Method for handling obstacles in an industrial truck and industrial truck

Description

[0001] The present invention relates to a method for obstacle handling in an industrial truck, which comprises at least one sensor unit arranged in the main direction of travel of the industrial truck and configured to detect obstacles within a predetermined angular range. Furthermore, the invention relates to an industrial truck configured to carry out such a method during operation.

[0002] In the daily use of transport equipment in logistics facilities, collisions between industrial trucks and warehouse equipment, industrial trucks and other vehicles, or industrial trucks and people can occur more frequently, especially during peak times. One approach to counteracting such collisions could be to use a radio-based system that informs the industrial trucks about the presence of obstacles. However, it has been shown that, especially in automated vehicles, the sensors currently used lead to unnecessary braking and thus limit the performance of such vehicles.

[0003] In order to also be able to include objects and persons without such radio equipment in the protection concept, it is known to use sensor units in floor conveyors, which can check the environment thereof for obstacles and in particular be mounted and aligned on the floor conveyors in the main travel direction. In this case, so-called protection fields are spanned, which are often in horizontal planes just above the travel surface.

[0004] If such a sensor unit detects an object, a corresponding information can be generated and / or a vehicle reaction can be triggered.

[0005] Of course, it is desirable that a corresponding vehicle only react when a collision is actually possible, i.e., when an obstacle is located within the vehicle's intended range of motion. Therefore, it is essential for such safety systems to define a collision zone or protection zone.

[0006] In previously known methods for defining collision zones, it was common practice to permanently program a number of collision zones in the form of parameterized geometric fields at suitable locations in a processing system so that they could be accessed during operation of such industrial trucks. To improve the protective effect at different speeds and steering angles of the respective industrial truck, the sensor unit would then switch back and forth between the various permanently programmed fields in its field of view to identify potential collision hazards while simultaneously masking out irrelevant areas.Accordingly, for example, protective fields of an autonomous transport system (AGV - Automated Guided Vehicle) could serve as a safety system of such an industrial truck, while within the scope of the present invention they can also be used in manually controlled industrial trucks in the manner described below.

[0007] However, it becomes apparent that the possible number of such fields is limited by the system, and the aforementioned switching through the zones requires a physical connection between the components of the processing system involved in this process, usually based on digital inputs and data connections. Furthermore, a different set of fields must be generated for each conceivable vehicle type and model series and made available to the corresponding sensor units on a dedicated memory. This entails considerable design and cost expenditure.

[0008] By way of example, reference is made in this context to US 2019 / 0271990 A1, which teaches a method for obstacle handling in an industrial truck in which a protection zone is calculated based on operating parameters of the vehicle, the method comprising: Detecting a current speed and a current steering angle of at least one steered wheel of the industrial truck by means of a speed sensor or a steering angle sensor of the industrial truck; calculating a protection zone based on the current speed and the current steering angle; evaluating the data supplied by the at least one sensor unit within the protection zone of the industrial truck, and triggering a predetermined measure upon detection of an obstacle in the protection zone.

[0009] It is therefore desirable within the scope of the present invention to use an improved approach for defining a protection zone in an industrial truck which can eliminate the disadvantages mentioned above. In particular, a method is to be used with which accidents caused by collisions with obstacles can be prevented in both automated and manually controlled industrial trucks, wherein the obstacles can be formed, for example, by people, pallets or other objects in the operating environment of the industrial truck. Depending on the type of industrial truck used, the causes of such collisions can lie, for example, in human error, for example an obstacle being overlooked by a driver of the industrial truck, or in errors in the sensor data processing or in the sensor itself in autonomously controlled industrial trucks.

[0010] However, when using such protection zones, it is also apparent that a variety of situations can occur in which false positive detections of obstacles occur, for example in cases where manually operated industrial trucks are cornering near a wall and a simple projection of the current path of the industrial truck into the future would lead to a collision with the wall, even though the driver of the industrial truck in question has the situation under control and would carry out appropriate counter-steering in time to end the cornering and then move, for example, parallel to the wall.Although corresponding scenarios are also conceivable in autonomous industrial trucks, since the planned route is deterministic and does not have to be aimed at the behavior of a human operator, it can be estimated in advance whether a possible violation of a protection zone is a deliberate behavior, for example in the context of cornering as mentioned above, or whether a collision with an initially unforeseen obstacle is to be feared.

[0011] There is therefore a need at this point for an assistance system and a corresponding method with which obstacles detected during operation of such an industrial truck can be handled in an improved manner and conclusions can be drawn as to the extent to which a current situation of the industrial truck is indeed problematic with regard to such obstacles in order to avoid or completely rule out false positive detections of obstacles, but without intervening in situations in which in particular a driver of the industrial truck has the situation under control and it is an expectable behavior without risk.

[0012] To achieve this object, the invention proposes a method for obstacle handling in an industrial truck, which has a known vehicle layout in a plan view and comprises at least one sensor unit which is arranged in the main direction of travel of the industrial truck and is designed to be able to detect obstacles in a predetermined angular range, the method comprising detecting a current speed and a current steering angle of at least one steered wheel of the industrial truck by means of a speed sensor or a steering angle sensor of the industrial truck, calculating a predicted vehicle contour based on the vehicle layout, the current speed and the current steering angle such that the predicted vehicle contour corresponds to an area to be covered by the industrial truck in a predetermined period of time,evaluating the data supplied by the at least one sensor unit within the predicted vehicle contour as a protection zone of the industrial truck, and upon detection of an obstacle in the protection zone, calculating a respective steering angle difference on both sides at which a collision with the obstacle is avoided, and classifying a current degree of difficulty of obstacle avoidance based on the calculated steering angle differences using a steering angle difference limit value, and / or triggering a predetermined measure based on the calculated steering angle differences using a steering angle difference limit value.

[0013] The method according to the invention makes it possible to classify current driving situations in which an obstacle has been detected in a protective zone of an industrial truck based on levels of difficulty, which are based at least on a steering angle difference that would be necessary to avoid the obstacle, and / or to intervene automatically in the operation of the vehicle by immediately triggering measures. Accordingly, in the example of cornering near a wall already mentioned above, it could be determined that even a small steering angle difference in a direction away from the wall could prevent a collision, so that such a situation would be classified with a low level of difficulty and / or it would be decided that no measure in the sense of intervening in the operation of the vehicle is necessary.The possible use of a steering angle difference limit in this context allows a human driver to distinguish between an intentional and an unintentional violation of the protective field in a relatively simple manner. This limit can depend on the current speed, the current steering angle, the driver's experience level, etc.

[0014] It turns out that the smaller of the two steering angle differences can be used to classify the current level of difficulty, since it can generally be assumed that an evasive maneuver would occur to the corresponding side, which corresponds to the typical behavior of a human driver of such a vehicle. Accordingly, in the above-mentioned example of cornering near a wall, it would be irrelevant that the required steering angle difference to avoid the obstacle in the direction toward the wall would be significantly larger, since evasive maneuvering away from the wall would usually occur.

[0015] Although the classification of current levels of difficulty in the operation of an industrial truck could also serve merely to collect data for evaluating a logistics environment being traveled through or similar, the method according to the invention could also, for example, trigger a predetermined measure on the industrial truck depending on the current level of difficulty in order to be able to immediately provide an assistance system for increased operational safety and to directly establish a causal relationship between the level of difficulty and the corresponding measure. The manner in which the predetermined measure is carried out can also depend on various other parameters, as will be discussed further below.

[0016] An example of such a predetermined measure could include reducing the current and / or maximum speed of the industrial truck, so that either the achievable speed of the industrial truck can be limited or it can be immediately automatically decelerated, for example, depending on the determined current level of difficulty. In particular, such a reduction in the maximum or current speed can be carried out in such a way that a complete stop in front of the obstacle remains possible in any case. This is an iterative process that will ultimately lead to a complete standstill of the vehicle if the vehicle continues to travel towards an obstacle.However, if it is determined in the meantime that the obstacle is no longer in the protection zone, for example because it has been avoided or the obstacle itself has moved out of the protection zone, the corresponding measure can be canceled and the vehicle can be accelerated again and / or its maximum speed can be increased again.

[0017] An additional or alternative predetermined measure could include issuing a corresponding message to an operator, for example, a warning on a display or an acoustic signal. Although this primarily applies to the driver of the industrial truck in the case of a manually controlled vehicle, it would of course also be conceivable for remote-controlled or autonomously driven vehicles to output a message to a remote operator or to a control center to inform an operator working there.

[0018] With regard to the type of output, different approaches are conceivable in principle. For example, only a warning light could light up in the operator's field of vision or an acoustic warning signal could be issued if a situation with a certain degree of difficulty occurs, or the operator could be provided with further information on a dedicated display device, for example a map view on which the corresponding obstacle is shown together with the vehicle in relative spatial relationship together with a warning.

[0019] According to the invention, further parameters can be taken into account in the present method for classifying the current level of difficulty and / or for triggering the predetermined measure, in particular the current steering angle of the industrial truck, the current speed of the industrial truck, the experience level of an industrial truck driver, and / or the calculated steering angle difference compared to the current steering angle. An example of this could be that, when traveling straight ahead and detecting an obstacle in the corresponding protection zone, a classification could always be made that would result in an immediate predetermined measure, since it can be assumed that no case should occur in which the industrial truck approaches an obstacle head-on.Likewise, braking could be applied earlier and more forcefully at a higher current speed, and it could be taken into account that, due to the centrifugal forces that occur, evading in a direction opposite to a current cornering movement is easier to execute and may therefore involve a lower degree of difficulty. Furthermore, it could be taken into account that in cases where the vehicle is already cornering, it may be more sensible to evade by steering straight ahead, even if the steering angle difference is greater than with an evasive maneuver towards the inside of the curve, since in this case, steering towards the inside of the curve can essentially mean reversing the vehicle, whereas in the other direction, steering straight ahead enables evasive maneuvering.When cornering, it may also be more realistic for the desired direction of travel to point in the direction of straight ahead rather than cornering with a smaller radius, for example in the case of delayed straight-line steering when cornering.

[0020] The driver's level of experience can be incorporated into the classification of the current level of difficulty and / or the triggering of the predetermined measure in such a way that corresponding data on the level of experience is stored in a suitable manner. For example, less severe measures are initiated for a more experienced driver upon detecting an obstacle than for a less experienced driver, since the two drivers are considered to have different levels of ability to avoid obstacles and deal with potentially critical situations. Likewise, certain situations could be tolerated for more experienced drivers, i.e., rated with a low level of difficulty or no difficulty at all, whereas for less experienced drivers they would already be rated with a higher level of difficulty or would trigger measures.The specific measures implemented can also be made dependent on the level of experience in a similar way, for example by applying more powerful automatic braking for a less experienced driver in order to achieve greater safety tolerances in the operation of the industrial truck.

[0021] Although the classification of the current difficulty levels initially allows for any number of gradations, it can at least include a low difficulty level and a high difficulty level. Thus, in addition to a state with no difficulty level (no protective field violation), two different categories corresponding to a tolerable protective field violation and an intolerable protective field violation, in which, for example, an evasive steering angle limit is exceeded or undershot. Furthermore, if the low difficulty level occurs, only a warning could optionally be issued, while if the high difficulty level occurs, automatic measures could be triggered in the industrial truck that affect its operation, for example, the automatic braking already mentioned several times.Alternatively, no action could be taken at the low difficulty level, and a warning could be issued at the high difficulty level. The decision as to which action is taken at which difficulty level could be based, for example, on the driver's experience level or the current speed. For example, at a comparatively low speed and a high difficulty level, only a warning could be issued, while at a comparatively high speed and a high difficulty level, automatic braking could occur.

[0022] In this context, a maximum steering angle of the industrial truck can also be specified, which cannot be exceeded in order to avoid a collision, so that in certain situations it can be determined that evasion in the corresponding direction is impossible under the current circumstances.

[0023] With regard to the detection of obstacles in the determined protection zone, the current speed of the industrial truck can be incorporated according to the invention in such a way that, through the evaluation of a predetermined period of time, the distance the industrial truck is expected to move in this predetermined period of time is mapped, which in turn will be reflected in the calculated protection zone. Furthermore, it can be assumed that the industrial truck has a known vehicle layout in a top view, and the protection zone can be calculated based on the vehicle layout in such a way that a predicted vehicle contour, which corresponds to an area to be covered by the industrial truck in a predetermined period of time, is used as the protection zone.

[0024] Thus, the method according to the invention can be used to precisely map the area expected to be swept by the vehicle in a predetermined period of time. Depending on the resolution of the available sensor data, a single protection zone can be obtained that adapts to the current operating situation of the industrial truck, which in turn can form the basis for the method described above. Accordingly, false detections can be avoided at this point, and the prediction of obstacles in the path of the industrial truck can be applied to a wide variety of vehicle types, as long as the respective known vehicle layout of the corresponding vehicle types is available when executing the method.Of course, in this context it is also possible to define the vehicle layout in such a way that it is selected to be larger than the actual external dimensions of the corresponding industrial truck, for example in order to be able to take into account loads to be picked up or distance tolerances to be maintained.

[0025] In this case, the calculation of the predicted vehicle contour can be carried out in polar coordinates, whereby in particular the pole of the polar coordinate system can correspond to a center point of the industrial truck in relation to its longitudinal and latitudinal axes and / or the polar axis of the polar coordinate system can correspond to the main direction of travel of the industrial truck.

[0026] By using polar coordinates, the computational effort for obstacle detection can be kept very low, as neither trigonometric functions nor roots need to be calculated. Instead, by interpolating the predicted vehicle contour specified by contour points, which corresponds to the resolution of the at least one sensor unit used, obstacle detection can be implemented simply as a comparison of detected distances with predicted distances and can therefore be traced back to a greater-than-or-equal-to operation. In other words, if an object is detected at a certain angle to the polar axis of the polar coordinate system, a comparison can be made between the determined distance between the object and the industrial truck and a predicted distance. If the distance is exceeded, a collision is to be expected.

[0027] Furthermore, the predicted vehicle contour can be calculated by calculating a plurality of support points, which corresponds to calculating the positions of the vehicle at successive points in the future. The number of support points can be selected depending on the current vehicle speed in order to obtain an optimally constructed protection zone in the manner described above. The granularity of the support point calculation can also be performed in a manner that offers an optimal compromise between computational effort and resolution of the protection zone. In particular, the trajectories containing the support points can also be interpolated or smoothed as boundary lines of the protection zone.

[0028] As already mentioned above, the present invention further relates to an industrial truck which is configured to carry out a method of the type just described during its operation, comprising a vehicle body, at least one sensor unit which is arranged in the main direction of travel of the industrial truck and is configured to be able to detect obstacles in a predetermined angular range, a speed sensor and a steering angle sensor, and a control unit which is configured to receive data from the speed sensor and the steering angle sensor, to calculate a protection zone in the manner described above, to calculate a steering angle difference on both sides, at each of which a collision with an obstacle detected within the protection zone is avoided,and to classify a current degree of difficulty of obstacle avoidance based on the calculated steering angle differences and / or to trigger a predetermined action based on the calculated steering angle differences.

[0029] As mentioned above, when determining the protection zone, a vehicle contour can be calculated based on a known vehicle outline. Here, the vehicle footprint used to calculate the predicted vehicle contour can again be selected to be larger than the actual vehicle body in order to take into account loads to be absorbed and clearance tolerances.

[0030] Furthermore, it should be noted at this point that the predetermined angular range in which the at least one sensor unit detects the surroundings of the industrial truck should expediently be at least as large as a possible steering angle of the industrial truck and should ideally be 180° around the main direction of travel.

[0031] Although different types of sensor units can be envisaged in industrial trucks according to the invention, this sensor unit can in particular comprise a LIDAR unit, such sensor types being characterized by high accuracy and reliability at a reasonable price.

[0032] Finally, it should be pointed out that the industrial truck of the present invention can be a manually operated industrial truck and, accordingly, the method according to the invention serves to assist a human driver thereof, although in principle, use as a safety system in an autonomously operated vehicle should not be excluded.

[0033] Further features and advantages of the present invention will become more apparent from the following description of an embodiment thereof, when considered together with the accompanying figures. These show in detail: Figure 1 shows a schematic representation of an operating situation of an industrial truck according to the invention at a predetermined steering angle; Figure 2 shows a schematic representation for defining a protection zone in the example from Figure 1 ; Figure 3 shows a schematic representation of an internal representation of the protection zone and the detection of an obstacle; Figure 4 shows a schematic representation of a calculation of steering angle differences to avoid a collision with an obstacle; Figure 5 shows a schematic representation of another operating situation of an industrial truck according to the invention; Figure 6 shows a comparative representation of two operating situations of an industrial truck according to the invention; Figure 7 shows an overview of several operating situations of an industrial truck according to the invention with corresponding levels of difficulty; and Figure 8 shows a schematic representation of a determination of a maximum permissible speed of an industrial truck according to the invention.

[0034] Figure 1 shows, in a schematic plan view, first of all an operating situation of an industrial truck 10 according to the invention, which makes a left turn with a steering angle of 15° with respect to its main direction of travel or longitudinal direction L in order to illustrate the calculation of a protection zone of the industrial truck 10.

[0035] The industrial truck 10 has a known vehicle footprint 12, which extends beyond the actual vehicle body in such a way that any loads carried by the vehicle 10 are also covered. Furthermore, the industrial truck 10 comprises a sensor unit 14, which is arranged at the front of the industrial truck 10 in the main direction of travel L and covers an angular range of at least 180°, as indicated by the schematically illustrated sensor field S in Figure 1is indicated, whereby the extent of the sensor field S in practice will of course extend considerably further around the vehicle 10 than in the schematic view from Figure 1 indicated.

[0036] Furthermore, the industrial truck 10 comprises a pair of unsteered wheels 16 and a steered wheel 18. In the case illustrated here, the industrial truck 10 is a manually controlled industrial truck designed and configured for transporting objects in logistics facilities. For this purpose, it further comprises a control unit 20, shown only schematically, as well as speed and steering angle sensors (not shown), which, like the sensor unit 14, deliver their data to the control unit 20.

[0037] As from Figure 1 As can be seen, the control unit 20 carries out a process for defining a protection zone, the outline of which is Figure 1is schematically indicated by two curved lines and designated by the reference symbol Z. The resulting protection zone Z corresponds to a predicted vehicle contour, which is determined on the basis of the known vehicle footprint 12, the instantaneous speed and the instantaneous steering angle, which are provided by the speed and steering angle sensors already mentioned.

[0038] Here, the method according to the invention for defining the protection zone Z is carried out by means of an iterative calculation of a plurality of support points P, which each correspond to the corners of the vehicle outline 12 when the vehicle 10 has advanced a certain distance on the aforementioned curved path. Such extrapolated positions of the industrial truck 10 are shown in Figure 1each shown in dashed lines. Based on the thus determined support points P, the protection zone Z can now be determined, whereby both the granularity of the evaluation of the support points P and the number of considered support points P can be selected appropriately and, if necessary, an interpolation of the support points P can be carried out to smooth the outlines of the protection zone Z.

[0039] Accordingly, when viewed in polar coordinates, in which the main direction of travel or longitudinal direction L of the industrial truck 10 corresponds to the polar axis 0°, a protection zone Z can be defined as in Figure 2 If this protection zone Z is Figure 2If this is now further plotted in a histogram in which the polar angle forms the x-axis, the result is the representation in Figure 3, in which again the main direction of travel or longitudinal direction L is at 0° and the fact that the vehicle 10 is currently in a left-hand bend means that the angular range between 30° and 60° represents a larger extent in relation to the protection zone Z.

[0040] In particular, by using polar coordinates, an obstacle H, which is in the Figures 2 and 3shown, can be classified as falling within the protection zone Z with little computational effort by performing a simple distance calculation at the corresponding angle. In this way, with the method according to the invention, an optimal protection zone Z can be determined in such an industrial truck in such a way that obstacles H can be reliably detected, but on the other hand, false positive results are minimized or even completely eliminated by the optimal definition of the protection zone Z.

[0041] Based on this definition of a protection zone, Figure 4 the calculation of a steering angle difference used according to the invention to prevent a collision with the obstacle on both sides is described.

[0042] In the Figure 4In the case shown in the middle, the aisle conveyor 10 is turning a right curve and it has been determined that an obstacle H in the form of a pallet is located on the corresponding predicted path, which corresponds to the protection zone of the vehicle 10. Starting from this current steering angle, both an increase in the current steering angle, i.e., a swerve to the right, and a decrease in the current steering angle, i.e., a swerve to the left, are simulated in real time. Based on the known vehicle footprint 12 of the aisle conveyor 10, it can be deduced that a steering angle difference of at least 10° to the right or left is necessary to avoid the obstacle H, as can be seen from the rightmost and leftmost illustrations in Fig. 4 while a steering angle difference of, for example, 3° to the right or left is respectively still insufficient, as can be seen from the further illustrations.

[0043] Thus, with this procedure, the respective required steering angle differences on both sides can be derived, which can be used in the classification of a current degree of difficulty of obstacle avoidance described below, whereby the smaller of the two steering angle differences is usually used for the classification.

[0044] First of all, Figure 5 which in its four representations 1 to 4 illustrates a driving through a curve in the area of ​​a rectangular wall W by an industrial truck 10, which in each case is arranged with its according to the method described above and in Fig. 1 shown in the procedure described. Such a situation represents a typical operating case of such an industrial truck 10 and should therefore be able to be handled without problems by a human driver of the industrial truck 10.

[0045] However, it turns out that after turning in Figure 1. Figure 5 In the state shown in Figure 2 and particularly Figure 3, the rectangular wall extends into the protection zone Z of the industrial truck 10 and is thus detected as an obstacle. However, the driver of the industrial truck 10 can prevent a collision with the wall by slightly counter-steering to the right or by straightening his steering wheel during normal cornering, so that due to the small required steering angle difference to the current value, a problematic situation never arises and consequently the degree of difficulty can be determined as low at any time. Accordingly, no measures need to be initiated and the driver of the industrial truck 10 can proceed unhindered and as shown in Figure 4. Figure 5As shown, straighten the steering at the exit of the curve and continue driving without the temporary presence of the wall in the protection zone Z having any influence on the described process.

[0046] In Figure 6 In illustration a, the situation is again shown Figure 5for comparison, which has just been discussed, while illustration b shows a case in which the corresponding situation is assessed as having a high degree of difficulty. Here, another industrial truck 100 is detected as an obstacle which enters the protection zone Z of the industrial truck 10 at a certain point in time. Since the industrial truck 10 is moving at a higher speed compared to illustration a and has already come closer to the obstacle, this situation is assessed as having a high degree of difficulty, even though a relatively small steering angle difference would be sufficient here to avoid the obstacle. It can thus be seen that the method according to the invention can be further improved by using further parameters in addition to the steering angle difference when assessing the current degree of difficulty.

[0047] Figure 7now shows some further scenarios in which a high degree of difficulty is determined and corresponding measures can be initiated, for example issuing a warning to a driver of the industrial truck 10 and / or automatically reducing a current or maximum speed thereof.

[0048] While as in connection with Figure 5 discussed and in Figure 7As shown again on the left, driving through a curve close to a right-angled wall is assessed as having a simple level of difficulty due to the small steering angle difference required to avoid a collision and no measures are therefore initiated. The other four illustrations each show cases in which high levels of difficulty are determined. In the case shown in the middle above, there is another industrial truck F in the area of ​​the right-angled wall W, which would require a significantly greater steering difference to the right at the exit of the curve and therefore causes a more difficult situation. Similarly, in the case shown above right, the industrial truck 10 followed the curved path too far and thus came very close to the wall W at an unfavorable angle.Here, too, a large steering angle difference to the right is necessary to avoid a collision and the situation is rated as having a high degree of difficulty.

[0049] In the illustration below right, another industrial truck F is present as an additional obstacle, and the industrial truck 10 considered here is traveling towards the wall at an angle that is unfavorable for it to swerve to the right or left. This also means that a high degree of difficulty exists here, and suitable measures such as automatic braking and / or warning a driver can be initiated. Finally, in the middle below, a case is shown in which an obstacle is detected in the protection zone Z while traveling straight ahead. For such cases, it can be specified that a classification with a high degree of difficulty is always made, since it can be assumed that under no circumstances should a case occur in which the industrial truck 10 travels head-on towards an obstacle.

[0050] Finally, with reference to Figure 8Another exemplary measure in the event of an obstacle being detected in a protection zone of an industrial truck 10 will be described, namely an automatic reduction in speed. In the left-hand illustration, it is first determined that the industrial truck 10, due to its current steering angle, is traveling toward a wall that has entered the protection zone of the industrial truck 10. Based on the procedure described above, it is then determined that this is a situation that requires the initiation of a measure, in this case, a reduction in the speed of the vehicle 10.

[0051] For this purpose, starting from the current speed of the industrial truck 10 of 2.2 m / s, it is determined by how much the speed must be reduced in order to bring the vehicle 10 to a stop just before reaching the obstacle. This results in a value of 1.7 m / s, while at a speed of 2.0 m / s a collision would still occur, as shown in the illustrations on the right and in the middle of Figure 8 indicated. Accordingly, the speed is reduced to 1.7 m / s, with further checks being carried out in the same way as the industrial truck 10 continues to travel, in order to be able to further slow down the vehicle 10 if it approaches the wall further or, if necessary, to cancel the speed limit again if it evades, ie steers to the left.

Claims

1. Method for handling obstacles in an industrial truck (10), which comprises at least one sensor unit (14) which is arranged in the main travel direction (L) of the industrial truck (10) and is designed to be able to detect obstacles (H) in a predetermined angular range (S), the method comprising: - detecting a current speed and a current steer angle of at least one steered wheel (18) of the industrial truck (10) by means of a speed sensor or a steer angle sensor of the industrial truck (10); - calculating a protection zone (Z) on the basis of the current speed and the current steer angle; - evaluating the data delivered by the at least one sensor unit (14) within the protection zone (Z) of the industrial truck (10), and - in the event of identifying an obstacle (H) in the protection zone (Z): ∘ calculating a respective steer angle difference on both sides, at which in each case a collision with the obstacle (H) is avoided; and ∘ classifying a current degree of difficulty of avoiding the obstacle, at least on the basis of the calculated steer angle differences on the basis of a steer angle difference limit value, and / or ∘ triggering a predetermined measure on the basis of the calculated steer angle differences on the basis of a steer angle difference limit value.

2. Method according to claim 1, wherein the smaller of the two steer angle differences is used for classifying the current degree of difficulty.

3. Method according to either claim 1 or claim 2, wherein a predetermined measure is triggered on the industrial truck (10) depending on the current degree of difficulty.

4. Method according to claim 3, wherein the predetermined measure includes reducing a current and / or maximum speed of the industrial truck (10).

5. Method according to claim 3, wherein the predetermined measure includes outputting a corresponding message to an operator.

6. Method according to any of the preceding claims, wherein during the classification of the current degree of difficulty and / or the triggering of the predetermined measure, further parameters are taken into account, in particular at least one of the following: - the current steer angle of the industrial truck (10), - the current speed of the industrial truck (10), - the level of experience of a driver of the industrial truck (10), - the calculated steer angle difference compared with the current steer angle.

7. Method according to any of the preceding claims, wherein the classification for current degrees of difficulty includes at least one simple degree of difficulty and one high degree of difficulty.

8. Method according to any of the preceding claims, further comprising fixing a maximum steer angle of the industrial truck (10), which cannot be exceeded, in order to avoid a collision.

9. Method according to any of the preceding claims, wherein the industrial truck (10) has a known vehicle outline (12) in plan view, and the protection zone (Z) is calculated on the basis of the vehicle outline (12) such that a predicted vehicle contour (Z), which corresponds to a surface to be covered by the industrial truck (10) in a predetermined period of time, is used as the protection zone (Z).

10. Method according to claim 9, wherein the calculation of the predicted vehicle contour (Z) is carried out in polar coordinates and preferably the pole of the polar coordinate system corresponds to a central point of the industrial truck (10) based on its longitudinal and width axis and / or the polar axis of the polar coordinate system of the main travel direction (L) of the industrial truck (10).

11. Method according to either of claims 9 and 10, wherein the calculation of the predicted vehicle contour (Z) is carried out by means of a calculation of a plurality of support points (P).

12. Method according to claim 11, wherein the number of support points (P) is selected depending on the current vehicle speed.

13. Industrial truck (10), which is configured for carrying out a method according to any of the preceding claims during its operation, comprising: - a vehicle body; - at least one sensor unit (14) which is arranged in the main travel direction (L) of the industrial truck (10) and is designed to be able to detect obstacles (H) in a predetermined angular range, - a speed sensor and a steer angle sensor; and - a control unit (20), which is configured: ∘ to obtain data from the speed sensor and the steer angle sensor, ∘ to calculate a protection zone (Z), ∘ to calculate a steer angle difference on both sides, at which in each case a collision with an obstacle (H) detected within the predicted vehicle contour (Z) is avoided; and ∘ classifying a current degree of difficulty of avoiding the obstacle on the basis of the calculated steer angle differences on the basis of a steer angle difference value, and / or ∘ triggering a predetermined measure on the basis of the calculated steer angle differences on the basis of a steer angle difference value.

14. Industrial truck (10) according to claim 13, wherein the at least one sensor unit (14) comprises a LIDAR unit.

15. Industrial truck (10) according to either of claims 13 and 14, wherein this is a manually guided industrial truck.