TECHNICAL FIELD

The invention relates to a road user warning arrangement for attachment to a vehicle, to a vehicle comprising such a road user warning arrangement and/or to use of a road user warning arrangement on an autonomous vehicle or on an autonomous vehicle combination.

The invention can be applied in heavy-duty vehicles, such as trucks, buses and construction equipment. Although the invention will be described with respect to an autonomous heavy-duty vehicle combination comprising a vehicle in the form of a trailer, the invention is not restricted to this particular vehicle, but may also be used in other vehicles such as light-weight trucks, articulated haulers, excavators, wheel loaders and backhoe loaders.

BACKGROUND

During driving of autonomous vehicles, safety is a critical issue. This is particularly important when larger and heavier vehicles and vehicle combinations are driven autonomously, such as during highway driving. For example, there is a need to ensure that correct information to other road users is available during autonomous driving, such as informing following road users of unplanned stops or if the autonomous vehicle is driving at a low speed. During such occasions, hazard lights or the like should be deployed to inform the following road users that the vehicle is travelling at low speed or has stopped on the road. To ensure that e.g. safety lights are deployed, redundancy is required. For example, double independent hazard lights may be used. However, in the transport industry it is common that towing vehicles switch between and connect to different trailers during operation. These trailers may not be fully compatible and/or equipped with necessary technology to provide safety critical redundancy, such as use of the aforementioned double independent hazard lights.

Therefore, in view of the above, there is a strive towards developing improved technology relating to safety critical road user warning arrangements. SUMMARY

In view of the above, an object of the invention is to provide an improved road user warning arrangement for attachment to a vehicle, such as to a trailer, and/or an improved vehicle comprising the road user warning arrangement, which at least in some aspect alleviates at least one of the drawbacks of the prior art, and/or to at least provide a useful alternative.

According to a first aspect of the invention, the object is achieved by a road user warning arrangement for attachment to a vehicle according to claim 1. According to a second aspect of the invention, the object is achieved by a vehicle according to claim 17. According to a third aspect of the invention, the object is achieved by use of a road user warning arrangement on an autonomous vehicle or on an autonomous vehicle combination according to claim 19.

According to the first aspect thereof, the object is achieved by a road user warning arrangement for attachment to a vehicle, comprising,

- a light reflecting and/or light emitting surface,

- a positioning structure being arranged to position the light reflecting and/or light emitting surface in a warning position as soon as a perceived velocity of the vehicle is lower than a first predetermined value, the warning position being a position in which the light reflecting and/or light emitting surface is visible at least by other road users following the vehicle,

- a controlling element being arranged to control the positioning structure in such a way that at least a part of the light reflecting and/or light emitting surface is moved into a non warning position as soon as a perceived velocity of the vehicle is higher than a second predetermined value, the non-warning position being a position in which at least the part of the light reflecting and/or light emitting surface is not visible by other road users following the vehicle.

By the term “perceived velocity of the vehicle " as used herein is meant a velocity of the vehicle which is perceived by the road user warning arrangement when it is attached to the vehicle. The perceived velocity may correspond to the actual velocity, or substantially the actual velocity, of the vehicle. However, the perceived velocity of the vehicle may also be different from the actual velocity of the vehicle depending on factors such as ambient wind and/or weather conditions. The present invention has shown to provide a more robust and reliable road user warning arrangement. More specifically, by providing a configuration in which the light-reflecting and/or light emitting surface is moved between a warning position and a non-warning position in dependence of perceived vehicle velocity when being attached to a vehicle, a road user warning arrangement may be provided which may not rely on and be connected to the vehicle’s electronic control system. Therefore, an arrangement which is redundant to other possible vehicle safety systems may be provided. Still further, by providing such an arrangement, which may be independent from a vehicle’s electronic control system, it may be attached to any vehicle, such as to any trailer, without the need of connecting the arrangement to any control electronics of the vehicle. Hence, the road user warning arrangement may also be attached to vehicles, such as trailers, which lack other redundant hazard light systems and/or which are not compatible with control electronics of e.g. a towing vehicle. Moreover, by use of the road user warning arrangement as disclosed herein, a warning sign to following road users can be automatically activated without the need of manual input by a user. Thus, the road user warning arrangement may be beneficially used for autonomous vehicles without on-board drivers.

Optionally, the road user warning arrangement may further comprise a biasing member which is connected to the light reflecting and/or light emitting surface so that the biasing member forces the light reflecting and/or light emitting surface towards and into the warning position. Still optionally, the biasing member may be a spring, such as a coil spring.

Optionally, the controlling element may comprise a wind-controlled member which is arranged to control the positioning structure in dependence on wind caused by perceived velocity of the vehicle in such a way that at least the part of the light reflecting and/or light emitting surface is moved into the non-warning position as soon as the perceived velocity of the vehicle is higher than the second predetermined value. Thereby a mechanical rather than an electronic control may be achieved, which may imply a more robust and reliable configuration which may not be dependent on electronic control. Still optionally, the wind-controlled member may be a wind-catching member, such as a wind-catching shield. Thereby, movement from the warning position to the non-warning position may be provided by use of kinetic wind energy, rather than by use of e.g. an electric motor. Optionally, the wind-controlled member may be configured to be provided at a rear top section of the vehicle. Thereby, the wind-controlled member, such as e.g. the aforementioned wind-catching member, may be able to catch wind flow acting above the vehicle when the vehicle is moving.

Optionally, the controlling element may comprise an electric motor which is arranged to be controlled in dependence on vehicle velocity and/or wind caused by perceived velocity of the vehicle. The electric motor may be connected to a power source, such as a separate battery or to a power source of the vehicle. For example, the electric motor may be connected to an accelerometer, or the like, which measures vehicle velocity and/or to a wind measuring device.

Optionally, the road user warning arrangement may further comprise an attachment member which is arranged to releasably attach the road user warning arrangement to the vehicle, preferably to a rear section of the vehicle. Hence, the road user warning arrangement may be attached to and released from different vehicles. This may imply a more versatile road user warning arrangement which may be used for different vehicles.

Optionally, the road user warning arrangement may further comprise a support arrangement for providing the road user warning arrangement on a road surface in a warning position. This may imply a further versatile road user warning arrangement which also may be used as a separate road user warning arrangement. Thus, the road user warning arrangement may be provided on a road surface nearby the vehicle in the warning position when e.g. the vehicle has experienced an unplanned stop.

Optionally, the controlling element may be connected to the positioning structure via a gearing. Thereby a gear ratio between the controlling element and the positioning structure may be provided. Thus, working cooperation between the controlling element and the positioning structure may be configured by providing a suitable gear ratio based on factors such as size, shape and weight of the different components of the road user warning arrangement.

Optionally, the positioning structure may comprise at least one lever arm which is connected to and arranged to move at least the part of the light reflecting and/or light emitting surface between the warning position and the non-warning position. The at least one lever arm may thus provide a lever effect to facilitate movement into the non-warning position.

Optionally, the first and second predetermined values may be identical. Still optionally, the first and second predetermined values may be different. If the predetermined values are different, initiation of movement from the warning position to the non-warning position will not be performed at the same perceived velocity of the vehicle as initiation of movement from the non-warning position to the warning position. Thereby, and purely by way of example, unnecessary activation of the warning position may be avoided when temporarily slowing down the vehicle and/or the warning position may be kept for a longer time when the vehicle accelerates after an unplanned stop has occurred.

Optionally, the controlling element may comprise a pull/push-member, which may be connected to the biasing member as mentioned in the above, for pulling the positioning structure into the warning position as soon as the perceived velocity of the vehicle is lower than the first predetermined value, and for pushing the positioning structure into the non warning position as soon as the perceived velocity of the vehicle is higher than the second predetermined value.

Optionally, the light reflecting and/or light emitting surface may be triangle-shaped. A triangle-shaped light reflecting and/or light emitting surface is well-known for indicating a slow-moving or still-standing vehicle. Still optionally, the triangle-shaped light reflecting and/or light emitting surface may comprise a first and a second diagonally extending surfaces forming part of the triangle-shaped surface, as seen when the road user warning arrangement is attached to the vehicle, wherein the first and second diagonally shaped surfaces are moved into the non-warning position as soon as the perceived velocity of the vehicle is higher than the second predetermined value. Thereby the visible triangle shaped surface may disappear and only a horizontal surface may remain when the perceived velocity of the vehicle is higher than the second predetermined value.

According to the second aspect thereof, the object is achieved by a vehicle comprising the road user warning arrangement according to any one of the embodiments of the first aspect of the invention. Advantages and effects provided by the second aspect of the invention are largely analogous to the advantages and effects provided by the first aspect of the invention. It shall also be noted that all embodiments of the second aspect of the invention are applicable to and combinable with all embodiments of the first aspect of the invention and vice versa.

Optionally, the vehicle may be an autonomous vehicle or a vehicle connectable to an autonomous vehicle, such as a trailer.

According to a third aspect thereof, the object is achieved by use of a road user warning arrangement according to any one of the embodiments of the first aspect of the invention on an autonomous vehicle or on an autonomous vehicle combination comprising an autonomous towing vehicle and at least one connected trailer.

Advantages and effects provided by the third aspect of the invention are largely analogous to the advantages and effects provided by the first and second aspects of the invention. It shall also be noted that all embodiments of the third aspect of the invention are applicable to and combinable with all embodiments of the first and second aspects of the invention and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

In the drawings:

Figs. 1a and 1b show perspective rear views of an autonomous vehicle combination comprising a vehicle in the form of a trailer according to an embodiment of the present invention.

Fig. 2a shows a rear view of a vehicle in the form of a trailer which is equipped with a road user warning arrangement according to an example embodiment of the present invention;

Fig. 2b shows a view of a part of the road user warning arrangement as shown in fig. 1a when it is in a warning position; Fig. 3a shows the trailer with the road user warning arrangement of fig. 1a when the road user warning arrangement is in a non-warning position; and

Fig. 3b shows a view of a part of the road user warning arrangement as shown in fig. 2a when the road user warning arrangement is in the non-warning position.

The drawings show diagrammatic exemplifying embodiments of the present invention and are thus not necessarily drawn to scale. It shall be understood that the embodiments shown and described are exemplifying and that the invention is not limited to these embodiments. It shall also be noted that some details in the drawings may be exaggerated in order to better describe and illustrate the invention. Like reference characters refer to like elements throughout the description, unless expressed otherwise.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION Perspective views of an autonomous heavy-duty vehicle combination comprising a vehicle in the form of a trailer 100 according to an embodiment of the present invention can be seen in figs 1a and 1b. A rear-view of the trailer 100 is shown in figs. 2a and 3a. The trailer 100 may be connected to e.g. an autonomous vehicle, such as an autonomous heavy-duty truck, as shown in figs. 1a and 1b, or an autonomous vehicle (not shown) which is adapted to tow heavy-duty trailers. Even though the described embodiments of the invention relate to a heavy-duty trailer for an autonomous vehicle, the invention is not restricted to this type of vehicle, but may also be used for other vehicles as e.g. mentioned in the above.

Figs. 1a-3b show embodiments of a road user warning arrangement 1 according to the present invention when being in a warning position (figs. 1a, 2a and 2b) and when being in a non-warning position (figs. 1b, 3a and 3b). The road user warning arrangement 1 as shown is also attached to a rear side of the trailer 100.

Furthermore, the road user warning arrangement 1 as shown has a triangle-shaped light reflecting surface 2, comprising first and second diagonally extending surfaces, 21 , 22 and one horizontally extending surface 23 connecting the first and second diagonally extending surfaces 21, 22 so that a triangle-shaped surface is provided, as seen when the road user warning arrangement 1 is attached to a vehicle. It shall however be noted that a triangle-shaped surface is only an example embodiment of the present invention, even though a triangle-shape may be preferred since it is recognized by many as an indication of a slow-moving or still-standing vehicle. Further, the surface 2 may not only be a reflecting surface, but may in addition or alternatively be a light emitting surface. The triangle-shaped surface 2 has been omitted in figs. 2b and 3b to better explain and show the details of the road user warning arrangement 1.

The road user warning arrangement 1 comprises the triangle-shaped light reflecting and/or light emitting surface 2, and a positioning structure 3 which is arranged to position the light reflecting and/or light emitting surface 2 in a warning position as soon as a perceived velocity of the vehicle 100 is lower than a first predetermined value. The warning position is a position in which the light reflecting and/or light emitting surface 2 is visible at least by other road users following the vehicle 100, as shown in figs. 1a and 2a. The road user warning arrangement 1 further comprises a controlling element 4 which is arranged to control the positioning structure 3 in such a way that at least a part of the light reflecting and/or light emitting surface 2 is moved into a non-warning position as soon as a perceived velocity of the vehicle 100 is higher than a second predetermined value. The non-warning position is a position in which at least the part of the light reflecting and/or light emitting surface 2 is not visible by other road users following the vehicle, as shown in figs. 1b and 3a. More specifically, in the shown embodiment, the two diagonally extending surfaces 21 , 22 are not visible for road users following the vehicle when the road user warning arrangement 1 is in the non-warning position.

The road user warning arrangement 1 may further comprise a biasing member 5, here in the form of a coil spring, which is connected to the light reflecting and/or light emitting surface 2 so that the biasing member forces the light reflecting and/or light emitting surface 2 towards and into the warning position. In the shown embodiment the biasing member 5 is connected to a pull/push member 42 of the controlling element 4. The pull/push member 42 is here in the form of an arm which extends substantially vertically in a z-axis direction from the positioning structure 3 and up to a wind-controlled member 41 of the controlling element 4, as seen when the road user warning arrangement 1 is attached to the vehicle 100. The pull/push-member 42 is configured to pull the positioning structure 3 into the warning position as soon as the perceived velocity of the vehicle 100 is lower than the first predetermined value, and to push the positioning structure 3 into the non-warning position as soon as the perceived velocity of the vehicle 100 is higher than the second predetermined value. It shall be noted that pushing/pulling may in an alternative embodiment be performed in a contrary manner, i.e. the pull/push member may be configured to push the positioning structure into the warning position and to pull the positioning structure into the non-warning position.

The wind-controlled member 41 is arranged to control the positioning structure 3 in dependence on wind caused by perceived velocity of the vehicle in such a way that at least the part of the light reflecting and/or light emitting surface 2 is moved into the non warning position as soon as the perceived velocity of the vehicle 100 is higher than the second predetermined value. As can be seen in the figs., the wind-controlled member 41 may be in the form of a wind-catching shield. Furthermore, as shown in the figs., the wind- controlled member 41 may be provided at a rear top section of the vehicle 100, such that it extends above a roof of the vehicle 100, at least when the road user warning arrangement 1 is in the non-warning position. Hence, when the vehicle 100 is moving forward, in an x-axis direction as shown in figs. 1b and 3b, a wind w will be acting in an opposite direction on the wind-controlled member 41 , which corresponds to a perceived velocity of the vehicle 100 in the x-axis direction.

The size/shape of the wind-controlled member 41 and the biasing force of the biasing member 5 may be configured so that the road user warning arrangement 1 is moved to the non-warning position when the vehicle is running at a perceived velocity which is higher than a second predetermined value, such as e.g. 30 km/h, and so that the road user warning arrangement is moved to the warning position when the vehicle is running at a perceived velocity which is lower than a first predetermined value, such as 30 km/h. It shall here be noted that ambient wind/weather conditions may result in that the perceived velocity of the vehicle is higher or lower than the actual vehicle velocity. Therefore, according to an example embodiment, means for adjusting the first and/or second predetermined values may be provided. For example, such means may be configured so that a user may manually adjust the first and/or second predetermined values. The means for adjusting may for example include adjusting a tensioning force of the biasing member 5, a gear ratio of the aforementioned gearing, a length of the lever arm 31 and/or a length of the pull/push member 42.

The road user warning arrangement 1 may further comprise an attachment member 6 which is arranged to releasably attach the road user warning arrangement 1 to the vehicle 100, preferably to a rear section of the vehicle 100. The attachment member 6 may for example comprise one or more hooks or the like for releasably attaching the road user warning arrangement 1 to the vehicle 100.

The controlling element 4 may be connected to the positioning structure 3 via a gearing (not shown). For example, a gearing with a specific gear ratio may be provided between the pull/push member 42 and a shaft member 32 of the positioning structure 3 which extends along a y-axis direction, which is parallel to a transverse direction of the vehicle 100.

The X-, y- and z-axis as used herein may refer to a Cartesian coordinate system whereby the axles are provided perpendicularly with respect to each other. The x-axis may correspond to a driving direction of the vehicle 100, the y-axis may correspond to a transverse direction of the vehicle 100 and the z-axis may correspond to a vertical direction of the vehicle 100.

The positioning structure 3 may further comprise at least one lever arm 31 which is connected to and arranged to move the light reflecting and/or light emitting surface 2 between the warning position and the non-warning position. Two lever arms 31 connected to the shaft member 32 are provided in the shown embodiment. More specifically, in the shown embodiment, the shaft member 32 of the positioning structure 3 is arranged to rotate about the y-axis when the pull/push member 42 is actuated by a force generated by the wind w acting on the wind-controlled member 41 , which in turn provides a rotation of the lever arms 31 about the y-axis. The lever arms 31 will then push on the diagonally extending surfaces 21, 22 which are moved to the non-warning position. The diagonally extending surfaces 21, 22 are pivoted about a respective axis (not shown) so that the reflecting surfaces are not visible from a position behind the vehicle 100, i.e. in the direction of the x-axis.

As mentioned in the above, the controlling element 4 may also or alternatively comprise an electric motor (not shown) which is arranged to be controlled in dependence on vehicle velocity and/or wind caused by perceived velocity of the vehicle. For example, the electric motor may be arranged to provide a rotation of the positioning structure 3 about the y- axis. The electric motor may be connected to an accelerometer (not shown), or anything else which is able to detect velocity of the vehicle 100. The electric motor may also be connected to a wind measuring device (not shown) which detects speed of ambient wind, which corresponds to perceived vehicle velocity.

The road user warning arrangement 1 may further comprise a support arrangement (not shown) for providing the road user warning arrangement on a road surface in a warning position. Thus, the road user warning arrangement may also be used as e.g. a standard warning triangle which is put on ground by a user after an unplanned stop of a vehicle along a road section. It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.