Method and device for guiding a vehicle on a surface

Abstract

Method for guiding a vehicle on a surface, wherein the vehicle is guided along a predeterminable route by means of a marking arranged at least in sections on the surface and a detector designed to detect the marking and assigned to the vehicle, wherein, in order to detect the marking on the surface, the marking is illuminated by means of an illumination device with a first illumination light and a second illumination light of different wavelengths and each with a predeterminable duration in a predeterminable sequence, wherein the wavelength of the first illuminating light and the wavelength of the second illuminating light are selected such that the marking is recognizable by the detector due to its definable remission spectrum when illuminated with the first illuminating light with a brightness or darkness that differs from the brightness or darkness when illuminated with the second illuminating light, wherein a corresponding detection result determined by the detector is used to guide the vehicle along the route and wherein the marking is strip-shaped with one track or several tracks or stripes.

Description

[0001] The invention relates to a method for guiding a vehicle on a surface, wherein the vehicle is guided along a predeterminable route by means of a marking arranged at least in sections on the surface and a detector designed to recognize the marking and assigned to the vehicle.

[0002] Furthermore, the present invention relates to a device for guiding a vehicle on a surface, in particular for carrying out the above method, wherein the vehicle can be guided along a predeterminable route by means of a marking arranged at least in sections on the surface and a detector designed to recognize the marking and assigned to the vehicle.

[0003] Methods and devices of the type mentioned above, in which a vehicle is guided along a surface, are known in practice and exist in various designs. Such vehicles are used, for example, as driverless transport systems (AGVs) in many areas of modern production, such as the automotive industry, which is characterized by a high degree of transformation and automation. A variety of AGVs perform various in-house transport tasks and thus make a decisive contribution to optimizing speed, safety, and cost-effectiveness in ongoing operations. Especially in the context of Industry 4.0, AGVs are experiencing a real hype and are helping not only automobile manufacturers to create lean, agile production facilities.

[0004] Furthermore, it is known to apply markings to a surface, for example a surface in the form of the floor in an industrial hall. The marking can be realized in the form of a colored track - even in black - which is detected by a suitable detector and used to guide the vehicle. Corresponding known systems work with such contrasting tracks. A light background with a black track is usual. However, this tracking is often indistinguishable from a "wrong track", which can be formed, for example, by an identical-looking narrow, dark skid mark on a light background or surface. Such "wrong tracks" can also be formed by grooves or expansion joints in which dirt has accumulated. In an unfavorable case, the detector recognizes this as the correct track and guides a vehicle in the wrong direction.As a result, the familiar guidance of a vehicle on a surface is error-prone and unreliable.

[0005] Furthermore, EP 3 167 252 B1 discloses a method and a device for determining the position of a vehicle, using markers arranged along a path. The markers may include a code.

[0006] Furthermore, JP 2000 - 029 516 A discloses a guidance sensor that can identify a guide strip with high accuracy. The guide strip can be arranged on a road to guide a vehicle.

[0007] DE 10 2017 006 630 A1 discloses a method and system for lane guidance, as well as a vehicle. A lane is illuminated with a first and a second color spectrum, and the reflected light intensities are measured.

[0008] The present invention is based on the object of specifying a method and a device for guiding a vehicle on a surface, according to which a particularly safe guidance of a vehicle on a surface is made possible with structurally simple means.

[0009] According to the invention, the above object is achieved by a method having the features of claim 1 and by a device having the features of claim 14.

[0010] According to claim 1, a method for guiding a vehicle on a surface is specified, wherein the vehicle is guided along a predeterminable route by means of a marking arranged at least in sections on the surface and a detector designed to detect the marking and assigned to the vehicle, wherein, in order to detect the marking on the surface, the marking is illuminated by means of an illumination device with a first illumination light and a second illumination light of different wavelengths and each with a predeterminable duration in a predeterminable sequence, wherein the wavelength of the first illuminating light and the wavelength of the second illuminating light are selected such that the marking is recognizable by the detector due to its definable remission spectrum when illuminated with the first illuminating light with a brightness or darkness that differs from the brightness or darkness when illuminated with the second illuminating light, wherein a corresponding detection result determined by the detector is used to guide the vehicle along the route and wherein the marking is strip-shaped with one track or several tracks or stripes.

[0011] Furthermore, according to claim 14, a device for guiding a vehicle on a surface is specified, wherein the vehicle can be guided along a predeterminable route by means of a marking arranged at least in sections on the surface and a detector designed to detect the marking and assigned to the vehicle, wherein for detecting the marking on the surface, the marking can be illuminated by means of an illumination device with a first illumination light and a second illumination light of different wavelengths and each with a predeterminable duration in a predeterminable sequence, wherein the wavelength of the first illuminating light and the wavelength of the second illuminating light are selected such that the marking is recognizable by the detector due to its definable remission spectrum when illuminated with the first illuminating light with a brightness or darkness that differs from the brightness or darkness when illuminated with the second illuminating light, wherein a corresponding detection result determined by the detector can be used by means of a guidance device to guide the vehicle along the route, and wherein the marking is strip-shaped with one track or several tracks or stripes.

[0012] The method involves implementing an illumination system that illuminates the marking with a first illumination light and a second illumination light of different wavelengths and each with a predeterminable duration in a predeterminable sequence. The wavelength of the first illumination light and the wavelength of the second illumination light are selected such that the marking, due to its definable reflectance spectrum for illumination light, is recognizable by the detector when illuminated with the first illumination light with a brightness or darkness that differs from the brightness or darkness when illuminated with the second illumination light.The detector can detect whether the marking is illuminated with the first or second illumination light. When selecting the first and second illumination light, one aim may be to make the difference in brightness or darkness created by switching from the first illumination light to the second illumination light, or vice versa, as great as possible and, preferably, with as much contrast as possible. For a marking having a code with different color elements, one aim may therefore be to use one illumination light to display one color of the code as dark as possible and another color as bright as possible, or vice versa. It can behave complementarily with the other illumination light. The aim here may be to achieve the highest possible contrast between a dark and a light image under a particular illumination color or under a particular illumination light.This predeterminable illumination sequence with the first illumination light and the second illumination light generates a defined remission from the marking, which is received by the detector. The detector uses this detection result—for example, by means of a suitable control device or guidance device—to guide the vehicle along the route. It can compare the received detection result with the detection result communicated to it—for example, by the above-mentioned control device or guidance device or a suitable additional control device—and expected based on the defined remission. If the received detection result corresponds to the expected detection result, the vehicle is on or along the predeterminable, correct route and can be guided correctly along the predeterminable route.This allows the position of the detector or vehicle to be determined relative to the marking. If the received detection result does not correspond to the expected detection result, a correction to the guidance can be made - for example, using the above-mentioned control device or guidance device - in order to bring the vehicle back onto the correct course along the predeterminable route. Ultimately, this can result in a clear identification or recognition of a marking or lane, with a distinction being made between "false markings" or "false lanes." Furthermore, with a view to particularly safe guidance of a vehicle, the marking is designed in a strip-shaped manner with one lane or stripe or several lanes or stripes in a structurally simple manner.

[0013] Consequently, the method and device according to the invention provide a method and device which enable particularly safe guidance of a vehicle on a surface using structurally simple means.

[0014] With regard to a particularly simple embodiment of the method, the marking can be recognizable by the detector due to its definable remission spectrum when illuminated with the first illumination light and not recognizable when illuminated with the second illumination light, or vice versa. This creates a particularly large difference for the detector when illuminated with the first illumination light and when illuminated with the second illumination light.

[0015] To ensure particularly reliable and safe vehicle guidance, the detection result can be used to determine whether the vehicle is still within a definable spatial or planar area around the marking or still at a definable distance from the marking. Such an area or distance can be defined wider or narrower depending on the specific application and the respective environmental conditions, for example, a spatial constraint. To minimize the risk of accidental deviation of the vehicle's movement from the predeterminable route and thus ensure the vehicle is guided as precisely as possible along the route, the area or distance can be selected to be relatively small.

[0016] To achieve particularly simple and safe guidance of the vehicle, the lighting device can be assigned to the vehicle, arranged on the vehicle, or integrated into the vehicle. This allows for a particularly compact device for guiding a vehicle without a lighting device that may be located at a considerable distance from the vehicle. In a further embodiment, however, the lighting device can also be implemented separately from the vehicle at a suitable position along the route.

[0017] Furthermore, with a view to a particularly compact and thus easy-to-handle device and method, the illumination device can be formed integrally with the detector or in a module with the detector. In this case, an integral illumination / detector head can be realized, which comprises both the illumination device and the detector. The detector can

[0018] In a particularly simple design, the detector can be equipped with a monochrome camera, which can capture one or more images at predefined times. Such a camera can also be used in a simple and economical way to detect and / or read codes arranged on the surface for position determination, with monochrome cameras typically being used for this purpose. In this respect, the detector's monochrome camera can perform a dual function, and it is cost-effective to eliminate the need to use two separate cameras for guidance and position determination.

[0019] Preferably, the striped marking extends parallel to the track. Alternatively, the striped marking or the lanes or stripes can extend transversely or diagonally to the direction of travel. Such striped markings can usually be easily detected with a detector.

[0020] Particularly advantageously, the multiple tracks or stripes can have different remission spectra. This allows for a particularly individual and thus meaningful combination of illumination and remission to be created, ensuring particularly reliable identification of one or more markings, tracks, or stripes by the detector.

[0021] In a specific embodiment, when using three adjacent tracks or stripes, two tracks or stripes—preferably the two outer tracks or stripes—can exhibit the same remission spectrum. Using three adjacent tracks or stripes, a particularly high degree of independence from the color of the background or floor can be achieved, thus enabling particularly reliable identification of one or more markings, tracks, or stripes by the detector.

[0022] Furthermore, with a view to particularly reliable identification of one or more markings, tracks, or stripes, and thus with a view to particularly safe vehicle guidance, the detector can detect the number of individual tracks or stripes and / or the width of each individual track or stripe. This allows for particularly good discrimination against "false markings" or "false tracks or stripes," which often vary greatly in number and / or width, if the number and / or width of the individual tracks or stripes is known.

[0023] In a further advantageous manner, the marking can comprise individual code elements. This allows for an economical combination of markings for guidance and code elements for position determination. Such a combination is advantageous, for example, when space is limited on a surface.

[0024] In principle, the position of the vehicle and / or the detector can be determined relative to the marking, in particular to a lane or stripe. In this case, positioning or position determination based on the marking or based on a lane or stripe in the transverse direction - Y direction - to the lane direction or direction of travel - X direction - of the vehicle is advantageous. A Y position resulting from this can reliably enable navigation using the marking, in particular based on a lane or stripe. In principle, the aim of position determination is to reliably obtain a Y position, i.e. a position transverse to a lane or stripe, which does not change depending on the lighting or when the lighting changes.

[0025] To implement a particularly customized lighting scenario, the predefined sequence of the first and second illumination lights can be irregularly sequenced or alternate between the first and second illumination lights. This allows for particularly reliable identification of a marking and thus guidance of a vehicle.

[0026] In principle, there are different ways to implement illumination using the illumination device. In a specific embodiment, the first and / or second illumination light can be monochromatic or can have multiple wavelengths or a wavelength spectrum. This depends on the specific application. With monochromatic illumination light, particularly reliable and secure detection of markings by the detector is possible.

[0027] Advantageous aspects and features of embodiments of the present invention: The detector used in the method and device can comprise a camera system with a monochrome camera. A color camera is not required. This means that images are captured in grayscale. This fundamentally does not allow for clear color recognition for vehicle guidance or lane tracking. Many, quite different colors are represented with the same gray values. Thus, additional features are used for lane tracking.

[0028] For example, two illumination colors or wavelengths can be used, which can be switched on and off alternately or in a predefined sequence and for a specific time period. This color or wavelength switching is used for marking or lane detection. The alternating illumination fades out or shows parts of the marking or the entire marking, resulting in different images when captured by the detector or camera depending on the illumination color or wavelength.A suitably selected detector or decoder within the detector, or a suitably selected evaluation device within the detector or camera, does not know which illumination color or wavelength has been selected for the marking by a security chip or corresponding control device, but can only derive this information from the image or image recording and the correspondingly read information. Thus, the detector, decoder, evaluation device, or camera essentially acts as a "black channel" between the secure information in a marking and a security chip or corresponding control device that performs the process or evaluation of security functions.

[0029] In embodiments of the present invention, for example, two colors of code elements or codes or bands or tracks can be used to define a multi-colored track band or a multi-colored marking or track. For this purpose, two or three colored bands or stripes can be applied next to each other on a substrate or floor. The changing illumination can then create a scene change depending on the illumination light or lighting, and the marking or track can thus be clearly identified. In this case, after an initial detection of the marking or track, the position of the marking or track can be determined with each recorded image or each individual detection process.

[0030] Embodiments of the present invention enable unambiguous detection of a marking or correct track through constantly changing images. "False tracks" are clearly filtered out, as they generally do not change significantly with the illumination color.

[0031] There are now various possibilities for advantageously embodying and developing the teaching of the present invention. Reference is made, on the one hand, to the dependent claims and, on the other hand, to the following explanation of preferred embodiments of the method according to the invention and the device according to the invention with reference to the drawing. In conjunction with the explanation of the preferred embodiments with reference to the drawing, generally preferred embodiments and developments of the teaching are also explained. The drawing shows: Fig. 1 shows a schematic representation of an embodiment of a design of a single-stripe marking for use in the method according to the invention, Fig. 2 shows a schematic representation of an embodiment of a design of a two-stripe marking for use in the method according to the invention, Fig. 3 in a schematic representation the scene in the lower part of the Fig. 2, but here with a light background, Fig. 4 shows a schematic representation of an embodiment of a design of a three-stripe marking for use in the method according to the invention and Fig. 5 shows a schematic representation of the scene in the lower part of the Fig. 4, but here with a light background.

[0032] Fig. 1 shows a schematic representation of an embodiment of a single-stripe marking for use in the method according to the invention, wherein in the left part of the Fig. 1 a reddish trace and alternatively in the right part of the Fig. 1 a blue trace is shown. In the lower part of the Fig. Figure 1 shows how the detector with a monochrome camera perceives the respective lanes when illuminated with red and blue light. When the reddish lane is illuminated with red light, the detector perceives nothing. When the reddish lane is illuminated with blue light, however, the detector perceives a dark stripe. For the blue lane shown on the right, the detector perceives nothing when illuminated with blue light. When illuminated with red light, however, the detector perceives a dark stripe. The respective lanes or stripes extend along a predefined path to guide a vehicle.

[0033] When the illumination changes with different illumination light in an irregular sequence—alternating between red and blue illumination light—the scene and the detector's perception change with each illumination change. This allows the mark or track to be clearly identified as a mark or track and distinguished from "false tracks" or "dummy tracks."

[0034] When using only one lane or lane color, the lane will be detected or not depending on the illumination color. Different suitable colors can be used, such as SIL colors like a code tape. When using other suitable colors, the detector's perception also varies depending on the illumination color.

[0035] Fig. Figure 2 shows a schematic representation of an embodiment of a two-lane marking for use in the method according to the invention, whereby a lane is realized with a combination of two adjacent individual stripes, which extends along the predeterminable route for guiding the vehicle. The left stripe is reddish and the right stripe is blue. Fig. Figure 2 further shows the perception of the track by a detector with a monochrome camera under different illumination conditions, namely red illumination light on the one hand and blue illumination light on the other. With red illumination light, the blue stripe is perceived as a dark stripe, and with blue illumination light, the reddish stripe is perceived as a dark stripe by the detector.

[0036] In the lower part of the Fig. Figure 2 shows the detector's perception of the track, with the track positioned against a dark background. The track can be clearly identified by a "jump" in the detector's perception—from one stripe to the next—in a Y direction, caused by a change in illumination from red to blue. For unambiguous identification, it is useful to previously capture several corresponding images with different illumination levels.

[0037] Fig. 3 shows a schematic representation of the scene as shown in the lower part of the Fig. 2, but with a bright background. Here, too, the track can be clearly identified by a "jump" in the detector's perception—from one stripe to the next—in a Y direction, caused by a change in illumination from red to blue. For clear identification, it is also useful to take several corresponding images beforehand with different illumination levels.

[0038] Fig. Figure 4 shows a schematic representation of an embodiment of a three-stripe marking for use in the method according to the invention, whereby a lane is realized with a combination of three adjacent individual stripes, which extends along the predeterminable route for guiding the vehicle. The left and right stripes are reddish, and the middle stripe is blue. Fig. 4 also shows the detection of the track by a detector using a monochrome camera under different lighting conditions, namely red illumination on the one hand and blue illumination on the other. With red illumination, the blue stripe is detected as a dark stripe, and with blue illumination, the reddish stripes are detected as dark stripes by the detector.

[0039] In the lower region of the Fig. 4 shows the detection of the track by the detector, where the track is arranged on a dark background. Here, the track can be clearly identified based on a change in detection by the detector - from two bright stripes to one bright stripe - caused by changing the illumination from red to blue light.

[0040] Fig. 5 shows a schematic illustration of the scene as in the lower region of the Fig.4, but here with a light background. Here, too, the track can be clearly identified by a change in the detector's perception—from one dark stripe to two dark stripes—created by changing the illumination from red to blue.

[0041] If the track is designed with at least three stripes, independence from the color of the surface or ground is guaranteed.

[0042] It is generally possible to create a track with more than three stripes or colored stripes. This results in a clearer contrast with the background or substrate. Likewise, information can be encoded using different combinations of the tracks or colored stripes. For example, the detector can report back how many stripes the track contains, thus providing information about the respective distance. Encoding using different widths of the colored stripes is also possible.

[0043] The tracks or colored tracks can be implemented in various ways. For example, a tape, such as a PVC tape, can be printed with different colors. Alternatively, the tape can be made of a desired color based on its base material and then printed with another color. Such a track is inexpensive and quick to apply and easy to remove. Furthermore, curved installation is simple. The tape can also be made using polycarbonate.

[0044] As an alternative to a tape, a track or color track can be created by painting, for example, with adjacent stripes. In the case of a track with three stripes, the outer color can be painted over the entire surface first, followed by a layer of paint in the middle of the stripes. This type of track is durable, robust, and also suitable for outdoor use to a limited extent.

[0045] As a further alternative, a track can be realized using color-printed metal strips, such as aluminum strips. This also provides a permanent track. The manufacturing method can include sub-anodized printing.

[0046] As a further alternative, both lane colors, i.e., both colored stripes, can be realized as strips made of a thermoplastic. These strips are placed side by side in two or three stripes and fused to the substrate by heating. Fusing into a floor groove is also possible. This creates a very robust and durable marking that is also suitable for outdoor use.

[0047] With regard to further advantageous embodiments of the method according to the invention and the device according to the invention, reference is made to the general part of the description and to the appended claims in order to avoid repetition.

[0048] Finally, it should be expressly pointed out that the exemplary embodiments described above serve only to explain the claimed teaching, but do not limit it to the exemplary embodiments.

Claims

[1] Method for guiding a vehicle on a surface, wherein the vehicle is guided along a predeterminable route by means of a marking arranged at least in sections on the surface and a detector designed to detect the marking and assigned to the vehicle, wherein, in order to detect the marking on the surface, the marking is illuminated by means of an illumination device with a first illumination light and a second illumination light of different wavelengths and each with a predeterminable duration in a predeterminable sequence, wherein the wavelength of the first illuminating light and the wavelength of the second illuminating light are selected such that the marking is recognizable by the detector due to its definable remission spectrum when illuminated with the first illuminating light with a brightness or darkness that differs from the brightness or darkness when illuminated with the second illuminating light, wherein a corresponding detection result determined by the detector is used to guide the vehicle along the route and wherein the marking is strip-shaped with one track or several tracks or stripes. [2] Method according to claim 1, characterized by that the marking is recognizable by the detector due to its definable remission spectrum when illuminated with the first illumination light and not recognizable when illuminated with the second illumination light or vice versa. [3] Method according to claim 1 or 2, characterized by that the detection result is used to determine whether the vehicle is still in a definable spatial or planar area around the marking or is still at a definable distance from the marking. [4] Method according to one of claims 1 to 3, characterized by that the lighting device is assigned to the vehicle, arranged on the vehicle or integrated into the vehicle. [5] Method according to one of claims 1 to 4, characterized by that the illumination device is formed integrally with the detector or in a module with the detector. [6] Method according to one of claims 1 to 5, characterized by that the detector has a monochrome camera. [7] Method according to one of claims 1 to 6, characterized by that the striped marking extends parallel to the route. [8] Method according to one of claims 1 to 7, characterized by that the multiple tracks or stripes have different reflectance spectra. [9] Method according to one of claims 1 to 8, characterized by that when using three adjacent tracks or stripes, two tracks or stripes - preferably the two outer tracks or stripes - have the same remission spectrum. [10] Method according to one of claims 1 to 9, characterized by that the detector detects the number of individual tracks or stripes and / or the width of the individual tracks or stripes. [11] Method according to one of claims 1 to 10, characterized by that the marking contains individual code elements. [12] Method according to one of claims 1 to 11, characterized by that the predeterminable sequence of first and second illumination light has an irregular sequence or an irregular alternation of first and second illumination light. [13] Method according to one of claims 1 to 12, characterized by that the first and / or the second illumination light is or is monochromatic or has or has multiple wavelengths or a wavelength spectrum. [14] Device for guiding a vehicle on a surface, in particular for carrying out the method according to one of claims 1 to 13, wherein the vehicle can be guided along a predeterminable route by means of a marking arranged at least in sections on the surface and a detector designed to detect the marking and assigned to the vehicle, wherein for detecting the marking on the surface, the marking can be illuminated by means of an illumination device with a first illumination light and a second illumination light of different wavelengths and each with a predeterminable duration in a predeterminable sequence, wherein the wavelength of the first illuminating light and the wavelength of the second illuminating light are selected such that the marking is recognizable by the detector due to its definable remission spectrum when illuminated with the first illuminating light with a brightness or darkness that differs from the brightness or darkness when illuminated with the second illuminating light, wherein a corresponding detection result determined by the detector can be used by means of a guidance device to guide the vehicle along the route, and wherein the marking is strip-shaped with one track or several tracks or stripes.

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