Transportation vehicle

The transport vehicle addresses the limitations of existing systems by using a load adjustment unit to enhance wheel grip during slip detection, ensuring efficient operation even without variable maximum acceleration and deceleration.

JP2025091216AActive Publication Date: 2025-06-18TOYOTA JIDOSHA KK
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Patent Information

Application Number
JP2023206354
Authority / Receiving Office
JP · JP
Patent Type
Applications
Current Assignee / Owner
Filing Date
2023-12-06
Publication Date
2025-06-18
Estimated Expiration
2043-12-06

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  • Figure 2025091216000001_ABST
    Figure 2025091216000001_ABST
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Abstract

To provide a transportation vehicle that is usable even when maximum acceleration and maximum deceleration cannot be variably utilized and can prevent conveyance time from becoming long.SOLUTION: A transportation vehicle 10 has a load carrying platform 11 for loading an object M, and one of a front wheel 12 and a rear wheel 13 is a driving wheel and the other is a follower wheel. The transportation vehicle 10 comprises: a slip detection unit 22d for detecting a slip of the driving wheel; and a load adjusting unit 22e that, when a slip of the driving wheel has been detected, adjusts a load on the driving wheel side so that the load on the driving wheel side of the transportation vehicle becomes larger.SELECTED DRAWING: Figure 1
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Description

Technical Field

[0001] The present disclosure relates to a transport vehicle.

Background Art

[0002] There has been proposed a transport vehicle that calculates a slip ratio of a wheel and calculates at least one of a maximum acceleration and a maximum deceleration of the transport vehicle that can maintain a grip state of the wheel with respect to a road surface (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, there is a problem that it cannot be used when the maximum acceleration and the maximum deceleration cannot be variably applied. In addition, there is a problem that the transport time becomes long by reducing the acceleration and deceleration.

[0005] The present disclosure has been made to solve such problems, and provides a transport vehicle that can be used even when the maximum acceleration and the maximum deceleration cannot be variably applied, and can prevent the transport time from becoming long.

Means for Solving the Problems

[0006] The transport vehicle according to the present disclosure includes a loading platform on which a load is loaded, and is a transport vehicle in which one of a front wheel and a rear wheel is a driving wheel and the other is a driven wheel, and includes a slip detection unit that detects slip of the driving wheel, and a load adjustment unit that adjusts the load on the driving wheel side so that the load on the driving wheel side of the transport vehicle increases when slip of the driving wheel is detected.

[0007] With such a configuration, it can be used even when the maximum acceleration and the maximum deceleration cannot be variably applied, and it is possible to prevent the conveyance time from becoming long.

[0008] Further, in the above-described transport vehicle, the load adjustment unit is a height adjustment unit that adjusts the height on the driven wheel side of the transport vehicle, and when slip of the drive wheel is detected, the height adjustment unit adjusts the height on the driven wheel side of the transport vehicle so that the load on the drive wheel side increases.

[0009] Further, in the above-described transport vehicle, the height on the driven wheel side of the transport vehicle may be adjusted so that the height on the driven wheel side of the transport vehicle becomes a target height.

[0010] Further, in the above-described transport vehicle, the target height may be changed according to the presence or absence of the load.

Advantages of the Invention

[0011] According to the present disclosure, it is possible to provide a transport vehicle that can be used even when the maximum acceleration and the maximum deceleration cannot be variably applied, and that can prevent the conveyance time from becoming long.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0013] Hereinafter, a transport vehicle 10 according to an embodiment of the present invention will be described with reference to the accompanying drawings. In each figure, corresponding components are denoted by the same reference numerals, and redundant descriptions are omitted.

[0014] FIG. 1 is a schematic configuration diagram of the transport vehicle 10.

[0015] As shown in FIG. 1, the transport vehicle 10 includes a loading platform 11 on which a load M is loaded, front wheels 12, and rear wheels 13, and is a transport vehicle in which one of the front wheels 12 and the rear wheels 13 is a driving wheel and the other is a driven wheel. The transport vehicle 10 travels autonomously, similar to an autonomous mobile robot (AMR). Note that since the configuration and functions as an autonomous mobile robot are well-known, the description thereof is omitted.

[0016] Hereinafter, a case where the front wheel 12 is a driving wheel and the rear wheel 13 is a driven wheel having a smaller diameter than the front wheel 12 will be described as an example. The front wheel 12 is rotated forward and backward by a motor (not shown) connected to the front wheel 12 via a speed reducer (not shown) or the like being controlled by a control unit 22. In the following description, an example in which the load M is a vehicle (automobile) will be described.

[0017] The transport vehicle 10 is provided with a load adjustment system 20.

[0018] As shown in FIG. 1, the load adjustment system 20 includes an air suspension 21, a control unit 22, and a positioning system 23.

[0019] The air suspension 21 is provided on each of the front wheel 12 side and the rear wheel 13 side. The length of the air suspension 21 expands and contracts under the control of the control unit 22. Hereinafter, the air suspension 21 on the front wheel 12 side will be referred to as the air suspension 21F, and the air suspension 21 on the rear wheel 13 side will be referred to as the air suspension 21B.

[0020] The control unit 22 is, for example, an ECU (Electronic Control Unit). The control unit 22 includes a processor 22a (e.g., a CPU), a memory 22b (e.g., a RAM), and a storage unit 22c (e.g., a ROM).

[0021] By executing a predetermined program read from the storage unit 22c into the memory 22b, the processor 22a functions as a slip detection unit 22d and a load adjustment unit 22e. Note that some or all of these may be realized by hardware.

[0022] The slip detection unit 22d detects the slip of the front wheels 12 which are drive wheels. For example, a positioning system 23 (e.g., a GPS receiver) attached to the transport vehicle 10 acquires the coordinates (current position coordinates) of the transport vehicle 10. Then, the transport vehicle 10 detects the presence or absence of slip from the difference between the travel distance of the transport vehicle 10 calculated by the control unit 22 (internal arithmetic unit) and the coordinates (current position coordinates) of the transport vehicle 10. Also, even when the control unit 22 controls (e.g., outputs a control signal) a motor (not shown) connected to the front wheels 12 which are drive wheels, if the current position of the transport vehicle 10 does not change, the slip of the front wheels 12 may be detected. At this time, the current position of the transport vehicle 10 may use the current position detected by the positioning system 23 or the like. Note that the timing of slip detection may be the timing of starting travel from the traveling stop state of the transport vehicle 10 or the timing of stopping travel from the traveling state.

[0023] When the slip of the front wheels 12 which are drive wheels is detected, the load adjustment unit 22e adjusts the load on the front wheel 12 side so that the load on the front wheel 12 side of the transport vehicle 10 increases. For example, as the load adjustment unit 22e, a height adjustment unit that adjusts the height hight (see FIGS. 2(a) and 2(b)) on the rear wheel 13 side which is a driven wheel can be used. Hereinafter, it is referred to as the height adjustment unit 22e.

[0024] When the slip of the front wheel 12 is detected, the height adjustment unit 22e controls the air suspension 21B on the rear wheel 13 side so that the load on the front wheel 12 side increases, and adjusts the height hight on the rear wheel 13 side of the transport vehicle 10. The height hight is the height from the road surface 30. For example, before the slip of the front wheel 12 is detected, the height hight on the rear wheel 13 side of the transport vehicle 10 is adjusted as shown in Fig. 2(a). On the other hand, when the slip of the front wheel 12 is detected, the air suspension 21B on the rear wheel 13 side is controlled to extend, and the height hight on the rear wheel 13 side of the transport vehicle 10 is adjusted as shown in Fig. 2(b).

[0025] As a result, the load on the front wheel 12 side, which is the driving wheel of the transport vehicle 10 (see arrow AR1 in Fig. 2(b) and arrow AR3 in Fig. 3(b)), becomes larger than the load before the slip of the front wheel 12 is detected (see arrow AR1 in Fig. 2(a) and arrow AR3 in Fig. 3(a)). Fig. 2(a) is a diagram showing the load before height adjustment (when the load M is loaded), and Fig. 2(b) is a diagram showing the load after height adjustment (when the load is loaded). Fig. 3(a) is a diagram showing the load before height adjustment (when the load M is not loaded), and Fig. 3(b) is a diagram showing the load after height adjustment (when the load is not loaded). Arrows A1, A2, A3, and A4 in Figs. 2(a), 2(b), 3(a), and 3(b) represent the magnitude of the load.

[0026] As described above, by using the air suspension 21B to raise the height on the rear wheel 13 side, which is the driven wheel, the load can be shifted to the front wheel 12 side, which is the driving wheel. As a result, the grip force of the front wheel 12, which is the driving wheel (the grip force on the road surface 30), can be increased, so that the slip of the front wheel 12, which is the driving wheel, can be suppressed.

[0027] Next, an operation example of the load adjustment system 20 with the above configuration will be described.

[0028] Fig. 4 is a flowchart of an operation example of the load adjustment system 20.

[0029] The following processes are mainly realized by the processor 22a executing a predetermined program (not shown) read from the storage unit 22c into the memory 22b.

[0030] First, it is determined whether the transport vehicle 10 is running (step S10). For example, the vehicle speed of the transport vehicle 10 is compared with a threshold value. If the vehicle speed of the transport vehicle 10 exceeds the threshold value, it is determined that the transport vehicle 10 is running (step S10: YES). On the other hand, if the vehicle speed of the transport vehicle 10 does not exceed the threshold value, it is determined that the transport vehicle 10 is not running (step S10: NO). Note that the vehicle speed of the transport vehicle 10 may be, for example, the vehicle speed detected by a vehicle speed sensor (not shown) attached to the transport vehicle 10. Also, the threshold value may be, for example, the threshold value stored in the storage unit 22c.

[0031] Next, when it is determined that the transport vehicle 10 is running (step S10: YES), it is determined whether there is slip of the front wheels 12 (step S11). For example, when the slip detection unit 22d detects slip of the front wheels 12, it is determined that there is slip of the front wheels 12 (step S11: YES). On the other hand, when the slip detection unit 22d does not detect slip of the front wheels 12, it is determined that there is no slip of the front wheels 12 (step S11: NO).

[0032] Next, when it is determined that there is slip of the front wheels 12 (step S11: YES), it is determined whether there is a load, that is, whether a load M is loaded on the loading platform 11 (step S12). For example, for preventing load collapse, when a load clamp unit (not shown) provided on the loading platform 11 clamps a part (for example, a tire) of the load M, it is determined that there is a load (step S12: YES). On the other hand, when the load clamp unit provided on the loading platform 11 does not clamp a part of the load M (state before clamping), it is determined that there is no load (step S12: NO).

[0033] Next, when it is determined that there is a load (step S12: YES), the height adjustment unit 22e determines whether the relationship hight < hight1 holds (step S13). hight is the height on the side of the rear wheel 13, which is a driven wheel (the height from the road surface 30). On the other hand, hight1 is the target height (the height from the road surface 30) on the side of the rear wheel 13 of the transport vehicle 10 with the load M loaded on the loading platform 11.

[0034] Next, when the relationship hight < hight1 holds (step S13: YES), since it means that the side of the rear wheel 13 of the transport vehicle 10 has not reached the target height hight1, the height adjustment unit 22e turns on the air suspension 21B on the side of the rear wheel 13 (step S14). As a result, the air suspension 21B extends.

[0035] Next, hight is incremented, that is, hight is added (added by a predetermined amount) (step S15), and the processes of steps S13 to S15 are repeatedly executed until the relationship hight < hight1 is not satisfied, that is, until the side of the rear wheel 13 of the transport vehicle 10 reaches the target height hight1.

[0036] And when the relationship hight < hight1 is not satisfied (step S13: NO), that is, when the side of the rear wheel 13 of the transport vehicle 10 reaches the target height hight1 (see Fig. 2(b)), the process ends.

[0037] As described above, the load on the side of the front wheel 12, which is the driving wheel of the transport vehicle 10 (see the downward arrow AR1 in Fig. 2(b)), can be increased compared to before the slip of the front wheel 12 is detected (see the downward arrow AR1 in Fig. 2(a)). Note that when there is a load (step S12: YES), in order to raise the height of the part (loading platform 11) that transports the load M, the loading platform 11 is arranged at a higher position than when there is no load (step S12: NO) (see Figs. 2(a) and 3(a)).

[0038] On the other hand, when it is determined that there is no load (step S12: NO), the height adjustment unit 22e determines whether the relationship hight < hight2 holds (step S16). Here, hight is the height on the side of the rear wheel 13, which is a driven wheel (the height from the road surface 30). On the other hand, hight2 is the target height (the height from the road surface) on the side of the rear wheel 13 of the transport vehicle 10 with no load M loaded on the loading platform 11.

[0039] Next, when the relationship hight < hight2 holds (step S16: YES), since it means that the rear wheel 13 side of the transport vehicle 10 has not reached the target height hight2, the height adjustment unit 22e turns on the air suspension 21B on the rear wheel 13 side (step S17). As a result, the air suspension 21B extends.

[0040] Next, hight is incremented, that is, hight is added (by a predetermined amount) (step S18), and the processes of steps S16 to S18 are repeatedly executed until the relationship hight < hight2 is no longer satisfied, that is, until the rear wheel 13 side of the transport vehicle 10 reaches the target height hight2.

[0041] Then, when the relationship hight < hight2 is no longer satisfied (step S16: NO), that is, when the rear wheel 13 side of the transport vehicle 10 reaches the target height hight2, the process ends.

[0042] As described above, slip suppression is achieved by using the air suspension 21 mounted on the transport vehicle 10, driving the air suspension 21 (21B) when slip is determined, and varying the load balance of the transport vehicle 10.

[0043] In this way, the load on the front wheel 12 side, which is the driving wheel of the transport vehicle 10 (the downward arrow AR1 in Fig. 2(b), the downward arrow AR3 in Fig. 3(b)), can be increased compared to before the slip of the front wheel 12 is detected (the downward arrow AR1 in Fig. 2(a), the downward arrow AR3 in Fig. 3(a)).

[0044] As described above, according to the present embodiment, it can be used even when the maximum acceleration and the maximum deceleration cannot be variably applied, and it is possible to prevent the conveyance time from becoming long.

[0045] Next, a modified example will be described.

[0046] In the above embodiment, a vehicle (automobile) is used as the load M, and an example in which the load M (vehicle) is loaded on the loading platform 11 in the orientation shown in FIG. 1 and the like has been described, but the present invention is not limited to this.

[0047] For example, since the front-rear weight distribution of the load M (for example, a vehicle) varies depending on its type, the loading orientation may be changed according to the type (front-rear weight distribution) of the load M (for example, a vehicle). FIG. 5 shows an example (modified example) of loading the load.

[0048] For example, when the front-side load of the load M (for example, a vehicle) (see arrow AR5 in FIG. 5) is larger than the rear-side load (see arrow AR6 in FIG. 5), the load M (vehicle) may be loaded on the loading platform 11 in the orientation shown in FIG. 5 (opposite to that shown in FIG. 1 and the like).

[0049] Thereby, the load on the front-wheel 12 side, which is the driving wheel, can be further increased, and the grip force of the front-wheel 12 can be further increased. Therefore, the slip of the front-wheel 12 can be further suppressed.

[0050] In the above embodiment, the case where the front-wheel 12 is the driving wheel and the rear-wheel 13 is the driven wheel has been described as an example, but the present invention is not limited to this. Conversely, the rear-wheel 13 may be the driving wheel and the front-wheel may be the driven wheel.

[0051] All the numerical values shown in the above embodiment are merely examples, and it goes without saying that appropriately different numerical values can be used.

[0052] The above embodiment is merely an illustration in every respect. The present invention is not to be construed in a limiting sense by the description of the above embodiment. The present invention can be implemented in various other forms without departing from its spirit or main features.

Description of Symbols

[0053] 10…Transport vehicle 11…Loading platform 12…Front wheel 13…Rear wheel 20…Load adjustment system 21(21B, 21F)…Air suspension 22…Control unit 22a…Processor 22b…Memory 22c…Storage unit 22d…Slip detection unit 22e…Load adjustment unit (height adjustment unit) 23…Positioning system 30…Road surface A1~A4…Arrow M…Loaded goods

Claims

1. A transport vehicle comprising a loading platform on which a load is loaded, wherein one of the front wheels and the rear wheels is a driving wheel and the other is a driven wheel, a slip detection unit that detects slip of the driving wheel, and a load adjustment unit that adjusts the load on the driving wheel side so that the load on the driving wheel side of the transport vehicle increases when slip of the driving wheel is detected.

2. The load adjustment unit is a height adjustment unit that adjusts the height of the driven wheel side of the transport vehicle, and the height adjustment unit adjusts the height of the driven wheel side of the transport vehicle so that the load on the driving wheel side increases when slip of the driving wheel is detected. The transport vehicle according to claim 1.

3. The height of the driven wheel side of the transport vehicle is adjusted so that the height of the driven wheel side of the transport vehicle becomes a target height. The transport vehicle according to claim 1.

4. The transport vehicle according to claim 3, wherein the target height is changed according to the presence or absence of the load.

Citation Information

Patent Citations

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