Method for traversing a route of an industrial truck for receiving or dispensing a load

Abstract

The invention relates to a method for traversing a route of an industrial truck (100) for receiving or dispensing a load (P), having the steps of obtaining an ideal target position (IZ) for receiving or dispensing the load (P); planning a first route (W1) to be traversed from the current first location of the industrial truck to the ideal target position (IZ) using at least one specified first planning criterion; traversing the planned first route (W1), wherein a detection of the surroundings of the industrial truck is carried out by at least one sensor unit (110) during the traversal of the planned first route (W1) by the industrial truck (100); analyzing the detection data supplied by the at least one sensor unit (110) in order to determine the actual target position (TZ) of the load (P); planning an optimized second route (W2) starting from a second location on the first route (W1) of the industrial truck (100) to the actual target position (TZ) using at least one specified second planning criterion; and traversing the planned second route (W2) from the second location to the actual target position (TZ).

Description

[0001] Procedure for driving along an access route of an industrial truck for picking up or dropping off a load

[0002] Description

[0003] The present application relates to a method for driving along an access route of an industrial truck for picking up or dropping off a load, as well as to an industrial truck which is designed to carry out such a method.

[0004] In the field of industrial trucks, and especially autonomous industrial trucks, load picking and unloading operations are an essential part of their regular operation. Various strategies for approaching the corresponding loading and unloading positions are conceivable. On the one hand, it is always desirable to approach such a position as efficiently as possible. On the other hand, in certain scenarios, the position of the load or unloading position is not precisely known and / or obstacles in the corresponding warehouse facility may be present that could make approaching the desired position difficult.

[0005] Accordingly, it is necessary to integrate a corresponding procedure for driving along an approach path of the industrial truck for picking up or dropping off the load into normal operating procedures, which are often defined by a driving order specified by a control center and also generally include driving to a wider loading area and transporting the load away or removing it from the loading area again after the load has been dropped off.

[0006] Autonomous industrial trucks used in such systems are typically equipped with a vehicle body pointing in the main direction of travel and a height-adjustable load-handling device, such as a load fork, pointing opposite to the main direction of travel. Accordingly, picking up or releasing a load from the load-handling device usually requires the vehicle to turn, as the corresponding target position must be approached with the load-handling device leading the way. Furthermore, it should be noted that corresponding industrial trucks designed to carry out such operational sequences and process travel tasks are typically equipped with at least one sensor unit for detecting their surroundings. This sensor unit is used, for example, to detect obstacles and thus avoid dangerous situations for both the vehicle itself and persons in its vicinity.In addition, corresponding sensor units can also be provided and used to detect target objects in the vicinity of the industrial truck, for example loads to be picked up or positions to be approached, so that a corresponding control unit of the industrial truck can adapt or regulate the operation of the vehicle within the scope of the current travel task on the basis of the data supplied by the at least one corresponding sensor unit.

[0007] This shows that, in particular, the planning and driving of a suitable approach route for picking up or dropping off a load in known vehicles of this type has not yet been carried out in an optimal manner, or that there is still potential for optimization in this area to enable improved integration of this process into the processing of a driving task and, in particular, to improve the flexibility of the vehicle with regard to situations in which an actual load position or drop-off position deviates from a corresponding assumed ideal position, thus necessitating an adjustment of the approach process. Such situations can occur, in particular, if a load has been moved since its last drop-off or has not been precisely positioned during the drop-off process.without the control system having received any knowledge of this, and consequently either the load itself for a picking-up operation or a drop-off position adjacent to the load is not present or is no longer present exactly at the position expected by the control system. For this purpose and to achieve the above-stated object, the present invention provides a method for traveling along an approach path of an industrial truck for picking up or dropping off a load, comprising the steps of obtaining an ideal target position for picking up or dropping off the load, planning a first path to be traveled from the current first location of the industrial truck to the ideal target position based on at least one predetermined first planning criterion, traveling along the planned first path, wherein, while traveling along the planned first path, the industrial truck detects its surroundings using at least one sensor unit,evaluating the detection data supplied by the at least one sensor unit to determine an actual target position of the load, planning an optimized second route starting from a second location on the first route of the industrial truck to the actual target position based on at least one predetermined second planning criterion, and traveling the planned second route from the second location to the actual target position.

[0008] The method according to the invention is therefore based on dividing a route for picking up or dropping off a load into a first and a second route, wherein the planning of the first route is based on an ideal target position which is transmitted to the vehicle, for example, by a control center, while the second route is subsequently planned based on an actual target position which is determined by the vehicle itself on the basis of sensor data about its surroundings.

[0009] To this end, the method according to the invention performs a survey of the surroundings while traveling along the first path to determine the actual target position. Following this, the second path is then planned, which can be followed to reach the actual target position. Traveling along the first path should also explicitly include times during which the vehicle is stationary while traveling along the first path.Accordingly, the last known target position can initially be used as a starting point, which is transmitted to the vehicle, for example, from a control center as part of a travel order or as part of a route to be traveled and already planned. As the vehicle approaches this ideal target position, an optimal approach to the actual target position can be planned and, at the second location, the vehicle can switch from the first route to the second route, thus enabling an optimized execution of the load picking or unloading process. It should be noted at this point that the ideal target position, like the actual target position, can also designate and include an orientation of the load or unloading location and thus also an alignment of the load or unloading location in space, since, in particular, picking up loads carried on pallets is only possible at certain approach angles.Accordingly, the term “position” is used in this application to include both a location and an orientation of the load, which is often referred to as a “pose” in this way.

[0010] In particular, planning the first path and / or the second path can comprise creating a plurality of candidate paths, discarding non-negotiable candidate paths, and selecting an optimal first or second path based on the corresponding at least one predetermined planning criterion. This embodiment makes it possible to first create a number of possible first and / or second paths based on predetermined strategies, then check them for plausibility or navigability, and then select the corresponding optimal path based on the at least one predetermined planning criterion.

[0011] Although, for example, a parameter space can be covered by varying one or more planning criteria in the form of parameters within a predetermined value range in order to obtain the majority of candidate paths, in a preferred embodiment, the creation of the candidate paths can also include applying modeled patterns to create systematic candidate paths and, if necessary, as a fallback solution, randomly creating alternative candidate paths located between the systematic candidate paths. In this way, several selected strategies can first be applied to create the systematic candidate paths, and subsequently, additional alternative candidate paths can be randomly created, for example, if none of the systematic candidate paths is determined to be passable.In this case, the sample models can in particular be parameterizable, for example, it can be provided that a start and end pose and a turning point are provided in a corresponding model, whereby these poses are then connected by suitable, simple curves using parameters or parameter variations.

[0012] Furthermore, the at least one first and / or the at least one second planning criterion can comprise at least one of the following: a shortest route to be traveled, a smallest and / or largest possible steering angle, an average steering angle value, a highest possible speed, a shortest possible travel time, avoiding the industrial truck turning on the spot, and avoiding one or more turning points. The above examples of corresponding planning criteria represent respective options for optimizing the approach to the target position in order to achieve the most efficient approach by the industrial truck.

[0013] In particular, the initial path can be planned along nodes and edges, which already allows for greater flexibility at this stage than planning strictly along a predefined path. For example, with this type of planning, potential obstacles in the surrounding area can be better considered and avoided, as long as the corresponding nodes of the planned path can be reached or at least sufficiently approached. In other words, an area along the edges and, if necessary, the nodes can be opened up for optimization or evasion by the vehicle.

[0014] Alternatively or additionally, the planning of the second route can be carried out in such a way that the second location corresponds to a turning point on the planned first route and / or the planning of the second route is carried out a single time. In this embodiment, the fact is taken into account that, particularly in the above-described design of vehicles with a load-handling device oriented against the main direction of travel, the vehicle must turn before picking up or releasing the load, which corresponds to a change in the direction of movement of the vehicle. This change in direction of movement accordingly takes place at the turning point just mentioned. Furthermore, however, scenarios are also conceivable in which the second location, i.e. the point at which the transition from the first route to the second route takes place, must be after the turning point, for example when entering an alley in which the load orthe drop-off position is located, which accordingly only allows for late detection of the corresponding position. In such cases, the transition from the first path to the second path can, for example, only be carried out once the pickup position or drop-off position has been reliably and reliably detected.

[0015] Although it is conceivable to plan the second path a single time based on the determined actual target position, it is alternatively also possible in a further development of the present invention to proceed iteratively when planning the second path and, in particular, to continue to detect the surroundings using the at least one sensor unit while traveling the second path and to evaluate the detection data supplied by the at least one sensor unit to determine an actual target position of the load and, if necessary, to further optimize the second path iteratively during its travel. This measure achieves a further increase in the precision of approaching the target position due to the additional data obtained regarding the actual target position while traveling the second path.Preferably, however, planning of the second path begins before passing a turning point for approaching the actual destination. The reason for this is that the position of the turning point(s) in space is particularly important for efficient approach to the actual destination. Depending on how the turning point is positioned and oriented relative to the current position of the industrial truck and the actual destination, the approach can be particularly efficient or inefficient, since, for example, a comparatively small or particularly large steering angle is required to pass through the turning point. At large steering angles, the maximum speed of the vehicle may be limited, for example.

[0016] Furthermore, in the method according to the invention, different first planning criteria can be used outside and within a predetermined minimum distance between the industrial truck and the ideal target position while traveling along the first path, and / or the evaluation of the detection data to determine the actual target position of the load can be carried out only within the predetermined minimum distance. An example of this can be that the first path initially comprises a unique, concrete first section to be traveled, which is traveled until the predetermined minimum distance to the ideal target position is reached. Subsequently, the vehicle can then be granted a greater degree of freedom in planning a second section of the first path, and this planning can take place, for example, based on the nodes and edges already mentioned above.Thus, the first path is divided into two sections in which different strategies for its planning are pursued, and it is additionally or alternatively conceivable to also carry out the evaluation of the acquisition data to determine the actual target position of the load only within this radius with increased planning freedom around the ideal target position.

[0017] In an alternative example, the entire planning of the first path could also take place based on nodes and edges, although within the predetermined minimum distance, a greater deviation from the specified edges and, if applicable, nodes would be permitted compared to the area outside the predetermined minimum distance. In particular, in any case, the planning of the first path can be carried out in practice in such a way that the nodes and edges are specified by a control center to the vehicle, which then carries out the concrete planning of the first path on this basis. It can have different degrees of planning freedom with regard to adhering to the specified nodes and edges within and outside the predetermined minimum distance.In such a specific case, both the nodes and edges as well as the specifications regarding the freedom of the vehicle for planning the specific route would be understood as the first planning criteria.

[0018] For the sake of completeness, it should also be mentioned at this point that it is also conceivable, in principle, to adapt the first and / or second planning criteria within the first and / or second path, for example, within the framework of logical subsections, to enable dynamic and / or further optimized generation of the corresponding paths. For example, it could be considered to only allow straight-ahead travel beyond a certain distance from the actual target position, corresponding to a vehicle steering angle of zero.

[0019] Furthermore, according to the invention, the evaluation of the detection data for determining an actual target position of the load can be carried out only within a predetermined area around the ideal target position. In this way, a region of interest is defined around the ideal target position, and the corresponding processing of the sensor data for determining the actual target position is carried out only within this region to increase the efficiency of the method. Depending on the sensor unit used, only a detection of the corresponding region can be carried out, i.e. the area detected by the sensor unit can be restricted to the region of interest, or the processing of the sensor data can be restricted to this region using software.

[0020] Furthermore, in the method according to the invention, determining the actual target position can include checking whether the actual target position is within a predetermined range around the ideal target position. This check represents both a plausibility check and a safety mechanism, since it can, on the one hand, rule out confusion between target positions, for example, if a different load than the one planned to be picked up by the vehicle is used to determine the actual target position. On the other hand, even if the correct load orThe delivery position also excludes the possibility of excessive deviations between the ideal and actual target positions, which could indicate a major problem in the corresponding area of ​​the logistics facility, for example, that loads have been moved significantly in an undesirable manner that was not reported to the control center. If, as a result, a significant distance between the ideal and actual target positions is detected, appropriate countermeasures could be initiated, for example, the approach to the target position could be aborted and appropriate warnings issued.

[0021] Although different procedures for determining the actual target position are conceivable, which may depend, among other things, on the type of sensor units used and also on the load to be transported, the evaluation of the detection data to determine the actual target position of the load can comprise searching the detection data for predetermined patterns which, for example, can correspond to the known shape of the load. This strategy can be applied both to a planned picking up and dropping off of the load, since suitable drop-off positions for loads can ultimately depend on their shape. An example of such a procedure can consist of searching the data supplied by the at least one sensor unit, in this case in particular a laser scanner or a 3D camera, for patterns which correspond to a pallet with known dimensions as the load to be picked up.For this purpose, neural networks or other techniques from the field of artificial intelligence could be used, among others. Regardless of the specific methodology used, however, the orientation of the load can also be reliably determined, which can also be derived from the corresponding sensor data using suitable algorithms. Similarly, depending on the sensor type used, the detection of the environment can be carried out periodically by means of the at least one sensor unit, and the actual target position can be determined only if the load or the delivery position is detected multiple times during the periodic detection and / or the actual target position can be obtained by averaging several determined positions of the load and the delivery position.These additional measures also contribute to verifying the plausibility and improving the precision of the actual target position. In particular, a minimum number of load detections can be specified, from which point the actual target position is considered to be determined, and / or it can be required that a corresponding detection must have taken place in successive cycles of the detection process. Furthermore, a consistency check of the multiple determined positions can be carried out based on predetermined criteria. In the event of inconsistent results, the process can be aborted or individual detections can be discarded. Likewise, embodiments are conceivable in which the averaging of the multiple determined positions takes place in a weighted or unweighted manner, whereby, for example, positions determined from a shorter distance could be included in the averaging with a higher weight.

[0022] During the last section of the approach to the actual target position when traveling along the second path, i.e. when the picking up or dropping off of the load is imminent, if a predetermined target distance between the industrial truck and the actual target position is undershot while traveling along the second path, at least one of switching a protective field of the at least one sensor unit to a special mode, moving a load handling device of the industrial truck to a predetermined height and activating a load shift detection system, in particular by means of the at least one sensor unit for detecting the surroundings and / or by means of a dedicated further sensor unit can be carried out.In this case, the load shift detection mentioned can remain activated, for example, during the entry of the vehicle's load handling device into a pallet acting as a load and / or a load detection can be carried out with regard to the correct pickup of the pallet on the load handling device.

[0023] According to a second aspect, the present invention relates to an industrial truck, in particular an autonomous industrial truck, comprising at least one sensor unit for detecting the surroundings of the industrial truck and a control unit coupled to the at least one sensor unit, which control unit is in particular configured to manage autonomous operation of the industrial truck, wherein the industrial truck is configured to carry out the method according to the invention just described.

[0024] In this case, one or more 3D cameras could be used as the at least one sensor unit; however, it is also conceivable for the at least one sensor unit to be designed as a laser scanner, which preferably allows all-round detection or is aligned in the load direction of the industrial truck and / or simultaneously serves as a safety sensor. In such embodiments with laser scanners, protective fields are usually switched as a safety function, i.e., areas around the vehicle are defined in which objects or people are not allowed to be present, or only in defined exceptional cases, in order to avoid collisions or accidents.

[0025] It should be noted here that the implementation of the method according to the invention, in particular the requirement for planning a second route for approaching an actual target position, arises particularly for vehicles that are unable to turn on the spot, or only very slowly, to do so. For example, vehicles designed as under-floor trucks that pick up a load by lifting it from below are often equipped with two wheels driven independently by electric motors and are thus able to turn on the spot very quickly by driving the wheels in opposite directions. In contrast, industrial trucks with a classic design, i.e. with load forks as the load-handling device, are often equipped with one or more non-driven and / or unsteered rollers on the load section, in particular per fork tine, and one or more driven and steered wheels on the vehicle body or drive section.Due to this asymmetrical design, turning or reversing these vehicles on the spot is not possible or only possible very slowly and, depending on the design and in particular the wheelbase, requires significantly more space than vehicles whose pivot point is geometrically centered. To ensure the most efficient approach of the load, it is therefore particularly advantageous for these vehicles if the approach is individually planned based on the actual target position for the vehicle.

[0026] Finally, it should be noted that the control unit of the industrial truck according to the invention can also be configured to optionally perform an alternative operation in which a route to the ideal target position is planned and followed directly without determining the actual target position. In such a case, the corresponding route could then be planned in a similar manner to the planning of the first route described above, based on predetermined planning criteria, for example, again using edges and nodes.

[0027] Further features and advantages of the present invention will become more apparent from the following description of embodiments thereof, when considered together with the accompanying figures. These show in detail:

[0028] Figures 1 - 6: schematic views of an industrial truck according to the invention during implementation of a method according to the invention

[0029] Figure 7: schematic view of an alternative scenario that may occur during the inventive method of Figures 1 - 6; and

[0030] Figures 8a - 8c: schematic views of further scenarios that can occur during the inventive method from Figures 1 - 6. In all of the figures discussed below, a schematic plan view of an industrial truck 100 according to the invention is shown, which is configured and intended to carry out the inventive method described with reference to the figures within a logistics facility. The industrial truck 100 is designed as an autonomous industrial truck with a vehicle body 102 and a load-handling device 104 in the form of a fork, which is arranged vertically displaceably thereon, as well as at least three wheels (not visible in the figures), by means of which the industrial truck 100 can move on the ground in a driven and steered manner. For reasons of clarity, the components of the vehicle 100 described below are only shown in Figure 1.

[0031] The industrial truck 100 is in particular connected to a control center by means of a communication device 106, from which travel orders are transmitted to the industrial truck, which in the example discussed here particularly relate to picking up or dropping off a load in the form of a pallet P at a target position. The control center initially knows an ideal target position IZ of the pallet P, at which the pallet P or the drop-off position should be located according to the control center's knowledge, for example because a pallet was placed at this position during a previous operation or because there is currently suitable free space for dropping off a pallet already carried by the vehicle 100.Here, the ideal target position IZ includes not only the location but also the orientation of the pallet P or the delivery position, since it is particularly important when picking up pallets to plan the approach in such a way that the load handling device 104 enters the pallet pockets. In particular, a method according to the invention will be described below, in which a pallet P is to be picked up by the industrial truck 100 at a target position.

[0032] For this purpose, the industrial truck 100 further comprises a position-determining device 108, with which it can determine its own position in space, for example, relative to a reference system tailored to the respective logistics facility. Various position-determining strategies are conceivable for this purpose; for example, active transmitters or passive markers could be provided in the logistics facility, based on which the industrial truck 100 can determine its own relative position using the position-determining device 108. Similarly, the position-determining device 108 could also comprise a suitable camera or a laser scanner, whereby the industrial truck's own position could then be derived from the images captured by this camera using pattern recognition.In addition, it would be conceivable to provide an odometry device as part of the position determination device 108, which can, for example, determine a number of wheel revolutions and a steering angle of at least one of the wheels and, from this, can determine a distance traveled since a last known location and thus a current position.

[0033] Furthermore, the industrial truck 100 comprises at least one sensor unit 110 for detecting its surroundings, which can be embodied in particular as a laser scanner and arranged in the load direction of the industrial truck 100, for example, to cover a scanning range of approximately 180°. Alternatively, a distributed provision of several laser scanners on the industrial truck 100 would also be conceivable, for example, in order to be able to detect the entire surroundings of the vehicle 100 over a full 360°.

[0034] Such laser scanners periodically scan a predetermined angle, for example, at a frequency in the order of approximately 20 Hertz, and output corresponding two-dimensional or three-dimensional detection data. In the present case, the sensor unit 110 serves, on the one hand, as a safety device that creates a protective field in the surroundings of the vehicle 100. If an object or person is detected within the protective field of the sensor unit 110, a suitable measure can be initiated, for example, issuing an alarm, slowing down, or even completely braking the vehicle 100. On the other hand, the sensor unit 110 serves, as will be explained further below, within the scope of the method described below, to determine the actual target position TZ.

[0035] Operatively coupled to the communication device 106, the position-determining device 108 and the at least one sensor unit 110, the industrial truck 100 further comprises a control device 112 which manages travel orders received from the control center, controls the operation of the industrial truck 100 and its components within the scope of the travel orders and is in particular configured to carry out the method according to the invention described below.

[0036] In this regard, reference is first made to Figure 1, in which the industrial truck 100 has already received a travel order from the control center, which in particular includes an assumed ideal target position IZ of the pallet P to be picked up, the expected load type, i.e. the concrete shape of the pallet P to be picked up, a region of interest R, within which the pallet P may be located and within which the pallet P will consequently be searched for, and a minimum distance A to the ideal target position IZ. Both the region of interest R and the minimum distance A can be stored in the vehicle as a defined area around the ideal target position IZ, whereby both do not necessarily have to be circular, but can in principle have any shape, for example rectangles, polygons or the like.However, in the specific case of Figure 1, the minimum distance A is shown as a dashed circular segment and is occasionally referred to as the “free roam radius” since, once this minimum distance A is reached, a freer movement of the vehicle 100 is permitted.

[0037] In Figure 1, the industrial truck is located precisely with its designated vehicle reference point 100a at the minimum distance A, having traveled to this position on a path that was created with a relatively low degree of planning freedom based on at least one predetermined planning criterion, for example, edges and nodes, and forms a first section of a first path W1 to the pallet P to be picked up, which is still created on the basis of the assumed ideal target position IZ. Upon entering the area within the minimum distance A, more free path planning of the vehicle 100 is now enabled based on the aforementioned nodes and edges, which are also indicated in the figures, allowing the vehicle 100, for example, to take obstacles present in its movement area into account, as will be explained further below with reference to Figures 8a - 8c.This planning of the second section of the first path continues to be carried out based on the ideal target position IZ and, in the example shown here, includes turning the vehicle 100 in order to be able to drive the load handling device 104 into the pockets of the pallet P in the assumed ideal target position IZ and to lift it.

[0038] In the example discussed here, the detection of the actual target position TZ, i.e. the concrete position and orientation of the pallet P in space, also begins at the time of entering the area within the minimum distance A, which in some cases will differ from the ideal target position IZ by a certain amount, although it is still required that the actual target position TZ lies within the region of interest R. In alternative variants of the method according to the invention, however, the detection of the actual target position TZ could also begin at an earlier or later time and not necessarily when entering the area within the minimum distance A.

[0039] In any case, for the purpose of detecting the actual target position TZ, the detection data supplied by the sensor unit 110 are evaluated and, in particular, searched for patterns that correspond to the known shape of the pallet P or, in general, to a plurality of permissible pallet shapes. It can be seen that the pallet P in the configuration shown in Figure 1 is not yet detectable by the sensor unit 110 because it is shadowed by a wall. Accordingly, the vehicle 100 continues to move along the planned first path W1, which is indicated by dashed lines in Figure 1. After a certain distance has been covered on this first path and the vehicle has reached the position shown in Figure 2, the pallet P becomes completely visible from one side, and a pattern that corresponds to the known pallet type will be detected in the data supplied by the sensor unit 110.Accordingly, from this point in time onwards, a determination of the actual target position TZ can be carried out, wherein due to the periodic functioning of the sensor unit 110, a plurality of target positions can be successively determined, which can be used for a plausibility check or for an improvement of the precision of the actual target position TZ.

[0040] After the actual target position TZ has been determined with sufficiently high confidence based on a plurality of individual measurements, it becomes apparent that there is a deviation between the ideal target position IZ and the actual target position TZ and therefore the previously planned first path W1 is not optimal for picking up the pallet P, since it would result in the load handling device 104 not ideally entering the pallet pockets. Accordingly, in the state shown in Figure 3, a second path W2 is planned based on the determined actual target position TZ using at least one predetermined second planning criterion. In the example shown here, this second path W2 begins at the turning point of the first path W1 and ends with correct entry into the pallet pockets of the pallet P at the actual target position TZ.Accordingly, the vehicle 100 first travels, as shown in Figure 4, to the turning point along the first path W1, and then, as shown in Figure 5, continues the journey on the second path W2, wherein the paths are each again related to the reference point 100a.

[0041] While it is in principle possible to carry out a single planning of the second path W2, the position of the pallet P can alternatively continue to be recorded and evaluated while moving on the second path W2 between the states of Figure 4 and Figure 5, so that an iterative adjustment of the second path W2 is possible at this time, if desired and necessary.

[0042] When the actual target position TZ is reached as shown in Figure 5 or when a predetermined target distance between the industrial truck 100 and the actual target position TZ is undershot, further processes can also be triggered, for example the protective field of the sensor unit 110 can be switched to a special field in order not to identify the pallet P to be picked up as an obstacle, the load handling device 104 can be lowered to a predetermined height and a load shift detection can be activated, wherein either the sensor unit 110 can detect a front edge of the pallet P or a dedicated additional sensor unit can be used, for example an analog distance or contact sensor.

[0043] During the entry of the load handling device 104 shown in Figure 6, a check is also performed to determine whether the pallet P is being shifted. However, due to the angle, detection by the sensor unit 110 is difficult, so an additional sensor unit is preferably used. Furthermore, an additional pallet sensor provided in the area of ​​the load handling device 104 can confirm the correct pickup of the pallet P during the last few millimeters of entry into the pallet pockets.

[0044] Figure 7 now shows an alternative scenario that can occur during the method according to the invention from Figures 1 - 6. In this case, the pallet P to be picked up is arranged within a pallet aisle, so that it cannot yet be sufficiently detected before the vehicle 100 turns on the first path W1. Accordingly, in this variant, the path W1 planned on the basis of the assumed ideal target position IZ will be traveled beyond the turning point, and only during the straight-line approach to the pallet P will the planning of a second path be possible and carried out as soon as the pallet P has been detected with sufficient confidence. However, it is necessary for the sensor device 110 to be able to detect its surroundings in the direction of the load handling device 104 in order to be able to determine the actual position TZ at this late stage of approaching the pallet position.

[0045] Similarly, Figures 8a-8c indicate further scenarios that can occur during the method according to the invention from Figures 1-6. In particular, the space available for the turning process of the vehicle 100 may be limited, so that the planning of the first and possibly second route must be adapted accordingly. Although the turning process shown in Figures 1-6 represents an optimal possibility, since the travel time required by the vehicle 100 is minimized and the method can therefore be carried out particularly efficiently, the present invention also allows, in particular, the planning of alternative routes that avoid walls or other known obstacles present in the vicinity of the pallet P or even involve maneuvering with multiple turns or turning on the spot, as indicated in Figure 8c.

[0046] Finally, it should be noted that although the present figures show a process for picking up a load, a method for releasing a load can also be carried out in a similar way, in which case a suitable target position can be determined by being free of objects and having dimensions that allow the load to be released.

Claims

Claims 1 . A method for driving along an access route of an industrial truck (100) for picking up or dropping off a load (P), comprising the steps: - Obtaining an ideal target position (IZ) for picking up or releasing the load (P); - Planning a first route (W1) to be traveled from a current first location of the industrial truck to the ideal target position (IZ) based on at least one predetermined first planning criterion; - Driving on the planned first route (W1), - wherein, while the industrial truck (100) is traveling along the planned first route (W1), its surroundings are detected by means of at least one sensor unit (110); - evaluating the detection data supplied by the at least one sensor unit (110) to determine an actual target position (TZ) of the load (P); - Planning an optimized second path (W2) starting from a second location on the first path (W1) of the industrial truck (100) to the actual target position (TZ) based on at least one predetermined second planning criterion; and - Driving the planned second route (W2) from the second location to the actual target position (TZ).

2. The method according to claim 1, wherein planning the first path (W1) and / or the second path (W2) comprises: - Creating a plurality of candidate paths; - Rejection of non-passable candidate routes; and - Selecting an optimal first (W1) or second path (W2) based on the corresponding at least one predetermined planning criterion.

3. The method according to claim 2, wherein the creation of the candidate paths comprises applying modeled patterns to create systematic candidate paths and, optionally as a fallback solution, randomly creating alternative candidate paths lying between the systematic candidate paths.

4. Method according to one of the preceding claims, wherein the at least one first and / or the at least one second planning criterion comprises at least one of: - the shortest route to be travelled; - a smallest and / or largest possible steering angle; - an average value of a steering angle; - the highest possible speed; - the shortest possible travel time; - avoiding turning the truck on the spot; and - avoiding one or more turning points.

5. Method according to one of the preceding claims, wherein the planning of the first path (W1) is carried out along nodes and edges.

6. Method according to one of the preceding claims, wherein the planning of the second route (W2) is carried out in such a way that the second location corresponds to a turning point on the planned first route (W1) and / or the planning of the second route (W2) is carried out a single time.

7. Method according to one of the preceding claims, wherein during travel along the second path (W2) furthermore a detection of the environment by means of at least one sensor unit (110) and an evaluation of the detection data supplied by the at least one sensor unit (110) is carried out to determine the actual target position (TZ) of the load (P), and if necessary the second path (W2) is further optimized iteratively during its travel.

8. Method according to one of the preceding claims, wherein outside and within a predetermined minimum distance (A) between the industrial truck (100) and the ideal target position (IZ) while traveling along the first path (W1), different first planning criteria are used and / or the evaluation of the detection data for determining the actual target position (TZ) of the load (P) is carried out only within the predetermined minimum distance (A).

9. Method according to one of the preceding claims, wherein the evaluation of the detection data for determining the actual target position (TZ) of the load (P) is carried out only within a predetermined range (R) around the ideal target position (IZ).

10. The method according to any one of the preceding claims, wherein determining the actual target position (TZ) comprises checking whether the actual target position (TZ) is located in a predetermined range (R) around the ideal target position (IZ).

11. Method according to one of the preceding claims, wherein the evaluation of the detection data for determining the actual target position (TZ) of the load comprises searching the detection data for predetermined patterns which, for example, correspond to the known shape of the load (P).

12. Method according to one of the preceding claims, wherein the detection of the environment is carried out periodically by means of the at least one sensor unit (110); and the actual target position (TZ) is determined only upon multiple detection of the load (P) or the delivery position during the periodic detection; and / or the actual target position (TZ) is obtained by averaging several determined positions of the load (P) or the delivery position.

13. Method according to one of the preceding claims, wherein if a predetermined target distance between the industrial truck (100) and the actual target position (TZ) is undershot while traveling along the second path (W2), at least one of the following processes is carried out: - switching a protective field of the at least one sensor unit (110) to a special field; - moving a load-handling device (104) of the industrial truck (100) to a predetermined height; and - Activating a load shift detection, in particular by means of the at least one sensor unit (110) for detecting the environment and / or by means of a dedicated further sensor unit.

14. Industrial truck (100), in particular autonomous industrial truck, comprising: - at least one sensor unit (110) for detecting the surroundings of the industrial truck (100); and - a control unit (112) coupled to the at least one sensor unit (110), which is particularly configured to manage autonomous operation of the industrial truck (100); wherein the industrial truck (100) is configured to carry out a method according to one of the preceding claims.

15. Industrial truck according to the preceding claim, comprising - a load section with at least one unsteered and / or non-driven wheel; and - a vehicle body with at least one steered drive wheel.

16. Industrial truck (100) according to claim 14 or 15, wherein the at least one sensor unit (110) is designed as a laser scanner, which preferably allows all-round detection or is integrated into a Load direction of the industrial truck and / or simultaneously serves as a safety sensor.

17. Industrial truck (100) according to one of claims 14 to 16, wherein the control unit is further configured to selectively carry out an alternative operation in which a route to the ideal target position (IZ) is planned and traveled directly without determining the actual target position (TZ).

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