the back cover interface design, a. Schematic diagram of the upper back cover interface b. Cross-sectional view of the back cover interface;

[0030] Figure 5 This is a schematic diagram of the outsole interface on the landing platform structure. The figure shows the outsole interface design schematic diagram, a. Schematic diagram of the lower outsole interface b. Cross-sectional view of the outsole interface;

[0031] Figure 6 The schematic diagram of the interface of the buffer mechanism on the landing platform structure shows the schematic diagram of the interface design with the outsole, a. Schematic diagram of the interface of the middle main buffer mechanism b. Schematic diagram of the interface of the auxiliary buffer mechanisms on both sides;

[0032] Figure 7 Schematic diagram of top plate design;

[0033] Figure 8 This is a schematic diagram of the side panel design;

[0034] Fig. 9 A schematic diagram of the partition design is provided;

[0035] Fig.10 Design a schematic diagram for the base plate;

[0036] Fig.11 It is a schematic diagram of the diagonal brace bracket;

[0037] Fig.12 Schematic diagram of the main angle relief box, a. Schematic diagram of the inside b. Schematic diagram of the outside;

[0038] Fig.13 Schematic diagram of auxiliary angle relief box, a. Schematic diagram of outer side b. Schematic diagram of inner side;

[0039] Fig.14 Schematic diagram of a typical corner box for structural connection: a. Corner box for connecting the side panel and the top panel b. Corner box for connecting the side panel and the bottom panel c. Corner box for connecting the partition panel and the top panel;

[0040] Fig.15Schematic diagram of metal reinforcement parts in the structural plate; a. Rear embedded connection seat in the top plate b. Embedded parts of the buffer boss on the side plate;

[0041] Fig.16 It is a schematic diagram of typical connection of side panels, where side panels 3, 4, 5, and 6 are connected in the same state, and partitions 7, 8, 9, and 10 are connected in the same state. a. Rear embedded connection seat in top panel b. Embedded parts of side panel buffer boss c. Typical connection between side panel and bottom panel and corner box d. Typical connection between side panel and bottom panel and main buffer corner box 1 e. Typical connection between side panel and diagonal support f. Typical connection between side panel and partition g. Typical connection between side panel, bottom panel and diagonal support pin h. Typical positioning connection between side panel and bracket i. Typical positioning connection between side panel and partition;

[0042] Fig.17 It is a schematic diagram of typical connections related to the top plate, where the connection status of side panels 3, 4, 5, and 6 are the same, and the connection status of partitions 7, 8, 9, and 10 are the same, a. Typical connection between top plate and partition b. Typical connection between top plate and diagonal brace bracket c. Typical positioning connection between top plate and partition d. Typical positioning connection between top plate and diagonal brace bracket e. Typical connection between top plate, partition and corner box.

[0043] Fig.18 Schematic diagram of typical connections related to the base plate, where the connection status of partitions 7, 8, 9, and 10 are the same, a. Typical connection between base plate and partition b. Typical connection between base plate and diagonal support c. Typical positioning connection between base plate and support. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with the embodiments.

[0045] The landing platform structure of the Mars Lander carries all payload equipment and equipment of the main service subsystems. It bears all mechanical environmental loads during launch, flight, and landing, and meets the main accuracy index requirements. Therefore, the structural design faces the following main technical problems in the design of bearing function:

[0046] ①Key technical issues of extremely high load-bearing and multi-load bearing.

[0047] In the operation mileage of the Mars lander, launch and landing are the processes with the largest load. During the launch process, the launch load in the active segment is relatively large. During the landing process, the parachute load is 190kN, the largest of all loads, the landing load is 31kN, and the simultaneous bending moment is no more than 1700Nm. The landing load exceeds the launch load and is the maximum load of the entire mechanical process. This is a key technical issue in mechanical bearing.

[0048] ②The various complex interfaces and high-precision connections of the Mars landing platform structure are key technical issues in configuration design.

[0049] In the Mars Lander, the landing platform structure needs to be equipped with all the payload equipment that performs functions, including the Mars rover. The Mars rover is the largest and is placed on the top of the platform. The tank is heavy and small and is placed at the bottom of the platform. The parachute is hung on the landing platform for safe landing. Therefore, the parachute opening and parachute ejection loads will also mainly act on the landing platform structure, located at the four corners of the platform structure. The landing platform carries the Mars rover, and when it lands safely, it needs the support of the landing legs with a buffer function. The landing legs are installed on the four oblique sides. In addition, the upper surface of the landing platform structure is equipped with a back cover structure, and the lower surface is equipped with a large bottom structure. There is a separation load at the installation point between the two large structures and the landing platform structure. A variety of complex payload equipment is installed on the entire landing platform structure, and the interface is complex, which is a key technical issue that determines the configuration design.

[0050] ③ Uneven load distribution leads to inconsistent force on structural parts, which is a key issue in the design of structural parts.

[0051] The Mars lander is equipped with a variety of payload equipment with inconsistent sizes and weights and asymmetric layouts, which results in uneven stress on the landing platform's structural components. The Mars lander has a complex mileage and experiences a wide variety of mechanical load conditions and many situations of concentrated stress, which also causes uneven stress on the same structural component. These difficulties are key technical issues that must be resolved in structural lightweight design.

[0052] From the analysis of the above technical problems, it is not difficult to see that the landing platform structure must be suitable for bearing a variety of large and uneven loads, and be able to provide a variety of complex interfaces and achieve high-precision connections. Based on these factors, a Mars landing platform structure is designed to meet the design needs of the Mars lander for main load support.

[0053] To this end, the technical solution provided by the present invention is:

[0054] ① Design an inverted trapezoidal quadrangular pyramid configuration to effectively solve the problem of the main force transmission path.

[0055] On the landing platform structure, the largest equipment is the Mars rover. At the top of the landing platform, the lower end of the landing platform is connected to the large bottom structure. Affected by the spherical structure of the large bottom, the landing platform is folded at the lower end. Therefore, the landing platform structure is designed to be an inverted trapezoidal shape with a large top and a small bottom. Since the load on the back cover is transmitted to the landing platform through the 4 groups of reinforcement beams evenly distributed inside it, and the connection between the landing platform and the back cover is designed at the 4 corners, corresponding to the position of the main force transmission reinforcement beam of the back cover, the four corners of the landing platform structure are designed to be an inverted trapezoidal tetrahedron configuration, that is, the four corners of the landing platform are the four edges of the tetrahedron. During the landing process, the landing load is transmitted to the landing platform through the various sides of the tetrahedron connected by the landing legs, and the direction corresponds to the top plate with the most load equipment installed. Therefore, in order to achieve direct force transmission, a partition is designed at the side plate position supported by the landing legs, that is, the main force transmission configuration of the inverted trapezoidal tetrahedron supported by the inner partition is formed.

[0056] ② The support design method strengthened by local reinforcement can bear the maximum concentrated load or non-uniform load.

[0057] For example, on the entire landing platform, the parachute load is the largest loading load, which is 190kN. As mentioned above, at the four edges, the four reinforcing beams on the back cover transfer the parachute load to the landing platform. Since the concentrated load at each location is very large, the landing platform cannot withstand such a large interface load capacity by relying on traditional honeycomb panels and their splicing forms. Therefore, lightweight diagonal braces with strong supporting capabilities are designed at the four edges of the inverted trapezoidal quadrangular pyramid to achieve continuous structural reinforcement.

[0058] For example, at the landing load impact position, the maximum load interface is transmitted through the outer panel to the support position of the partition plus auxiliary corner box designed on the back. The auxiliary corner boxes added on both sides can greatly improve the strength and local stiffness of the support position.

[0059] ③ The design and implementation method of high-precision multi-association interface is realized by combining post-embedding with precise positioning assembly.

[0060] The landing platform is connected to the back cover and the large bottom respectively. Both components are large-scale structures. The product body and the assembly state are complex, and the key interfaces composed of multiple parts are the main characteristics of the product connection state. Diagonal braces are arranged at the four corners of the landing platform. The diagonal braces are connected into a whole through the bottom plate, the top plate and the partition plate. The upper and lower end faces of the four groups of diagonal braces are coplanar respectively, and directly provide the large bottom interface to indirectly support the back cover. The large bottom connection surface is coplanar formed by the smaller ends of the four groups of diagonal braces. The diagonal braces are connected into a whole through the top plate and the side plate to achieve a stable supporting state; the back cover connection surface is realized by 4 groups of rear embedded connecting seats on the top plate, and the diagonal braces are connected into a whole through the bottom plate, the side plate and the top plate to achieve a stable supporting state.

[0061] In order to solve the manufacturing challenges of large spans and high interface precision, four groups of diagonal bracing brackets are positioned with tooling to ensure high-precision, low-stress assembly, and combined processing is performed on the mounting surface and connecting holes to ensure interface precision and achieve high-precision connection of multiple interfaces.

[0062] The present invention is further described below by taking a Mars landing platform structure as an example in conjunction with the accompanying drawings. The product is located in the middle of the entire structure, connected to the back cover at the top and the large bottom at the bottom, and carries the main load equipment - the Mars rover, such as Figure 1 As shown, its device layout status is as follows Figure 2 The product dimensions are 2944.3mm (length) × 2680mm (width) × 461mm (height).

[0063] (1) The structure of the Mars landing platform is a combination of multiple components, such as Figure 3 As shown, the combination is as follows:

[0064] The top plate 1 is the largest single component in the landing platform structure. Figure 7 As shown in FIG. 1 , it undertakes 90% of the equipment installation functions on the landing platform structure and is the assembly basis of the entire landing platform structure. Four diagonal braces 11 are symmetrically distributed on the -X plane of the top plate 1 (as shown in FIG. Fig.11 ), and 10 side panels and top panel connection corner boxes 15 are symmetrically arranged between every two diagonal bracing brackets 11 (as shown in FIG. Fig.14 As shown in a), and 2 auxiliary angle boxes 12 (as shown in a Fig.13 As shown), +Z partition 7, -Y partition 8, -Z partition 9, +Y partition 10 are symmetrically assembled between every two diagonal support brackets 11 (as shown in FIG. Fig. 9 As shown), and 2 auxiliary supporting partitions and top plate connecting corner boxes 14 (as shown) are installed between the +Z partition 7, -Y partition 8, -Z partition 9, +Y partition 10 and the top plate 1 Fig.14 As shown in c), 2 main angle relief boxes 13 are assembled at the -X end of +Z partition 7, -Y partition 8, -Z partition 9, and +Y partition 10 (as shown in Fig.12 As shown), on the plane formed by every two diagonal bracing brackets 11 and the 10 side panels and top panel connecting corner boxes 15, two auxiliary angle boxes 12, and two main angle boxes 13, +Z side panels 3, -Y side panels 4, -Z side panels 5, and +Y side panels 6 are installed respectively (as shown in FIG. Figure 8 As shown), 10 side panels and bottom panel connection corner boxes 16 (as shown) are symmetrically assembled on the +Z side panel 3, -Y side panel 4, -Z side panel 5, and +Y side panel 6. Fig.14 As shown in b), the bottom plate 2 is assembled on the -X surface formed by +Z partition 7, -Y partition 8, -Z partition 9, +Y partition 10, 4 diagonal support brackets 11, 8 main angle boxes 13, 40 side panels and bottom plate connecting angle boxes 16 (as shown in b). Fig.10 As shown), the remaining space on the top plate can be used to install gas cylinders, electronic control equipment, etc. as needed. To ensure that all connection links are stable and reliable, the fitting surfaces and connecting screws of some parts are sealed with glue during the structural assembly process, and the fitting surfaces and all threads of the connecting screws of all remaining assembly parts are sealed with glue before launch.

[0065] (2) A specific implementation method for solving the problem of efficient force transmission using an inverted trapezoidal quadrangular pyramid configuration.

[0066] ① Transfer of back cover separation load: The back cover separation load (such as Figure 3 The load of the back cover separation is transmitted to the side panels and the bottom panel 2 (as shown in a) on the -X surface, and the two oblique ribs with an angle of 25° with the mounting surface are installed on the large triangular diagonal support bracket 11 to transfer the back cover separation load to the side panels and the bottom panel 2 (as shown in a) on the -X surface. Figure 3 b, 4), and is ultimately supported by the entire landing platform structure, with the diagonal ribs on the diagonal brace bracket 11 having an angle of 25° with the mounting surface forming four oblique edges at the four corners.

[0067] ②Transmission of the large bottom separation load: The large bottom separation load acts directly on the four diagonal braces 11 and is transmitted to the bottom plate 2 (such as Figure 3 , 18 As shown), and to +Z side plate 3, -Y side plate 4, -Z side plate 5, +Y side plate 6 (as shown Figure 3 b, 5), and transferred to the top plate 1 (as shown in Fig.17 The load is also transferred to the +Z partition 7, -Y partition 8, -Z partition 9, +Y partition 10 through the bottom plate 2, +Z side plate 3, -Y side plate 4, -Z side plate 5, +Y side plate 6, and main angle box 13 (as shown in FIG. Figure 3 , 15 , as shown in 18).

[0068] ③Transmission of landing load: During the landing process, the landing buffer mechanism installed in the space on the side 4 receives the landing load on each side buffer mechanism through the +Z side plate 3, -Y side plate 4, -Z side plate 5, +Y side plate 6 and the main buffer angle box 13 and auxiliary buffer angle box 12 supporting them. Figure 3 b (only one side plate is shown in the figure, and the other three sides are omitted), 6, and the load is transferred to the top plate 1, the bottom plate 2, the +Z partition 7, the -Y partition 8, the -Z partition 9, and the +Y partition 10 through the larger nearly fan-shaped flanges on the main buffer angle box 13 and the auxiliary buffer angle box 12, as shown in FIG. Figure 3As shown in c, the +Z side plate 3, -Y side plate 4, -Z side plate 5, +Y side plate 6 transfer the load to the diagonal support bracket 11 and each partition, or transfer the load to the bottom plate 2 and the top plate 1 through the side plate and the bottom plate connecting corner box 16 and the side plate and the top plate connecting corner box 14, as shown in FIG. Figure 4 b in Fig.16 As shown, through these transmission paths, each connecting surface will quickly transmit the buffer load to the entire landing platform structure. Each side is connected to one main buffer mechanism and two auxiliary buffer mechanism interfaces at the same time. The best force transmission direction is that the +Z side plate 3, -Y side plate 4, -Z side plate 5, and +Y side plate 6 are at a 60° angle to the top plate 1 and the bottom plate 2 respectively. In addition, since the top plate 1 has many +X surface interfaces and the back cover interface is far away, the top plate 1 is large in size, and the bottom plate 2 mainly bears the large bottom interface with a smaller distance. Therefore, the bottom plate 2 is small in size. In addition, the side plate is at a 60° angle with the top plate 1 and the bottom plate 2, forming a structural form of an inverted trapezoidal four-sided pyramid with a large top and a small bottom, which also becomes the best force-bearing configuration for efficient load transmission.

[0069] (3) Specific implementation methods of local reinforcement support design:

[0070] In order to meet the extremely stringent lightweight design requirements, a high proportion of high modulus carbon fiber composite materials are used in the landing platform structure. However, due to the brittleness of carbon fiber composite materials, they are easily damaged at the interface. Therefore, local strong support is achieved through local metal reinforcement, that is, the back cover separation load is received by the rear buried connection seat 18 designed in the back cover interface area on the +X surface of the top plate 1 (such as Figure 3 The load is quickly transferred to the -X surface of the top plate 1, and the load is transferred to the bottom plate 2, +Z side plate 3, -Y side plate 4, -Z side plate 5, +Y side plate 6 (as shown in Fig. Fig.16 , 17 , 18), and transmitted to the entire landing platform structure, the large bottom separation load is directly transmitted through the upper, middle and lower flanges of the metal diagonal support bracket 11 (such as Fig.11 The landing load is borne by the outer surface of the buffer boss embedded parts 17 in the +Z side plate 3, -Y side plate 4, -Z side plate 5, +Y side plate 6 (as shown in FIG. Figure 3 As shown in b in , b in 6 , b in 8 , and b in 14 , the load is transferred from the buffer boss embedded part 17 to the inner surface of the side plate, received by the main buffer angle box 13 and the auxiliary buffer angle box 12 , and quickly transferred to the entire landing platform structure. The high-strength homogeneous metal structure is used to ensure local damage and rapid and continuous transmission of loads along the entire force transmission route, achieving the goal of strong support.

[0071] On the top of the landing platform structure, the largest load-bearing equipment, the Mars rover, is supported. Its installation interface on the top plate is subjected to concentrated loads, and local reinforcement is achieved by embedding annular reinforcement beams (such as Figure 7 Such strengthening methods effectively ensure load sharing and eliminate the problem of insufficient local strength of brittle composite materials.

[0072] (4) Specific implementation methods of high-precision multi-association interfaces.

[0073] ① In order to achieve accurate installation and stress-free separation of the landing platform structure and the back cover structure, a high-precision back cover interface must be provided on the top plate of the landing platform structure. The implementation method is to design four rear buried connection seats 18 (such as Figure 3 , 7 , 15), according to the requirements of the interface position of the lower back cover of the whole device, the four rear buried holes of the rear buried connection seat 18 on the top plate 1 are combined and processed, that is, the assembly basis of the rear buried connection seat 18 is ensured to be accurate, and then the four rear buried connection seats 18 are accurately assembled by positioning the end of the interface (as shown in FIG. Figure 7 As shown), it is buried in the corresponding rear buried hole of the top plate 1, so as to achieve high-precision matching with the back cover.

[0074] ② In order to achieve accurate installation and stress-free separation between the landing platform structure and the outsole, a high-precision outsole interface must be provided at the -X end of the landing platform structure. Since the outsole separation interface is located at the top of the four diagonal support brackets 11 (such as Figure 3 As shown), that is, on the bracket positioning seat 19, therefore, its implementation method needs to be implemented in the state of landing platform structure assembly. First, the relative position relationship between the upper and lower surface hole positions of the diagonal support bracket 11 is controlled by high-precision positioning requirements, and the parallelism and height difference relationship between the upper and lower surfaces of the diagonal support bracket 11 is accurately controlled by high-precision parallelism requirements. On this basis, accurate positioning and assembly relationship is achieved through high-precision positioning tooling, and better relative position relationship and coplanarity of the top ends of the four diagonal support brackets 11 are achieved, ensuring that the bracket positioning seat 19 has an excellent assembly foundation; secondly, on the above-mentioned assembly foundation, the four bracket positioning seats 19 are positioned and assembled through high-precision positioning tooling to achieve high-precision matching with the outsole.

[0075] ③ To ensure that there is no assembly stress between the parts after the landing platform structure is assembled, and to avoid the position change of the key interfaces on the four diagonal brace brackets 11 during the stress release process, the +Z side plate 3, -Y side plate 4, -Z side plate 5, +Y side plate 6 and the two positioning pin holes on the two flanges of the diagonal brace bracket 11 should be in a strict stress-free hole position relationship during the assembly process (such as Figure 3 , 8 , 16), the implementation method for ensuring the accuracy of the hole position is to drill the positioning pin holes on the side plate through trial assembly to ensure that the two pin holes on the side plate and the diagonal support bracket 11 are accurately aligned, so as to achieve the alignment assembly of the pins and holes under a stress-free state.

[0076] (5) Implementation method of the rubber-screw connection design: In order to ensure that the entire structure can withstand a large number of loads in multiple stages such as launch, base separation, back cover separation, parachute, and landing, threaded connection alone cannot achieve the best load-bearing and highest reliability. Therefore, a comprehensive rubber-screw implementation method should be used, that is, all the fitting surfaces between the parts are coated with glue on both sides, such as the overlapping fitting surfaces between the top plate 1, bottom plate 2, side plates (3-6), partitions (7-10) and diagonal brace brackets 11, and various corner boxes (12-16). At the same time, multiple screw connection states are designed on the entire fitting surface. During the molding process, the quality of the bonding is ensured by applying pressure from the front of the tooling and auxiliary pressure by the connecting screws. The bonding shear strength is tested with the furnace parts to verify the bonding molding quality. The comprehensive effect of rubber and screw ensures efficient load transfer, and the implementation of threads can ensure that the bonding surface has strong anti-peeling ability.

[0077] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0078] Parts not described in detail in the present invention belong to common knowledge of those skilled in the art.

Claims

1. A Mars exploration landing platform structure that bears complex and heavy loads, used to connect the back cover and the large bottom of the landing rover, characterized by: It includes a top plate, a bottom plate, four side plates, four diagonal bracing brackets, and four partitions; A rover interface is provided on the top surface of the top plate, and rear-buried connection seats for connecting to the reinforcing beam in the back cover are provided at the four corners; four diagonal brace brackets are installed on the back of the top plate, and the position of one end of the diagonal brace bracket connected to the top plate corresponds to the position of the rear-buried connection seat; side panels are installed between adjacent diagonal brace brackets, and the side panels form the side surfaces of an inverted trapezoidal quadrangular pyramid, and the diagonal brace brackets are located at the edge positions of the inverted trapezoidal quadrangular pyramid; landing buffer mechanism interfaces are respectively provided on the four side edges, and buffer corner boxes are installed inside the side panels at the interface positions, and the buffer corner boxes transmit force to the top plate or the bottom plate; a partition is installed at the buffer corner box position that transmits force to the bottom plate, and the three sides of the partition are respectively connected to the bottom plate, the side plate and the top plate, and the fourth side is suspended, and an auxiliary support corner box is installed at the junction of the suspended side and the top plate; The interior of the inverted trapezoidal quadrangular pyramid is used to install the engine and the tank, and the bottom plate is connected to the side and the diagonal support bracket; the support positioning seat is installed on the diagonal support bracket to be connected to the large bottom interface; The diagonal support bracket is a multi-rib bracket with a triangular side surface. The end surface of the bracket placed between the bottom plate and the two side plates is a non-hollow structure. A protruding truncated cone for mounting the bracket positioning seat is provided inwardly on the surface. Flanges for connecting with the side edges are provided on both sides of the surface, and the flanges are used to diffuse stress. A connecting frame is set between the two triangular side surfaces. The parts where the triangular side surfaces are connected to the top plate, the side edges and the bottom plate are continuous structures. The triangular side surfaces and the end surfaces connected to the top plate are hollowed out on the basis of meeting the structural strength. The buffer angle box that transmits force to the base plate is called the main buffer angle box, which is composed of three mutually perpendicular surfaces. A cylindrical connecting port is set in the surface for connecting with the landing buffer mechanism interface, and the cylindrical connecting port is connected to the two vertical surfaces through reinforcing ribs; the sum of the areas of the above three mutually perpendicular surfaces must be at least five times greater than the sum of the end surface areas of all cylindrical connecting ports.

2. The Mars exploration landing platform structure according to claim 1, characterized in that: A reinforcing beam is arranged inside the top plate at the position of the auxiliary supporting corner box installed at the junction of the suspended edge of the partition and the top plate; and an annular reinforcing beam is arranged inside the top plate at the position of the Mars rover interface.

3. The Mars exploration landing platform structure according to claim 1, characterized in that: A reinforcing beam is embedded in the portion where the side plate is connected to the flange.

4. The Mars exploration landing platform structure according to claim 1, characterized in that: The position of the support locating seat on the diagonal support is required to be lower than half the height of the edge of the inverted trapezoidal quadrangular pyramid.

5. The Mars exploration landing platform structure according to claim 1, characterized in that: The bracket positioning seat is a symmetrical structure with a center hole, the upper end surface of the center hole is the mounting surface of the large bottom, the outer ring of the mounting surface is provided with a flange structure, the lower end surface of the center hole is provided with a flange plate for connecting to the diagonal support bracket, reinforcing ribs are provided between the above-mentioned flange structure and the flange plate, an annular cavity is provided between the lower end surface of the center hole and the flange plate, and support ribs consistent with the position of the reinforcing ribs are provided inside the annular cavity.

6. The Mars exploration landing platform structure according to claim 5, characterized in that: The flatness of the protruding frustum of the four diagonal bracing brackets is not higher than 0.15 mm. Taking the mounting surface of any bracket positioning seat installed on the diagonal bracing bracket as a reference, the remaining bracket positioning seats are adjusted to ensure that the flatness of the four mounting surfaces is not higher than 0.1 mm.

7. The Mars exploration landing platform structure according to claim 1, characterized in that: The rear embedded connection seat is a symmetrical structure with a central hole, the upper end surface is an annular cone for bearing shear load, at least four bosses are evenly distributed around the annular cone for supporting and connecting the reinforcing beam in the back cover, and a support ear interface is arranged on the flange below the boss in the same position as the boss, which is used to realize the screw connection with the embedded parts inside the top plate; A reinforcing rib is arranged below the flange at a position consistent with the boss, and the reinforcing rib is connected to the lower surface flange.

8. The Mars exploration landing platform structure according to claim 1, characterized in that: The partition is a skin sandwiched honeycomb core structure, and a fan-shaped carbon skin reinforcement layer is added to the outer side of the end surface that is bonded to the corresponding buffer corner box. The thickness of the reinforcement layer is more than three times the thickness of the skin.

9. The Mars exploration landing platform structure according to claim 1, characterized in that: The buffer angle box that transmits force to the top plate is called an auxiliary buffer angle box, which consists of two end faces at a certain angle to each other. A cylindrical connecting port is set in the surface for connecting with the landing buffer mechanism interface. The cylindrical connecting port is connected to the two end faces through reinforcing ribs; the sum of the areas of the two end faces must be at least five times greater than the sum of the end face areas of all cylindrical connecting ports.

10. The Mars exploration landing platform structure according to claim 1, characterized in that: The bottom plate is provided with an avoidance hole for the engine and the tank, and a carbon cloth reinforcement area is provided around the avoidance hole. The width of the carbon cloth reinforcement area is not less than 25 mm, and the thickness is not less than 2 mm.

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