Snow vehicle

Abstract

The invention relates to a snow vehicle (1) having at least one lighting element for orientation in the surroundings (9) of the vehicle and for optical detection of obstacles (10, 11) and topographical conditions of the surroundings (9), wherein the lighting element is a laser (7, 33) having at least one laser beam (8, 8a, 8b), which projects a pattern having a structure (28, 28a, 28b, 37, 40) on the ground (38) of the surroundings (9), said pattern being distorted in a visually recognizable manner on the obstacle to be detected or on the topographical conditions.

Description

Snow vehicle The invention refers to a snow vehicle with at least one lighting element for orientation in the surroundings. Such a snow vehicle can operate, for example, as a snow groomer for the maintenance of ski slopes and cross-country ski trail, as well as a transport vehicle for the transportation of goods and people on snow-covered ground. For orientation in snow-covered surroundings at night, such a vehicle has, at least, one headlight that illuminates the surroundings and allows the driver to detect obstacles. For example, snow groomers intended for the maintenance of ski slopes may have additional headlights on the driver's cabin to illuminate the area surrounding the ski slope to be maintained at night. DE 10 2011 089 836 A1 shows a snow groomer for treating and modelling snow surfaces, with at least two headlights located in recesses of a front cover. The disadvantage of this lighting is that the surrounding ground becomes blurred with the sky and obstacles are difficult or impossible to detect, especially during harsh weather conditions. Even during the daytime, the driver experiences difficulties orienting himself or herself in the surroundings during harsh weather conditions. An example of this is the so-called whiteout effect: this refers to the appearance of diffused luminosity that produces scattered sunlight when the ground is covered in snow (due to clouds, fog, or snowfall). The strong scattered reflection of sunlight and the extremely high minimum luminance causes a stark reduction in contrast and the entire field of vision appears to be uniformly bright. This results in the disappearance of the horizon, whereby ground and sky merge seamlessly. Even contours or shadows are no longer visible and the observer has the feeling of being in a completely empty, infinite grey space. Whiteouts are a considerable factor of risk in a skiing area: in areas subject to the risk of falls, obstacles or abysses can no longer be recognised. Distances and the steepness of the ground cannot be detected. Even if the vehicle's lighting system is operational at close range, conventional lighting produces only a two-dimensional light, which means that obstacles can only be detected late—or not at all. DE 101 54 635 A1 shows a tillage machine with a sensor device by means of which an area of the soil to be tilled can be scanned in the direction of movement and a signal is generated to adjust the height of the tillage tool, which can be a blade, for example. For this purpose, the sensor configuration comprises a laser transmitter and receiver which emits light beams and analyses the beams reflected from the ground in the receiver in terms of runtime and amplitude to control the tillage tool. The disadvantage of this device is that the sensor configuration is complex and extremely susceptible to weather conditions. In addition, even if the tillage tool enters into operation, the driver still does not know whether he or she is heading for an obstacle, which is why a evasive manoeuvre cannot be timely performed. The task of the present invention is therefore to improve the illumination of such a snow vehicle so that obstacles and topographical conditions near the vehicle can easily be detected. An essential feature consists of the lighting element for orientation in the surroundings of the snow vehicle, said lighting element being a laser with at least one laser beam, which projects a pattern with a structure onto the surrounding ground, said pattern being distorted in a visually recognizable manner on the obstacle to be detected or the topographical condition. By using a laser that projects a defined pattern onto the ground, with at least one sharply focusable laser beam, the driver of the vehicle is therefore able to visibly recognise the surroundings in relation to the object. This object-related recognition allows for the recording of topographic surface characteristics of the surroundings. The presence of an obstacle can be inferred from a deviating displacement or curvature of the image of the beam pattern. Such a laser beam can advantageously be projected over a longer distance, whereby such a long distance can be for example, between 6 to 25 metres in front of the snow vehicle. The primary laser that emits the laser beam is equipped with special optics that optically transform the laser beam so that it creates a specific structure, from its mounted position on the snow vehicle, directed towards the ground, whereby preferably a specially made cut for the lens is used. The wave structure of light enables the finest microstructures to deflect the light. The laser beam is optically transformed by such a lens in a way that it creates the pattern with a defined structure when it is directed towards the ground from its mounted position on the snow vehicle. In alternative, a laser beam can be directed onto the ground by means of a rotating mirror element or a movable optical element, for example. The lasers used on the snow vehicle can be extended and retracted by means of a telescopic arm, for example. The telescopic arm can, for example, be controlled electrically or by means of an electric motorised actuator. The laser according to the invention projects an accurate light pattern onto the ground, which can be visually interpreted by the driver of the vehicle. Three- dimensional objects can therefore be made visible thanks to a light grid generated by the laser and projected onto the ground. Nevertheless, the invention is not limited to this. In addition to a light grid or cross-shaped grid, other structures can also be generated by the laser, such as for example point structures, circular structures, multiple lines, or circles. These structures can be used to detect the depth and / or shape of obstacles or topographical conditions of the surroundings. In a development of the present invention, the laser used is self-levelling, i.e. the laser lines are always 100 percent straight, meaning that the lens compensates the inclined position, when the snow vehicle is in an inclined position. In another embodiment of the invention, the laser control system includes a lens which allows the laser to be oriented in an extremely precise manner (north, west, south, east). The gyroscope sensor allows to accurately identify changes in direction. When this information is combined with the measurement of distances, this can be used to determine the current location. For example, if the snow vehicle is driving in a valley with no available GPS, the gyroscope turns on and provides the missing information. Such a sensor can detect the tilt or inclination of the snow vehicle and take appropriate countermeasures via the laser control. In this way, the light pattern on the ground always outlines the desired structure. If a vehicle heads towards an uneven object in the landscape or an object such as a tree stump, the cross grid projected onto the ground by the laser is defined in three dimensions. This results in a spatial deformation of the laser grid lines, which change in terms of the distance between each other or are bent. This allows to ultimately infer the type of object set in front of the snow vehicle, as well as the object dimensions. Surface geometries can be distinguished and identified with the laser according to the invention. According to the state of the art, such object recognition would not be possible with a diffuse incident light, such as that emitted by a halogen headlamp. A red laser light is preferable, as this suppresses the ambient light and the laser lines are more visible. Nevertheless, the invention is not limited to this. The use of a different colour scheme for the laser, such as green or blue, is also claimed with the present invention. Such a colour can be produced, for example, by upstream colour filters. The structure projected onto the ground moves together with the snow vehicle in the direction of movement; it is nevertheless slower than the vehicle, creating the effect that the vehicle moves over the pattern. The advantage of moving over the pattern, besides providing better orientation, among other things, is that the displayed pattern does not flicker and thus avoids the driver getting distracted by such a flicker. The laser projection on the ground is controlled depending on the driving speed v, the steering angle <semantics>φ<annotation encoding="application / x-tex">\varphi< / annotation>< / semantics> and the selected gear G, as well as by inertial sensors which detect the inclination of the snow vehicle on the terrain. This allows to react to the steering angle so that the laser always shines in the direction of movement. If the driver changes to reverse gear, for example, at least one laser on the rear of the snow vehicle is switched on and the surface of the rear surrounding is illuminated. Irrespective of this, it is also possible for the driver of the snow vehicle to manually determine which area in the immediate surroundings of the snow vehicle should be covered. In a further development of the invention, at least one side laser is placed on the side of the driver's cab. This side laser can also be used to project a grid-like pattern onto the ground. Nevertheless, the invention is not limited to this. A circular structure can also be projected onto the ground from the laser. Depending on the size of the circle, the driver can infer the distance to an object. If the driver steers along the edge of a forest, for example, the circle projected onto the trees is smaller than if the laser beam is emitted onto an open area. The subject-matter of the present invention results not only from the subject-matter of the individual patent claims, but also from the combination of the individual patent claims. Any information and features disclosed in the documents, including those disclosed in the summary, and, in particular, the spatial arrangement outlined in the drawings, are claimed to be essentially inventive to the extent that they are - on an individual basis or in combination - new compared to the state of the art. The invention is explained in greater detail below, with drawings showing several embodiments. The drawings and their descriptions exhibit additional essential features and advantages of the invention. In those instances where individual items are designated as "essential for the invention" or "important", this does not imply that these items must necessarily be the subject of an independent claim. This is determined solely by the currently valid version of the independent patent claim. The figures show: Figure 1: Front view of the snow vehicle Figure 2: Side view of the snow vehicle Figure 3: Perspective view of the laser Figure 4: Side view of the rotating laser, 1st variant Figure 5: Top view of the rotating laser, 1st variant Figure 6: Overview of the rotating laser, 2nd variant Figure 7: Side view of the rotating laser, 2nd variant Figure 8: Top view of the snow vehicle Figure 9: Top view of the snow vehicle with the searchlightFigure 10: Front and side view with the searchlight Figure 11: Block diagram Figure 1 shows a snow vehicle 1, which can move on two undercarriages 4 that can be controlled independently of each other on the ground 38 of the surrounding area 9. The snow vehicle 1 includes a driver's cab 5, with room for at least one driver who steers the snow vehicle 1. The driver's cab 5 has a windscreen 32 through which the driver can monitor the surroundings 9. In this embodiment example, two lasers 7, which emit laser beams 8 in the direction of movement of the snow vehicle 1, are placed above the driver's cab 5, as well as two side lasers 33, which emit the laser beams towards the side of the snow vehicle and onto the ground 38. The laser beams 8 are thus projected onto a defined area of the ground 38. When the snow vehicle 1 approaches an object in the direction of movement, shown here as tree stump 10, the laser beams 8 illuminate this object and, as a result of the short distance of the laser beams when it hits the object, the laser beams 8, which previously shone on the ground 38, are no longer as long as they were before, and now form the beams 8a, 8b. Depending on the distance of the laser 33 from the tree stump 10, the laser beams 8a, 8b are of different lengths and shorter than the laser beams 8, which continue to beam unobstructed onto the ground 38. Such a difference between the individual laser beams 8, 8a, 8b allows the driver of the snow vehicle to visually distinguish this, so the driver can detect the object in the direction of movement and, if necessary, perform an evasive manoeuvre. When the snow vehicle 1 reaches the trench 11, the laser beams 8 from laser 7 illuminate this obstacle. As a result of the extended distance of the laser beams shining through the object, the length of the laser beams 8, which previously shone on the ground 38, is also extended and now forms the beams 8a', 8b'. Depending on the distance of the laser 7 from the area of the trench 11, the laser beams 8a', 8b' are of different lengths and longer than the laser beams 8, which continue to beam unobstructed onto the trench 11. Such a difference between the individual laser beams 8, 8a', 8b' allows the driver of the snow vehicle to visually distinguish this, so that the driver can detect the object in the direction of movement and, if necessary, perform an evasive manoeuvre or perform maintenance on the ground 38 at this point. This enables the driver to detect an obstacle or a topographical change on the ground from a spatial deformation of the projected laser beams. Figure 2 displays a side view of the snow vehicle 1 from figure 1, the laser beams 8 emitted from laser 7 being projected as a cone of light onto the ground 38. The snow vehicle 1 has a blade 3 on the front end for removing the snow, which allows to level the uneven surface of the ground 38. In addition to the laser 7, which lights up in the direction of movement, at least one side laser 33 is also attached to the side of the driver's cab 5, this side laser 33 illuminating the surroundings next to the snow vehicle. Figure 3 shows the laser 7 (or 33) used, which emits a primary laser beam 35 from a primary body 30. The primary laser beam 35 passes through the lens 31, wherein the lens 31 shapes the laser light so that the laser beam generates a cross-shaped structure 16. This cross-shaped structure 16 consists of two intersecting, fan- shaped laser beams, which are at an angle 17, 18 to each other. In the example shown here, both angles 17, 18 are ninety degrees, so that two axes at right angles are emitted. Figure 4 shows another embodiment of the present invention, this time using a drum body 25, which rotates around the axis of rotation 24 in the direction of arrow 21. Primary lasers 30 are mounted at specific distances on the drum body 25, which lasers emit the laser beams through different lenses 26, 27. In the example shown here in figure 4, the lenses 26 emit a horizontal line pattern, while the lenses 27 emit a vertical line pattern. If a laser beams passes through these lenses, these project it horizontally or vertically, depending on the lens 26, 27. Since this is a rotating drum body, panels 29 are attached to the outer circumference of the drum body 25 to protect the driver of the snow vehicle and to allow orientation in the area to be exposed to the beams. The panels 29 also have a protective effect against snow and icing. Figure 5 shows a top view of the drum body 25. The panel 29 does not enclose the drum body 25 by 360° degrees but has an opening 36 which can be emitted onto the surroundings 9 by the laser beams 8. In a further development of the invention, according to Figures 4 and 5, the individual primary lasers 30 can be controlled by sliding contacts: in this way, the rotating lasers can emit a beam 8 only when they take on a specific position and are inactive without contact. Figure 6 displays a further development of the invention, where a primary laser 30 directs a primary laser beam 35 onto a drum 20. This is surrounded by a panel 29, which protects the sensitive drum body from snow and ice and has a front opening 36 through which the laser beams 8 can be emitted into the surroundings 9. The drum 20 rotates around the axis 24 in the direction of arrow 21 and has a glass element 22 around its outer circumference in which several mirror elements are embedded. These mirror elements reflect the primary beam 35 at a specific angle and emit it as laser beams 8. According to Figure 7, the glass element 22 has a surface that is cut in a way that an emitted primary laser beam 35 is reflected by the mirror element 23 embedded in the glass element 22 and is shaped in such a way that it emerges from the drum 20 with a cross-shaped structure. The laser beams 8 formed this way hit the ground 38, where the lattice-shaped structure becomes visible. The grid consists of the horizontal transverse lines 28, as well as the longitudinal lines 37 crossing the transverse lines 28. Figure 8 shows a top view of the snow vehicle 1. The snow vehicle 1 travels in the direction of movement 39 over the ground 38. Through the lasers 7 mounted on the roof of the driver's cab, snow vehicle 1 illuminates the ground 38. Thanks to the special shape of the laser beams 8, a grid pattern 40 is projected onto the ground 38. The grid pattern 40 consists of the transverse lines 28 and the longitudinal lines 37 crossing the transverse lines 28. When snow vehicle 1 reaches the trench 11, the grid pattern 40 that is projected in front of the snow vehicle is deformed, resulting in a spatial deformation of the transverse and longitudinal lines 28, 37. The driver of the snow vehicle can visually recognise such a spatial deformation, meaning that he or she can detect an obstacle or a topographical change on the ground 38. Through the trench 11, the transverse lines 28 of the grid pattern 40 are represented as curved lines 28a, 28b, while the longitudinal lines 37 continue to hit the ground 38 straight. The different curvatures of the transverse lines 28a, 28b allow the driver to infer the depth and perimeter of the trench. Figure 8 displays another embodiment example where the laser beams 8 hit a three-dimensional object 10, shown here as a tree stump. The position of the object 10 in the beam direction of the laser beams 8 shortens the path of the laser beams 8 so that the shortened beams 8a, 8b hit the object. By changing the beam length and illuminating the object 10 via the laser beams 8a, 8b, the driver can detect the object and the size of the object 10 and perform a suitable manoeuvre to avoid the object. In addition to the lasers 7, the side lasers 33 are located on the driver's cab 5, these lasers illuminating the side areas of the surrounding area 38 next to the snow vehicle 1. Figure 9 shows a snow vehicle 1 with a searchlight 41, which projects a narrowly defined grid pattern 40 onto the ground 38. The searchlight 41 is operated manually and can be turned and swivelled in all directions. In addition, the grid pattern 40 can be enlarged in the direction of arrow 42. Figure 10 shows a side and front view of searchlight 41, which is mounted on a long, adjustable telescopic arm 49 and extends through the cabin's roof 46. The searchlight 41 can be operated via a handle 44 and can be adjusted in the swivel angle 47 and / or in the direction of rotation 48. A switch 45 can be used to switch the searchlight on and off, and to set the magnitude of the grid pattern. The searchlight 41 is equipped with a photo laser diode 43 which creates a grid pattern. The cross-shaped structure 16 of the grid pattern consists of two intersecting, fan-shaped laser beams, which are at an angle 17, 18 to each other. In the example shown here, both angles 17, 18 are ninety degrees, so that two axes at right angles are emitted. Figure 11 displays a block diagram of the switch used for the snow vehicle 1. A signal converter 50 converts the signals of the vehicle electronics (CAN BUS) into PLC-compatible signals. The signals 14 from snow vehicle 1, such as speed, direction of movement, steering angle, position, and inclination, are this way converted into PLC control signals. A PLC CPU 19 processes all input signals and performs all necessary calculations to subsequently issue the commands and output signals to the individual components. The PLC CPU 19 calculates the target values 60-63 from the fed in actual values and transmits them to the various controllers 52-55. The controllers 52-55 then use the motor voltages 56-59 to control the motor used to move the two lasers 7a, 7b or the searchlight 41. These parts each have a drive motor 68-71 (DC or AC gear motors, depending on requirements) with an assigned rotary encoder 64-67. A transverse adjustment 75 serves as a swivel motor for the deflections of the grid pattern system, so that the grid pattern that moves in the direction of movement does not collapse in the grid structure during a turn. The rotary encoders 64-67 measure the position, speed and direction of the motors and can be used for various control tasks. They transmit signals that are processed by the PLC CPU 19. Depending on the type of encoder used (impulses, sine waves, voltage, etc.), different control systems can be implemented. For example, if the snow vehicle accelerates, the projection units 72-74 of the lasers 7a, 7b or the searchlight 41 are controlled in such a way that the grid pattern 40 moves towards the snow vehicle 1 at a relative speed. The driver of the vehicle therefore has the impression that he or she is driving over the grid pattern. If the snow vehicle slows down, the relative speed of the grid pattern is also reduced. The advantage of generating a dynamic grid pattern is that the generated grid pattern is projected in a stable manner onto the surface to be driven over, irrespective of vehicle oscillations and rolling movements. To control the laser, for example, the rotation speed of drums 20 and 25 can be adjusted, as displayed in figures 5 and 6. The entire system is controlled by a control unit 51 from which all adjustable parameters can be selected, changed, and visualised (displayed). A power supply module 15 is used to supply power to all components. Drawing legend 1. Snow vehicle 31. Lens 2. 32. Windscreen 3. Blade 33. Side laser 4. Undercarriage 34. 5. Driver's cab 35. Primary laser beam 6. Lighting body 36. Opening (part of 29) 7. Laser 7a 7b 37. Longitudinal lines 8. Laser beam 8a, 8b, 8a', 8b' 38. Ground 9. Surrounding 39. Direction of movement 10. Object 40. Grid pattern 11. Trench 41. Searchlight 12. Rotary encoder 42. Direction of the arrow 13. Signal 43. Photo laser diode 14. Signal 44. Handle 15. Power supply module 45. Switch 16. Cross 46. Cabin roof 17. Angle 47. Swivel angle 18. Angle 48. Direction of rotation 19. PLC CPU 49. Telescopic arm 20. Drum 50. Signal converter 21. Direction of the arrow 51. Control unit 22. Glass element (specially cut) 52. Controller 23. Mirror element 53. Controller 24. Axis of rotation 54. Controller 25. Drum 55. Controller 26. Lens 56. Motor voltage 27. Lens 57. Motor voltage 28. Transverse line 28a, 28b 58. Motor voltage 29. Panel 59. Motor voltage 30. Primary laser 60. Target value 61. Target value 69. Drive motor 62. Target value 70. Drive motor 63. Target value 71. Drive motor 64. Rotary encoder 72. Projection unit 65. Rotary encoder 73. Projection unit 66. Rotary encoder 74. Projection unit 67. Rotary encoder 75. Transverse adjustment 68. Drive motor

Claims

1. A snow vehicle having at least one lighting element for orientation in the surroundings of the vehicle and for optical detection of obstacles and topographical conditions of the surroundings, wherein the lighting element is a laser having at least one laser beam, which projects a pattern having a structure on the ground of the surroundings, said pattern being distorted in a visually recognizable manner on the obstacle to be detected or on the topographical conditions, wherein a. the vehicle is a snow vehicle for the maintenance of ski slopes and cross- country ski trails; b. the driver of the vehicle performs an object-related optical recognition of the surroundings; and c. the laser is self-levelling via a gyroscope sensor.

2. The vehicle according to claim 1, wherein a determination of the current location is performed by a gyroscope that detects changes in direction in conjunction with measuring distances.

3. The snow vehicle according to any one of claims 1 or 2, wherein the laser projection onto the ground can be controlled as a function of the driving speed, the steering angle, the selected gear, as well as via inertial sensors, which detect the inclination of the snow vehicle on the terrain.

4. The snow vehicle according to any one of claims 1 to 3, wherein a lens optically transforms the laser beam in such a way that it generates the pattern with the defined structure from its mounted position on the snow vehicle, directed towards the ground.

5. The snow vehicle according any one of claims 1 to 4, wherein the structure is a grid pattern or a point structure, or a circular structure or a line structure.

6. The snow vehicle according to any one of claims 1 to 5, wherein a side laser, mounted on the side on or on top of the driver's cab projects an additional structure onto the ground beside the snow vehicle.

7. The snow vehicle according to any one of claims 1 to 6, wherein a number of lasers are mounted on a rotatable drum body on the side of the vehicle, the drum body emitting the laser beams through different lenses, whereby at least one of these lenses emit a horizontal line pattern, while the other lenses emit a vertical line pattern.

8. The snow vehicle according to any one of claims 1 to 6, wherein one or more glass elements, in which a number of mirror elements are embedded and which reflect one or more laser beams, are arranged on the outer circumference of a rotatable drum body on the vehicle.

9. The snow vehicle according to claim 8, wherein the glass element has a cut on the surface that allows a reflected laser beam to be formed so that it emerges from the drum with a cross-shaped structure.

10. The snow vehicle according to any one of claims 1 to 9, wherein the lasers are mounted on an extendable and retractable telescopic arm.

11. The vehicle according to claim 10, wherein the telescopic arm is controllable electrically or by means of an electric motorized actuator.