Patent Description:
The invention can be applied in heavy-duty vehicle s, such as trucks and construction equipment. Although the invention will be described mainly with respect to a semi-trailer vehicle, the invention is not restricted to this particular vehicle, but may also be used in other vehicles such as different types of rigid trucks, dumpers, trailers, and also in some types of forklifts.

A drivable area is a region which a vehicle can traverse without significant interference from obstacles. Given information about drivable areas, autonomous or semi-autonomous functions can be implemented, such as reversal assistance functions and automatic docking and parking functions.

<CIT> describes a system where an articulated vehicle keeps track of an area swept by the vehicle as it moves. The swept area is determined based on vehicle positions along a track and respective articulation angles of the vehicle. This swept area is then considered a drivable area which can be used to, e.g., control the steering of the towing vehicle when reversing the articulated vehicle along the specified path, such that the articulated vehicle does not extend outwards of the swept area during the reversal.

However, there may be obstacles of varying severity present in the swept area. Some obstacles may be possible to drive over and may therefore not influence the extent of the swept area. These obstacles may, however, affect comfort or safety and should preferably be avoided. On the other hand, a choice may have to be made between reaching some destination while passing some obstacles or not reaching the destination at all.

<CIT> describes a method for determining a drivable area for a vehicle along a track, wherein data related to the track and the dimensions of the vehicle are used to find a swept area of the vehicle for the track. The determined swept area is combined with sensor data relating to obstacles to find the drivable area. <CIT>, which is seen as the closest prior art, does in particular not disclose how cargo information may be used in said method in order to determine said drivable area as in claim <NUM>.

A more refined estimation of drivable area is therefore preferred in order to improve autonomous and semi-autonomous vehicle operation, including reversal assist functions and the like.

It is an object of the present disclosure to provide improved methods for determining drivable areas by vehicles. This object is at least in part obtained by a method for determining a drivable area by a vehicle. The method comprises obtaining data related to a track of the vehicle, wherein the data comprises a plurality of positions, with corresponding headings of the vehicle along the track. The method also comprises obtaining size information of the vehicle and determining a swept area of the vehicle for the track based on the data and on the size information of the vehicle. The method also comprises configuring a sensor on the vehicle to detect when the vehicle drives over an obstacle, recording any obstacles detected by the sensor, and determining the drivable area based on the swept area and on recorded obstacles.

This way a refined representation of the drivable area is obtained in that not only the swept area, i.e., the area traversed by the vehicle, is considered, but also any obstacles encountered while determining the swept area. Consequently, the vehicle may drive over obstacles as the swept area is being established, but these obstacles will be recorded and may influence the final estimation of the drivable area. Notably, the disclosed methods determine drivable areas. This is different from simply recording presence of obstacles, since the latter does not provide information about drivable area, only about areas not suitable for traversing by some types of vehicles.

According to aspects, the sensor comprises a heading detection unit, and the method comprises detecting a heading of the rear end of the vehicle. The sensor unit is then used both for obstacle detection as well as for detecting a heading of the rear end of the vehicle, which is efficient. The heading data is advantageously used in the determining of the swept area.

According to aspects, wherein the vehicle is an articulated vehicle, and wherein the method comprises obtaining a heading of a front end of the articulated vehicle and estimating an articulation angle value based on a difference between the headings of the rear and front ends of the articulated vehicle. Thus, advantageously, articulation angle can be estimated independent of any sensors arranged in connection to, e.g., a fifth wheel or connection joint of the articulated vehicle. This redundant articulation angle estimate can be used to verify output from external articulation angle sensors, and therefore increases fault tolerance and robustness of the overall system. In other words, according to come aspects, the method comprises verifying an output from an external articulation angle sensor of the articulated vehicle based on the estimated articulation angle value.

According to other aspects, the sensor comprises an inertial measurement unit, IMU, configured to detect when the vehicle drives over an obstacle and/or to detect when the vehicle impacts an obstacle laterally, based on a measured acceleration. The IMU may be co-located with other sensor functions, which provides for an efficient and easily assembled unit. The IMU can be used to detect different types of obstacles based on measured accelerations along different axes, and possibly also to classify obstacles depending on if the vehicle drives over the obstacle, if the vehicle hits the obstacle from the side, or if the obstacle represents a combination of accelerations. Thus, a pot-hole giving rise to mainly vertical acceleration by the IMU can be distinguished from a curb which, when hit, would give rise to mainly horizontal acceleration, unless the curb is driven over in which case the resulting acceleration would be a combination of vertical and horizontal acceleration.

According to further aspects, the sensor comprises a measurement device arranged in connection to the trailer suspension system configured to detect when the vehicle drives over an obstacle. This type of sensor represents a cost-efficient means to detect obstacles, since the sensor is already present in many modern vehicles.

According to some aspects, the recording comprises classifying a detected obstacle according to a pre-configured list of obstacle types. This information can later be used by, e.g., algorithms for autonomous driving. For instance, suppose some vehicle is loaded with non-fragile cargo like gravel, then certain types of obstacles may be permitted to drive over, compared to the case where the vehicle is loaded with fragile cargo, like furniture, in which case those same obstacles are to be avoided at all costs.

According to some further aspects, the recording comprises determining a severity level associated with each detected obstacle. The severity level may be used as input to autonomous driving functions and the like, or be used in route planning, for instance during a reversal assist maneuver.

According to aspects, the recording comprises recording a location associated with each detected obstacle, and/or uploading information related to the determined drivable area to a remote server. This way an overview of drivable areas in a region can be obtained. Drivable areas determined by one vehicle may be shared with other vehicles, which is an advantage. Thus, according to some such aspects, the method comprises updating map information, by the remote server, based on the uploaded information.

There are also disclosed herein computer programs, computer program products, control units, systems, and vehicles associated with the above-mentioned advantages.

The skilled person realizes that different features of the present invention may be combined to create embodiments other than those described in the following, without departing from the scope of the present invention as defined by the appended claims.

In particular, although some examples are given based on articulated vehicles, it is appreciated that the disclosed techniques are also applicable with rigid trucks, such as tipper trucks, dumpers, and the like.

<FIG> shows a schematic articulated vehicle combination <NUM> comprising a towing vehicle <NUM> and two towed vehicles <NUM>, <NUM>. The towing vehicle may be a regular truck adapted for commercial highway use or a tractor having a fifth wheel but may also be an off-road truck or a bus. The first towed vehicle or trailer <NUM> is in the shown example a dolly having a drawbar connected to the trailer coupling of the truck. The dolly is provided with two wheel-axles <NUM>. The second towed vehicle or trailer <NUM> is a semitrailer, which is provided with a kingpin <NUM> that is connected to the fifth wheel of the dolly. This example shows a common type of a longer vehicle combination, but it is also possible to use other types of vehicle combinations having other types of towing vehicles and other types and numbers of towed vehicles. Different vehicle combinations may include a truck with a regular trailer, a truck with a center axle trailer, a truck with a dolly and a semitrailer, a tractor with a semitrailer, a tractor with a B-link and a semitrailer, a tractor with a semitrailer and a regular trailer or a tractor with a semitrailer dolly and a semitrailer.

The towing vehicle may be provided with various autonomous or semi-autonomous driving functions such as an automatic reverse assistance function, in which the steering of the vehicle combination is automated during reversing and where the speed of the vehicle combination may be controlled by the driver.

In the shown vehicle combination, the effective wheel base Leq1 of the towing vehicle, i.e. the truck, is the length from the front axle <NUM> to the virtual axle <NUM> of the truck. The effective wheel base Leq2 of the first towed vehicle, i.e. the dolly, is the length from the drawbar connection to the virtual axle <NUM> of the dolly. The effective wheel base Leq3 of the second towed trailer extends from the king pin <NUM> to the to the virtual rear axle <NUM> of the trailer <NUM>.

Based on the vehicle geometry and travelled path, a swept area can be determined. Details on the determining of swept areas or different types of vehicle configurations are disclosed in <CIT> and will therefore not be discussed in more detail herein.

<FIG> shows a vehicle combination with a modified swept area <NUM> for the last part of a travelled path <NUM>. In <FIG>, the modified swept area <NUM> is comprised of the swept area <NUM> and of tolerance bands <NUM>, one on each side of the swept area <NUM>. The purpose of the tolerance band is to compensate for tolerances in the steering actuator and for tolerances and noise in the measured values from different sensors.

<FIG> also indicates the presence of obstacles in the swept area. A bump <NUM> is present which is enforceable, i.e., possible to drive over, by the vehicle <NUM>. A curb <NUM> is also shown. This curb is not easily enforceable. Thus, when hit by the vehicle the vehicle course will change due to the lateral impact from the curb.

When autonomously operating the vehicle <NUM> in the swept area, it may be desired to avoid obstacles like the bump <NUM> depending on scenario. Thus, if the vehicle is a heavy duty truck for transporting stone and gravel, a relatively minor bump may be of no consequence. On the other hand, in case the cargo is fragile, it may be more desirable to avoid even smaller obstacles. The curb <NUM> on the other hand represents a more severe obstacle which is not easily enforceable. Either this obstacle is avoided in its entirety, or a heavy-duty truck may need to hit the obstacle at some speed in other to pass over it.

The present disclosure evolves around the key concept of not only determining swept areas, but also recording obstacles in those swept areas. This way preferred areas for driving can be distinguished from areas comprising obstacles which may present problems, or which may simply be uncomfortable to drive over. To summarize the main concepts, the articulated vehicle <NUM> shown in <FIG> determines a drivable area by first obtaining data related to a track <NUM> of the articulated vehicle <NUM>. This data comprises a plurality of corresponding positions, headings and articulation angles <NUM> of the articulated vehicle along the track. The technique also comprises obtaining size information of the articulated vehicle <NUM>. Based on the size information and on the track-related data, the swept area <NUM> is determined. On way to do this was outlined in <CIT>. Furthermore, the disclosed technique also comprises configuring a sensor on the articulated vehicle to detect when the articulated vehicle makes contact with an obstacle such as the bump <NUM> or the curb <NUM>. Any encountered obstacle is recording, and a drivable area is then determined based on the swept area and on any recorded obstacles.

Herein, a position and heading may be either a position and heading in some global reference system like WGS-<NUM>, or it may be a relative position estimate based on a local reference point and orientation.

Global reference position data can be determined based on, e.g., a global positioning system (GPS) receiver or other satellite-based positioning system. A global position estimate can also be determined based on known landmarks or other reference information.

Global heading data can be determined using a compass.

A relative position can be defined based, e.g., on the vehicle location and orientation at some point in time, or it can be defined based on some fixed landmarks detected by a radar or lidar sensor.

A relative position estimate and heading can be transferred into a global reference system and back to the relative position estimate using a linear transform and its inverse transform.

Thus, it is appreciated that the herein disclosed techniques are applicable both in scenarios where global position reference data is available as well as in scenarios where only relative position data is available, e.g., due to not having a clear view of the sky as in mines, tunnels, and the like.

Different driving surfaces have different levels of roughness or evenness. A high quality asphalt road may be substantially different in roughness compared to a lower quality gravel road. Also, the asphalt road may comprise road shoulders with gravel. <FIG> illustrates an area <NUM> associated with some unevenness. Depending on vehicle and scenario, this area may be desirable to avoid.

Aspects of the disclosed techniques comprises detecting a surface roughness level of the drivable area in addition to the detection of obstacles. This information may be used to detect when the vehicle drives onto a road shoulder or drives off the road, even if no severe obstacles are encountered there.

Surface roughness can, e.g., be estimated based on vibrations in the air suspension system, and or based on detected minor disturbances in accelerations measured by an IMU.

<FIG> schematically illustrates an articulated vehicle <NUM>. The vehicle comprises a sensor <NUM> arranged in connection to a rear end <NUM> of the articulated vehicle to detect at least when the rear end of the articulated vehicle drives over an obstacle <NUM>, <NUM> and/or to detect a surface roughness level of the drivable area.

According to an example, the sensor <NUM> comprises a heading detection unit <NUM>. This heading detection unit may, e.g., operate based on any of a compass or a global positioning system receiver, GPS. The heading detection unit <NUM> can be used to detect a heading of the rear end of the articulated vehicle.

This heading of the rear end of the articulated vehicle can be used to refine the determination of the swept area. However, in case the front end of the articulated vehicle <NUM> also comprises a heading detection unit, then an estimate of articulation angle <NUM> can be obtained based on a difference between the headings of the rear and front ends of the articulated vehicle. This estimated articulation angle can be used to determine the swept area as shown by the example calculations in <CIT>. Advantageously, the estimated articulation angle by the difference in headings is independent from any other articulation angle sensors, such as a sensor <NUM> arranged in connection to a fifth wheel or kingpin <NUM> of the articulated vehicle. Consequently, the articulation angle value obtained in this way can be used to verify output from an external articulation angle sensor <NUM> of the articulated vehicle based on the estimated articulation angle value.

The sensor unit <NUM> may also comprise circuitry to determine an angle <NUM> of the rear end of the vehicle with respect to a horizontal level. This ground angle information can also be incorporated into the drivable area information. For instance, some areas may not be drivable due to a too steep slope or bank, which may cause risk of vehicle roll-over.

<FIG> shows another example vehicle <NUM> comprising the sensor unit <NUM>. Notably, this sensor unit is mounted separate from a door <NUM> of the vehicle. Therefore, the sensor unit is not affected if the door <NUM> is opened or removed from the vehicle for some reason.

The sensor units <NUM> discussed herein may according to some aspects comprise an inertial measurement unit (IMU), <NUM> configured to detect when the articulated vehicle drives over an obstacle and/or to detect when the articulated vehicle impacts an obstacle laterally, based on a measured acceleration.

The sensor units <NUM> discussed herein may according to some other aspects comprise a measurement device arranged in connection to the trailer suspension system configured to detect when the articulated vehicle drives over an obstacle.

Different obstacles can of course be present in the swept area. The obstacles are likely to differ in severity, and different operating scenarios may associate different levels of severity with different types of obstacles. For instance, a heavy duty truck for operating in a mine may not be overly sensitive to smaller bumps on the ground, while a semi-trailer having low ground clearance may be much more sensitive to uneven ground conditions with bumps and pot-holes.

The sensor units <NUM> discussed herein may also, according to some further aspects comprise a measurement device arranged in connection to the trailer suspension system configured to detect a level of road surface roughness. This information may be used to detect when the vehicle drives onto a road shoulder or drives off the road, even if no severe obstacles are encountered.

Consequently, the techniques disclosed herein may comprise classifying a detected obstacle according to a pre-configured list of obstacle types. The pre-configured list may comprise manually configured obstacle types and may comprise information related to severity and whether an autonomous driving algorithm is allowed to pass the obstacle, and if so with what speeds. As noted above, some obstacles may require a certain minimum speed in order to be traversed, in which case the autonomous driving algorithm may actually need to speed up in order to pass an obstacle.

The obstacle recording may comprise any of; determining a severity level of the obstacle, e.g., on a scale from <NUM> to <NUM>, recording a location of the obstacle, or a location associated with a recorded obstacle.

<FIG> illustrates an articulated vehicle <NUM> comprising the sensor unit <NUM>. This vehicle is configured to be connected to a remote server <NUM> for uploading and downloading data <NUM> related to drivable areas and to recorded obstacles. This way the vehicle can share information with other vehicles via the remote server.

<FIG> illustrates a system <NUM> for updating map information related to drivable areas at a remote server <NUM>. The system is arranged to receive information 530a, 530b from articulated vehicles related to drivable areas 21a, 21b. This way an articulated vehicle may obtain information related to drivable areas despite never having visited the area.

<FIG> is a flow chart illustrating methods disclosed herein and which summarize the above discussions. The methods are performed by the sensor unit <NUM>, or by the control unit <NUM>, or by a combination of sensor unit and control unit.

There is illustrated a method for determining a drivable area by a vehicle <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The method comprises obtaining S1 data related to a track <NUM> of the vehicle, wherein the data comprises a plurality of corresponding positions, headings and articulation angles <NUM> of the vehicle along the track, obtaining S2 size information of the vehicle, determining S3 a swept area <NUM> of the vehicle for the track based on the data and on the size information of the vehicle, configuring S4 a sensor <NUM> on the vehicle to detect when the vehicle drives over an obstacle <NUM>, <NUM>, recording S5 any obstacles detected by the sensor, and determining S6 the drivable area based on the swept area and on recorded obstacles.

According to aspects, the sensor <NUM> is arranged in connection to a rear end <NUM> of the vehicle to detect at least when the rear end of the vehicle drives over an obstacle <NUM>, <NUM>.

According to aspects, the sensor <NUM> comprises a heading detection unit <NUM>, and the method comprises detecting S11 a heading of the rear end of the vehicle.

According to aspects, the heading detection unit <NUM> comprises any of a compass or a global positioning system receiver (GPS).

According to aspects, the vehicle is an articulated vehicle, and the method comprises obtaining S12 a heading of a front end of the articulated vehicle <NUM> and estimating an articulation angle <NUM> value based on a difference between the headings of the rear and front ends of the articulated vehicle.

According to aspects, the method comprises verifying S13 an output from an external articulation angle sensor <NUM> of the articulated vehicle based on the estimated articulation angle value.

According to aspects, the sensor <NUM> comprises an inertial measurement unit (IMU) <NUM> configured to detect when the vehicle drives over an obstacle and/or to detect when the vehicle impacts an obstacle laterally, based on a measured acceleration.

According to aspects, the sensor <NUM> comprises a measurement device arranged in connection to the trailer suspension system configured to detect when the vehicle drives over an obstacle.

According to aspects, the recording comprises classifying S51 a detected obstacle according to a pre-configured list of obstacle types.

According to aspects, the recording comprises determining S52 a severity level associated with each detected obstacle.

According to aspects, the recording comprises recording a location S53 associated with each detected obstacle.

According to aspects, the method comprises uploading information S7 related to the determined drivable area to a remote server <NUM>.

According to aspects, the method comprises updating map information S8, by the remote server, based on the uploaded information.

<FIG> schematically illustrates, in terms of a number of functional units, the components of a control unit <NUM> or sensor unit <NUM> according to embodiments of the discussions herein. Processing circuitry <NUM> is provided using any combination of one or more of a suitable central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP, etc., capable of executing software instructions stored in a computer program product, e.g. in the form of a storage medium <NUM>. The processing circuitry <NUM> may further be provided as at least one application specific integrated circuit ASIC, or field programmable gate array FPGA.

Particularly, the processing circuitry <NUM> is configured to cause the control unit <NUM> or sensor unit <NUM> to perform a set of operations, or steps, such as the methods discussed in connection to <FIG>. For example, the storage medium <NUM> may store the set of operations, and the processing circuitry <NUM> may be configured to retrieve the set of operations from the storage medium <NUM> to cause the control unit <NUM> or sensor unit <NUM> to perform the set of operations.

The control unit <NUM> or sensor unit <NUM> may further comprise an interface <NUM> for communications with at least one external device, such as the antenna array comprising the phase controllers and the mechanically rotatable base plate.

The processing circuitry <NUM> controls the general operation of the control unit <NUM> or sensor unit <NUM>, e.g., by sending data and control signals to the interface <NUM> and the storage medium <NUM>, by receiving data and reports from the interface <NUM>, and by retrieving data and instructions from the storage medium <NUM>.

The control unit <NUM> optionally comprises a heading detection unit <NUM>, such as a compass or GPS module. The control unit may also comprise an IMU <NUM>.

The sensor unit <NUM> may optionally comprise any of a heading unit <NUM> and an IMU <NUM>.

<FIG> thus schematically illustrates a sensor unit <NUM> for determining a drivable area by a vehicle <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Notably, the sensor unit is arranged to detect when the vehicle drives over an obstacle <NUM>, <NUM>, and to record any obstacles detected by the sensor, and to transmit data related to any recorded obstacles to a control unit <NUM>.

<FIG> also schematically illustrates a control unit <NUM> for determining a drivable area by a vehicle <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Notably, the control unit is arranged to obtain data related to a track <NUM> of the vehicle, wherein the data comprises a plurality of positions and corresponding headings and articulation angles of the vehicle along the track, and to determine a swept area <NUM> of the vehicle for the track based on the data and on size information of the vehicle. The control unit <NUM> is arranged to receive data related to one or more obstacles <NUM>, <NUM> detected by a sensor unit <NUM>, and to determine the drivable area based on the swept area and on the received data.

Claim 1:
A method for determining a drivable area by a vehicle (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), the method comprising;
obtaining (S1) data related to a track (<NUM>) of the vehicle, wherein the data comprises a plurality of corresponding positions and headings of the vehicle along the track,
obtaining (S2) size information and cargo information of the vehicle,
determining (S3) a swept area (<NUM>) of the vehicle for the track based on the data and on the size information of the vehicle,
configuring (S4) a sensor (<NUM>) on the vehicle to detect when the vehicle makes contact with an obstacle (<NUM>, <NUM>),
recording (S5) any obstacles detected by the sensor, and
determining (S6) the drivable area based on the swept area, on recorded obstacles, and on cargo information.