WO2014148988A1

WO2014148988A1 - Control system and method for control of a vehicle in connection with detection of an obstacle

Info

Publication number: WO2014148988A1
Application number: PCT/SE2014/050307
Authority: WO
Inventors: Jon Andersson; Joseph Ah-King; Tom NYSTRÖM
Original assignee: Scania Cv Ab
Priority date: 2013-03-19
Filing date: 2014-03-13
Publication date: 2014-09-25
Also published as: SE1350336A1; DE112014001002T5; SE536983C2

Abstract

A control system comprising one or several scanning devices, each of which is adapted to scan the road ahead for one of the vehicle's wheels. By identifying particularly dangerous objects, such as "cat heads", in this defined road, the vehicle may steer aside and avoid these objects, A "cat head" in a mining environment is a fist-sized rock with sharp edges, known to puncture vehicle wheels. By using control systems to identify such objects, the vehicle may avoid getting its wheels punctured and thus avoid interruptions in production because the vehicle needs to be at a standstill and blocks the production line, or needs to be removed to have its wheels repaired.

Description

Control system and method for control of a vehicle in connection with detection of an obstacle

Field of the invention

The present invention pertains to technology to detect objects ahead of autonomous vehicles, and in particular objects which are especially known to puncture vehicle wheels.

Background of the invention

A vehicle which may be driven without a driver on the ground is called an unmanned ground vehicle (UGV). There are two types of UGVs, namely remote- operated and autonomous vehicles.

A remote-operated UGV is a vehicle that is controlled by a human operator via a communications link. Ail measures are decided by the operator based on either direct visual observation or with the use of sensors, such as digital video cameras.

One simple example of a remote-operated UGV is a remote-controlled toy car.

There is a great variety of remote-operated vehicles used today. Often, these vehicles are used in dangerous situations and in environments which are unsuitable for people, e.g. to disarm bombs and in connection with hazardous chemical releases. Remote-operated, unmanned vehicles are also used in connection with surveillance and similar.

An autonomous vehicle herein means a vehicle which is capable of navigating and manoeuvring without human control. The vehicle uses sensors to obtain an understanding of the surrounding environment. Sensor data are then used by control algorithms to determine the vehicle's next step with respect to a superior goal for the vehicle, such as to collect and deliver goods at different positions.

More specifically, an autonomous vehicle must be able to scan the surrounding environment sufficiently well to be able to carry out the task which it has been allocated, e.g. "move the boulders from place A to place B via the mine gallery C".

The autonomous vehicle needs to plan and follow a route to the chosen destination, while detecting and avoiding obstacles on the way. in addition, the autonomous vehicle must complete its task as quickly as possible without making any mistakes. Autonomous vehicles were developed, among other things, for use in hazardous environments, such as the defence and war industry and the mining industry, both above ground and underground. If people or ordinary, manually controlled vehicles approximate the operating area of the autonomous vehicles, for safety reasons they normally trigger an interruption in the operation. Once the operating area is clear, the autonomous vehicles may be ordered to resume operation.

The autonomous vehicle uses information relating to the road, the surrounding environment and other aspects that impact the progress in order to automatically regulate throttle, braking and steering. A careful assessment and identification of the planned progress is necessary in order to assess whether a road is navigable, and is also necessary in order to successfully replace a person's assessment when driving the vehicle. Road conditions may be complex, and when driving an ordinary manned vehicle the driver makes hundreds of observations per minute and adjusts the operation of the vehicle based on the perceived road conditions in order to find e.g. a navigable path around an object which may be on the road. To replace the human perception ability with an autonomous system entails, among other things, that the ability to perceive objects in an exact manner is required in order to be able to control the vehicle effectively when steering past these objects.

The technological methods used to identify an object in connection with the vehicle comprise, among other things, the use of one or several cameras and radar to create pictures of the surrounding environment. Laser technology is also used, both scanning lasers and fixed lasers, in order to detect objects and to measure distances. These are often called LIDAR (Light Detection and Ranging) or LADAR (Laser Detection and Ranging). In addition, the vehicle is equipped with different sensors, among other things, to detect speed and accelerations in different directions. Positioning systems and other wireless technology may also be used to determine whether the vehicle is e.g. getting close to a junction, a narrowing of the road, and/or other vehicles.

Autonomous vehicles are used today as load carriers in areas such as mining - both in open pits and underground mines. A vehicle accident in a bottleneck, such as a transportation route or in a mining site, in many cases immediately stops the entire production line with significant loss of income as a result. A common cause for vehicle accidents in a terrain environment is a puncture caused by the sharp edges on fist-sized rocks called "cat heads" in the mining industry. The driver in a manually controlled vehicle has the task of spotting and not hitting these rocks with any of the vehicle's wheels. For an autonomous vehicle it is a great challenge to detect these objects, since they are relatively small and have an appearance that does not differ much from the surface in a mine. Another problem with autonomous vehicles is that it may be difficult to know where they are planning to go, as opposed to vehicles with a driver, who looks in the direction into which he/she intends to drive.

US-6151539-A describes a system for autonomous vehicles and a method for how to control these. The system consists of a range of sensors that are intended to ensure that the vehicle maintains its course, and to ensure that the vehicle avoids collision with various obstacles, A laser scanner pointed downward may be used to detect holes or small obstacles on the ground.

US-20090088916-A1 describes a system for autonomous vehicles which is able to plan its path automatically, while simultaneously avoiding collision with different types of obstacles. The system uses mathematical algorithms to calculate the correct path and how the vehicle should avoid obstacles. The system uses different types of sensors, among others laser, in order to gather necessary information and data. US-20120035788-A1 describes a system for autonomous vehicles which discovers various obstacles on the road and which, with the help of a laser, calculates the best route.

US-20 001 14416-A1 describes a system for autonomous vehicles which uses a laser scanner that scans the surrounding environment in order to obtain information about the appearance of the road and whether there are obstacles on the road.

The above described systems are relatively complicated and are not directly adapted to be used in terrain. The systems are usually also adapted to detect objects generally, and not to distinguish specific objects.

It is thus an objective of the invention to provide an improved system to prevent that an autonomous vehicle suffers a puncture in a terrain environment.

Summary of the invention

According to one aspect, the above-mentioned objective is achieved through a control system for controlling an autonomous vehicle with wheels when an object is detected, in accordance with the first independent claim. The control system comprises one or several scanning devices, each of which is adapted to scan the road ahead for one of the vehicle's wheels. By identifying particularly dangerous objects, such as "cat heads", on this road ahead, the vehicle may steer aside and avoid these objects. A "cat head" in a mining environment is a fist-sized rock with sharp edges, known to puncture vehicle wheels. By using the control system to identify such objects, the vehicle may avoid getting its wheels punctured, and thus avoid interruptions in production because the vehicle needs to be at a standstill and blocks the production line, or needs to be removed to have its wheels repaired.

The scanning devices may be set according to the road ahead for the vehicle's wheels. Since the objects are very small, it is sufficient to detect a narrow path in front of each wheel, i.e. a narrow width of the vehicle's path which corresponds to the width of the wheels. Thus it is possible to have simpler and cheaper scanning devices, which cope well with a hazardous mining environment.

According to another aspect, the objective is achieved through a method for regulating an autonomous vehicle equipped with wheels upon detection of objects according to the second independent claim.

The preferred embodiments are defined by the dependent patent claims. Brief description of the drawings

Figure 1 shows a schematic view of a part of a traffic system with three autonomous vehicles displayed.

Figure 2 shows an autonomous vehicle equipped with two scanning devices. Figure 3 shows a block diagram for a control system according to one

embodiment of the invention.

Figure 4 shows a flow chart for the method according to one embodiment of the invention.

Detailed description of preferred embodiments of the invention

Figure 1 shows a schematic view of a traffic system, comprising three

autonomous vehicles 2 which are travelling along a road. The arrows in the autonomous vehicles 2 show their respective driving directions. The autonomous vehicles 2 may communicate with a control centre 1 via e.g. V2I communication (Vehicle-to-lnfrastructure) 3 and/or with each other via e.g. V2V communication (Vehicle-to-Vehicle) 4. This communication is wireless and may take place via a WLAN protocol (Wireless Local Area Network) IEEE 802.1 1 , e.g. IEEE 802.1 1 p. Other wireless ways to communicate are also possible. The control centre 1 organises the autonomous vehicles 2 and assigns tasks for them to complete. When an autonomous vehicle receives a task, the vehicle may independently ensure that the task is completed. A task may consist of an instruction to collect goods at a goods collection point A. The vehicle 2 then has the capacity to determine its current position, to determine a path from the current position to the goods collection point A, and to go there. On the way, the vehicle must also have the capacity to avoid obstacles and to handle other autonomous vehicles 2, which might have a more important task and must be granted preference. In a terrain environment, such as a mine, there are some objects which are more dangerous for a vehicle than other objects. One example are the so-called cat heads, which are fist-sized rocks with sharp edges. These objects are known to puncture air- filled vehicle wheels, and it is desirable to avoid driving over them. In a driver- controlled vehicle, the driver may locate these objects and drive around them. The driver is able to see that the object is precisely a cat-head, and may also calculate the path to drive around them. With respect to an autonomous vehicle 2, the task is significantly more difficult The control system 10, which will be described below, is designed to carry out this task.

Figure 2 shows an autonomous vehicle 2, in which parts of the control system 10 are displayed. The vehicle 2 has four airborne wheels 7 and is equipped with at least one scanning device 5, 8, herein two scanning devices 5, 6, each of which is adapted to scan the road ahead 8 for one of the vehicle's two front wheels 7. if the vehicle 2 had been e.g. a motorcycle, one scanning device 5 might have been sufficient. Each scanning device 5, 6 is adapted to generate a detection signal s-i , s₂ which indicates an object 9 in the road ahead 8. One object 9, in the form of a cat head, is illustrated here as being in the road 8, and will be detected by the scanning device 5,

The road ahead 8 of the vehicle's wheels 7 is the space which the vehicle's 2 wheels 7 will occupy along the road ahead, taking into consideration the width w of the wheels 7 and how the vehicle 2 will drive. Preferably, the road 8 is scanned ahead of the front wheel pair, but if is also possible to scan the road ahead of a rear wheel 7 or the road ahead of two rear wheels. One wheel 7 may also comprise two or more wheels which are joined together. The width of the wheels 7 is as displayed in the figure as w, and this width needs to be defected a bit further ahead in the road 8 in order to provide for a possibility to drive around an object 9 in the path of the vehicle. The width w is, according to one embodiment, between 20 and 100 cm. The scanning devices 5, 6 are preferably placed high up on the vehicle 2 in order to have as great an angle as possible in relation to the road 8 to be able to scan the road 8 with greater precision. The scanning devices 5, 6 are preferably set to scan the road 8 at a distance I of 5-30 m ahead of the vehicle 2, according to one embodiment at 10 m in front of the vehicle 2. The scanning devices 5, 8 generate information from which at least one distance di , k| to the object 9 may be determined.

Figure 3 shows a block diagram for the control system 10. Control system 10 comprises, in addition to at least one scanning device 5, 6, which is described with reference to Figure 2, also an analysis device 1 1 , which is adapted to receive the detection signal or the detection signals si, S2 from the scanning devices 5, 6. Further, the analysis device 1 1 is adapted to determine at least one distance di , ki to the object 9, to compare the distance di , ki to a reference distance d_refdi . reiki and to determine at least one object profile based on the result of the comparison. One object profile for an object 9 in each of the roads 8 may thus be determined. This object profile may then be used to distinguish a cat head from e.g. a hole in the ground. The reference distances d_refai , d_refki may be saved on e.g. a memory 14 connected to the analysis device 11.

According to one embodiment, the sensor signal s-i , sa also indicates distances di , ki from the vehicle's wheels 7 to the road 8 when no object 9 has been detected. The analysis device 1 1 may then be adapted to determine a reference distance refcn , drefki which is an average value of several previously determined distances di , ki from the vehicle's 2 wheels 7 to the road when no object 9 has been detected. Thus, reference distances d_refdi , _refki to the road 8 may be determined, which the analysis device 11 may use to compare with specific distances d i and ki and thus produce a difference between a reference distance drefdi , drefk and the specific distances di , ki. If there is a difference, this difference may be used to produce an object profile. The analysis device 1 1 is also adapted to compare the object profile with at least one reference object profile, and to determine a result signal s_ri , Sr2 which indicates the result of the comparison. A reference object profile is a profile which identifies a specific object. According to one embodiment, the object reference profile characterises a fist-sized rock, e.g. a cat head. The reference object profile comprises predetermined characteristics for the special object, e.g. a height within a certain interval and/or a width within a certain interval. If there is a match between the object profile and the reference object profile, this is indicated in the result signals s_ri , s_r2 for the respective object.

The control system 10 also comprises a control device 12 which is adapted to receive the said result signal s,i , s_r2 and to determine one or several control signals s_COntr according to predetermined rules based on the result of the comparison or comparisons. The predetermined rules comprise, according to one embodiment, rules for how the vehicle 2 should be controlled in order for the vehicle's wheels 7 to avoid a defined object 9 in the road 8. The predetermined rules comprise vehicle-specific determinations such as the distance between wheel pairs, etc. in order to decide how the vehicle 2 should be controlled in order to avoid an object 9, the control device 12 may be adapted to receive a trajectory signal s_b which indicates the road ahead for the vehicle 2. The trajectory signal s may comprise a trajectory for the vehicle 2. Thanks to information about the trajectory for the vehicle 2, the distance to the object 9 and e.g. the distance between the front wheels 7 and the width w of the wheels 7, the control device 2 may determine how the vehicle should be controlled in order to avoid the object 9. If an object 9 has been identified as a cat head, the vehicle 2 must drive around the cat head. One or several control signals s_COntr are then determined in order to drive the vehicle 2 around the object 9. The control device 12 is further adapted to send control signals s_COi1tr to a control system 13 in the vehicle 2, so that the vehicle 2 is controlled in accordance therewith. The control system 13 may be a control system 13 which controls the steering of the vehicle 2. Where the control system 10 comprises two or more scanning devices 5, 6 which are adapted to scan the road ahead 8 of each one of the vehicle's 2 wheels 7, the control device 12 is adapted to determine control signals s_∞nir also based on object 9 in the road ahead 8 for the other wheel 7 of the vehicle. The other wheel 7 of the vehicle 2 in this context means the second wheel of a front wheel pair. The scanning devices 5, 8, which were partly described above, may each comprise one or several lasers which may determine distances di , ki to the road 8 or an object 9. The laser may be a scanning laser which is adapted to scan the width w of the road 8. From this scanning, a number of primarily simultaneous distances d d_x, k k_x to object 9 may be determined. The scanning devices 5, 6 may instead comprise several lasers each, which are placed in a row or in a matrix. For example, three lasers may be placed alongside each other and be adjusted so that they jointly defect the width w at a certain distance I in front of the vehicle 2. According to one embodiment, the analysis device 11 in this case is adapted to determine several primarily simultaneous distances d d_x, k k_x to the object 9, and to compare the simultaneous distances di-d_x, ki-k_x with one or several reference values drera drefdx, _refk d_reikx, and to determine an object profile based on the results of the comparisons. A time series of determined distances may also be used. In this case, the analysis device 11 is adapted to determine an object profile based on a time series of results of comparisons from a time series of distance determinations. The reference object profile in this case has equivalent determinations for how the reference objects appear in order to enable comparison with the determined object profile. If the lasers are placed in a matrix, e.g. 2x2 or 3x3, they may directly detect an object 9 in three dimensions. An object profile in 3D may then be determined, which may be compared to a reference object profile in 3D. The scanning devices 5, 6 may instead comprise cameras, from pictures of which it is possible to identify the objects 9 and to determine the distances di , ki to these, in order to determine depth, however, two cameras are required in each of the scanning devices 5, 8.

The control device 12 may, as described above, be adapted to receive a trajectory signal s_& which indicates the vehicle's road ahead 8. The trajectory signal may comprise a trajectory for the vehicle 2 which may be determined with

consideration for how the vehicle 2 is steered, e.g. the adjustment of the steering wheel or the wheel adjustment, and is continuously updated. The trajectory may indicate where the vehicle's 2 middle line in the direction of travel should be, and the control device may then be adapted to determine the trajectories 8 of the wheels. Alternatively, the trajectory signal S may indicate trajectories for the respective wheels 7. The trajectory signal s_b may instead only indicate a final destination for the vehicle 2, and the control device 12 must in this case be adapted to independently determine trajectories 8 for the wheels 7 of the vehicle 2. In order to determine trajectories for the wheels 7 of the vehicle, the control device 12 may use information about the distance between the front wheels 7 and the width of the wheels v. The control device 12 is further adapted to determine at least one adjustment for at least one scanning device 5, 8 based on the road ahead 8 of the vehicle 2, so that the scanning device 5, 8 detects the road ahead 8 for one of the wheels 7 of the vehicle. In order to determine one or several adjustments for the scanning devices 5, 6, the control device 12 may use the determined trajectories for the wheels 7 of the vehicle, the chosen distance I in front of the vehicle 2, and at which height of the vehicle 2 the scanning devices 5, 6 are installed. Through geometrical calculations, the control device 12 may then determine adjustments for the scanning devices 5, 6, so that they detect in an area of the road ahead 8 of the wheels 7 at a certain distance I in front of the vehicle 2. Each scanning device 5, 8 may thus be adjusted so that it detects a particular road 8. The control device 12 is also adapted to generate an adjustment signal s_seti , s_set2 which indicates the adjustment, and to send this to the scanning devices 5, 8, so that the scanning device 5 is adjusted according to the adjustment. Each scanning device 5, 8 is thus adapted to be adjustable so that it detects a dedicated road 8. Thus, the control system 10 may continuously detect the road 8, where the vehicle's wheels 7 will be placed.

Depending on how the vehicle 2 turns, or plans to turn, the scanning devices 5, 6 will thus be adjusted accordingly. This adjustment may be visible to other road users and thus they are informed of where the vehicle 2 is heading. The analysis device 1 and the control device 12 may be comprised in a computer in the vehicle 2, or in a control device (ECU - Electronic Control Unit). The control system 10 preferably comprises a processor and a memory 14 to carry out the methods described herein. The control system 10 is adapted to communicate with different devices and systems in the vehicle 2 via one or several different networks in the vehicle 2, such as a wireless network, via CAN (Controller Area Network), LIN (Local Interconnect Network) or Fiexray, etc,

The invention also pertains to a method for controlling an autonomous vehicle 2 equipped with wheels upon detection of an object 9, as described below with reference to the flow chart in Figure 4, The method comprises a first step A1) to detect the road ahead 8 of at least one of the wheels 7 of the vehicle 2. This may be achieved with one or several scanning devices 5, 8, as described above in connection with the control system 10, In a second step A2), at least one distance di , ki to an object 9 in the road 8 is determined. In a third step A3), the distance di , ki is compared to a reference distance drefdi , drew , and an object profile is determined based on the result of the comparison. In a fourth step A4), the object profile is compared to a reference object profile, and a result of the comparison is determined. The reference object profile may characterise e.g. a fist-sized rock, a so-called cat head. If the object profile comprises one or several features of a cat head, the result of the comparison is that the object profile matches the reference object profile, and a cat head has been identified, in order to avoid the identified cat head, the method comprises, in a fifth step A5), determining one or several control signals s_COnir according to predetermined rules based on the result of the comparison. The rules comprise rules on how the vehicle 2 should be controlled in order to avoid the defined object 9, which was explained above in connection with the control system 10. In a sixth step A6), the one or several control signals s_COntr are sent to a control system 13 in the vehicle 2, so that the vehicle 2 is controlled in accordance therewith.

According to one embodiment, the method comprises determining a reference distance _rerai , d_rew which is an average value of several previously determined distances di , ki of the wheels 7 of the vehicle to the road 8 when no object 9 has been detected. Thus, the difference values between a reference distance d_refdi , drew and determined distances to an object 9 may be obtained. According to one embodiment, the method comprises, in step A2), determining several simultaneous distances d d_x, k_rk_x to the object 9, and, in step A3), comparing said several simultaneous distances di-d_x, krk_x with one or several reference values d_refdi-dreidx, refki- refkx, and determining an object profile based on the results of the comparisons. Thus, a more reliable analysis may be carried out. According to another embodiment, the step A3 comprises determining an object profile based on a time series of results of comparisons originating from a time series of distance determinations. Thus, a 2D or 3D object profile may be constructed and compared to an equivalent reference object profile. Thus, an even more reliable analysis may be carried out.

According to one embodiment, the method comprises the steps of:

B1) receiving information about the vehicle's 2 road ahead; B2) determining at least one adjustment for at least one scanning device 5, 8 based on the vehicle's 2 road ahead, so that each one or several scanning devices 5, 6 scan the road ahead 8 for one of the vehicle's wheels 7; B3) sending the adjustment to the detection device or the scanning devices 5, 8, so that the scanning device or scanning devices 5, 6 are adjusted according to the adjustment. Thus, the scanning devices 5, 6 may continuously scan the road ahead 8 for the vehicle's 2 wheels 7.

The invention also pertains to a computer program P in an autonomous vehicle 2, where the computer program P comprises program code to induce the control system 0 to carry out the steps according to the method. Figure 3 shows the computer program P as a part of the memory 14. The computer program P is thus stored in the memory 4. The memory 14 is connected to the analysis device 1 1 , and when the computer program P is executed by the analysis device 1 1 , at least parts of the methods described herein are carried out. The invention also comprises a computer program product comprising a program code stored on a computer-readable medium in order to carry out the method steps described herein when the program code is executed in the control system 10, The memory 14 may also be connected to the control device 12.

The present invention is not limited to the preferred embodiments described above. Various alternatives, modifications and equivalents may be used. The embodiments above shall therefore not be deemed to limit the scope of the invention, which is defined by the enclosed patent claims.

Claims

Patent claim

1. Control system ( 0) to control an autonomous vehicle (2) equipped with wheels upon detection of an object (9), the autonomous vehicle being adapted to operate in a terrain environment and where the control system (10) comprises

- at least one scanning device (5, 6), each of which is adapted to scan the road ahead (8) for one of the vehicle's wheels (7), and to generate a detection signal Si , s₂ indicating an object (9) in the road ahead (8);

- an analysis device (11) which is adapted to receive said detection signal si, s₂ and to determine at least one distance di , ki to the object (9), to compare the distance di, ki with a reference distance d_refdi ,d_refki and to determine at least one object profile based on the result of the comparison; the analysis device (11) further being adapted to compare the object profile with a reference profile, and to determine a result signal s_ri, Sr2 indicating the result of the comparison;

- a control device (12) which is adapted to receive said result signal s_r and to determine one or several control signals s_COntr according to predetermined rules based on the result of the comparison, the control device (12) further being adapted to send said control signals s_COntr to a control system (13) in the vehicle (2), the vehicle (2) being controlled in accordance therewith.

2. Control system (10) according to claim 1 , wherein the detection signal si, ss also indicates the distance di, ki from the vehicle's wheels (7) to the road (8) when no object (9) is detected; the analysis device (1 1) being adapted to determine a reference distance d_refdi, _refki which is an average value of several previously determined distances di, ki from the vehicle's wheels to the road when no object has been detected,

3. Control system (10) according to claim 1 or 2, wherein the analysis device (1 1) is adapted to determine several simultaneous distances d d_x, k_rk_x to the object (9), wherein the analysis device (11) is adapted to compare said several simultaneous distances drd_x, krk_x to one or several reference values drefd drefox, d_refki-drefkx, and to determine an object profile based on the results of the comparisons.

4. Control system (10) according to any of the previous claims, wherein said analysis device (11 ) is adapted to determine an object profile, based on a time series of results of comparisons from a time series of distance

determinations.

5. Control system (10) according to any of the previous claims, wherein the control device is adapted to receive a trajectory signal s which indicates the vehicle's road ahead, wherein the control device (12) is adapted to determine at least one adjustment for said at least one scanning device (5, 8) based on the vehicle's road ahead, so that the scanning device (5, 6) scans the road ahead (8) for one of the vehicle's wheels (7), wherein the control device (12) is adapted to generate an adjustment signal s sen , Sset2 indicating said adjustment and to send this to the scanning device (5, 6), wherein the scanning device (5, 6) is adjusted according to the adjustment. 6. Control system (10) according to any of the previous claims, wherein said at least one scanning device (5,

6) comprises at least one laser.

7. Control system ( 0) according to any of the previous claims, wherein said object reference profile characterises a fist-sized rock.

8. Control system (10) according to any of the above claims, wherein said predetermined rules comprise rules for how the vehicle (2) should be controlled in order for the vehicle's wheels (7) to avoid a defined object (9) in the road (8) for the vehicle's wheels(7).

9. Control system (10) according to any of the above claims, comprising two scanning devices (5, 6) adapted to scan the road ahead of each one of the vehicle's wheels, the control device (12) being adapted to determine control signals s_COntr also based on an object (9) in the road ahead (8) for the other wheel (7) of the vehicle.

10, Method to control a wheel-equipped autonomous vehicle (2) in the detection of an object (9), the autonomous vehicle being adapted to operate in a terrain environment, the method comprising the steps to:

- scan the road ahead (8) for at least one of the vehicle's wheels (7);

- determine at least one distance di , ki to an object (9) in the road (8);

- compare the distance di, ki to a reference distance drerai , d_refki , and

determine an object profile based on the result of the comparison;

- compare the object profile with a reference object profile and determine a result of the comparison.

- determine one or several control signals s_contr, according to predetermined rules, based on the result of the comparison;

- send said one or several control signals s_contr to a control system (13) in the vehicle (2), where the vehicle (2) is controlled in accordance therewith.

1 1 . Method according to claim 10, the method comprising determining a reference distance d_refdi, d_refki which is an average value of several previously known distances di , ki from the vehicle's wheels (7) to the road (8) when no object (9) has been detected.

12. Method according to claim 10 or 1 1 , the method comprising determining several simultaneous distances d_rd_x, k_rk_x to the object (9), to compare said several simultaneous distances di-d_x, ki-k_x with one or several reference values drera drefdx, d_refki-drefk_X, and to determine an object profile based on the results of the comparisons.

13. Method according to any of the claims 10 to 12, the method comprising determining an object profile based on a time series of results of comparisons originating from a time series of distance determinations.

14. Method according to any of the claims 10 to 13, the method comprising the steps of

- receiving information about the vehicle's (2) road ahead;

- determining at least one adjustment for at least one scanning device (5, 6) based on the road ahead of the vehicle, so that the scanning device (5, 6) detects the road ahead (8) for one of the wheels (7) of the vehicle;

- sending the adjustment to the scanning device (5, 6), the scanning device (5, 6) being adjusted according to the adjustment.

15, Method according to any of the claims 10 to 14, wherein said object reference profile characterises a fist-sized rock.

18. Method according to any of the claims 10 to 15, wherein said predetermined rules comprise rules for how the vehicle (2) should be controlled in order for the vehicle's (2) wheels (7) to avoid a defined object (9) in the road ahead (8) of the vehicle's wheels(7).

17. Computer program (P) in an autonomous vehicle, said computer program (P) comprising program code to induce a control system (10) to carry out the steps according to any of claims 10 to 16.

18. Computer program product comprising a program code stored on a computer-readable medium in order to execute the method steps according to any of claims 10 to 16, when said program code is executed in a control system (10).