Analog vehicle with a sensor sensitive layer

Abstract

The present invention relates to a simulated vehicle (100) for testing a driver assistance system. The simulated vehicle (100) has vehicle components (101) that form parts of the vehicle to be simulated. The vehicle components (101) form a housing structure (103), wherein the housing structure has an outer layer (104) and an inner layer (105). In the housing structure (103), the outer layer (104) is arranged more outward than the inner layer (105). The outer layer (104) is configured to be transparent to the sensor signals of the sensors of the driver assistance system, while the inner layer (105) is configured to be sensor-sensitive to the sensor signals of the sensors of the driver assistance system.

Description

Technical Field

[0001] The present invention relates to a simulated vehicle for testing a driver assistance system. Background Art

[0002] Vehicle simulation prostheses, such as motorcycle simulation prostheses or car simulation prostheses, are generally used to test the driver assistance systems of vehicles. Such vehicle simulation prostheses are the same as the vehicles they are supposed to mimic in at least one aspect or characteristic. For example, a vehicle simulation prosthesis may have a geometric shape or size similar to that of the object to be simulated.

[0003] In many tests of driver assistance systems, collision or near - collision situations are inevitable and are even often required to investigate extreme cases or train driver assistance systems. The vehicle simulation prostheses should remain undamaged as much as possible after a collision so that they can be used for multiple test runs. In addition, the produced vehicle simulation prostheses should cost - effectively simulate the vehicle and still realistically mimic the vehicle to be simulated. Summary of the Invention

[0004] An object of the present invention is to provide a vehicle simulation prosthesis that realistically mimics the vehicle to be simulated with a simple structure.

[0005] This object is achieved by a vehicle simulation prosthesis for testing a driver assistance system.

[0006] According to a first aspect of the present invention, there is provided a simulated vehicle for testing a driver assistance system. The simulated vehicle has vehicle elements that form parts of the vehicle to be simulated. The vehicle elements construct a shell structure, wherein the shell structure has an outer layer and an inner layer. In the shell structure, the outer layer is arranged more outward (in the direction towards the surrounding environment of the vehicle element) than the inner layer. The outer layer is configured to be transparent to the sensor signals of the sensors of the driver assistance system, while the inner layer is configured to be sensor - sensitive to the sensor signals of the sensors of the driver assistance system.

[0007] Correspondingly, according to another aspect, the present invention relates to a method for testing a driver assistance system by the above - mentioned simulated vehicle.

[0008] A driver assistance system describes a system that assists the driver of a vehicle (such as a motor vehicle) when driving the vehicle. A driver assistance system can also be used in autonomous vehicles, where the driving of the vehicle is taken over completely or almost completely by an autonomous system, such as a system supported by artificial intelligence, especially the corresponding computer software. Driver assistance systems are, for example, emergency braking assistance, lane - change assistance, parking assistance, distance controllers, traffic - sign assistance, or night - vision assistance.

[0009] A driver assistance system may have sensors, in particular radar sensors or temperature sensors, which receive sensor signals from the surrounding environment. By evaluating these received sensor signals, various aspects of the surrounding environment can be identified, in particular the characteristics of different objects (such as other vehicles) in the surrounding environment. These characteristics can be, for example, the distance, geometric dimensions, temperature or speed of other vehicles. The speed can be determined relative to the environment, for example relative to the road, or also relative to the vehicle having the driver assistance system. An object can have a total speed or a center-of-gravity speed, but parts of the object can also move relative to each other and relative to the center of gravity in an arbitrary manner. The driver assistance system can also have a transmitter of signals, which are characteristically altered by the surrounding environment and are then at least partially received by the sensors, for example a transmitter of radar waves. In particular, sensor signals can be transmitted which penetrate an outer layer and are then only reflected by an inner layer. The sensor signals can be electromagnetic radiation (such as radar waves, radio waves or microwaves), thermal radiation, light, X-ray radiation or infrared radiation.

[0010] When testing a driver assistance system, a vehicle can be equipped with the driver assistance system. A vehicle equipped in this way can be exposed to a predefined situation on a test track, where the reaction of the driver assistance system to the predefined situation is observed and evaluated according to given criteria. The driver assistance system can also be tested without being built into a vehicle.

[0011] The vehicle to be simulated is a movable vehicle. The vehicle is, for example, a two-wheeler (in particular a bicycle or a motorcycle), a passenger car, a truck or any other movable vehicle detectable by the driver assistance system.

[0012] The simulated vehicle according to the invention forms the vehicle to be simulated. In particular, sensors of the driver assistance system, such as temperature sensors or radar sensors, can sense or identify the simulated vehicle. The simulated vehicle can move in the surrounding environment of a vehicle in which the driver assistance system is built in.

[0013] The simulated vehicle according to the invention has at least one vehicle element or a plurality of different vehicle elements. The vehicle elements form parts of the vehicle to be simulated. For example, a vehicle element can be configured as part of a door, a frame member or a body member. In particular, the vehicle elements form parts of the vehicle to be simulated which, for example, have a metallic structure or reflect radar waves. For example, a vehicle element is configured as a body member, such as a door, a hood or an in-vehicle structure (such as an engine block).

[0014] The vehicle component particularly has a housing structure, which has an outer structure or outer layer and an inner structure or inner layer. Compared with the inner layer, the outer layer is on the outside around the vehicle component. In addition to the inner layer and the outer layer, the housing structure can also have a plurality of other layers. For example, there can be a plurality of layers between the outer layer and the inner layer. Thus, the inner layer is at a certain distance from the outer layer. The inner layer can also be directly and internally fastened to the outer layer. In addition, additional layers can be applied on the outside of the outer layer, and correspondingly, additional layers can be applied on the inside of the inner layer. In an exemplary embodiment, the outer layer can be the layer of the housing structure that contacts the surrounding environment of the vehicle component. The inner layer can be the layer of the housing structure that contacts the internal cavity.

[0015] The outer layer is particularly constructed of a lightweight foam material, which is, for example, elastic and dimensionally stable. The foam material is particularly constructed such that the vehicle component is self-supporting. Here, the outer layer is transparent to sensor signals from sensors. In other words, for sensor signals, the outer layer is almost completely penetrable, or does not affect the outer layer when penetrating it. In particular, the outer layer is constructed so as not to affect the sensor signals perceivable by the sensors.

[0016] The outer layer is constructed more firmly than the inner layer, i.e., more rigid and harder. Thus, the outer layer is used on the one hand for the dimensional stability of the vehicle component and on the other hand for protecting the inner layer, especially in the case of a collision with a simulated vehicle.

[0017] In order to make the vehicle component visible to sensors, an inner layer with sensor-sensitive material is provided on the inner side relative to the outer layer. In particular, the inner layer does not contribute to the dimensional stability of the vehicle component, but can be constructed flexibly, for example. For example, the inner layer can emit radiation as a sensor signal, such as temperature radiation. For example, a signal generator of the sensor signal, such as a heat source, can be arranged in the vehicle component, and the inner layer emits this thermal radiation outward. For example, the engine block of a vehicle can be simulated. Alternatively, in the case of a body component as a vehicle component, the inner layer can be constructed to reflect signal waves. For example, the inner layer can be constructed to reflect radar waves or other electromagnetic waves. Thus, sensor-sensitive means that the inner layer is constructed as a radiation-emitting layer, a radiation-absorbing layer, and / or a radiation-reflecting layer.

[0018] With the combination of a sensor-transparent outer layer and a sensor-sensitive inner layer, the simulated vehicle can have a vehicle component that is lightweight, dimensionally stable, and structurally firm, so that the fragile sensor-sensitive layer will not be damaged in a collision. Thus, the simulated vehicle can be used for collision tests multiple times.

[0019] For example, in a conventional analog vehicle, radar reflection elements are fastened to the surface layer of the analog vehicle at certain positions. This may result in damage to the radar reflection elements in the event of a collision with another vehicle. With the housing structure according to the present invention, the sensor-sensitive or radar-reflecting inner layer is protected from collisions with the outer layer. Most importantly, the cooperating components (i.e., the vehicle to be tested or its occupants) are protected. Thereby, the sensitive or high-cost sensor-sensitive inner layer can be implemented, for example, in a thinner or less collision-resistant manner, so that a cheaper sensor-sensitive material can be used.

[0020] According to another exemplary embodiment, the housing structure forms a hollow body having an internal volume.

[0021] According to another exemplary embodiment, the housing structure has a filling material, and an inner layer is applied or extends around the filling material. The internal volume can be constructed, for example, of foam material or other lightweight materials, and thus stability is increased. The sensor-sensitive inner layer can be applied directly to the filling material here, or other layers can be arranged between the inner layer and the filling material.

[0022] According to another exemplary embodiment, the inner layer has a heat-reflective material.

[0023] According to another exemplary embodiment, the inner layer can be heated. For example, metal wires can extend in the inner layer to achieve resistive heating. In addition, the inner layer can be heated by means of a temperature medium.

[0024] According to another exemplary embodiment, the inner layer has a radar-reflective material. For example, the inner layer can be constructed as a metal film. In addition, the inner layer can have a mesh structure of metal.

[0025] According to another exemplary embodiment, the outer layer is radar-transparent.

[0026] According to another exemplary embodiment, the outer layer is composed of foam material. For example, the outer layer can consist of rigid foam or elastic foam material, so as to achieve dimensional stability with a light weight.

[0027] According to an exemplary embodiment of the present invention, the outer layer is non-conductive. In other words, the material can be electrically insulating and accordingly non-conductive, so that radar wave reflection can be achieved only by the radar-reflecting inner layer.

[0028] According to another exemplary embodiment, the thickness of the outer layer and the thickness of the inner layer are configured in such a way that the area of the inner surface is at least 70% of the outer surface, in particular 80% to 90% of the outer surface. Compared with the actual components of the vehicle to be simulated, the vehicle element has a smaller radar-reflecting outer surface because the reflecting inner layer is located on the inside and the outer layer through which radar waves can penetrate does not reflect any parabolas. According to the present invention, if now a component of the vehicle to be simulated is simulated with the vehicle element according to the present invention at a 1:1 dimensional ratio, the area of the radar-reflecting outer layer of the component of the vehicle to be simulated is larger than the area of the radar-reflecting inner layer of the vehicle element.

[0029] It has been found that due to the low resolution of the radar sensors in vehicle assistance systems, the area of the inner surface of the inner layer can reach 70% of the area of the outer surface of the outer layer, and nevertheless, the radar sensors still correctly identify the vehicle element as the corresponding component of an isolated vehicle. Therefore, compared with the vehicle component to be simulated, it is not necessary to increase the external dimensions of the vehicle element, thereby achieving the same surface area as the outer surface of the component. In other words, in the above embodiment, due to the smaller surface area of the radar-reflecting inner layer, the external dimensions of the vehicle element are retained without causing incorrect measurements by the driver assistance system.

[0030] According to another exemplary embodiment, the thickness of the outer layer is about 0.1 cm (centimeters) or 0.5 cm to 30 cm, in particular 2 to 15 cm, in particular 5 cm to 10 cm. In other words, the thickness of the outer layer is, for example, less than 20 cm, in particular less than 10 cm or 5 cm.

[0031] According to another exemplary embodiment, the inner layer is designed as a thin film. For example, the thin film can have a thickness of less than 0.4 cm, in particular less than 0.1 cm.

[0032] According to another exemplary embodiment, the inner layer is electrically conductive.

[0033] According to another exemplary embodiment, the inner layer is a metal layer. For example, the inner layer can be configured as a metal thin film. In addition, the metal layer can be composed of a metal wire mesh. The metal device can be, for example, embedded in a carrier matrix made of, for example, a non-conductive material. Alternatively, in the corresponding exemplary embodiment, special conductive metal particles can be embedded in the carrier matrix.

[0034] According to another exemplary embodiment, the outer layer is made of plastic, in particular made of polyvinyl chloride, polyolefin materials (polyethylene, polypropylene) or polyurethane.

[0035] In particular, the outer layer can be made of a foam material. The unit volume weight or total density of the outer layer can be, for example, 15 to 150 kg / m³.

[0036] According to another exemplary embodiment, an optical layer, in particular a film, is applied to the outer layer. The optical layer can be applied, for example, as a thin film or as a paint. For example, the optical layer simulates an optical element on the outside of a vehicle component, such as a wheel, a window or a headlight. The optical layer consists, for example, of polyvinyl chloride or polyurethane.

[0037] According to another exemplary embodiment, the simulated vehicle has a coupling element for coupling to a platform movable on the floor. For example, the movable platform can be individually controlled along a travel path on the floor. The simulated vehicle can be detachably coupled to the movable platform by means of the coupling element, which can be, for example, a mechanical or magnetic coupling element.

[0038] According to another exemplary embodiment, the simulated vehicle has additional vehicle components without a radar-reflective layer. For example, the additional vehicle components can be adjacent to vehicle components having a radar-reflective layer, such that the vehicle components and the additional vehicle components together form a hollow body. Alternatively, the vehicle components and the additional vehicle components can form separate hollow bodies.

[0039] The additional vehicle components, for example, form parts of the vehicle to be simulated that also have no or hardly any radar-reflective properties. For example, the additional vehicle components can form the window area or the tire area of the simulated vehicle.

[0040] According to another exemplary embodiment, the vehicle components and the additional vehicle components are integrally constructed. For example, the vehicle components and the additional vehicle components can be integrally manufactured from a foam material, wherein no radar-reflective inner layer is provided in the area of the additional vehicle components.

[0041] The simulated vehicle according to the invention can have a plurality of vehicle components with a radar-reflective inner layer and a plurality of additional vehicle components without a radar-reflective layer in order to simulate the vehicle to be simulated.

[0042] It should be noted that the embodiments described here only represent a limited selection of possible embodiment variants of the invention. Thus, the features of the individual embodiments can be combined with one another in a suitable manner, such that for a person skilled in the art, a large number of different embodiments can be clearly derived from the embodiment variants explicitly shown here. In particular, some embodiments of the invention are described by product claims, while other embodiments of the invention are described by method claims. However, when reading the present invention, it will be apparent to a person skilled in the art that, unless otherwise explicitly stated, not only can the features belonging to one type of inventive subject matter be combined with one another, but also the features belonging to different types of inventive subject matter can be combined with one another. Description of the Drawings

[0043] Next, for further elaboration and better understanding of the present invention, exemplary embodiments will be described in more detail with reference to the accompanying drawings. Among them:

[0044] Figure 1 shows a schematic diagram of a simulated vehicle for simulating a motorcycle according to an exemplary embodiment of the present invention; and

[0045] Figure 2 shows a schematic diagram of a simulated vehicle for simulating a car according to an exemplary embodiment of the present invention. Detailed Embodiments

[0046] Identical or similar components in different drawings have the same reference numerals. The representations in the drawings are schematic.

[0047] Figure 1 Shows a simulated vehicle 100 in the form of a motorcycle for performing tests of a driver assistance system according to an exemplary embodiment of the present invention. The simulated vehicle 100 has a vehicle element 101, and the vehicle element 101 forms a component of the vehicle to be simulated. The vehicle element 101 is configured as a shell structure 103, wherein the shell structure has an outer layer and an inner layer. In the shell structure 103, the outer layer is arranged more outward than the inner layer 105. The outer layer 104 is transparent to the sensor signals of the sensors of the driver assistance system, wherein the inner layer 105 is sensor-sensitive to the sensor signals of the sensors of the driver assistance system.

[0048] In Figure 1 the exemplary embodiment, the shell structure 103 is configured as a hollow body, wherein the shell structure has an outer layer 104 and an inner layer 105.

[0049] The simulated vehicle 100 according to the present invention forms the motorcycle to be simulated. In particular, the simulated vehicle 100 can be sensed or recognized by the radar sensor of the driver assistance system of another vehicle. The simulated vehicle 100 can move around a vehicle equipped with a driver assistance system.

[0050] The simulated vehicle 100 according to the present invention has a plurality of different vehicle elements 101. Each vehicle element 101 forms a component of the vehicle to be simulated. The vehicle element 101 can form, for example, the longitudinal axis, fuel tank, engine block, seat or base frame of the motorcycle to be simulated. The vehicle element 101 particularly forms components of the motorcycle to be simulated that, for example, have a metal structure and, for example, reflect radar waves.

[0051] The inner layer 105 is the layer of the shell structure 103 that contacts the cavity. The inner layer 105 is shown in Figure 1 dashed lines.

[0052] The outer layer 104 is in particular constructed from a lightweight foam material that is, for example, elastic and dimensionally stable. The foam material is in particular constructed in such a way that the vehicle element 101 is self-supporting.

[0053] An inner layer 105 with a sensor-sensitive (e.g., radar-reflective) material is provided on the inner side of the outer layer 104. In particular, the inner layer 105 does not contribute to the shape stability of the vehicle element 101, but can be constructed flexibly, for example.

[0054] The outer layer 104 is non-conductive. In other words, the material can be electrically insulating and accordingly non-conductive, so that radar wave reflection is achieved only by the radar-reflective inner layer 105.

[0055] As Figure 1 shown, the thickness of the outer layer 104 and the thickness of the inner layer 105 are constructed such that the area of the inner surface is at least 70% of the outer surface, in particular 80% to 90% of the outer surface.

[0056] The inner layer 105 is conductive. The inner layer 100 is in particular a metal layer. For example, the inner layer 105 can be constructed as a metal film. The outer layer 104 consists of a rigid foam (e.g., made of polyvinyl chloride, polyphenol, or polyurethane), for example.

[0057] The simulated vehicle 100 also has a coupling element 106 for coupling to a platform movable on the ground. For example, the movable platform (not shown) can be controlled individually along a travel path on the floor.

[0058] In addition, a further vehicle element 102 without a radar-reflective layer is also shown. The further vehicle element 102 can, for example, be adjacent to the vehicle element 101 with a radar-reflective layer, so that the vehicle element 101 and the further vehicle element 102 together form a hollow body 103. Alternatively, the vehicle element 101 and the further vehicle element 102 can form separate hollow bodies.

[0059] For example, the further vehicle element 102 forms a component of the vehicle to be simulated that also has no or hardly any radar-reflective properties. The further vehicle element 102 can, for example, be an opening in a motorcycle rim as Figure 1 shown.

[0060] In addition, the vehicle element 101 can have a cavity 103 that simulates the specific shape of a metal component to be simulated of the vehicle to be simulated. For example, in Figure 1In this case, the engine block 107 is simulated by means of a cavity 103 in the chassis of the vehicle element 101 of the motorcycle shown. Here, the cavity 103 has the specific shape of the engine block 107. An inner layer 105 with radar reflection characteristics surrounds the cavity 103 on the inside, thus simulating the shape of the engine block 107. The inner layer 105 can, for example, emit radiation as a sensor signal, such as temperature radiation. For example, a generator of the sensor signal (such as a heat source) can be arranged in the vehicle element 101, where the inner layer 105 emits such thermal radiation outwards. For example, the motor block 107 of the vehicle can be simulated.

[0061] Therefore, by means of the construction of this shell structure, for example, a solid body representing the outer layer can be formed, in which a cavity conforming to the shape of the object to be simulated is constructed. The inner layer is arranged on the outer layer around the cavity, so that, for example, in addition to the external geometry of the vehicle element, internal components of the vehicle with radar reflection, such as the engine block, can be simulated.

[0062] Figure 2 A simulated vehicle 100 in the form of a motor vehicle is shown. The simulated vehicle 100 shown has a plurality of different vehicle elements 101. Each vehicle element 101 forms a component of the motor vehicle to be simulated. The vehicle element 101 can, for example, form the engine hood, body or door of the motor vehicle to be simulated. The vehicle element 101 with the inner layer 105 having radar reflection particularly forms a component of the motor vehicle to be simulated, such as having a metal structure or reflecting radar waves.

[0063] In addition, a region of the simulated vehicle 100 is also shown, which represents another vehicle element 102. The other vehicle element 102 forms, for example, the window area or headlight of the motor vehicle to be simulated. The vehicle element 102 does not have or has hardly any inner layer 105 with radar reflection here.

[0064] The vehicle element 101 and the other vehicle element 102 can be constructed integrally. For example, the vehicle element 101 and the other vehicle element 102 can be integrally manufactured from foam material, where the inner layer 105 with radar reflection is not provided in the region of the other vehicle element 102.

[0065] In addition, it should be noted that "including" does not exclude any other elements or steps, and the word "a" does not exclude a plurality. It should also be noted that the features or steps described with reference to one of the above exemplary embodiments can also be used in combination with other features or steps of the above other exemplary embodiments. The reference signs in the claims should not be regarded as limiting.

[0066] List of reference signs

[0067] 100 Simulated vehicle

[0068] 101 Vehicle component

[0069] 102 Another vehicle component

[0070] 103 Hollow body

[0071] 104 Outer layer

[0072] 105 Inner layer

[0073] 106 Connecting element

[0074] 107 Motor housing

Claims

1. A simulated vehicle (100) for testing a driver assistance system, the simulated vehicle (100) comprises: a vehicle component (101) that forms a part of the vehicle to be simulated, wherein the vehicle component (101) constructs a shell structure (103), wherein the shell structure has an outer layer (104) and an inner layer (105), wherein in the shell structure (103), the outer layer (104) is arranged more outward than the inner layer (105), wherein the outer layer (104) is configured to be transparent to the sensor signals of the sensors of the driver assistance system, wherein the inner layer (105) is configured to be sensor-sensitive to the sensor signals of the sensors of the driver assistance system, wherein the outer layer (104) is constructed more robustly than the inner layer (105), wherein the thickness of the outer layer (104) and the thickness of the inner layer (105) are set such that the area of the inner surface is at least 70% of the outer surface.

2. The simulated vehicle (100) according to claim 1, wherein, the shell structure (103) is configured as a hollow body having an internal volume.

3. The simulated vehicle (100) according to claim 1, wherein, the shell structure has a filling material, and the inner layer (105) is applied around the filling material.

4. The simulated vehicle (100) according to any one of claims 1 to 3, wherein, the inner layer (105) has a heat-reflective material.

5. The simulated vehicle (100) according to any one of claims 1 to 4, wherein, the inner layer (105) can be heated.

6. The simulated vehicle (100) according to any one of claims 1 to 5, wherein, the inner layer (105) has a radar-reflective material.

7. The simulated vehicle (100) according to any one of claims 1 to 6, wherein, the outer layer (104) is radar-transparent.

8. The simulated vehicle (100) according to any one of claims 1 to 7, wherein, the outer layer (104) is made of a foam material.

9. The simulated vehicle (100) according to any one of claims 1 to 8, wherein, the outer layer (104) is non-conductive.

10. The simulated vehicle (100) according to any one of claims 1 to 9, wherein, the thickness of the outer layer (104) and the thickness of the inner layer (105) are set such that the area of the inner surface is at least 80% to 90% of the outer surface.

11. The simulated vehicle (100) according to any one of claims 1 to 10, wherein, the thickness of the outer layer (104) is 0.1 cm to 30 cm or 0.5 cm to 30 cm.

12. The simulated vehicle (100) according to claim 11, wherein, the thickness of the outer layer (104) is 2 cm to 15 cm.

13. The simulated vehicle (100) according to claim 12, wherein, the thickness of the outer layer (104) is 5 cm to 10 cm.

14. The simulated vehicle (100) according to any one of claims 1 to 13, wherein, The inner layer (105) is designed as a thin film.

15. The simulated vehicle (100) according to any one of claims 1 to 14, wherein, the inner layer (105) is conductive.

16. The simulated vehicle (100) according to any one of claims 1 to 6, wherein, the inner layer (105) is configured as a metal layer.

17. The simulated vehicle (100) according to any one of claims 1 to 16, wherein, the outer layer (104) is made of polyvinyl chloride, polyolefin material or polyurethane.

18. The simulated vehicle (100) according to any one of claims 1 to 16, wherein, the outer layer (104) is made of polyvinyl chloride, polyethylene, polypropylene or polyurethane.

19. The simulated vehicle (100) according to any one of claims 1 to 18, wherein, an optical layer is coated on the outer layer (104).

20. The simulated vehicle (100) according to claim 19, wherein, the optical layer is an optical film.

21. The simulated vehicle (100) according to claim 19, wherein the optical layer is made of polyvinyl chloride or polyurethane.

22. The simulated vehicle (100) according to any one of claims 1 to 21, the simulated vehicle further comprising: a coupling element (106) for coupling to a movable platform on the ground.

23. The simulated vehicle (100) according to any one of claims 1 to 22, the simulated vehicle further comprising: an additional vehicle element (102) that does not have a radar reflective layer.

24. The simulated vehicle (100) according to claim 23, wherein, the additional vehicle element (102) forms a window area of other components of the vehicle to be simulated.

25. The simulated vehicle (100) according to claim 23 or 24, wherein, the vehicle element (101) and the additional vehicle element (102) are integrally constructed.

26. The simulated vehicle (100) according to any one of claims 23 to 25, wherein, the additional vehicle element (102) has an additional shell structure, and the additional shell structure and the shell structure of the vehicle element (101) are constructed together as a hollow body.

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