Transport vehicles

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

Description

[Technical Field]

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

[0002] A transport vehicle has been proposed that calculates the slip ratio of wheels and calculates at least one of the maximum acceleration and the maximum deceleration of the transport vehicle that enables the wheels to maintain a gripped state with respect to the road surface (see, for example, Patent Document 1). [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2021-047528 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] However, Patent Document 1 has a problem that it cannot be used when the maximum acceleration and maximum deceleration cannot be variably operated. In addition, there is a problem that reducing acceleration and deceleration results in an increase in transportation time.

[0005] The present disclosure has been made to solve such problems, and provides a transport vehicle that can be used even when maximum acceleration and maximum deceleration cannot be variably operated, and can prevent an increase in transportation time. [Means for Solving the Problem]

[0006] The transport vehicle according to the present disclosure is a transport vehicle that includes a cargo bed on which a load is loaded, one of front wheels and rear wheels being drive wheels and the other being driven wheels, the transport vehicle including: a slip detection unit that detects slip of the drive wheels; and a load adjustment unit that adjusts the load on the drive wheel side such that the load on the drive wheel side of the transport vehicle increases when slip of the drive wheels is detected.

[0007] This configuration allows the system to be used even when the maximum acceleration and maximum deceleration cannot be variably controlled, and it also prevents the transport time from becoming excessively long.

[0008] Furthermore, in the above-mentioned transport vehicle, 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 may adjust the height of the driven wheel side of the transport vehicle so that the load on the drive wheel side increases when slip of the drive wheel is detected.

[0009] Furthermore, in the above-mentioned transport vehicle, the height of the driven wheel side of the transport vehicle may be adjusted so that the height of the driven wheel side of the transport vehicle becomes the target height.

[0010] Furthermore, in the above-mentioned transport vehicle, the target height may be changed depending on whether or not there is a load. [Effects of the Invention]

[0011] This disclosure makes it possible to provide a transport vehicle that can be used even when the maximum acceleration and maximum deceleration cannot be variably controlled, and that can prevent the transport time from becoming excessive. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of the transport vehicle 10. [Figure 2] (a) A diagram showing the load before height adjustment (when cargo M is loaded), and (b) A diagram showing the load after height adjustment (when cargo is loaded). [Figure 3] (a) is a diagram showing the load before height adjustment (when no load M is loaded), and (b) is a diagram showing the load after height adjustment (when no load is loaded). [Figure 4] This is a flowchart illustrating an example of the operation of the load adjustment system 20. [Figure 5] This is an example (modified version) of loading cargo. [Modes for carrying out the invention]

[0013] Hereinafter, a transport vehicle 10 that is an embodiment of the present invention will be described with reference to the accompanying drawings. Corresponding components in each drawing are denoted by the same reference numerals, and overlapping 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 cargo bed 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 drive wheel and the other is a driven wheel. The transport vehicle 10 travels autonomously in the same manner as an Autonomous Mobile Robot (AMR). Since the configuration and functions of the autonomous mobile transport robot are publicly known, description thereof will be omitted.

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

[0017] The transport vehicle 10 includes 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 is referred to as air suspension 21F, and the air suspension 21 on the rear wheel 13 side is referred to as 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., CPU), a memory 22b (e.g., RAM), and a storage unit 22c (e.g., ROM).

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

[0022] The slip detection unit 22d detects slip of the front wheels 12, which are driving wheels. For example, the coordinates (current position coordinates) of the transport vehicle 10 are acquired by a positioning system 23 (e.g., a GPS receiver) attached to 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 device) and the coordinates (current position coordinates) of the transport vehicle 10. Further, when the current position of the transport vehicle 10 does not change despite the control unit 22 controlling a motor (not shown) connected to the front wheels 12, which are driving wheels (e.g., outputting a control signal), slip of the front wheels 12 may be detected. In this case, the current position detected by the positioning system 23 or the like may be used as the current position of the transport vehicle 10. Note that the timing of slip detection may be the timing when the transport vehicle 10 starts traveling from a stopped state or the timing when the transport vehicle 10 stops traveling from a traveling state.

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

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

[0025] As a result, the load on the front wheels 12, which are the drive wheels of the transport vehicle 10 (see arrow AR1 in Figure 2(b) and arrow AR3 in Figure 3(b)), becomes larger than the load before the slip of the front wheels 12 is detected (see arrow AR1 in Figure 2(a) and arrow AR3 in Figure 3(a)). Figure 2(a) shows the load before height adjustment (when cargo M is loaded), and Figure 2(b) shows the load after height adjustment (when cargo is loaded). Figure 3(a) shows the load before height adjustment (when cargo M is not loaded), and Figure 3(b) shows the load after height adjustment (when cargo is not loaded). Arrows A1, A2, A3, and A4 in Figures 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 of the driven rear wheels 13, the load can be shifted to the driven front wheels 12. This increases the grip force (grip force against the road surface 30) of the driven front wheels 12, thereby suppressing slippage of the driven front wheels 12.

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

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

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

[0030] First, it is determined whether the transport vehicle 10 is in motion (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 in motion (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 in motion (step S10: NO). 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. The threshold value may be, for example, a threshold value stored in the storage unit 22c.

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

[0032] Next, if it is determined that the front wheels 12 are slipping (Step S11: YES), it is determined whether or not there is a load, that is, whether or not there is a load M loaded on the cargo bed 11 (Step S12). For example, if a load clamp (not shown) provided on the cargo bed 11 is clamping a part of the load M (for example, a tire) to prevent the load from shifting, it is determined that there is a load (Step S12: YES). On the other hand, if the load clamp provided on the cargo bed 11 is not clamping a part of the load M (pre-clamping state), 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 or not the relationship hight < hight1 is satisfied (step S13). hight is the height (height from the road surface 30) on the rear wheel 13 side which is a driven wheel. On the other hand, hight1 is the target height (height from the road surface 30) on the rear wheel 13 side of the transport vehicle 10 with a load M loaded on the loading platform 11.

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

[0035] Next, hight is incremented, that is, hight is added (a predetermined amount is added) (step S15), and the processes of steps S13 to S15 described above are repeatedly executed until the relationship hight < hight1 is no longer satisfied, that is, until the rear wheel 13 side of the transport vehicle 10 reaches the target height hight1.

[0036] Then, when the relationship hight < hight1 is no longer satisfied (step S13: NO), that is, when the rear wheel 13 side of the transport vehicle 10 has reached the target height hight1 (see FIG. 2(b)), the process ends.

[0037] As described above, the load on the front wheel 12 side, 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)). When there is a load (step S12: YES), in order to increase the height of the portion (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 FIG. 2(a) and FIG. 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 or not the relationship hight < hight2 is satisfied (step S16). hight is the height on the rear wheel 13 side, which is a driven wheel (height from the road surface 30). On the other hand, hight2 is the target height (height from the road surface) on the rear wheel 13 side of the transport vehicle 10 when no load M is loaded on the loading platform 11.

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

[0040] Next, hight is incremented, that is, hight is added (a predetermined amount is added) (step S18), and the processes of steps S16 to S18 described above 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 has reached the target height hight2, the process is terminated.

[0042] As described above, slip suppression is realized 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] As described above, the load on the front wheel 12 side, which is the drive wheel of the transport vehicle 10 (downward arrow AR1 in FIG. 2(b), downward arrow AR3 in FIG. 3(b)), can be increased compared to that before slip of the front wheel 12 is detected (downward arrow AR1 in FIG. 2(a), downward arrow AR3 in FIG. 3(a)).

[0044] As described above, this embodiment can be used even when the maximum acceleration and maximum deceleration cannot be variably controlled, and it can prevent the transport time from becoming excessively long.

[0045] Next, I will explain some variations.

[0046] In the above embodiment, a vehicle (automobile) was used as the cargo M, and an example was described in which the cargo M (vehicle) was loaded onto the cargo bed 11 in the orientation shown in Figure 1, etc., but the embodiment is not limited to this.

[0047] For example, since the front-to-rear weight distribution of the cargo M (e.g., a vehicle) differs depending on its type, the orientation in which the cargo is loaded may be changed according to the type of cargo M (e.g., a vehicle) (front-to-rear weight distribution). Figure 5 shows an example (modified version) of loading cargo.

[0048] For example, if the front load (see arrow AR5 in Figure 5) of the load M (e.g., a vehicle) is greater than the rear load (see arrow AR6 in Figure 5), the load M (vehicle) may be loaded onto the cargo bed 11 in the orientation shown in Figure 5 (opposite to that shown in Figure 1, etc.).

[0049] This allows for an increased load on the front wheels 12, which are the drive wheels, and further enhances the grip of the front wheels 12, thereby further suppressing slippage of the front wheels 12.

[0050] Furthermore, although the above embodiment was described using the case where the front wheels 12 are drive wheels and the rear wheels 13 are driven wheels as an example, it is not limited to this. Conversely, the rear wheels 13 may be drive wheels and the front wheels may be driven wheels.

[0051] The numerical values ​​shown in the above embodiments are all examples, and it goes without saying that other appropriate numerical values ​​can be used.

[0052] The embodiments described above are merely illustrative in all respects. The invention is not to be construed as being limited by the descriptions of the embodiments above. The invention can be carried out in various other ways without departing from its spirit or main features. [Explanation of Symbols]

[0053] 10…Transport vehicles 11...Cargo bed 12…Front wheel 13... Rear wheel 20…Load adjustment system 21 (21B, 21F)... Air suspension 22... Control Unit 22a… Processor 22b...Memory 22c...Storage section 22d...Slip detection unit 22e...Load adjustment section (height adjustment section) 23…Positioning systems 30…road surface A1~A4...Arrow M...Cargo

Claims

[Claim 1] A transport vehicle equipped with a cargo bed on which cargo is loaded, with the front wheels being drive wheels and the rear wheels being driven wheels, A slip detection unit for detecting the slip of the drive wheel, When slippage of the drive wheel is detected, a height adjustment unit adjusts the height of the driven wheel side of the transport vehicle so that the load on the drive wheel side increases, A cargo clamp section provided on the aforementioned cargo bed, The system includes a determination unit that determines whether or not the cargo is loaded on the cargo bed, The determination unit determines that the load is loaded if the load clamping unit is clamping a portion of the load, and determines that the load is not loaded if the load clamping unit is not clamping a portion of the load. The height adjustment unit is If it is determined that the aforementioned cargo is loaded, the height of the driven wheel side of the transport vehicle is adjusted until it reaches the first target height on the rear wheel side of the transport vehicle on which the aforementioned cargo is loaded. If it is determined that the cargo is not loaded, the transport vehicle adjusts the height of the driven wheels on the transport vehicle's platform until it reaches a second target height on the rear wheel side of the transport vehicle where the cargo is not loaded.

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