SE533777C2 - Method for calibrating a tilt angle sensor on a vehicle, method for calibrating a distance scanner on a vehicle and vehicles - Google Patents

Abstract

SUMMARY The present invention relates to an apparatus and method for calibrating a hinge angle sensor (110) on a vehicle (100) comprising a first (100b) and a second portion (100a) connected to a hinge (107) provided with a hinge angle sensor. (1 10) for measuring an articulation angle (d) between the first (100b) and the second portion (100a). According to the invention, the following steps are included: positioning the vehicle (100) so that the articulation angle (d) is approximately 0 °, the articulation angle sensor (110) indicating a measured articulation angle; generating an image having a hinge angle dependent position (125, 126); projecting the image on the object (124); determining the first position (125) of the image on the object (124); moving the vehicle (100) toward or away from the object (124) so that the articulation angle sensor (110) continues to display the same measured articulation angle; determining the second position (126) of the image on the object (124); and adjusting the zero position of the articulation angle sensor (110). Fig. 3B

Description

25 533 ??? 2 autonomously, at the same time as signals from various sensors arranged on the vehicle are recorded. In step two, a route generation is performed where, based on at least a part of the above recorded sensor signals, a coordinate system is created, which comprises the area in which the vehicle is to be driven. The road that the vehicle travels during the route recording is described in this coordinate system together with information about, for example, the appropriate speed for different parts of the route.

The third step consists of playback, where coordinate information regarding how the vehicle was driven manually. and a representation of the surroundings is used to autonomously drive the vehicle along the same distance as the vehicle in step one was driven manually.

During autonomous play (tramming) of a route it is determined, e.g. by estimation, the position of the vehicle in the coordinate system in which the representation of the surroundings and the desired route are fi niered.

The representation of the surroundings used in the position determination may consist of a map representation of the walls in the tunnels in which the vehicle is to be driven autonomously, and may either be generated in advance or generated by means of the above-mentioned collected sensor information. Thus, when the route generation has reached its end, a representation may have been generated.

Regardless of how the representation of the environment has been generated, in systems of the above type it is very important that it constitutes a correct description of the environment, as if it for some reason constitutes a poor representation of what the environment really looks like in corresponding parts of the route, . there is a risk of the vehicles getting lost or driving incorrectly and causing damage to the vehicles or the environment.

The processes used to generate such representations of the environment can be complicated and many things can go wrong. As mentioned above, the map generation can be based on sensor information from many different sensors. Examples of such sensors consist of waist angle sensors or other 10 15 20 25 533 TP? 3 articulation angle sensors, sensors for measuring the distance traveled, and one or more laser distance scanners or other distance scanners.

One of the problems with this system is that it is sensitive to how well the joint angle is calibrated. In order for the vehicle to be able to follow the recorded route with high precision, it is important that the joint angle is correctly calibrated, i.e. that the right angle is known at which a longitudinal displacement of the vehicle does not result in a lateral movement or a change of the angle between the lateral centerline of the vehicle and an external reference. Suitably, the joint angle sensor is calibrated so that its zero position coincides with said joint angle.

The precision requirement for the vehicles to be able to follow a recorded route at speeds of the order of 4-5 m / s or higher while maintaining route tracking precision is that the joint angle calibrated with a tolerance of the order of a few tenths of a degree. An example of a certain trajectory algorithm is that a calibration error of 1 ° corresponds to 25 cm lateral offset on the trajectory at 5 m / s. The corresponding figure at 8.3 rn / s is 0.7 m, as the offset grows. This exceeds the precision requirement for a standard LH D vehicle that is driven manually. exponentially. precision requirements wide Similarly, it is sensitive to how well the distance scan frames are calibrated.

The precision requirement here is a tolerance of the order of a couple of tenths of a degree.

There is thus a need for a calibration procedure that meets these high precision requirements.

DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a method for calibrating a joint angle sensor with a high accuracy. This object is achieved with a method with features according to claim 1.

The present invention relates to a device and a method for calibrating a hinge angle sensor on a vehicle, which vehicle comprises a first portion and a second portion connected to a hinge, which hinge is provided with a hinge angle sensor for measurement. of a joint angle between the first portion and the second portion. According to the invention, the method comprises the steps of: Positioning the vehicle so that the articulation angle is approximately 0 °, the articulation angle indicating a measured articulation angle. Generating an image that has a hinge angle dependent position.

Projection of the image on a first object. Determining the first position of the image on the first object. Movement of the vehicle a distance towards or from the first object, so that the articulation angle sensor continues to show substantially the same measured articulation angle. Determining the second position of the image on the first object.

Adjustment of the zero position of the articulation angle sensor when a distance between the first position of the image and the second position is greater than the distance corresponding to the least acceptable error in the articulation angle measurement for the performed movement.

The advantages of this method are that an accurate calibration is obtained in a fast and safe way and can be performed by a single operator.

According to an embodiment of the invention, there is also included a device and a method for calibrating a distance scanner on a vehicle, which vehicle comprises a first portion and a second portion connected to a hinge, which hinge is provided with a hinge angle sensor for measuring a hinge angle between it. the first party and the second party. According to the invention, the method comprises the steps of: Calibrating the joint angle sensor. Position the vehicle so that the joint angle indicates zero position. Generating an image in a jam line. Projection of the image on a second object. Adjusting the zero position of the distance scanner so that the other object is in the zero position of the distance scanner.

The advantages of this embodiment are that an accurate calibration is obtained in a fast and safe manner and can be performed by a single operator.

DESCRIPTION OF THE DRAWINGS The invention will now be explained in more detail with the aid of preferred embodiments and with reference to the accompanying drawings, in which: Figs. 1A-C show a vehicle from the side and from above, respectively, in which the present invention can be used to advantage. 10 15 20 25 533 77? Fig. 2 shows an example of a mine where the present invention can be advantageously applied.

Fig. 3A-B shows a device for calibrating a hinge angle sensor. Fig. 4 shows a fate diagram for calibrating a hinge angle sensor. Fig. 5A-C shows a device for calibrating a distance scanner. Figs. 1A-C show a vehicle 100 from the side and from above, respectively. The vehicle 100 constitutes a truck to which the present invention can be advantageously applied.

The vehicle 100 comprises a bucket 101, wheels 102-105 connected to wheel axles 113, 114, and a control unit 106, which controls various of the functions of the vehicle 100. As shown in fi g. 1b, the vehicle is a hinge vehicle, where a front portion 100a is joined to a rear portion 100b via a hinge 107. The hinge 107 can be set to the desired hinge angle d. these signals to the control unit 106. The vehicle may also include e.g. a wheel rotation sensor 108 such as e.g. an odometer, which can be arranged at the shaft emanating from the transmission and emit signals representing the rotation of the drive wheels and / or the distance traveled. Further, the vehicle 100 includes an engine or other device (not shown) for moving the vehicle 100.

The vehicle 100 further comprises a front 111 and a rear 112 laser distance scanner in each laser housing, which laser distance scanners 111, 112 are also connected to the control unit 106 and emit sensor signals representing measured distances, i.e. distance to the nearest obstacle that stops the path of the laser beam. The laser distance scanners 111, 112 may, for example, be arranged to measure the distance in certain directions in an angular range. In the present example, laser distance scanners are used which measure the distance to the nearest object in the longitudinal direction of the front portion 100a forward (respectively in the longitudinal direction of the rear portion 100b backward) and the distance to the nearest object 10 15 20 25 30 533 77? 6 (as rock) for habit full degree at 90 ° from the respective longitudinal direction. Each respective laser distance scanner thus measures distances at 181 respective measuring points. As will be appreciated, of course, laser distance scanners that measure distances in significantly different directions can be used, as well as those that measure distances in significantly fewer directions. Likewise, a single omnidirectional laser can be used instead. In an alternative exemplary embodiment, only the scanner that is currently “pointing” in the direction of travel is used (ie the front 111 if the vehicle is driven forwards and vice versa). It is also not essential for the invention that the directions are measured via laser distance scanners, but arbitrary distance meters can be used, as long as these can provide distance measurements with acceptable accuracy. Examples of other types of possible distance meters consist of distance meters based on radar technology or sonar technology.

Furthermore, in the exemplary embodiment shown here, a distance scanner is used which measures distance in only one plane (the horizontal plane of the vehicles). It should be understood, however, that distance scanning can take place än more than one plane, e.g. also in a vertical plane for measuring tunnel height, or other planes lying between horizontal and vertical planes, and thus position estimation. In a further alternative exemplary embodiment, one or more of the side-facing scanners may instead be used, or in addition thereto. further refine the possibilities of a correct Furthermore, the above-mentioned sensors emit sensor signals to the control unit 106 at applicable times, such as e.g. continuously or every 40 ms or more often or less frequently. The controller 106 then uses received signals as will be described below. l fi g. 2 shows an example of a mine where the present invention can be advantageously applied. In the example shown, the vehicle 100 loads rock masses at site A by means of the bucket 101 and then transports loaded masses for dumping at site B. When the vehicle 100 is to be set up for autotramming, e.g. the three-step principle described above is applied, i.e. first a route recording is performed where a sensor signal recording of signals from the above sensors is activated. The loading-transport-dump-return-transfer procedure may be arranged to be performed as a single route, but usually the transfer from A to B is performed as a first separate route and the transfer from B to A as a second separate route. . For recording a route from A to B, the sensor signal recording is thus activated, whereby an operator with the vehicle stationed at point A reverses towards point C to thereby turn the vehicle, whereby transport according to a dashed line is then performed to point B where the route recording is stopped.

Based on the recorded sensor signals, the route is then created, ie how the vehicle is to be driven and at what speed the vehicle should be driven at different parts of the route. As mentioned above, the sensor signals can be read e.g. was 40 ms. If each sensor signal reading were to constitute a route point, the number of route points would be very extensive. For this reason, the route points can instead consist of signals determined at e.g. every half meter the vehicle moved. The data stored for the route is preferably the position, the direction of the vehicle and the desired speed. Thus, a route is obtained which in principle consists of a number of points, where for each point it is stated where the vehicle is to be, what direction it should be and the speed with which it is to be driven during subsequent autotramming.

However, when the vehicle is then to move autonomously along the route, as mentioned above, this information alone is not normally sufficient for the desired movement to be carried out, e.g. p.g.a. that uncertainties in the sensor signals mean that the end position will in all probability deviate from the calculated one, whereby also the start position at the next route will deviate from the original one. For this reason, a representation of the environment is also used, such as e.g. route maps, in order to be able to compare signals measured during the auto tram with the map in order to be able to more accurately determine the position of the vehicle, and to periodically restore uncertainties in the estimated position.

The representation of the surroundings (route maps) can, for example, consist of a coordinate system which can advantageously be local to the specific route and which also. can be created based on the recorded sensor signals. 10 15 20 25 30 533 77? The coordinate system thus only needs to cover the area in which the vehicle is to be driven, and can have its origin where the point on the vehicle that constitutes a reference during positioning, such as e.g. center on the front axle of the vehicle, stops when recording starts. n The road that the vehicle travels during the route recording can then be described in this coordinate system together with information about, for example, the appropriate speed for different parts of the route.

Thus, when the route generation has reached its end, a representation corresponding to that in fi g. 2 has been generated, which can then be used in subsequent route playback. Thus, it can be said that, after the map has been generated, the state of each box in the map is a function of the measured distance of all the laser beams that have hit / passed through the box during the measurements. The map can be represented by a relatively mesh grid, for example with a resolution of 1 cm or 1 dm / square.

As mentioned above, a problem with such maps, regardless of type, is that the environment in which the route is recorded may be such that the quality of the map becomes poor, for example due to the presence of objects or surfaces that absorb or re-reflect the map generation on sensor information from many different sensors such as hinge angle sensor, measured distance and laser distance scanners, and in some cases also information from a gyro that measures the light from the laser distance scanner frames. Wdare based sensors to the direction of travel of the vehicles. If one or more of these sensors provide incorrect information, the map will probably also be incorrect. In addition, detailed geometric information about vehicle construction and sensor placement on the vehicles is needed for the maps to become a relevant representation of the environment.

During the development of the system, a manual method has been used to calibrate the articulation angle sensor 110. This method involves a person standing on the "bumper" behind the vehicle's cooler 100 and creating a line of sight over the center of Iaserhusen 111, 112. By observing how this line of sight moves relatively slightly distant stationary objects when the vehicle 100 is driven a distance of 20-30 m, a measure is obtained of whether the vehicle is straight with the joint. I.e. whether the joint angle starts 10 15 20 25 30 533 77? 9 in its correct zero position, the previously determined line of sight is fixed at one and the same point on the distant object.

If, on the other hand, the joint 7 is slightly angled, the vehicle 100 will turn and the line of sight will no longer point to one and the same point when the vehicle 100 is driven forwards or backwards. By evaluating with this aim line procedure how the vehicle 100 turns at different articulation positions, the position corresponding to the vehicle 100 going straight ahead can be determined, i.e. the angle to be considered as the zero position of the hinge angle.

This procedure has your shortcomings, the most important of which are: 1) In some countries there are rules that do not allow people to stand or hang on the vehicle while driving. 2) The procedure requires at least two people - one driver and one who assesses how the line of sight fl works. 3) The precision will depend on how well the person reading the line of sight can assess how the vehicles turn. 4) The procedure is very time consuming as the vehicle operator and the aimer have to communicate between each test on how to change the articulation angle.

Figures 3A and B show a device for an automated variant of this method. W imagine, compare Fig. 1C, that there is a lateral centerline 115 for the first portion 100b and a lateral centerline 116 for the second portion 100a, where a centerline is a line running midway between the wheels 103, 105, 102, 104. on each portion 100b, 100a and is perpendicular to the wheel axis 113, 114 of each portion. If the angle of inclination u is 0 °, then these center lines 115 and 116 will coincide or be parallel. This insight is used in the embodiment of the invention below. In the example of Figures 3A and B, the laser housings 111 and 112 are arranged on the center lines 115, 116 (compare Fig. 1C), so arrangement on the laser housings 111, 112 is advantageous. A slit laser 121 is mounted on the first laser housing 112 on the first portion 1-00b and an obstacle 122 in the form of a plate or the like with a hole 123 is mounted on the second laser housing 111 on the second portion 100a. Preferably, the hole 123 is a vertical slot which is e.g. about 10 mm wide and about 5-10 cm high. An imaginary jam line 120 passes the slit laser 121 and the obstacle 122. 10. 15 20 25 533 77? The slit laser 121 is designed to generate a laser line in a horizontal plane and has brackets for attachment to the first laser housing 112, so that the center of the slit laser 121 is in the center line 115b of the first portion 100b. and the obstacle 122 are arranged at respective portions 100b, 100a at locations other along the center lines 115, 116 than on the laser housings 111, 112, alternatively arranged in parallel at equal distances from the center lines 115, 116.

It is also possible to use other types of light than slit lasers. In the same way, it is conceivable to use a medium other than light, e.g. other electromagnetic paths, - preferably radar. Furthermore, it is conceivable to use sound, preferably based on sonar technique or some type of particle beam, such as water or paint.

When the slit laser 121 illuminates forward, the obstacle 122 will partially obscure the light, except in the slit 123. This provides a point laser, the point of which can be projected as an image of a first object 124 for calibrating the articulation angle sensor 110.

Of course, a projected image other than a point can be used, e.g. a vertical line or some more complicated image. It would also be possible to create a projection not through a hole, but e.g. along an edge or on both sides of a stick. The word "image" should be interpreted broadly and also include a pattern such as. generated by sound or other means.

The first object 124 can be anything where the image can be seen. It is easiest if the first object 124 is stationary.

It would also be possible to calibrate the hinge angle sensor 110 by selecting any other hinge angle dependent property of the image other than position on the first object 124.

The method for calibrating the articulation angle sensor then becomes, see Fig. 4, that the vehicle 100 'is positioned so that the articulation angle α is approximately 0 ° and so that the aiming line 120 points towards the first object 124, step 210. The articulation angle sensor 110 then indicates a measured articulation angle which should be about 0 °. The dot laser 121, 122 generates a 10 15 20 25 30 533 7 '? 7 11 image in the form of e.g. a point, step 220, which is projected on the first object 124 in a first position 125, step 230. The first position 125 of the image is determined, step 240.

This can be done manually e.g. by memorizing where the image's first position 125 is or by making a selection with e.g. a pen. This can also be done automatically by the first object 124 being sensitive to the light or second medium reaching the first object 124, so that e.g. the first position 125 of the image is stored electronically.

Then the vehicle 100 is moved towards or from the first object 124 perhaps 20-30 meters, without actively changing the joint angle of the vehicle, so that the joint angle sensor 110 always substantially continues to show the same measured joint angle, step 250. The image then reflects after the vehicle's movement in a second position 126, which second position 126 is determined, step 260. If now the joint angle α is in its perfect zero position, then the second position 126 is the same as the first position 125.

But if the trail 107 is slightly angled, then the vehicle 100 will turn slightly and the line of sight 120 will no longer point in the same place on the first object 124, i.e. the image has fl moved to a second position 126. The distance between the first position 125 of the image and the second position 126 of the image corresponds to the error in the previous hinge angle calibration. The direction in which the image has been talar indicates which direction the calibration should take place. Adjustment can then be made of the zero position of the articulation angle sensor 110, step 270, e.g. by changing the offset in the measurement. Normally, if the image of the first object 124 moves to the right of the vehicle, when the vehicle has been driven forward, the vehicle has turned clockwise and the actual zero position of the articulation angle then becomes an angle counterclockwise from the articulated angle measured during the movement.

If the first object 124 can store the image's first position 125 and second position 126, then the calibration can take place automatically, by means of e.g. the control unit 106.

Otherwise, an operator can manually calculate how much the zero position of the articulation angle sensor 110 should be adjusted and in which direction.

After the calibration of the articulation angle sensor 110, the test can be conveniently repeated to check that it was correct. Otherwise, the procedure is repeated until sufficient precision is achieved. Either the vehicle can be driven back and forth on the same 10 15 20 25 30 533 77? 12 area or the vehicle can continue in the same direction with adjustment of the joint angle between each turn. Suitably, the hinge angle sensor 110 is calibrated so that the error becomes less than 0.5 °, preferably less than 0.1 °.

The advantage of calibrating the articulation angle sensor 110 in this way is that only one operator is needed to perform the calibration. Calibration is also faster because the operator does not need to communicate with others.

In addition, the calibration becomes more accurate because a quantitative measure of the calibration precision is obtained.

A well-calibrated hinge angle sensor 110 can also be used to calibrate the vehicle's laser distance scanners 111, 112 or other distance scanners of e.g. type of radar or sonar. In order to make a correct map of the surroundings, it is necessary that also the distance scanner frames 111, 112 are mounted in the correct place and at the correct angle in relation to a reference point and direction of the vehicle 100. That the distance scanner 111, 112 is mounted in the correct place is relatively simple. to measure with satisfactory precision, while it is considerably more difficult to measure if the distance scanner 111, 112 is mounted in the correct direction.

The precision requirement for the direction of the distance scanner 111, 112 in relation to the reference direction of the vehicle 100 is in the order of a few tenths of a degree.

The reference direction is selected from the center line 115, 116. suitably parallel or coincident with During the development of the system, a manual procedure has been used to ensure that the distance scanner frames are mounted in the correct direction. This method involves two people holding up wooden boards in the measuring plane 111, 112 of the respective distance scanners 111, while data from the distance scanning frames 111, 112 are stored in a file. The wooden boards are held so that they form corners corresponding to the corners of the vehicle 100, but offset parallel to the measuring plane of the distance scanner 111, 112.

By analyzing the data stored in said fi 1, with respect to whether the corners registered in the data appear symmetrically, a measure can be obtained of whether the distance scanner frames 111, 112 are mounted in the correct direction. The problems with this procedure are i.a. that it requires fl your people help. In addition, the precision depends on how well those who lift the wooden boards 10 15 20 25 30 535 '77? 13 manages to keep these in a position which gives a correct picture of the vehicle's corner in the laser plane. There is a great deal of uncertainty in the measurement because it assumes that the corners of the vehicle 100 are symmetrically placed with respect to the lateral centerline of the vehicle 100.

Figures 5A-C show a device for calibrating the front distance scanner 111. To calibrate the distance scanner, a line of sight must be known.

The target line 120 in this case should suitably be an imaginary line passing through the distance scanner 111, 112 to be calibrated and coinciding with or parallel to the center line 115, 116 of the portion 100a, 100b of which the distance scanner 111, 112 is arranged. An easy way to find the line of sight is through the method described above for the articulation angle sensor 110, although of course other methods exist. Preferably, the hinge angle sensor 110 is thus calibrated first, step 310 in Fig. 6, before the calibration of the distance scanner 111 takes place.

The same equipment can be used for the calibration of the distance scanner 111 as for the calibration of the articulation angle sensor 110, i.e. a slit laser or the like 121 and an obstacle in the form of e.g. a plate or the like 122 with a slot or the like 123, which together act as a dot laser or the like.

In addition, a second object 140 is used, preferably in the form of a vertical bar. It is also conceivable that the second object 140 is e.g. a large plate with a vertical hole in it. The important thing in this context is to have a second object 140 which makes it possible to easily detect a distance difference between the second object 140 and the surroundings in such a way that the line of sight 120 can be detected . Thus, e.g. a vertical edge acts as other objects 140.

The method of calibrating the distance scanner 111 then becomes to position the vehicle 100 so that the cold-bred joint angle sensor 110 indicates zero position, step 320. A point or other image 143 is generated by the slit laser 121 and the obstacle 122 in the line of sight 120 in the same manner as described above, step 330. Pictures 143. then becomes an indication of where the aiming line 120 is located and which line the distance scanner 111 is to be calibrated along. The second object 140 is placed in the line of sight 120, by making sure that the image 143 is projected on the second object 1015 20 533 ?? 7 14 140, step 340. It may be convenient to place the second object 140 about 10-20 m in front of the vehicle .

The distance scanner 111 then measures the distance to objects within an area 141.

If the distance from the distance scanner to other objects 142 in the vicinity of the aim line 120 is greater than to the second object 140, then a clear marking of the position of the second object 140 in the data from the distance scanner 111 and the distance of the distance scanner 111 relative to the aim line 120 can be determined. . This can e.g. is done by means of an offline analysis, by showing measured laser data on the vehicle's display or via an automatic analysis of the data initiated by the operator. The distance scanner 111 can then be adjusted manually or automatically, e.g. by changing its offset so that its zero position coincides with the line of sight 120, step 350. Preferably, the distance scanner 111 is calibrated so that the error becomes less than 0.5 °, preferably less than 0.3 °. with The rear distance scanner 112 can be calibrated accordingly, by swapping places on the slit laser 121 and the obstacle 122.

The advantages are that one person is enough to carry out the measurement.

In addition, the calibration speed is faster because it can be performed directly by the operator, without over-analysis of laser data. Furthermore, a higher precision is obtained. Although the description above has only been about calibration of the joint angle sensor and distance scanner in self-propelled mining vehicles, the design can of course also be used in other vehicles.

The invention is of course not limited to the example described above, but can be modified within the scope of the appended claims.

Claims (1)

1. 0 15 20 25 30 533 77? A method for calibrating a hinge angle sensor (110) on a vehicle (100), said vehicle (100) comprising a first portion (100b) having a first centerline (115) and a second portion (100a) having a second centerline (116), which first portion (100b) and second portion (100a) are connected to a hinge (107), which hinge (107) is provided with a hinge angle sensor (110) for measuring a hinge angle (a) between the first portion (100b) and the second portion (100a), characterized by the following steps: 2) Method for (210) positioning the vehicle (100) so that the articulation angle (a) is approximately 0 ° and so that the intended line of sight (120) points towards a first object (124), which intended line of sight passes between a beam generating device (121) arranged on the first portion (100b) at a distance from the first center line (115) and an obstacle (122) arranged on the second portion (100a) on the same distance from the second center line (116), the articulation angle sensor (110) indicating a measured articulation angle; (220) irradiating a medium from the beam generating device (121) so that the medium partially passes the obstacle (122) and the medium is partially stopped by the obstacle (122) so that the medium produces an image; (230) projecting the image on the first object (124); (240) determining the first position (125) of the image on the first object (124):, (250) for fl moving the vehicle (100) a distance towards or from the first object (124), so that the articulation angle sensor (110) continues to show essentially the same measured joint angle; (260) determining the second position (126) of the image on the first object (124); ; calibration of a hinge angle sensor according to claim 1, characterized in that the distance is zero. 10 15 20 25 30 i. 3) 4) 5) 5) 7) 533 77? Method for calibrating a hinge angle sensor according to any one of claims 1-2, characterized in that the medium is one of the group: electromagnetic waves - preferably laser or radar; sound - preferably sonar; particles - preferably water or paint. Method for calibrating a hinge angle sensor according to any one of claims 1-3, characterized by calibration until the error in the zero position is less than 0.5 °, preferably less than 0.1 ". A method for calibrating a distance scanner (121, 122) on a vehicle (100), the vehicle (100) comprising a first portion (100b) and a second portion (100a) connected to a joint (107), which joint (107) is provided with a hinge angle sensor (110) for measuring a hinge angle (u) between the first portion (100b) and the second portion (100a), characterized! of the following steps: - (310) calibration of the hinge angle sensor (110) according to any one of claims 1-4; - (320) positioning the vehicle (100) so that the articulation angle sensor (110) indicates zero position; _ - (330) generating an image in a line of sight (120); - (340) projecting the image onto a second object (140); and - (350) adjusting the zero position of the distance scanner (121, 122) so that the second object (140) is in the zero position of the distance scanner (121, 122). Method for calibrating a distance scanner according to claim 5, characterized by calibration until the error in the zero position is less than 0.5 °, preferably less than 0.3 °. Vehicles comprising a first portion (100b) having a first centerline (115) and a second portion (100a) having a second centerline (116), said first portion (100b) and second portion (100a) being connected to a joint (107) , which joint (107) is provided with a joint angle sensor (110) for measuring a joint angle (u) between the first portion (100b) and the second portion (100a), characterized in that the vehicle (100) comprises: a beam generating device ( 121) arranged on the first portion (100b) at a distance from the first center line (115), an obstacle (122) arranged on the second portion (100a) at the same distance from the second center line (116), which beam generating 25 3) 9) 533 77? Device (121) is arranged to radiate a medium, so that the medium partly passes the obstacle (122) and is partially stopped by the obstacle (122), so that an image is generated; a device for positioning the vehicle (100) so that the angle (0) is approximately 0 ° and such that an imaginary line of sight (120) between the beam generating device (121) and the obstacle (122) points towards a first object (124), the articulation angle being (110) is arranged to indicate a measured joint angle; a device (121, 122) for projecting the image of the first object (124) into a first position (125); a means for moving the vehicle (100) a distance towards or from the first object (124), so that the articulation angle sensor (110) continues to show the same measured articulation angle; a device (121, 122) for projecting the image of the first object (124) into a second position (126); and a device for adjusting the articulation angle sensor (MO) zero position if a distance between the first position (125) of the image and the second position (126) is greater than the distance corresponding to the least acceptable error in the articulation angle measurement for the performed movement. Vehicle according to claim 7, characterized in that the distance is zero. Vehicle according to claim 7 or 8, characterized in that the medium is something from the group: electromagnetic waves - preferably radar or laser; sound - preferably sonar; particles - preferably water or paint. Vehicle according to one of Claims 7 to 9, characterized in that the obstacle (122) is a plate with a hole (123). Vehicle according to one of Claims 7 to 10, characterized in that the first object (124) is a screen sensitive to the medium. Vehicle according to one of Claims 7 to 11, characterized in that the vehicle is arranged to calibrate until the error in the zero position is less than 0.5 °, preferably less than 0.1. Vehicle (100) according to one of Claims 7 to 11, characterized in that the vehicle further comprises a device for positioning the vehicle (100) so that the articulation angle sensor (1 10) indicates a zero position; a device (121, 122) for generating an image in a line of sight (120), the image being projected onto a second object (140); and a device for adjusting the zero position of the distance scanner (111, 112) so that the second object (140) is in the zero position of the distance scanner (111, 112). Vehicle according to claim 13, characterized in that the vehicle is arranged to calibrate the distance scanner (111, 112) until the error in the zero position is less than 0.5 °, preferably less than 0.3 '. 15) Vehicle 13-14, the distance scanner (121) is something from the group of lasers, radar and sonar. according to any one of the claims, characterized in that 16) Vehicle according to any one of claims 7-15, characterized in that the vehicle is a mining and / or construction vehicle. Vehicle according to one of Claims 7 to 16, characterized in that the vehicle is a self-propelled vehicle.