Method for transporting and depositing a load by an autonomous forklift truck

Abstract

This autonomous forklift truck (1) comprises: - a lifting member (2) movable at least vertically, - a drive system (6) for moving the forklift truck, - a first contactless detection device (9) fixed with respect to the forklift truck and making it possible to detect an obstacle situated in front of the forklift truck, and - a control unit (8) able to control the forklift truck depending on the information from the first detection device, and able to control the movement of the lifting member (2). The forklift truck further comprises a second contactless detection device (11) which is fixed with respect to the forklift truck (1), arranged above the first detection device (9) and able to detect an obstacle situated in front of the forklift truck (1). The control unit (8) is able to control the forklift truck (1) depending on the information from the second contactless detection device (11).

Description

[0001] DESCRIPTION

[0002] TITLE: Autonomous load transport forklift, and associated method

[0003] Technical field

[0004] The present invention relates to the field of autonomous vehicles for the automated transport of loads, such as autonomous forklifts.

[0005] State of the prior art

[0006] Autonomous vehicles for transporting loads are increasingly used to increase productivity and improve logistics management in factories and warehouses.

[0007] Automated forklifts are an example of such vehicles and allow, for example, loading, transporting and positioning a load at height without human intervention.

[0008] However, in environments such as factories or warehouses, human intervention is still necessary to complement automated operations, for example to monitor the smooth running of these operations or to perform tasks that cannot be performed by machines alone. These environments are therefore shared between humans and autonomous machines.

[0009] The safety of people is fundamental in such working environments and therefore requires the implementation of specific procedures.

[0010] For example, in order to limit the risk of collision, autonomous forklifts are traditionally equipped with contactless obstacle detection devices.

[0011] Such a contactless detection device is attached to the truck and emits a light beam that is directed forward to detect whether an obstacle is present in its detection field. When the presence of an obstacle is detected, the autonomous forklift slows down or even makes an emergency stop. During the load deposit phase, the forklift approaches a storage structure, until it reaches a deposit position allowing unloading. When the forklift approaches, the detection field of the contactless detection device must be deactivated so that the structure is not detected by it and prevents it from reaching the deposit position.

[0012] Therefore, there is a risk of a pedestrian being crushed between the load supported by the forklift and the structure.

[0013] Statement of the invention

[0014] In view of the above, the aim of the invention is therefore to propose an autonomous forklift capable of increasing the level of safety of load depositing operations.

[0015] The subject of the invention is an autonomous forklift truck comprising a lifting member which is movable at least vertically and provided with at least two arms for lifting loads, a drive system for moving the forklift truck, a first contactless detection device which is fixed relative to the truck and capable of emitting a first light beam having a main emission direction which is oriented horizontally towards the front of the forklift truck to detect an obstacle located in front of said truck.

[0016] According to a general characteristic, the forklift truck further comprises a control unit capable of receiving information representative of the presence of an obstacle from the first contactless detection device, capable of controlling the operation of the drive system to autonomously guide the forklift truck according to the information from the first contactless detection device and capable of controlling the movement of the lifting member.

[0017] According to another general characteristic, the forklift truck further comprises a second non-contact detection device, said second non-contact detection device being fixed relative to the truck and arranged above the first non-contact detection device. The second non-contact detection device is capable of emitting a second light beam having a main emission direction which is oriented horizontally towards the front of the forklift truck to detect an obstacle located in front of said truck.

[0018] According to another general characteristic, the control unit receives information representative of the presence of an obstacle from the second contactless detection device.

[0019] According to another general characteristic, the control unit is capable of controlling the operation of the drive system to autonomously guide the forklift truck based on information from the second contactless detection device.

[0020] With such an autonomous forklift, it becomes possible to ensure, during load depositing operations, that the vehicle is brought closer to the structures intended to accommodate loads without the risk of crushing pedestrians.

[0021] Advantageously, the second contactless detection device is fixed to said forklift at a constant height from the ground of between 150 mm and 2000 mm. Indeed, the applicant has observed that the risk of crushing a pedestrian increases with storage structures within this height range.

[0022] Advantageously, the second contactless detection device is fixed to said forklift at a height from the ground of between 300 mm and 1100 mm, and preferably between 700 mm and 900 mm. For information purposes, the second contactless detection device may be fixed to said forklift at a height from the ground of 830 mm. The autonomous forklift comprises an on-board location device configured to acquire position data of the forklift and communicating with the control unit. Preferably, the first and second contactless detection devices are separate from the location device.

[0023] According to a particular configuration, the light beam emitted by each of the first and second detection devices scans at least one predefined flat detection zone. The flat detection zone may be defined by four distinct points delimiting a rectangle, or by three distinct points delimiting a triangle. It is possible to provide for the first and / or the second detection devices a light beam of different flat shape, for example a circle, an ellipse, etc.

[0024] In a first embodiment, the lifting member is provided with a vertically movable fork comprising said two arms.

[0025] In this case, the second contactless detection device may be offset towards the rear of said forklift relative to said two arms.

[0026] The fork of the lifting device may also further comprise at least two uprights each supporting one of said two arms. The second contactless detection device may then be offset towards the rear of said forklift relative to the uprights.

[0027] Said two fork arms are movable between an extreme high position and an extreme low position which corresponds to a rolling position. Preferably, the first contactless detection device is fixed below said two arms in their extreme low position.

[0028] In a second alternative embodiment, the lifting member is provided with a vertically movable and rotatable clamp comprising said two arms. In this case, the second contactless detection device can be offset towards the rear of said forklift relative to said two arms.

[0029] According to another aspect, the invention relates to a method for transporting and depositing a load by an autonomous forklift as described above.

[0030] The transport and removal process includes:

[0031] - a step of positioning the forklift truck relative to a structure intended to support the load in an approach position relative to said structure, the first contactless detection device being in an activated state during the step of positioning the truck,

[0032] - when the carriage has reached the approach position, a step of lifting the arms of the lifting member above the second non-contact detection device, and a step of deactivating the first non-contact detection device,

[0033] - after the step of lifting the arms of the lifting device of the forklift, a step of activating the second contactless detection device,

[0034] - after the step of activating the second detection device, a step of advancing the autonomous forklift to a drop-off position if no obstacle is detected by the second contactless detection device,

[0035] - a step of deactivating the second contactless detection device after the autonomous forklift has reached the drop-off position, and

[0036] - after or simultaneously with the step of deactivating the second contactless detection device, a step of lowering the arms of the lifting device of the forklift to deposit the load in the deposit position.

[0037] With this removal process, the safety of operators working or who may be near storage structures is improved by making it possible to check that there is no operator between an autonomous forklift truck carrying a load to be removed and a storage structure, when the forklift truck approaches the structure during removal operations.

[0038] Preferably, when the forklift has reached the approach position, the step of deactivating the first non-contact detection device is carried out after the step of lifting the arms of the lifting member above the second light beam of the second non-contact detection device.

[0039] Alternatively, it is possible to carry out the step of deactivating the first contactless detection device before the step of lifting the arms of the lifting member above the second light beam of the second contactless detection device.

[0040] Brief Description of the Drawings Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0041] [Fig 1] is a perspective view of an autonomous forklift according to a first exemplary embodiment of the invention;

[0042] [Fig 2] [Fig 3] [Fig 4] [Fig 5] schematically illustrate the forklift of figure 1 during its use in a method of transporting and depositing a load according to an embodiment of the invention;

[0043] [Fig 6] illustrates the flowchart of a method for transporting and depositing a load according to an embodiment of the invention; and

[0044] [Fig 7] is a perspective view of an autonomous forklift according to a second exemplary embodiment of the invention.

[0045] Detailed description of at least one embodiment

[0046] Figure 1 shows the main elements of an autonomous forklift 1 according to one embodiment of the invention.

[0047] The architecture of the forklift 1 is given by way of example and does not limit the invention to the sole configuration of the architecture presented. It is understood that the invention also relates to forklifts intended to operate in manual mode and which have been adapted to allow a second mode of operation in autonomous mode.

[0048] The self-propelled forklift 1 illustrated in Figure 1 comprises a lifting member 2 comprising an apron 3 and provided with a fork 4 comprising two arms 4a, 4b spaced laterally and extending towards the front of the truck. The fork 4 also comprises two uprights 4'a, 4'b which each support one of the arms 4a, 4b.

[0049] The arms 4a, 4b of the fork are generally used to insert into insertion tunnels provided in the transport pallets supporting the loads to be lifted. The uprights 4'a, 4'b allow the arms 4a, 4b to be raised in order to be able to lift a pallet to be transported or another type of load and to be able to place or pick up a pallet or another type of load at height.

[0050] The fork 4 is able to move in translation in a vertical plane V defined by the apron 3, along a vertical mast 5 of the carriage. The uprights 4'a, 4'b can slide along the mast 5. The arms 4a, 4b of the fork are movable between an extreme high position, and an extreme low position which is illustrated in figures 1 and 2 and which corresponds to a rolling position. In the extreme low position, the arms 4a, 4b are located at a distance from the ground.

[0051] The longitudinal axes of the arms 4a, 4b of the fork 4 are parallel. These longitudinal axes are oriented parallel to a horizontal axis X, and define a horizontal plane H called the lifting plane. The arms 4a, 4b of the fork 4 are perpendicular to the vertical plane V. The arms 4a, 4b of the fork are also preferably laterally movable relative to each other.

[0052] Alternatively, the arms of the fork 4 could also be telescopic or retractable, and / or angularly orientable around their longitudinal axis.

[0053] In a manner known per se, the trolley 1 is equipped with a drive system 6 allowing the trolley 1 to move. The drive system comprises at least one electric or thermal motor (not shown) allowing the wheels of the trolley 1 to be driven.

[0054] The truck 1 is also equipped with an on-board location device 7, and an on-board control unit 8 (figure 2) receiving information from the location device 7 to autonomously control the movement of the forklift.

[0055] The control unit 8 comprises the hardware and software means for controlling the operation of the drive system 6 based on the information received from the location device 7. The control unit 8 also makes it possible to control the autonomous movement of the lifting member 2.

[0056] The trolley 1 is equipped with a first contactless detection device 9 which is fixed to the trolley 1 without the possibility of relative movement relative to said trolley. The contactless detection device 9 is fixed at a constant height relative to the ground. The contactless detection device 9 is located below the arms 4a, 4b of the lifting member 2 in their extreme low position. The contactless detection device 9 is fixed to the trolley 1. The contactless detection device 9 is fixed to the trolley 1 without the possibility of relative movement in translation relative to said trolley. The contactless detection device 9 is located below the mast 5 and is offset towards the rear of the forklift relative to the arms 4a, 4b and relative to the uprights 4'a, 4'b.

[0057] The carriage 1 is further equipped with a second contactless detection device 11 which is also fixed to the carriage 1. The contactless detection device 11 is fixed to the carriage 1 without the possibility of relative translational movement relative to said carriage. The contactless detection device 11 is fixed at a constant height relative to the ground. The contactless detection device 11 is arranged above the contactless detection device 9. The contactless detection devices 9, 11 respectively form lower and upper detection devices. The detection devices 9, 11 are distinct from each other. The detection devices 9, 11 are also distinct from the location device 7. The detection devices 9, 11 may for example be laser sensors of the Lidar type.

[0058] The contactless detection device 11 is located above the arms 4a, 4b of the lifting member 2 in their extreme low position. The contactless detection device 11 is fixed to the mast 5. The contactless detection device 11 is offset towards the rear of the forklift relative to the arms 4a, 4b and relative to the uprights 4'a, 4'b.

[0059] The second contactless detection device 11 is arranged at a constant height relative to the ground which may for example be between 150 mm and 2000 mm, and preferably between 300 mm and 1100 mm, and even more preferably between 700 mm and 900 mm. The second contactless detection device 11 may for example be arranged at a height equal to 830 mm. As will be described in more detail below, the detection devices 9, 11 are each capable of emitting a light beam having a main emission direction which is oriented horizontally towards the front of the forklift 1 to detect an obstacle located at the front of said truck. The light beams emitted by the detection devices 9, 11 are distinct.

[0060] The detection devices 9, 11 are configured to acquire data on the presence of an obstacle, and to transmit to the control unit 8 information representative of the presence of the obstacle detected within at least one predefined detection zone. Depending on the information received, the control unit 8 then controls the operation of the drive system 6 and the vertical movement of the lifting member 2. The control unit 8 also makes it possible to control the activated state or the deactivated state of each of the detection devices 9, 11.

[0061] We will now describe, with reference to figures 2 to 5, the operating principle of the autonomous forklift 1 for the operation of depositing a load 12 on a structure 13 and the associated depositing method 20 illustrated in figure 6.

[0062] The method 20 begins with the step 21 of positioning the forklift 1 in a predefined approach position relative to the structure 13 intended to support the load.

[0063] In this initial phase, the control unit 8 controls the operation of the trolley 1 to obtain its approach to the structure 13 according to the data from the location device 7 and the information from the detection device 9. This positioning step 21 is carried out in an activated state of the first contactless detection device 9 which emits a first light beam 10 oriented horizontally towards the front of the trolley 1. If the presence of an obstacle located in front of the trolley is detected by the detection device 9, the control unit 8 controls the emergency stop of the trolley 1 and the placing of the trolley 1 on standby for reordering by an operator (step 21'). On the contrary, if the first contactless detection device 9 does not detect any obstacle, the control unit 8 continues to advance the trolley 1 until it reaches the approach position.

[0064] When the carriage 1 reaches the approach position, the method 20 continues with a step 22 of lifting the arms and a step 23 of deactivating the contactless detection device 9. The control unit 8 therefore issues an instruction to deactivate the contactless detection device 9 and an instruction to lift the arms 4a, 4b.

[0065] In step 22, the movement of the arms is controlled by the control unit 8 so that they are located above the contactless detection device 11 as illustrated in figure 3.

[0066] Preferably, step 23 of deactivating the contactless detection device 9 is carried out after step 22 of lifting the arms 4a, 4b of the lifting member. Alternatively, step 23 of deactivation can be carried out before step 22 of lifting the arms or simultaneously.

[0067] The method 20 continues with a step 24 of activating the contactless detection device 11. The control unit 8 for this purpose issues an instruction to activate the contactless detection device 11 which then emits a second light beam 14 (figure 3). The light beam 14 is located below the arms 4a, 4b of the lifting member. In figure 3, the light beam 14 is located above the structure 13.

[0068] After step 24 of activating the detection device 11, the method 20 continues with a step 25 of advancing the forklift 1 to a predetermined drop-off position.

[0069] If the contactless detection device 11 detects an obstacle, the control unit 8 commands the emergency stop of the trolley 1 and the placing of the trolley 1 on hold to allow an operator to put it back in order (step 25').

[0070] On the contrary, if the second contactless detection device 11 does not detect any obstacle, the control unit 8 continues to advance the carriage 1 until it reaches said predetermined depositing position. When the carriage 1 has reached said depositing position, the method 20 continues with a step 26 of deactivating the contactless detection device 11. For this purpose, the control unit 8 issues an instruction to deactivate the contactless detection device 11.

[0071] The method 20 continues with a step 27 of lowering the arms 4a, 4b of the lifting member to deposit the load in the depositing position. Step 27 can be carried out after step 26 of deactivating the contactless detection device 11, or simultaneously with this step.

[0072] During this step 27, the control unit 8 controls the lowering of the arms 4a, 4b of the lifting member until the load 12 comes into contact with the part of the structure 13 intended to accommodate it. The control unit 8 then continues the lowering of the arms 4a, 4b inducing a relative vertical movement between the arms 4a, 4b and the load 12 meaning that the latter is no longer in contact with the arms 4a, 4b and rests entirely on the structure 13.

[0073] In the embodiment described, the lifting member of the forklift is equipped with a vertically movable fork and equipped with the two arms 4a, 4b.

[0074] It is not outside the scope of the invention if the forklift truck is equipped, instead of the fork 4, with a clamp 30, as illustrated in Figure 7 in which identical elements bear the same references. The clamp 30 of the forklift truck is movable vertically along the mast 5 and movable in rotation around a horizontal axis 31 and equipped with two arms 32 capable of gripping the load to be deposited, only one of the two arms being visible in Figure 7.

[0075] In a manner known per se, the clamp 30 is equipped with a slide 33 which can slide along the mast 5 and supports the arms 32. The arms 32 of the clamp are movable between an extreme high position and an extreme low position which corresponds to a rolling position. In the extreme low position, the arms 32 are located at a distance from the ground.

[0076] In this case, the positioning of the detection devices 9, 11 is similar to that described previously. The contactless detection device 9 is fixed to the carriage 1 in a manner similar to the first embodiment. The contactless detection device 9 is located below the arms 32 of the clamp in their extreme low rolling position. The contactless detection device 9 is located below the mast 5 and is offset towards the rear of the forklift relative to the arms 32 and relative to the slide 33.

[0077] The contactless detection device 11 is also fixed to the carriage 1 in a manner similar to the first embodiment. The contactless detection device 11 is arranged above the contactless detection device 9. The contactless detection device 11 is located above the arms 32 of the clamp in their extreme lower rolling position. The contactless detection device 11 is fixed to the mast 5. The contactless detection device 11 is offset towards the rear of the forklift truck relative to the arms 32 of the clamp and relative to the slide 33.

Claims

DEMANDS 1. Method (20) for transporting and depositing a load (12) by a self-propelled forklift (1) comprising: - a lifting device (2) movable at least vertically and equipped with at least two arms (4a, 4b; 32) for lifting loads, - a drive system (6) for moving the forklift (1), - a first non-contact detection device (9) which is fixed relative to the trolley and capable of emitting a first light beam (10) having a main emission direction which is oriented horizontally towards the front of the forklift to detect an obstacle located in front of said trolley, - a control unit (8) capable of receiving information representative of the presence of an obstacle from the first non-contact detection device (9), capable of controlling the operation of the drive system (6) to autonomously guide the forklift based on information from the first non-contact detection device (9), and capable of controlling the movement of the lifting mechanism, and - a second non-contact detection device (11) which is fixed relative to the forklift (1) and arranged above the first non-contact detection device (9) characterized in that it comprises the following steps: - a step (21) of positioning the forklift (1) relative to a structure (13) intended to support the load in an approach position relative to said structure, the first non-contact detection device (9) being in an activated state during the positioning step of the forklift (1), - when the forklift (1) has reached the approach position, a step (22) of lifting the arms (4a, 4b) of the lifting member (2) above the second non-contact detection device (11), and a step (23) of deactivating the first non-contact detection device (9), - after step (22) of raising the arms (4a, 4b) of the lifting element (2) of the forklift (1), a step (24) of activating the second non-contact detection device (11), - after step (24) of activation of the second non-contact detection device (11), a step (25) of advancement of the autonomous forklift (1) to a drop-off position if no obstacle is detected by the second non-contact detection device (11), - a step (26) of deactivating the second non-contact detection device (11) after the autonomous forklift (1) has reached the drop-off position, and - after or simultaneously with step (26) of deactivation of the second non-contact detection device (11), a step (27) of lowering the arms (4a, 4b) of the lifting member (2) of the forklift (1) to deposit the load in the deposit position.

2. Method according to claim 1, wherein when the forklift (1) has reached the approach position, the step (23) of deactivating the first non-contact detection device (9) is carried out after the step (22) of raising the arms (4a, 4b) of the lifting member (2) above the second light beam (14) of the second non-contact detection device (11).

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