Methods of operating a fleet of autonomous vehicles

Abstract

The present invention relates to a method for operating a fleet of autonomous vehicles at a work site having a loading area, wherein a loading device is provided at the loading area for loading materials onto the autonomous vehicles. The method comprises: controlling a first vehicle to travel in a first driving mode until the first vehicle reaches a starting position of the loading area; deactivating the first driving mode by controlling the first vehicle to be positioned in the loading area in a second driving mode; controlling a second vehicle to come into contact with the first vehicle and push the first vehicle along the loading area and past the loading device for loading materials onto the first vehicle as the first vehicle passes the loading device; and reactivating the first driving mode of the first vehicle when the second vehicle has pushed the first vehicle to an end position of the loading area.

Description

Technical Field

[0001] The invention relates to a method of operating a fleet of autonomous vehicles. The invention also relates to a computer program and a computer-readable medium for implementing the method. The invention also relates to a control unit for implementing the method. The invention additionally relates to a system comprising such a control unit.

[0002] The invention may be applied to autonomous vehicles, such as construction equipment, in particular autonomous work machines in the form of load-carrying vehicles. Although the invention will be described with reference to work machines, the invention is not limited to this particular vehicle, but may also be used in other vehicles such as trucks or other vehicles having load-carrying capabilities. Background Art

[0003] Work machines in the form of articulated haulers, wheel loaders, trucks, transfer vehicles and dump trucks are frequently used for loading and / or transporting loads of material on construction sites, in forestry and the like. The load receiving container of a hauler or dump truck can, for example, be loaded with unprocessed material, such as rock fragments, at a loading location, transport these materials to another location and dump the material into a material handling device, for example into a buffer feeder of a crusher, wherein the crusher is arranged to crush the rock fragments into smaller fragments. Alternatively, a wheel loader, excavator or other work machine can dump the material directly into such a material handling device. The smaller fragments can in turn be loaded onto other load-bearing work machines for further transport.

[0004] Recent developments have shown that the use of autonomous vehicles can be advantageously used to transport materials, such as crushed rock fragments. However, loading materials onto such autonomous vehicles can present challenges, particularly when it comes to reducing spillage of material that accidentally falls to the ground next to the work machine rather than onto the material receiving portion of the work machine. For example, the timing associated with when the autonomous vehicle should enter and / or exit the loading area can be improved to reduce the risk of spillage. Summary of the invention

[0005] It is an object of the present invention to provide a method of operating a fleet of autonomous vehicles at a work site having a loading area, which method reduces the risk of spillage.

[0006] The object is achieved by a method according to the invention. Therefore, according to a first aspect of the invention, there is provided a method of operating a fleet of autonomous vehicles at a work site having a loading area, wherein a loading device is provided at the loading area for loading material onto the autonomous vehicles, the method comprising:

[0007] - controlling a first vehicle among the autonomous vehicles to travel in a first driving mode until the first vehicle reaches a starting position of the loading area,

[0008] - deactivating the first driving mode of the first vehicle by controlling the first vehicle to be positioned in the loading area in a second driving mode,

[0009] - controlling a second one of the autonomous vehicles to come into contact with the first vehicle and to push the first vehicle along the loading area and past the loading device so that material is loaded from the loading device onto the first vehicle as the first vehicle passes the loading device,

[0010] - when the second vehicle has pushed the first vehicle to the end position of the loading area, reactivating the first driving mode of the first vehicle.

[0011] By providing a method whereby the second vehicle pushes the first vehicle along the loading area and past the loading device, continuous unloading from the loading device can be performed while reducing the risk of material falling between the two vehicles. In other words, since the first vehicle and the second vehicle are in contact with each other during the passage of the first vehicle through the loading area, a substantially seamless switch can be made from loading the material on the first vehicle to loading the material on the second vehicle via the loading device. Compared to the prior art where material may more frequently fall to the ground and then need to be picked up and dumped onto the carrying vehicle, the advantage is that the risk of material falling is greatly reduced or eliminated, thereby reducing or eliminating the time to pick up such fallen material, thereby improving productivity and efficiency.

[0012] In summary, it will be appreciated that the invention is generally based on the recognition that the distance between a loaded (or being loaded) vehicle and the next vehicle in the queue can be controlled to reduce the risk of spillage. In particular, the risk of spillage is reduced by controlling the distance to zero at the loading area, i.e. by controlling the next vehicle in the queue to push the vehicle being loaded through the material feed loading device.

[0013] According to at least one exemplary embodiment, the first vehicle and the second vehicle are designed so that when the second vehicle contacts and pushes the first vehicle, the front end of the second vehicle overlaps the rear end of the first vehicle. This is advantageous because it allows the front of the material receiving portion of the second vehicle to overlap the rear of the material receiving portion of the first vehicle, whereby when the first vehicle has reached the end position of the loading area, the material can continue to fall smoothly into the second vehicle.

[0014] In summary, it can be understood that, at least in some exemplary embodiments, the end position of the loading area can be a position where the first vehicle will receive the material dropped from the loading device at the rear of the material receiving portion unless the front of the second vehicle overlaps the rear of the first vehicle. Similarly, it can be understood that, at least in some exemplary embodiments, the starting position of the loading area can be a position where the front of the material receiving portion of the vehicle receives the material dropped from the loading device.

[0015] Suitably, the method may be repeated with a plurality of vehicles, depending on the number of autonomous vehicles and the size of the work site. Suitably, the number of autonomous vehicles may be such that a substantially continuous flow of vehicles may be achieved through the loading arrangement according to the method. Thus, when the second vehicle has reached the start position of the loading area (which may suitably be substantially simultaneous with the first vehicle reaching the end position of the loading area), the second vehicle may then be deactivated from its first driving mode (which it used when pushing the first vehicle), and a third vehicle may contact and push the second vehicle through the loading area. Thus, in general, the nth autonomous vehicle may be contacted and pushed by the (n+1)th autonomous vehicle.

[0016] According to at least one exemplary embodiment, in the second driving mode, the motor of the first vehicle (such as an electric motor) generates a fixed negative torque or zero torque. By causing the first vehicle to generate a negative torque or zero torque, the second vehicle will easily come into contact with the first vehicle. Controlling the first vehicle in the second driving mode may include generating zero torque at one point in time and generating negative torque at another point in time. For example, when the first vehicle has arrived at the loading area, the first driving mode is deactivated, and the second driving mode is activated by setting the motor of the first vehicle to generate zero torque. When the second vehicle has come into contact with the first vehicle, the motor of the first vehicle may be set to generate a fixed negative torque, thereby ensuring that the first vehicle will not roll away from the pushed second vehicle, but will maintain such contact. Even before the second vehicle has come into contact with the first vehicle, the motor of the first vehicle may be set to generate a negative torque, whereby the first vehicle may slowly reverse to meet the approaching second vehicle, and then maintain a negative torque after having come into contact until the first vehicle reaches the end position of the loading area.

[0017] According to at least one exemplary embodiment, in the second driving mode, the first vehicle is temporarily stationary or reversed, for example, slowly reversed. By making the first vehicle temporarily stationary or reversed, the second vehicle will easily come into contact with the first vehicle.

[0018] It should be understood that for each vehicle in the fleet of autonomous vehicles, the second driving mode may include any suitable operating behavior that allows the following vehicle (which is in the first driving mode) to contact and push the vehicle in front of it (which is in the second driving mode) so that both vehicles can load material while avoiding material from falling between the two vehicles. For example, the second driving mode may be that the first vehicle is idling. As described above, the second driving mode of the first vehicle may be that the motor of the first vehicle is generating a fixed negative torque and / or the first vehicle is reversing, appropriately slowly. In fact, in some exemplary embodiments, the second driving mode may even include that the first vehicle may continue to drive forward very slowly, as long as the second vehicle has time to make contact with the first vehicle and maintain contact to avoid material from the loading device falling between the two vehicles.

[0019] As can be appreciated from the above, suitably, in the second driving mode of the vehicle, less propulsion power is provided from the propulsion device of the vehicle to the wheels of the vehicle than in the first driving mode of the vehicle. This may be independent of the type of propulsion device (e.g. electric motor, internal combustion engine, etc.). The propulsion power may even be zero. In fact, when the first vehicle passes along the loading area for receiving material from the loading device, the movement of the first vehicle may be entirely caused by the propulsion power from the propelling second vehicle.

[0020] As described above, according to at least one exemplary embodiment, the second vehicle arrives at the starting position of the loading area simultaneously with the first vehicle arriving at the end position of the loading area, wherein the method includes: controlling the second vehicle to travel in the first driving mode until the second vehicle arrives at the starting position of the loading area. This is advantageous because when the first vehicle is ready to leave the loading area (i.e., at the end position), the second vehicle is already ready to receive material at the starting position of the loading area. Therefore, there is no need to interrupt the material flow from the loading device.

[0021] The first driving mode described above may include driving at a work site outside the loading area, and may also include pushing another vehicle at the loading area. Thus, when a second vehicle pushes a first vehicle, the second vehicle is in the first driving mode. The first vehicle may arrive at the starting position by pushing the previous vehicle through the loading area or by driving there without pushing any vehicle. Either case is considered to be included in the so-called first driving mode.

[0022] According to at least one exemplary embodiment, the length of the first vehicle is substantially equal to the length of the second vehicle. In addition, the length of the material receiving part (e.g., container) of the first vehicle is suitably equal to the length of the material receiving part of the second vehicle. According to at least one exemplary embodiment, the distance between the starting position and the ending position of the loading area substantially corresponds to the length of each vehicle and / or the length of each material receiving part of the vehicle. This is beneficial because it will help the second vehicle to arrive at the starting position at the same time as the first vehicle arrives at the ending position. Suitably, all vehicles in the fleet have the same length and / or each material receiving part (e.g., container) of the corresponding vehicles of the fleet has the same length. However, it should be noted that in other exemplary embodiments, the vehicles in the fleet of autonomous vehicles may have mixed lengths. Therefore, the length of one or more vehicles may be different from the length of any other vehicle in the fleet. For example, this can be envisaged by implementing dynamic start and / or end points.

[0023] In at least some exemplary embodiments, the distance between the starting position and the end position may be (slightly / slightly) smaller than the length of the material receiving part (e.g., container) of the vehicle. For example, the starting position may be selected such that it is at a position where a (minor) portion of the material receiving part has passed the loading device. This allows a (first) vehicle that has reached the starting position to slowly reverse to come into contact with the pushed (second) vehicle without risk of spillage.

[0024] Suitably, the vehicle may be provided with a buffer or other resilient or force absorbing or distributing structure for providing relatively smooth contact between the vehicles when the control vehicle pushes the other vehicle. In addition, as described above, the vehicle having reached the starting position of the loading area may be slowly reversed in the second driving mode until the vehicle makes contact with the second vehicle following behind the first vehicle.

[0025] According to at least one exemplary embodiment, the step of controlling the second vehicle to push the first vehicle comprises:

[0026] - determining vehicle parameters and / or load parameters,

[0027] - determining a propulsion speed based on the determined vehicle parameters and / or load parameters, and

[0028] - controlling the second vehicle to push the first vehicle at the determined pushing speed.

[0029] Vehicle parameters are to be understood as relating to the properties of the vehicle itself. Load parameters are to be understood as relating to the properties of the material to be loaded or the loading device. By basing the pushing speed on the determined vehicle parameters and / or load parameters, a good utilization of the vehicle fleet can be achieved. For example, the size of the loaded material fragments and the loading speed may influence how quickly the first vehicle will be fully loaded or at least fully loaded, and thereby how quickly the first vehicle should be pushed in the case of continuous feeding of material from the loading device. Another parameter, a vehicle parameter, may be the available load capacity, which also influences how quickly the first vehicle will become fully loaded. Of course, other vehicle parameters may also be used to determine the pushing speed.

[0030] According to at least one exemplary embodiment, the vehicle parameter is selected from the group consisting of (this selection may include one or more of the following):

[0031] - the state of charge of the traction battery of the first vehicle,

[0032] - the fuel level of the first vehicle,

[0033] - the available load capacity of the first vehicle,

[0034] - the permissible laden weight of the first vehicle,

[0035] - the geometry of the material receiving part of the first vehicle,

[0036] - the tire pressure in the tires of said first vehicle,

[0037] - the efficiency of the electric motor of the first vehicle.

[0038] If the state of charge of the traction battery of the first vehicle is low, it may be advisable to avoid fully loading the first vehicle to reduce the risk of the traction battery being completely exhausted before reaching the charging facility. Thus, another vehicle parameter that may form the basis for determining the pushing speed may be the distance to the first vehicle or the time until the traction battery of the first vehicle is recharged. Similar considerations apply to fuel (e.g. diesel) based vehicles, in which case a low fuel level may trigger a relatively high pushing speed so that the first vehicle does not become overloaded.

[0039] In some exemplary embodiments, if the state of charge of the traction battery is below a predetermined value, the propulsion speed is selected such that the material loaded onto the first vehicle is below a predetermined threshold weight and / or threshold volume.

[0040] Measuring the geometry of the material receiving portion of the first vehicle may be advantageous in various aspects. For example, the material receiving portion may be in the form of a bucket. During filling of the bucket, the pushing speed may be varied depending on the shape of the bucket to achieve a desired fill factor and center of gravity. It may also be advantageous to base the pushing speed on tire pressure or the efficiency of the electric motor. For example, if the first vehicle has low tire pressure, a defective electric motor or other limiting characteristics, it may be necessary to reduce the maximum permissible load and thereby increase the pushing speed.

[0041] It will be appreciated that the determination of the propulsion speed may be based on two or more parameters, for example on at least two vehicle parameters, or on at least two load parameters, or on at least one vehicle parameter and at least one load parameter.

[0042] As can be appreciated from the above, according to at least some exemplary embodiments, the autonomous vehicles of the fleet may suitably be electric vehicles, each vehicle being powered by one or more traction batteries.

[0043] According to at least one exemplary embodiment, the first vehicle comprises a first local control unit, wherein the method comprises:

[0044] - transmitting a signal representing the determined vehicle parameter and / or load parameter from the first local control unit to a second local control unit arranged on the second vehicle or to a central control unit arranged separately from the vehicle, and / or

[0045] - transmitting a signal representing the determined propulsion speed to a second local control unit arranged on board the second vehicle or to a central control unit arranged separately from the vehicle.

[0046] This is advantageous because a signal may be sent from the first vehicle providing real-time information of the relevant parameters. For example, the first local control unit may transmit one or more signals comprising data relating to the state of charge of the traction battery of the first vehicle, the available load and / or the available load weight. The first vehicle may be suitably provided with suitable sensors, such as weight sensors and / or level sensors, which may be operatively connected to the first local control unit for providing data continuously or periodically to the first local control unit for transmitting said signals. However, the first local control unit does not necessarily have to transmit such parameter representative signals, but in some exemplary embodiments may perform calculation operations based on the received sensor data and then transmit said signal representative of the determined propulsion speed.

[0047] In summary, it should be understood that the determination of the pushing speed can be accomplished by any suitable computing unit, such as a computing operation performed by any one of the first local control unit, the second local control unit, or the central control unit. For example, in some exemplary embodiments, the first local control unit can calculate a signal representing the determined pushing speed and send the signal to the second local control unit or to the central control unit. In other exemplary embodiments, the second local control unit itself can perform the calculation. In other exemplary embodiments, the central control unit can perform the calculation and then transmit a signal representing the determined pushing speed to the second local control unit, which will then control the vehicle to travel at the determined pushing speed.

[0048] Each of the control units, i.e. each of the first local control unit, the second local control unit and the central control unit may comprise a microprocessor, a microcontroller, a programmable digital signal processor or another programmable device. Each of these control units may also or alternatively comprise an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device or a digital signal processor. Where the control unit comprises a programmable device such as a microprocessor, a microcontroller or a programmable digital signal processor as described above, the processor may also comprise a computer executable code, which controls the operation of the programmable device.

[0049] According to at least one exemplary embodiment, the load parameter is selected from the group consisting of the following (this selection may include one or more of the following):

[0050] - the dimensions of the material to be loaded onto said first vehicle,

[0051] - the weight of the material to be loaded onto said first vehicle,

[0052] - the speed at which said material is loaded onto said first vehicle,

[0053] - Type of material.

[0054] The load parameters may be provided as manual input or automatic input. For example, a person such as an operator or fleet manager may input the feed rate of the loading device via a user interface. The input information may then be transmitted to a control unit, such as the central control unit discussed above. In the case of automatic input, sensors may be provided, such as optical sensors, weight sensors, speed sensors, which may be appropriately arranged at the loading device and may communicate operatively with one or more control units (e.g., the central control unit) directly or indirectly via another unit. With respect to the type of material, it should be understood that different types of materials have different filling factors. For example, rock fragments have a different filling factor than sand, and therefore different margins may be required.

[0055] According to at least one exemplary embodiment, the determined pushing speed is further determined based on one or more of the following parameters:

[0056] a fleet distribution parameter in the form of a geographical distribution of the vehicles of the fleet of autonomous vehicles at the work site,

[0057] an energy cost parameter in the form of energy consumed per unit of load by the first vehicle to transport the load to the unloading area,

[0058] a productivity parameter in the form of a load delivered per unit time of the first vehicle delivering loads to the unloading area,

[0059] - Environmental parameters in the form of current weather and / or road conditions at the work site.

[0060] Basing the pushing speed on the fleet distribution parameters may be beneficial to provide a smooth flow of vehicles. For example, if there are several vehicles near the loading area, but there are hardly any vehicles between the loading area and the dump point or unloading area, then the vehicles may need to be controlled to receive less load (i.e., higher pushing speed) to avoid queuing later. Similarly, if there is a gap between the second vehicle and any following vehicles near the loading area, then time may need to be bought, whereby the first vehicle will be loaded to full or nearly full (i.e., low pushing speed) to allow the following vehicle to catch up, whereby interruption of the vehicle chain at the loading area can be avoided (assuming the fleet has multiple vehicles, not just two).

[0061] If it is desired to reduce the energy cost per ton (tons / Ah) for transporting loaded material from the loading area to the unloading area, the energy cost parameter can be advantageously used as an input for controlling the pushing speed. This can be tailored to the specific cycle / process and machine learning can be appropriately involved to obtain the desired energy cost level.

[0062] In some cases, the site manager may wish to achieve the highest possible productivity (tons / hour), regardless of the cost of completing the order in a timely manner. In this case, the push speed and thus the load can be set in different ways depending on the production plan parameters.

[0063] Weather and / or road conditions at the work site may affect the maximum possible load that the vehicle can transport in a sufficiently safe manner and may therefore advantageously be used as an input parameter for determining the propulsion speed.

[0064] As already mentioned above, the method proposed in connection with the first vehicle and the second vehicle can be appropriately repeated in the third and / or subsequent vehicles. Therefore, according to at least one exemplary embodiment, the convoy of autonomous vehicles also includes a third vehicle, wherein, when the second vehicle has reached the starting position of the loading area, the method comprises:

[0065] - deactivating the first driving mode of the second vehicle by controlling the second vehicle to be positioned in the loading area in the second driving mode,

[0066] - controlling the third vehicle to come into contact with the second vehicle and to push the second vehicle along the loading area and past the loading device so that material is loaded from the loading device onto the second vehicle as the second vehicle passes the loading device,

[0067] - when the third vehicle has pushed the second vehicle to the end position of the loading area, reactivating the first driving mode of the second vehicle.

[0068] By having three or more vehicles pass a continuous feed of material from the loading device, the risk of spillage is reduced over an extended period of time.

[0069] According to at least one exemplary embodiment, the starting location and the ending location are defined by geographic coordinates, wherein the method includes determining the geographic location of the autonomous vehicle by using a global navigation satellite system. A global navigation satellite system (GNSS) can be any satellite constellation that provides positioning, navigation, and timing (PNT) services on a global or regional basis. Examples of such systems include GPS, BeiDou, Galileo, GLONASS, IRNSS, and QZSS. This is advantageous because it provides an efficient determination of the location of each vehicle.

[0070] According to at least one exemplary embodiment, position tracking is provided by a vehicle presence detector configured to generate data indicating the presence of a vehicle, wherein a processing unit is configured to receive the generated data from the presence detector and the processing unit is configured to determine the position of the vehicle based on the received data. In at least some exemplary embodiments, the vehicle presence detector is an image capture unit, such as a camera. In at least some exemplary embodiments, the vehicle presence detector comprises a wave transmitter and a wave receiver for receiving reflected waves, wherein the vehicle presence detector is suitably one of a lidar, a radar or an ultrasonic detector. In environments where global navigation satellite system signals are weak or non-existent, it may be advantageous to use a vehicle presence detector. This may be the case in underground mining or near large buildings, etc. Of course, vehicle presence detectors may also be used where satellite system signals are satisfactory. It should be understood that the geographic coordinates may be global geographic coordinates (e.g., based on GNSS), or these geographic coordinates may be local coordinates of the work site where the vehicle is operating. The latter is particularly suitable for underground mining, for example.

[0071] According to at least one exemplary embodiment, the loading device comprises a position tracking device, wherein the method comprises:

[0072] - Sending a signal representing the geographical location of the loading device from the position tracking device to a central control unit.

[0073] By knowing the geographical position of the loading device, the central control unit can define the geographical positions of the starting position and the ending position of the loading area. Suitably, the rotational orientation of the loading device can also be provided to the central control unit.

[0074] Therefore, according to at least one exemplary embodiment, the method includes:

[0075] - defining a starting position of the loading area and an ending position of the loading area based on the geographical position of the loading device.

[0076] As mentioned above, the starting and ending positions of the loading area may be defined by a central control unit. Alternatively, it is conceivable that these positions are calculated by different calculation units, or even by a person inputting the defined positions via a user interface of the fleet management system.

[0077] Similarly, according to at least one exemplary embodiment of the method, each vehicle may be provided with a respective local location tracking device configured to send a signal representative of the geographic location of the respective vehicle to the central control unit.

[0078] According to at least one exemplary embodiment, the loading device comprises a conveyor belt from which material can be dropped onto the autonomous vehicle. This is advantageous because it allows material to be fed continuously from the conveyor belt. Working machines such as wheel loaders, excavators, etc. can supply material to the conveyor belt directly or via some other device (e.g., via a crusher). However, it should be understood that in other exemplary embodiments, the loading device may be a different type of feeder, or may even be an actual working machine, such as a wheel loader or an excavator. Therefore, in some exemplary embodiments, the loading device (e.g., a conveyor belt) may be configured to feed material continuously to the loading area, while in other exemplary embodiments, the loading device (e.g., a wheel loader) may be configured to periodically provide material to the loading area.

[0079] According to at least one exemplary embodiment, the method includes controlling the fleet of autonomous vehicles so that there is a continuous flow of vehicles past the loading device. This is particularly advantageous in the case where material is continuously fed from the loading device (e.g., from a conveyor belt) and the vehicles are configured to pass under a dispensing end of the loading device to receive material dropped from the dispensing end of the loading device. Therefore, according to at least one exemplary embodiment, the loading device has a dispensing end, and the second vehicle is controlled to push the first vehicle under the dispensing end so that material dropped from the dispensing end of the loading device is received by the first vehicle.

[0080] According to the second aspect of the present invention, the object is achieved by a computer program, which includes a program code device. When the program is run on a computer, the program code device is used to execute the steps of the method of the first aspect of the present invention (including any embodiment thereof).

[0081] According to the third aspect of the present invention, the purpose is achieved by a computer-readable medium carrying a computer program, wherein the computer program includes a program code device, and when the program product is run on a computer, the program code device is used to execute the steps of the method of the first aspect of the present invention (including any embodiment thereof).

[0082] According to a fourth aspect of the present invention, the object is achieved by a control unit for controlling the operation of a fleet of autonomous vehicles, the control unit being configured to perform the steps of the method of the first aspect (including any embodiment thereof).

[0083] The advantages of the second, third and fourth aspects of the present invention are largely similar to those of the first aspect of the present invention.

[0084] According to a fifth aspect of the present invention, the object is achieved by a system for operating a fleet of autonomous vehicles, the system comprising a control unit according to the fourth aspect (including any embodiment thereof).

[0085] The advantages of the fifth aspect of the present invention are largely similar to those of the first, second, third and fourth aspects of the present invention.

[0086] Furthermore, the fifth aspect of the present invention has many exemplary embodiments, some of which are presented below.

[0087] According to at least one exemplary embodiment, the control unit is a central control unit arranged separately from the vehicle. The central control unit may suitably form part of a fleet management system. The central control unit may be configured to receive information, data, signals relating to different vehicle parameters, load parameters and other parameters that may be useful for calculating and determining appropriate operational controls for each vehicle in the group of autonomous vehicles.

[0088] According to at least one exemplary embodiment, the system further comprises a local control unit, each vehicle being equipped with a corresponding local control unit. As explained above in connection with the first aspect of the invention, some information may suitably be provided directly from the local control unit, and in some exemplary embodiments, some calculations may even be performed by the local control unit.

[0089] According to at least one exemplary embodiment, the local control unit is configured to send a signal representing the vehicle parameters and / or the load parameters to the central control unit (discussed in conjunction with the first aspect of the invention), wherein the central control unit is configured to control the operation of the vehicle based on the received signal.

[0090] According to at least one exemplary embodiment, the system further comprises a position tracking device configured to send a signal representing the geographical location of the loading device to the central control unit. As described above, the central control unit can then define a starting position and an ending position of the loading area.

[0091] According to at least one exemplary embodiment, each vehicle is provided with a local location tracking device configured to send a signal to the central control unit indicating the geographic location of the corresponding vehicle. Thus, the central control unit will be able to accurately control the vehicle and send instructions about which driving mode to be in, such as forward driving, reverse driving, turning, vehicle speed, etc.

[0092] According to at least some exemplary embodiments, the vehicles in the fleet of autonomous vehicles travel along a predetermined path through the work site. The predetermined path may suitably form a closed curve, so that when material has been unloaded from the vehicle, the vehicle may be controlled again to travel to a loading area to receive a new load of material. Thus, a steady flow of vehicles along the loading area may be achieved. When the vehicle has received a load, the vehicle may suitably be controlled to a target area, for example for unloading material.

[0093] Further advantages and advantageous features of the invention are disclosed in the following description and in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] Various embodiments of the present invention listed as examples will be described in more detail below with reference to the accompanying drawings.

[0095] In the attached figure:

[0096] Figure 1 is a schematic diagram of at least one exemplary embodiment of a vehicle that may be included in a fleet of autonomous vehicles. Such a fleet may be operated according to a method based on at least one exemplary embodiment of the present invention,

[0097] Figure 2a to Figure 2f shows an exemplary sequence that may occur when performing a method according to at least one exemplary embodiment of the present invention,

[0098] Figure 3 Another example of an exemplary embodiment for carrying out the method of the present invention is shown.

[0099] Figure 4 is a diagram schematically illustrating a method according to an exemplary embodiment of the present invention, and

[0100] Figure 5 are views schematically illustrating methods according to some other exemplary embodiments of the present invention. DETAILED DESCRIPTION

[0101] Figure 1 is a schematic diagram of at least one exemplary embodiment of a vehicle 2 that may be included in a convoy of autonomous vehicles. Such a convoy may be operated according to a method based on at least one exemplary embodiment of the present invention.

[0102] The vehicle 2 is an autonomous vehicle and may suitably be electric. For example, the vehicle may be powered by one or more traction batteries that power an electric motor. In other exemplary embodiments, the vehicle may be a fuel (e.g., diesel) based vehicle, a hybrid vehicle, a hydrogen powered vehicle, etc. The illustrated vehicle 2 may be in the form of a van having an open top at a material receiving portion 4. The material receiving portion 4 may be in the form of a container having a volume into which material may be dispensed.

[0103] The vehicle 2 may be in the form of a work machine used in one or more industrial applications, such as in quarries, mines, forests, etc. The vehicle 2 may be driven at least in a forward direction, and where appropriate also in a rearward direction. In the example shown, the vehicle 2 is provided with two pairs of wheels 6, however in other embodiments there may be more pairs of wheels, such as three or four pairs, etc. At least one pair of wheels 6 may be controlled to steer the vehicle 2.

[0104] The vehicle 2 may be provided with a local control unit. The local control unit 8 may include or may be included in a processing circuit. The processing circuit may include a microprocessor, a microcontroller, a programmable digital signal processor, or another programmable device. The processing circuit may also or alternatively include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. In the case where the processing circuit includes a programmable device such as a microprocessor, a microcontroller, or a programmable digital signal processor as described above, the processor may also include a computer executable code that controls the operation of the programmable device. It should be understood that all or some portions of the functionality provided by the processing circuit (or generally discussed as a "processing circuit") may be at least partially integrated with the local control unit 8.

[0105] Thus, the local control unit 8 can control the vehicle 2 to activate different driving modes, such as driving forward, driving backward, temporarily stationary. The local control unit 8 can also set the speed of the vehicle 2 and the angle of the wheels 6 for steering the vehicle 2. In an exemplary embodiment, the local control unit 8 can also be configured to tip over the material receiving part 4 of the vehicle 2 to allow the material contained therein to be removed. For example, the vehicle 2 can be provided with a hydraulically actuated tipping mechanism, such as comprising a retractable cylinder 10 as shown in the figure. Thus, the local control unit 8 can be configured to control such a tipping mechanism.

[0106] like Figure 1As shown, the vehicle 2 may also be provided with a local location tracking device 12, which is configured to send a signal representing the geographic location of the vehicle 2 to the central control unit 14. The local location tracking device 12 may be a separate component that communicates with the central control unit 14, or may be operatively connected to the local control unit 8 (or even an integrated part of the local control unit), and the location of the vehicle 2 may be transmitted to the central control unit 14 via the local control unit 8. It should be understood that in a fleet of autonomous vehicles, each vehicle may be provided with a local location tracking device 12 that is configured to send a signal representing the geographic location of the vehicle 2 to the central control unit 14. Figure 1 Thus, each vehicle may include a local control unit and a local position tracking device.

[0107] The communication between the local components on the vehicle 2 (ie the position tracking device 12 and / or the local control unit 8) and the central control unit 14 may be in the form of wireless communication (eg any form of radio communication).

[0108] The central control unit 14 will thus be able to accurately control the vehicle and send commands as to which driving mode to use (e.g. forward travel, reverse travel, turning, vehicle speed, etc.). It should be noted that some decisions regarding the operation of the vehicle 2 may be made by the local control unit 8, while other operational decisions may be made by the central control unit 14 (which suitably has an overview of the entire fleet), in which case the central control unit 14 will send operational commands to the local control units 8. For example, the local control unit 8 will typically decide on emergency braking in the event of a pedestrian or other sudden obstacle appearing in front of the moving vehicle 2, while it will typically be the central control unit 14 that decides to which unloading location the vehicle 2 should transport a received material load.

[0109] Figure 1 The vehicle 2 is further shown to have a front end 16 and a rear end 18. The underside of the front end 16 extends diagonally upward toward a front end 20 of the vehicle 2. Conversely, the top of the rear end 18 extends diagonally downward toward a rear end 22 of the vehicle 2.

[0110] Figure 2a to Figure 2f 2 shows an exemplary sequence that may occur when performing a method according to at least one exemplary embodiment of the present invention. In this sequence, only two vehicles 2a, 2b are shown for simplicity. The vehicles 2a, 2b may appropriately belong to a combination of Figure 1 The types discussed and shown are shown, although other vehicle embodiments are contemplated. Figure 2a to Figure 2f Only two vehicles 2a, 2b are shown (this indeed reflects the embodiment covered by the inventive concept), but in other exemplary embodiments of the method, more vehicles may advantageously be present in the convoy, which will be described later in conjunction with Figure 3 Have a discussion.

[0111] from Figure 2a Initially, the figure shows two autonomous vehicles 2a, 2b, a first vehicle 2a and a second vehicle 2b, which are comprised in a convoy of autonomous vehicles. Suitably, all vehicles in the convoy may be of the same type. The vehicles 2a, 2b are arranged for operation at a work site having a loading area 30. This may be, for example, at a quarry, in a mine, in a forest or any other environment / implementation area where material should be loaded onto the vehicle for transport to a different location. The loading area 30 may suitably be defined by geographical coordinates. Figure 2a , a work site is schematically shown as representing a quarry. A work machine 32, such as a wheel loader or an excavator, can pick up large pieces of material 34 (e.g., rocks) in order to release the materials so that they fall into a crusher 36, where the pieces are broken into smaller pieces of material. The crushed material is then transported via a loading device 40 (e.g., a conveyor belt) so that the material lands at a loading area 30. It should be understood that the objects shown are only one of many examples. For example, in some cases, the crusher 36 can be omitted, different types of loading devices can be used, etc. Therefore, the overall inventive concept is not limited to a specific loading device, nor is it limited to how the material 34 is provided to the loading device, but is based on how the autonomous vehicles 2a, 2b in the fleet operate at the loading area 30.

[0112] like Figure 2a As shown, the first vehicle 2a and the second vehicle 2b are both traveling towards the loading area 30 in the first driving mode. When the first vehicle 2a reaches the starting position 30a of the loading area 30 (the starting position can generally be defined by geographic coordinates that can be identified by any appropriate global navigation satellite system (GNSS)), the first driving mode of the first vehicle 2a is deactivated. The deactivation can cause the first vehicle 2a to stop, or the deactivation can be a reversing (generally a slow reversing). Therefore, such a stationary or reversing is the second driving mode of the first vehicle 2a. The control of the first vehicle 2a in the first driving mode and its deactivation can be performed by the local control unit or by the central control unit sending a command to the local control unit (for example, in Figure 1 The control unit 8, 14 shown in FIG. Figure 2a As shown, the loading area 30 also has an end location 30b (which may similarly be defined by geographic coordinates identifiable by any suitable global navigation satellite system (GNSS)).

[0113] Reference numerals 30, 30a and 30b are only Figure 2a and has been removed for clarity Figure 2b to Figure 2fis omitted to keep the drawings concise and easy to understand. However, it should be understood that when combined with Figure 2b to Figure 2f When discussing the loading area 30, the starting position 30a and the ending position 30b, the positions of these reference numerals are intended to be the same as those of Figure 2a Same position as shown in .

[0114] It should also be understood that each vehicle has a certain length. Therefore, the starting position 30a and the ending position 30b can be appropriately defined relative to a specific point or a specific portion of the vehicle. For simplicity, in this example, the starting position 30a and the ending position 30b have been defined with reference to the front end 20 of each vehicle. However, it will be readily understood that the starting position 30a and the ending position 30b can be defined in other ways so that any other point or area of ​​the vehicle can be used as a reference for determining when the vehicle arrives at the starting position 30a and the ending position 30b.

[0115] Therefore, according to at least one exemplary embodiment of the present invention, a reference point or a reference area is defined for each vehicle, wherein when the reference point or the reference area has reached the starting position, it is determined that the vehicle has reached the starting position, and when the reference point or the reference area has reached the ending position, it is determined that the vehicle has reached the ending position. Therefore, different steps of an exemplary embodiment of the method may involve reference points or reference areas. For example, in an exemplary embodiment, the method according to the first aspect may include the following steps:

[0116] - controlling a first vehicle of the autonomous vehicle to travel in a first driving mode until a reference point or a reference area of ​​the first vehicle reaches a starting position of a loading area,

[0117] - when the second vehicle has pushed the first vehicle so that the reference point or the reference area of ​​the first vehicle has reached the end position of the loading area, the first driving mode of the first vehicle is reactivated.

[0118] Figure 2b It is shown that the first vehicle 2a has reached the starting position 30a and the first driving mode has been deactivated. The first vehicle 2a waits for the second vehicle 2b to make contact with the first vehicle 2a. In some embodiments, such contact can also be achieved by controlling the first vehicle 2a to slowly reverse to meet the approaching second vehicle. Figure 2b , the second vehicle 2b has now come into contact with the first vehicle 2a.

[0119] When the second vehicle 2b has come into contact with the first vehicle 2a, the second vehicle is controlled so that it pushes the first vehicle 2a along the loading area 30 and past the loading device 40. Figure 2c, which shows that when the first vehicle 2a passes the loading device 40, the material 34 is loaded from the loading device 40 onto the first vehicle 2a.

[0120] As mentioned above, and with reference to Figure 1 , vehicle 2 (and thus in Figure 2a to Figure 2f The vehicles 2a, 2b in the embodiment of the present invention may have a front end 16, the underside of which extends diagonally upward toward the front end 20 of the vehicle 2. The top of the rear end 18 may extend diagonally downward toward the rear end 22 of the vehicle. This has the effect that when the second vehicle 2b pushes the first vehicle 2a, the front end 16 of the second vehicle 2b will overlap the downwardly inclined rear end 18 of the first vehicle 2a. Therefore, when the second vehicle 2b has reached the starting position 30a of the loading area 30 (in some embodiments, this may occur at the same time as the first vehicle 2a has reached the end position 30b of the loading area 30), the feeding of material 34 from the loading device 40 will smoothly transition from falling into the first vehicle 2a to falling into the second vehicle 2b. However, in at least some exemplary embodiments, it is conceivable to place the end position 30b further away, so that for a portion of the second vehicle 2b that travels under the loading device 40, this portion continues to push the first vehicle 2a. Thus, in at least some exemplary embodiments, the distance between the starting location 30a and the ending location 30b may be greater than the length of the material receiving portion of the vehicle 2, 2a, 2b, or greater than the length of the vehicle 2, 2a, 2b.

[0121] Figure 2d The transition is shown when loading of material 34 onto the first vehicle 2a has been completed or is nearly completed, and the second vehicle 2b is about to receive the dropped material.

[0122] exist Figure 2e, the first vehicle 2a has been pushed to the end position 30b of the loading area 30 (the end position can generally be defined by geographical coordinates that can be identified by any appropriate global navigation satellite system (GNSS)). At the same time, the second vehicle 2a may have arrived at the starting position 30a of the loading area 30 and has begun to receive material 34. Now that the first vehicle 2a has reached the end position 30b by the second vehicle pushed, the first driving mode of the first vehicle 2a can be reactivated. It should be understood that in the present invention, reactivating the first driving mode means canceling the second driving mode. Therefore, the control of the vehicle is first switched from the first driving mode to the second driving mode (deactivation step), and then, the control of the vehicle is switched from the second driving mode to the first driving mode (reactivation step). Reactivation can be controlled by a local control unit of the first vehicle 2a or by a command sent from a central control unit to a local control unit. Therefore, the first vehicle 2a can be controlled to independently drive away from the loading area without any continuous push from the second vehicle 2b. Suitably, the first vehicle 2a travels along a predetermined path to an unloading area where the material 34 transported by the first vehicle may be unloaded, after which the first vehicle 2a may return to the loading area 30 to receive another batch of material.

[0123] In summary, it should now be clear that, since the second vehicle 2b is in contact with the first vehicle 2a when the first vehicle 2a passes under the loading device 40, when the first vehicle 2a has reached the end position 30b and the second vehicle 2b has reached the start position 30a, the material flow from the loading device 40 will fall smoothly and substantially seamlessly into the second vehicle 2b. Therefore, the risk of material spillage is reduced.

[0124] Figure 2f A first vehicle 2a is shown in its first driving mode travelling to different locations to unload received material loads. When a second vehicle 2b is already loaded, this second vehicle can also drive away from the loading area 30 to unload the received material load 34 elsewhere. In this very simple exemplary illustration with two vehicles 2a, 2b, when the second vehicle 2b is already loaded with material 34, the loading device 40 should be appropriately closed to avoid overflow. However, in actual application, it may be advantageous to have a convoy of multiple vehicles so that a continuous flow of vehicles arrives at the starting position of the loading area and waits for vehicles approaching from behind to come into contact with the waiting vehicle to be pushed along the loading area. This is particularly useful in the embodiment of the present invention. Figure 3 This is explained in .

[0125] therefore, Figure 3Another example of an exemplary embodiment for carrying out the method of the invention is shown. The number of vehicles in the convoy is selected so that a continuous flow of vehicles can be provided to be pushed through the loading area. Thus, the number of vehicles in the convoy may depend on the driving distance, driving time, unloading time, etc. Furthermore, it is appropriate to take into account that not all vehicles may be able to operate at the same time, for example, the traction batteries of some vehicles may need to be charged and temporarily removed from the flow of vehicles.

[0126] exist Figure 3 In the embodiment, the loading area 30, the starting position 30a and the ending position 30b may correspond appropriately to Figure 2a Those shown in, however, for clarity, are Figure 3 These reference numerals and their associated reference lines are not indicated in FIG.

[0127] By having a continuous flow of vehicles, the loading device 40 can suitably continuously feed material into the loading area 30. Figure 3 , the first vehicle 2a has left the loading area 30, and the first driving mode of the second vehicle 2b is deactivated when the second vehicle 2b reaches the starting position 30a of the loading area 30. The third vehicle 2c has been controlled to come into contact with the second vehicle 2b and now pushes the second vehicle 2b along the loading area 30 and past the loading device 40 so that the material 34 is loaded onto the second vehicle 2b from the loading device 40 as the second vehicle 2b passes the loading device 40. When the second vehicle 2b has been pushed to the end position 30b, the first driving mode may be appropriately reactivated so that the second vehicle 2b can transport the material load to the unloading area and then return to the vehicle queue.

[0128] The third vehicle 2c may suitably arrive at the starting position 30a of the loading area 30 at the same time as the second vehicle 2b has arrived at the ending position 30b. In addition, at this time, the fourth vehicle 2d may have suitably approached and come into contact with the third vehicle 2c so as to push the third vehicle 2c (which has deactivated its first driving mode) along the loading area 30 for receiving the continuously falling material sheets.

[0129] The pushing vehicle, whether the second vehicle 2b, the third vehicle 2c, the fourth vehicle 2d or another vehicle 2e, can be controlled to push at a determined pushing speed. This pushing speed is appropriately based on vehicle parameters and / or load parameters. Examples of such parameters have been mentioned above in the present invention.

[0130] A first local control unit of the vehicle (eg Figure 1The first local control unit may transmit a signal representing the determined vehicle parameter and / or load parameter to a second local control unit of a following vehicle (which will push the vehicle in front of the pushing vehicle) or to a central control unit. The central control unit may then calculate and send a command to the second local control unit in the form of a transmission signal representing the determined pushing speed. In some exemplary embodiments, the first local control unit may calculate the pushing speed and send a command directly to the second local control unit without involving the central control unit.

[0131] like Figure 3 As shown in FIG. 1 , the loading device 40 may suitably include a position tracking device 42, such as a device similar to Figure 1 The local position tracking device 12 of the vehicle 2 is shown in FIG. Figure 2a to Figure 2f It is not shown, but it should be understood that Figure 2a to Figure 2f The loading device 40 in the apparatus may also be provided with a position tracking device.

[0132] According to at least one exemplary embodiment of the present invention, a signal representing the geographic location of the loading device 40 can be sent to the central control unit. The signal can be sent directly from the location tracking device 42 or via an operably connected transmitter. The geographic location of the loading device 40 can be used to define the geographic coordinates of the starting location 30a and the ending location 30b of the loading area 30.

[0133] An exemplary embodiment of the system of the present invention for operating a fleet of autonomous vehicles may include a central control unit located separately from the vehicles, such as Figure 1 The central control unit 14 illustrated in FIG. The central control unit can perform the steps of the exemplary embodiments of the present invention. The system can also include a local control unit (e.g., Figure 1 The system may also include a location tracking device (e.g., Figure 3 The system may include a location tracking device 42 in the loading device 40, which is configured to send a signal to the central control unit indicating the geographical location of the loading device 40. Similarly, the system may include a local location tracking device (e.g., Figure 1 The local position tracking device 12 illustrated in the figure), each vehicle is provided with a corresponding local position tracking device, which is configured to send a signal representing the geographic location of the corresponding vehicle to the central control unit (directly or via an operably connected transmitter, such as a transmitter included in the local control unit).

[0134] Figure 41 is a diagram schematically illustrating a method 100 according to an exemplary embodiment of the present invention. Therefore, a method 100 of operating a fleet of autonomous vehicles at a work site having a loading area, where a loading device is provided for loading materials onto the autonomous vehicles, is provided, the method comprising:

[0135] - in step S1, controlling a first vehicle among the autonomous vehicles to travel in a first driving mode until the first vehicle reaches a starting position of a loading area,

[0136] - in step S2, deactivating the first driving mode of the first vehicle by controlling the first vehicle to be positioned in the loading area in a second driving mode (e.g., zero torque, temporary standstill, fixed negative torque and / or slow reverse),

[0137] - in step S3, controlling a second vehicle of the autonomous vehicles to come into contact with the first vehicle and to push the first vehicle along the loading area and past the loading device so that the material is loaded from the loading device onto the first vehicle as the first vehicle passes the loading device,

[0138] In step S4 , when the second vehicle has pushed the first vehicle to the end position of the loading area, the first driving mode of the first vehicle is reactivated.

[0139] Figure 5 2 is a diagram schematically illustrating a method 200 according to some other exemplary embodiments of the present invention. In particular, Figure 5 It is shown that a number of different additional steps may be performed.

[0140] For example, in at least some exemplary embodiments, step S3 may include the following sub-steps:

[0141] - in sub-step S3a, vehicle parameters and / or load parameters are determined,

[0142] - in sub-step S3b, determining a propulsion speed based on the determined vehicle parameters and / or load parameters, and

[0143] - In sub-step S3c, the second vehicle is controlled to push the first vehicle at the determined pushing speed.

[0144] In an exemplary embodiment where the first vehicle comprises a first local control unit, the method may include:

[0145] - in step S5, transmitting a signal representing the determined vehicle parameter and / or load parameter from the first local control unit to a second local control unit arranged in the second vehicle or to a central control unit arranged separately from the vehicle, and / or

[0146] In step S6 , a signal representing the determined propulsion speed is transmitted to a second local control unit arranged on board the second vehicle or to a central control unit arranged separately from the vehicle.

[0147] In an exemplary embodiment where the fleet of autonomous vehicles includes a third vehicle, when the second vehicle has arrived at the starting position of the loading area, the method may include:

[0148] - in step S7, deactivating the first driving mode of the second vehicle by controlling the second vehicle to be positioned in the loading area in a second driving mode (eg, zero torque, temporary stationary, and / or slow reverse),

[0149] - in step S8, controlling the third vehicle to come into contact with the second vehicle and to push the second vehicle along the loading area and past the loading device so that the material is loaded from the loading device onto the second vehicle as the second vehicle passes the loading device,

[0150] In step S9 , when the third vehicle has pushed the second vehicle to the end position of the loading area, the first driving mode of the second vehicle is reactivated.

[0151] In some exemplary embodiments, the starting location and the ending location are defined by geographic coordinates, wherein the method comprises:

[0152] - In step S10 , the geographic location of the autonomous vehicle is determined by using a global navigation satellite system.

[0153] In some exemplary embodiments where the loading device includes a position tracking device, the method may include:

[0154] - In step S11, a signal indicating the geographical location of the loading device is sent from the location tracking device to the central control unit, and optionally

[0155] In step S12 , a starting position of the loading area and an ending position of the loading area are defined based on the geographical location of the loading device.

[0156] It should be noted that although Figure 5 It has been shown as if some steps are performed in groups, but it should be understood that the embodiments are not limited to the grouping shown. For example, in some exemplary embodiments, it is possible to perform Figure 5 In addition, the steps may be performed in a different order than shown. For example, steps S11 and S12 may be performed before step S10.

[0157] The present invention has been described above with reference to specific embodiments. However, other embodiments than those described above are possible and within the scope of the present invention. Method steps different from those described above may be provided within the scope of the present invention and the method may be performed by hardware or software. Therefore, according to an exemplary embodiment, a non-transitory computer-readable storage medium storing one or more programs is provided, the one or more programs being configured to be executed by one or more processors of a system for simulating remote control of a vehicle via a wireless network, the one or more programs comprising instructions for performing a method according to any of the above-described embodiments.

[0158] Alternatively, according to another exemplary embodiment, a cloud computing system may be configured to perform any method aspect presented herein. The cloud computing system may include distributed cloud computing resources that, under the control of one or more computer program products, jointly perform the method aspects presented herein.

[0159] The processor (associated with the fleet operating system) may be or include any number of hardware components for performing data or signal processing or for executing computer code stored in memory. The fleet operating system may have associated memory, and the memory may be one or more devices for storing data and / or computer code for use in completing or facilitating the various methods described in this specification. The memory may include volatile memory or non-volatile memory. The memory may include database components, object code components, script components, or any other type of information structure for supporting the various activities described herein. According to an exemplary embodiment, any distributed or local storage device may be used with the systems and methods described herein.

[0160] According to an exemplary embodiment, the memory is communicatively connected to the processor (eg, via a circuit or any other wired, wireless, or network connection) and includes computer code for performing one or more processes described herein.

[0161] The different features and steps of the embodiments may be combined in other combinations than those described.

[0162] It should be understood that the present invention is not limited to the embodiments described above and shown in the drawings; rather, those skilled in the art will recognize that many changes and modifications are possible within the scope of the appended claims.

Claims

1. A method of operating a fleet of autonomous vehicles at a job site having a loading area, wherein a loading device is provided at the loading area for loading materials onto the autonomous vehicles, the method comprising: - controlling a first vehicle in the fleet of autonomous vehicles to travel in a first driving mode until the first vehicle reaches a starting position of the loading area, - deactivating the first driving mode of the first vehicle by controlling the first vehicle to be positioned in the loading area in a second driving mode, - controlling a second vehicle in the convoy of autonomous vehicles to come into contact with the first vehicle and to push the first vehicle along the loading area and past the loading device so that material is loaded from the loading device onto the first vehicle as the first vehicle passes the loading device, - when the second vehicle has pushed the first vehicle to the end position of the loading area, reactivating the first driving mode of the first vehicle.

2. The method according to claim 1, wherein: In the second driving mode, the motor of the first vehicle generates a fixed negative torque or zero torque.

3. The method according to any one of claims 1 to 2, wherein: The second vehicle reaches the starting position of the loading area at the same time as the first vehicle reaches the ending position of the loading area, wherein the method includes controlling the second vehicle to travel in the first driving mode until the second vehicle reaches the starting position of the loading area.

4. The method according to any one of claims 1 to 2, wherein: The step of controlling a second vehicle in the fleet of autonomous vehicles to come into contact with the first vehicle and to push the first vehicle along the loading area and past the loading device comprises: - determining vehicle parameters and / or load parameters of said first vehicle, - determining a propulsion speed based on the determined vehicle parameters and / or load parameters, and - controlling the second vehicle to push the first vehicle at the determined pushing speed.

5. The method according to claim 4, wherein: The vehicle parameter is one or more selected from the group consisting of: - the state of charge of the traction battery of the first vehicle, - the fuel level of the first vehicle, - the available load capacity of the first vehicle, - the permissible laden weight of the first vehicle, - the geometry of the material receiving part of the first vehicle, - the tire pressure in the tires of said first vehicle, - the efficiency of the electric motor of the first vehicle.

6. The method according to claim 4, wherein: The first vehicle comprises a first local control unit, wherein the method comprises: - transmitting a signal representing the determined vehicle parameter and / or load parameter from the first local control unit to a second local control unit arranged on board the second vehicle or to a central control unit arranged separately from the fleet of autonomous vehicles, and / or - transmitting a signal representing the determined propulsion speed to a second local control unit arranged on board the second vehicle or to a central control unit arranged separately from the fleet of autonomous vehicles.

7. The method according to claim 4, wherein: The load parameter is one or more selected from the group consisting of: - the dimensions of the material to be loaded onto said first vehicle, - the weight of the material to be loaded onto said first vehicle, - the speed at which said material is loaded onto said first vehicle, - Type of material.

8. The method according to claim 4, wherein: The determined pushing speed is further determined based on one or more of the following parameters: a fleet distribution parameter in the form of a geographical distribution of the vehicles of the fleet of autonomous vehicles at the work site, an energy cost parameter in the form of the load per unit of energy consumed by the first vehicle to transport the load to the unloading area, a productivity parameter in the form of a load delivered per unit time of the first vehicle delivering loads to the unloading area, - Environmental parameters in the form of current weather and / or road conditions at the work site.

9. The method according to any one of claims 1 to 2, wherein: The fleet of autonomous vehicles further includes a third vehicle, wherein when the second vehicle has reached a starting position of the loading area, the method includes: - deactivating the first driving mode of the second vehicle by controlling the second vehicle to be positioned in the loading area in the second driving mode, - controlling the third vehicle to come into contact with the second vehicle and to push the second vehicle along the loading area and past the loading device so that material is loaded from the loading device onto the second vehicle as the second vehicle passes the loading device, - when the third vehicle has pushed the second vehicle to the end position of the loading area, reactivating the first driving mode of the second vehicle.

10. The method according to any one of claims 1 to 2, wherein: The starting location and the ending location are defined by geographic coordinates, wherein the method includes determining the geographic location of the autonomous vehicle by using a global navigation satellite system.

11. The method according to claim 10, wherein: The loading device includes a position tracking device, wherein the method includes: - Sending a signal representing the geographical location of the loading device from the position tracking device to a central control unit.

12. The method according to claim 11, comprising: - defining the starting position of the loading area and the ending position of the loading area based on the geographical position of the loading device.

13. The method according to any one of claims 1 to 2, wherein: The loading device comprises a conveyor belt from which material can be dropped onto the autonomous vehicle.

14. The method according to any one of claims 1 to 2, comprising: The fleet of autonomous vehicles is controlled so that there is a continuous flow of vehicles past the loading device.

15. A computer-readable medium carrying a computer program, the computer program comprising program code for executing the steps of the method according to any one of claims 1 to 14 when the computer program is run on a computer.

16. A control unit for controlling the operation of a fleet of autonomous vehicles, the control unit being configured to perform the steps of the method according to any one of claims 1 to 14.

17. A system for operating a fleet of autonomous vehicles, the system comprising a control unit according to claim 16.

18. The system of claim 17, wherein: The control unit is a central control unit that is arranged separately from the fleet of autonomous vehicles.

19. The system according to claim 18, further comprising a local control unit, each vehicle being equipped with a corresponding one of the local control units.

20. The system of claim 19, wherein: The local control units are configured to send signals representing corresponding vehicle parameters and / or load parameters of each vehicle to the central control unit, and Therein, the central control unit is configured to control the operation of the autonomous vehicle based on the received signal.

21. The system of any one of claims 17 to 20, further comprising a location tracking device configured to send a signal indicative of the geographic location of the loading device to the central control unit.

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