Cargo handling movable body

Abstract

To provide a cargo handling movable body capable of miniaturizing the cargo handling movable body.SOLUTION: The cargo handling movable body 10 is an inverted wheel type. The posture control part swings the vehicle body 11 by the right wheel drive motor and the left wheel drive motor to move the center of gravity G of the cargo handling movable body 10 in the front-rear direction so that the cargo handling movable body 10 is inverted in a state where the cargo W is supported by the fork 45. Before the cargo handling movable body 10 is inverted in a state where the load W is supported by the forks 45, the posture control unit moves the center of gravity G of the cargo handling movable body 10 to the rear of a state where the load W is not supported by the forks 45.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a cargo handling vehicle. [Background technology]

[0002] For example, Patent Document 1 discloses a robot that is an example of an inverted wheel type mobile body. The robot includes a body, two legs, and an articulated arm. The body includes an inverted pendulum body and a counterbalance body. The counterbalance body and the inverted pendulum body are rotatably connected by a rear joint. The inverted pendulum body is also connected to an articulated arm. By rotating the counterbalance body relative to the inverted pendulum body, the center of mass of the robot moves relative to the vertical axis of gravity. This changes the posture of the robot and enables it to maintain balance.

[0003] Each of the two legs includes an upper part and a lower part, the upper part and the lower part being connected by a knee joint. The upper part of the leg extends from a first end of the leg to the knee joint. The lower part of the leg extends from the knee joint to a second end. The knee joint is actuated by a knee actuator.

[0004] A first end of the leg is rotatably connected to a hip joint of the body. The hip joint is driven by a leg actuator. The leg actuator rotates the upper part of the leg relative to the body. A second end of the leg is connected to a drive wheel. The drive wheel is driven by a torque actuator as a drive unit. When the drive wheel is rotated by the drive of the torque actuator, the robot can move. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2022-524973 Summary of the Invention [Problem to be solved by the invention]

[0006] An inverted wheel type mobile body can move and stand upright by rotating the drive wheels with a drive unit. However, in the robot of Patent Document 1, the torque actuator serving as the drive unit moves not only the legs but also the inverted pendulum body and the counterbalance body, and therefore requires a large output because a large torque is applied when moving these. As a result, the specifications of the torque actuator become larger, which results in an increase in the size of the robot. [Means for solving the problem]

[0007] The cargo handling vehicle for solving the above-mentioned problems is an inverted wheel type cargo handling vehicle, and includes a pair of left and right drive wheels, a vehicle body that can swing around an axis that is coaxial with the axles of the pair of left and right drive wheels, and a cargo handling device supported on the vehicle body, the cargo handling device having a support member that supports a load, and the vehicle body includes a drive unit that drives the pair of left and right drive wheels, a control device that controls the drive of the drive unit and the cargo handling device, and a power source for the drive unit and the cargo handling device, and the control device controls the drive of the drive unit to swing around the axis The vehicle body is provided with an attitude control unit that controls the attitude of the vehicle body by swinging the vehicle body around a swing center, and the attitude control unit swings the vehicle body using the drive unit to move the center of gravity of the loading and unloading vehicle in the front-to-rear direction in order to invert the loading and unloading vehicle with the load supported by the loading device, and the attitude control unit moves the center of gravity of the loading and unloading vehicle further rearward than in a state where the load is not supported by the loading and unloading device before inverting the loading and unloading vehicle with the load supported by the loading device.

[0008] According to this, the vehicle body is a heavy object including a drive unit, a control unit, and a power source. The attitude control unit causes the drive unit to swing the vehicle body, which is a heavy object, to shift the center of gravity of the load handling vehicle in the forward and backward directions, thereby enabling the load handling vehicle to invert while the load is supported by the load handling device. Furthermore, before the load handling vehicle is inverted while the load is supported by the load handling device, the attitude control unit shifts the center of gravity backward. This simulates a state in which the expected shift in the center of gravity when the load is supported by the load handling device is offset. This can also be said to be a state in which the shift in the center of gravity when the load is supported by the load handling device is offset by the counterweight. In other words, the load handling vehicle can simulate a state in which the load handling vehicle is equipped with a counterweight by controlling the attitude control unit.

[0009] When the loading device actually supports a load, the posture control unit shifts the center of gravity to invert the loading vehicle while supporting the load, but the amount of shifting of the center of gravity required to achieve this can be reduced. Therefore, the loading vehicle can be inverted without using a counterweight, and the amount of driving of the drive unit to achieve this can also be reduced.

[0010] Therefore, the load-handling vehicle can be inverted and moved by the drive unit without the need for a separate heavy object such as a counterweight. As a result, compared to when a separate counterweight is required for the vehicle body, the torque applied to the drive unit when moving the vehicle body can be reduced, and the output required by the drive unit can be reduced. Therefore, since a counterweight is not required and the drive unit can be made smaller, the load-handling vehicle can be made smaller.

[0011] The cargo handling vehicle for solving the above-mentioned problems is an inverted wheel type cargo handling vehicle, comprising a pair of left and right drive wheels, a vehicle body that can swing around an axis that is coaxial with the axles of the pair of left and right drive wheels as a swing center, and a cargo handling device supported on the vehicle body, the cargo handling device having a support member that supports a load, the vehicle body comprising a drive unit that drives the pair of left and right drive wheels, a control device that controls the drive of the drive unit and the cargo handling device, and a power source for the drive unit and the cargo handling device, the control device controls the drive of the drive unit to swing the axis forward around the swing center. The vehicle is provided with an attitude control unit that controls the attitude of the vehicle body by swinging the vehicle body, and the attitude control unit swings the vehicle body using the drive unit to move the center of gravity of the loading and unloading vehicle in the forward and backward directions in order to invert the loading and unloading vehicle when the loading device is not supporting the load, and the attitude control unit moves the center of gravity of the loading and unloading vehicle forward from the state when the loading device is supporting the load before releasing the load and changing the state from when the loading device is supporting the load to when the loading device is not supporting the load.

[0012] According to this, the vehicle body is a heavy object including a drive unit, a control unit, and a power source. The attitude control unit swings the vehicle body, which is a heavy object, using the drive unit to shift the center of gravity of the load handling vehicle in the forward / backward direction, thereby enabling the load handling vehicle to invert when no load is being supported by the load handling device. Furthermore, before inverting the load handling vehicle when no load is being supported by the load handling device, the attitude control unit shifts the center of gravity forward relative to when the load is being supported by the load handling device. This allows a simulated state to be created in which the expected shift in the center of gravity when the load is released is offset. This can also be said to be a state in which the shift in the center of gravity when the load is released is offset by the counterweight. In other words, the load handling vehicle can simulate a state in which the load handling vehicle is equipped with a counterweight by controlling the attitude control unit.

[0013] When the load is actually released, the posture control unit shifts the center of gravity to invert the load handling vehicle while not supporting the load, but the amount of shifting of the center of gravity required to achieve this can be reduced, so the load handling vehicle can be inverted without using a counterweight, and the amount of driving of the drive unit required to achieve this can also be reduced.

[0014] Therefore, the load-handling vehicle can be inverted and moved by the drive unit without the need for a separate heavy object such as a counterweight. As a result, compared to when a separate counterweight is required for the vehicle body, the torque applied to the drive unit when moving the vehicle body can be reduced, and the output required by the drive unit can be reduced. Therefore, since a counterweight is not required and the drive unit can be made smaller, the load-handling vehicle can be made smaller.

[0015] With respect to the cargo handling vehicle, the posture control unit may acquire a load signal relating to the load in advance before the load is supported by the cargo handling device. This allows the time required to invert the loading / unloading mobile body to be reduced compared to, for example, a case where the posture control unit acquires a load signal and moves the center of gravity of the loading / unloading mobile body at the same time as the loading device supports the load or releases the load. [Effects of the Invention]

[0016] According to the present invention, the cargo handling vehicle can be made smaller. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view showing a cargo handling vehicle according to the first embodiment. [Figure 2] FIG. 2 is a diagram showing the cargo handling vehicle of the first embodiment. [Figure 3] FIG. 3 is a side view showing the loading platform, the pallet, and the cargo handling vehicle in the reference position. [Figure 4] FIG. 4 is a block diagram showing the control device. [Figure 5] FIG. 5 is a flowchart showing the cargo handling process. [Figure 6] FIG. 6 shows the forward tilting posture and the rearward tilting posture when the fork is in the reference position. [Figure 7] FIG. 7 is a side view showing the cargo handling vehicle in a backward tilted position before supporting a load. [Figure 8] FIG. 8 is a side view of the fork when it is in the tilt-up position. [Figure 9] FIG. 9 is a side view showing the cargo handling vehicle in a backward tilted position. [Figure 10] FIG. 10 is a side view showing a cargo handling vehicle that moves in a forward tilted position. [Figure 11] FIG. 11 is a flowchart showing the process during movement. [Figure 12] FIG. 12 is a diagram showing a cargo handling vehicle according to the second embodiment. [Figure 13] FIG. 13 is a side view showing the cargo handling vehicle in the reference position. [Figure 14] FIG. 14 is a block diagram showing a control device according to the second embodiment. [Figure 15] FIG. 15 is a side view showing a cargo handling vehicle supporting a load. [Figure 16] FIG. 16 is a side view showing a cargo handling vehicle supporting a load. [Figure 17] FIG. 17 is a side view showing a state in which a load on a traveling surface is supported on the upper surface of the fork. [Figure 18] FIG. 18 is a flowchart showing another example of cargo handling processing. [Figure 19] FIG. 19 is a diagram showing another example of a cargo handling vehicle. [Figure 20] FIG. 20 is a side view showing another example of a cargo handling vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0018] (First embodiment) A first embodiment of a cargo handling vehicle will be described below with reference to FIGS. 1 to 11. FIG.

[0019] <Overall cargo handling vehicle> As shown in Figures 1 and 2, the cargo handling vehicle 10 is an inverted wheel type. The cargo handling vehicle 10 includes a vehicle body 11, a right drive wheel 31, a left drive wheel 32, and a cargo handling device 40. In the following description, front, rear, left, right, top, bottom, and bottom are determined based on the cargo handling vehicle 10. The front-rear direction X can be considered the direction of travel of the cargo handling vehicle 10, that is, either the forward direction or the backward direction. The left-right direction Y can be considered the width direction of the cargo handling vehicle 10. The direction of gravity Z can be considered the height direction of the cargo handling vehicle 10.

[0020] <Body> The vehicle body 11 includes a machine base 12, a battery 33, a control device 50, a housing 35, a right wheel drive unit 21, and a left wheel drive unit 25.

[0021] The machine base 12 is plate-shaped. The machine base 12 has a first main surface 121 and a second main surface 122. The first main surface 121 and the second main surface 122 are surfaces that are opposite to each other in the thickness direction of the machine base 12. The thickness direction is the direction from one of the first main surface 121 and the second main surface 122 of the machine base 12 to the other.

[0022] The battery 33 and the control device 50 are each disposed on the second main surface 122. The battery 33 is a power source for the cargo handling vehicle 10. The battery 33 may be a primary battery or a secondary battery as long as it is dischargeable. The control device 50 controls the driving of the cargo handling vehicle 10. The control device 50 will be described later.

[0023] The housing 35 is disposed on the second main surface 122. The housing 35 is box-shaped. The housing 35 includes a base 35a and four side walls 35b extending cylindrically from the base 35a toward the machine base 12. The base 35a is the top plate of the housing 35. The upper surface of the base 35a is an installation surface 351 for the loading device 40. A space defined by the base 35a and the four side walls 35b is formed inside the housing 35. The space surrounded by the second main surface 122 of the machine base 12 and the inner surface of the housing 35 is the storage space S. The battery 33 and the control device 50 are housed in the storage space S.

[0024] The right wheel drive unit 21 is installed on the first main surface 121 of the machine base 12. The right wheel drive unit 21 includes a right wheel drive motor 22, a right axle 23, a right wheel encoder 24, and a right cover 29a. The right wheel drive motor 22 and the right wheel encoder 24 are installed below the first main surface 121. The right wheel drive motor 22 and the right wheel encoder 24 are housed in the right cover 29a. The right axle 23 is connected to the rotating shaft of the right wheel drive motor 22. The right axle 23 rotates when driven by the right wheel drive motor 22. The right axle 23 penetrates the right cover 29a and protrudes outside the right cover 29a. The right drive wheel 31 is fixed to a protruding portion of the right axle 23 that protrudes from the right cover 29a. When the right wheel drive motor 22 is driven, the right drive wheel 31 is driven via the right axle 23. The right wheel encoder 24 detects the rotation angle of the right drive wheel 31 as the amount of rotation.

[0025] The left wheel drive unit 25 is installed on the first main surface 121 of the machine base 12. The right wheel drive unit 21 and the left wheel drive unit 25 are installed on the first main surface 121 and spaced apart in the left-right direction Y. The left wheel drive unit 25 includes a left wheel drive motor 27, a left axle 26, a left wheel encoder 28, and a left cover 29b. The left wheel drive motor 27 and the left wheel encoder 28 are installed below the first main surface 121. The left wheel drive motor 27 and the left wheel encoder 28 are housed in the left cover 29b. The left axle 26 is connected to the rotating shaft of the left wheel drive motor 27. The left axle 26 rotates when driven by the left wheel drive motor 27. The left axle 26 penetrates the left cover 29b and protrudes outside the left cover 29b. The left drive wheel 32 is fixed to a portion of the left axle 26 protruding from the left cover 29b. When the left wheel drive motor 27 is driven, the left drive wheel 32 is driven via the left axle 26. The left wheel encoder 28 detects the rotation angle of the left drive wheel 32 as the amount of rotation.

[0026] <Right and left drive wheels> The right drive wheel 31 and the left drive wheel 32 support the vehicle body 11 and the cargo handling device 40. The right drive wheel 31 comes into contact with the traveling surface. The left drive wheel 32 comes into contact with the traveling surface. The traveling surface is a horizontal plane. The right drive wheel 31 and the left drive wheel 32 rotate, causing the cargo handling vehicle 10 to move.

[0027] The right drive wheel 31 and the left drive wheel 32 are a pair of left and right drive wheels provided on the cargo handling vehicle 10. The central axis of the right axle 23 and the central axis of the left axle 26 are located on the same axis L. Therefore, the left and right axles 23, 26 of the pair of left and right drive wheels 31, 32 are located on the same axis. The vehicle body 11, which integrally includes the base 12, the battery 33, the control device 50, the housing 35, the right wheel drive unit 21, and the left wheel drive unit 25, can swing around the axis L as the swing center. The right wheel drive unit 21 and the left wheel drive unit 25 are drive units that drive the pair of left and right drive wheels 31, 32. The right wheel drive unit 21 and the left wheel drive unit 25 are driven by power supplied from the battery 33. Therefore, the battery 33 is the power source for the right wheel drive unit 21 and the left wheel drive unit 25.

[0028] <Loading equipment> The cargo handling device 40 is provided on the installation surface 351 of the base 35a. Therefore, the cargo handling device 40 is supported by the vehicle body 11. The cargo handling device 40 is driven by power supplied from the battery 33. Therefore, the battery 33 is the power source for the cargo handling device 40.

[0029] The cargo handling device 40 includes a support base 41, a cargo handling motor 42, a cargo handling encoder 43, a cargo handling bar 44, and a pair of forks 45 as support members. The support base 41 is provided at the center of the installation surface 351 of the base 35a in the front-rear direction X and the left-right direction Y. The cargo handling motor 42 is supported by the support base 41. The cargo handling encoder 43 detects the rotation angle as the amount of rotation of the cargo handling motor 42. The cargo handling bar 44 extends in the left-right direction Y from the cargo handling motor 42. The cargo handling bar 44 extends coaxially with the rotation shaft (not shown) of the cargo handling motor 42. When the rotation shaft of the cargo handling motor 42 is rotated by the drive of the cargo handling motor 42, the cargo handling bar 44 swings.

[0030] The forks 45 are provided at both ends of the loading bar 44 in the left-right direction Y. The top surfaces 45a of the forks 45 are flat. The forks 45 are shaped like long plates. The forks 45 have a base end and a tip end. The tip end of the forks 45 is the end opposite the base end in the longitudinal direction of the forks 45.

[0031] The base ends of the forks 45 are fixed to the loading bar 44. Here, a side view of the loading vehicle 10 is defined as a view of the loading vehicle 10 from the outside in the left-right direction Y. In the side view, the forks 45 extend from the loading bar 44 and hence from the loading motor 42. Therefore, in the side view, the tip ends of the forks 45 are located away from the loading bar 44 and hence from the loading motor 42 in the front-rear direction X. The direction in which the forks 45 extend from the base ends to the tip ends of the forks 45 is the forward direction of the traveling direction of the loading vehicle 10. The direction in which the forks 45 extend from the tip ends to the base ends of the forks 45 is the backward direction of the traveling direction of the loading vehicle 10. The forks 45 swing around the base ends of the forks 45 as the swing center.

[0032] As shown in Fig. 3, the state in which no load W is supported on the upper surface 45a of the fork 45 is a non-loaded state. As shown in Fig. 9, the state in which the load W is supported on the upper surface 45a of the fork 45 is a loaded state.

[0033] The position of the center of gravity G of the cargo handling vehicle 10 in the longitudinal direction X is determined in the non-load-carrying state based on the weight of the vehicle body 11, the weight of the cargo handling device 40, and the posture of the vehicle body 11. The position of the center of gravity G of the cargo handling vehicle 10 in the transverse direction Y is located at the center of the transverse direction Y, assuming that the load W is supported at the center of the transverse direction Y.

[0034] In the following description, in a non-load-carrying state where the fork 45 is not supporting a load W on the upper surface 45a thereof and is in a reference position as shown in Fig. 3, in a reference posture T1 where the fork 45 is in a reference position, the center line N is assumed to coincide with the line of gravity M, and the position of the center of gravity G in the left-right direction Y is assumed to be the center of the left-right direction Y. The position of the center of gravity G in the front-rear direction X will be described below.

[0035] The forks 45 can be in a reference position, a tilt-up position, and a tilt-down position by driving the cargo handling motor 42. The reference position is a position where the upper surfaces 45a of the forks 45 are parallel to the installation surface 351. The tilt-up position is a position where the tips of the forks 45 are higher than the reference position. The tilt-down position is a position where the tips of the forks 45 are lower than the reference position. These positions of the forks 45 are implemented by driving the cargo handling motor 42.

[0036] <Vehicle position> The cargo handling vehicle 10 can assume a standard posture T1, a forward tilt posture T2, and a backward tilt posture T3 in a side view.

[0037] 3, in a side view of the cargo handling vehicle 10, the reference posture T1 is a posture in which the upper surfaces 45a of the forks 45 are parallel to the traveling surface and the installation surfaces 351 are parallel to the traveling surface. In other words, the forks 45 are in the reference position.

[0038] 10, in a side view of the cargo handling vehicle 10, the forward tilted attitude T2 is an attitude in which the vehicle body 11 is tilted forward more than the reference attitude T1. In a side view of the cargo handling vehicle 10, the installation surface 351 in the forward tilted attitude T2 is tilted forward. Note that "tilted forward" means that the tip end side of the extension direction of the forks 45 on the installation surface 351 is tilted downward, that is, the front side of the installation surface 351 in the traveling direction is tilted downward.

[0039] As shown by the two-dot chain line in Fig. 6, the cargo handling vehicle 10 can take a forward leaning posture T2 while keeping the forks 45 at the reference position. In this case, the forks 45 tilt forward. Also, as shown in Fig. 10, the cargo handling vehicle 10 can take the forward leaning posture T2 while keeping the forks 45 in the tilt-up position in order to make the upper surfaces 45a of the forks 45 parallel to the traveling surface.

[0040] 9, in a side view of the cargo handling vehicle 10, the rearward tilted attitude T3 is an attitude in which the vehicle body 11 is tilted rearward from the reference attitude T1. In a side view of the cargo handling vehicle 10, the installation surface 351 in the rearward tilted attitude T3 is tilted rearward. Note that "rearward tilted" means that the base end side of the installation surface 351 in the extension direction of the forks 45 is tilted downward, that is, the rear side of the installation surface 351 in the traveling direction is tilted downward.

[0041] As shown by the solid line in Fig. 6, the cargo handling vehicle 10 can take a rearward tilting posture T3 while keeping the forks 45 at the reference position. In this case, the forks 45 tilt downward toward the rear. Also, as shown in Fig. 9, the cargo handling vehicle 10 can take the rearward tilting posture T3 while keeping the forks 45 in the tilt-down position in order to make the upper surfaces 45a of the forks 45 parallel to the traveling surface.

[0042] The control device 50 can place the vehicle body 11 in the reference posture T1, the forward tilt posture T2, or the backward tilt posture T3 by controlling the drive of the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25. In addition, the control device 50 can move the position of the center of gravity G of the cargo handling vehicle 10 in the fore-and-aft direction X by controlling the drive of the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25.

[0043] The position of the center of gravity G of the cargo handling vehicle 10 in the longitudinal direction X is determined in a loaded state based on the weight of the vehicle body 11, the weight of the cargo handling device 40, the weight of the load W, and the posture of the vehicle body 11. The position of the center of gravity G of the cargo handling vehicle 10 in the transverse direction Y is located at the center of the transverse direction Y and at a predetermined position in the transverse direction X, assuming that the load W is supported at the center in the transverse direction Y and at a predetermined position in the transverse direction X.

[0044] As shown in Fig. 6, in a side view of the cargo handling vehicle 10, an imaginary line passing through the axis L in the gravity direction Z is defined as a gravity line M. The smaller of the angles formed between the gravity line M and the center line N of the vehicle body 11 in the fore-and-aft direction X is defined as the tilt angle θ of the vehicle body 11.

[0045] 3, in the reference posture T1 when the fork 45 is in the reference position, the center line N coincides with the gravity line M, and the center of gravity G is located on the gravity line M. Therefore, the tilt angle θ is zero.

[0046] As shown in Figure 6, when the position of the center of gravity G moves due to a transition from a non-load-loading state to a loaded state, a change in the position of the forks 45, or a movement of the load handling vehicle 10, the tilt angle θ of the vehicle body 11 changes. Specifically, when the load handling vehicle 10 in the reference posture T1 transitions from a non-load-loading state to a loaded state, the position of the center of gravity G moves forward in accordance with the weight of the load W. The heavier the load W, the more the position of the center of gravity G moves forward in the fore-and-aft direction X. Furthermore, when the load handling vehicle 10 in the reference posture T1 transitions from a loaded state to a non-load-loading state, the position of the center of gravity G moves backward in accordance with the weight of the load W. When acceleration occurs as the load handling vehicle 10 moves in the reference posture T1, the position of the center of gravity G moves in the direction opposite to the traveling direction of the load handling vehicle 10.

[0047] The control device 50 controls the attitude of the vehicle body 11 to one of the reference attitude T1, the forward tilt attitude T2, and the backward tilt attitude T3 to adjust the tilt angle θ according to the position of the center of gravity G. This controls the attitude of the vehicle body 11. As a result, the cargo handling vehicle 10 can stand upright.

[0048] <Control device> The control device 50 controls the entire cargo handling vehicle 10. The control device 50 also controls the right wheel drive unit 21, the left wheel drive unit 25, and the driving of the cargo handling device 40.

[0049] The control device 50 includes a processor and a memory unit. Examples of the processor include a central processing unit (CPU), a graphics processing unit (GPU), and a digital signal processor (DSP). The memory unit includes a random access memory (RAM) and a read-only memory (ROM). The memory unit stores program code or instructions configured to cause the processor to execute a process. The memory unit, i.e., a computer-readable medium, includes any available medium accessible by a general-purpose or special-purpose computer. The control device 50 may be configured with hardware circuits such as an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). The control device 50, which is a processing circuit, may include one or more processors operating according to a computer program, one or more hardware circuits such as an ASIC or an FPGA, or a combination thereof.

[0050] 4, the control device 50 includes an attitude control unit 51, a position control unit 52, and a cargo handling control unit 53. An input unit 55 and a communication unit 56 are connected to the control device 50.

[0051] <Input section> The input unit 55 outputs various command values ​​for driving the cargo handling vehicle 10. The input unit 55 inputs the various command values ​​to the control device 50.

[0052] <Communications Department> The communication unit 56 receives information related to the weight of the load W transported by the cargo handling vehicle 10 as a load signal from a higher-level control unit (not shown). The communication unit 56 outputs the received load signal to the posture control unit 51.

[0053] <Position control unit> The input unit 55 inputs a position command value to the position control unit 52. The position command value is a command value for moving the cargo handling vehicle 10, such as the movement route and movement speed of the cargo handling vehicle 10. The position command value for the movement route is, for example, a command value for the cargo handling vehicle 10 from the standby position to the unloading position via the loading position. In accordance with this position command value, the cargo handling vehicle 10 moves from the standby position to the loading position, and then supports the load W on the upper surfaces 45a of the forks 45 at the loading position. Furthermore, in accordance with the position command value, the cargo handling vehicle 10 moves from the loading position to the unloading position while supporting the load W on the upper surfaces 45a of the forks 45. Then, in accordance with the position command value, the cargo handling vehicle 10 unloads the load W at the unloading position. Note that the position command value for the movement route may be changed as desired. For example, the position command value for the movement route may be from the standby position to the loading position, or from the loading position to the unloading position.

[0054] The position command value relating to the moving speed is a command value for commanding the speed at which the cargo handling vehicle 10 is moved. The moving speed can be changed arbitrarily. As shown in FIG. 3, a loading platform 100 is installed at the loading position included in the position command value. A pallet 101 is placed on a loading surface 100a of the loading platform 100. The pallet 101 is formed with pallet holes 101a through which a pair of forks 45 can be inserted and removed. A load W is placed on the pallet 101. Of the hole-forming surfaces that define the pallet holes 101a, the surface that is located above the direction of gravity Z is a contact surface 101b. In the pallet 101 placed on the loading surface 100a, the contact surface 101b is parallel to the running surface. However, due to a slight inclination of the loading platform 100 or the loading surface 100a, the contact surface 101b may be slightly inclined from being parallel to the running surface.

[0055] The cargo handling vehicle 10 moves to a cargo receiving position where the pair of forks 45 can be inserted into the pallet holes 101a in accordance with the position command value. Note that when the cargo handling vehicle 10 moves, the forks 45 may be in any of the reference position, tilt-up position, and tilt-down position. However, when the forks 45 are inserted into the pallet holes 101a, the forks 45 are located in the reference position. Furthermore, even after the pair of forks 45 are inserted into the pallet holes 101a, the forks 45 remain in the reference position. Thereafter, to lift the load W, the forks 45 are moved to the tilt-up position. Then, the contact surface 101b comes into contact with the upper surface 45a of the forks 45, and the pallet 101 is supported by the upper surface 45a.

[0056] The position control unit 52 calculates the acceleration and target speed of the cargo handling vehicle 10 in accordance with the position command value output from the input unit 55. The position control unit 52 drives the right wheel drive motor 22 and the left wheel drive motor 27 in accordance with the calculated acceleration and target speed. As a result, the cargo handling vehicle 10 travels along the travel route at the travel speed.

[0057] The position control unit 52 receives an input of a detection signal related to the rotation angle of the right drive wheel 31 from the right wheel encoder 24. The position control unit 52 also receives an input of a detection signal related to the rotation angle of the left drive wheel 32 from the left wheel encoder 28. The position control unit 52 acquires the detection signal output from the right wheel encoder 24 and the detection signal output from the left wheel encoder 28. Based on the acquired detection signals, the position control unit 52 detects the rotation angular velocity of the right drive wheel 31 and acquires the rotation angular velocity of the left drive wheel 32. The position control unit 52 drives the right wheel drive motor 22 and the left wheel drive motor 27 based on the acquired rotation angular velocities. Under the control of the position control unit 52, the cargo handling vehicle 10 moves along the movement path at a movement speed in accordance with the position command value.

[0058] <Attitude control unit> The input unit 55 inputs an attitude command value to the attitude control unit 51. The attitude command value is a command value for controlling the attitude angle of the vehicle body 11. The attitude control unit 51 controls the driving of the right wheel drive unit 21 and the left wheel drive unit 25 in accordance with the attitude command value, and controls the attitude of the vehicle body 11 by swinging the vehicle body 11 around the axis line L as the swing center.

[0059] The attitude control unit 51 is connected to a measurement unit 51a, a right wheel drive motor 22, and a left wheel drive motor 27. The measurement unit 51a is an IMU (Inertial Measurement Unit). The measurement unit 51a is built into the control device 50. The measurement unit 51a detects three-dimensional inertial motion. The inertial motion is translational motion and rotational motion in three orthogonal axial directions. The measurement unit 51a detects translational motion using a built-in acceleration sensor and detects rotational motion using a built-in gyro sensor.

[0060] The measurement unit 51a measures the tilt angle θ of the vehicle body 11 when a load W is supported by the forks 45 or when the load W is lowered from the forks 45. The tilt angle θ measured by the measurement unit 51a changes in accordance with changes in the posture of the vehicle body 11. In other words, the tilt angle θ is a change amount that changes in accordance with the position of the center of gravity G in the fore-and-aft direction X of the vehicle body 11. The measurement unit 51a detects changes in the tilt angle θ of the vehicle body 11 in the fore-and-aft direction X.

[0061] The posture control unit 51 acquires a detection signal related to the tilt angle θ measured by the measurement unit 51a. Based on the acquired detection signal related to the tilt angle θ, the posture control unit 51 synchronously drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 so as to position the center of gravity G on the gravity line M. Then, the posture of the vehicle body 11 is controlled to the reference posture T1, the forward tilt posture T2, or the backward tilt posture T3 depending on the position of the center of gravity G, and the cargo handling vehicle 10 is inverted in the controlled posture. Therefore, in order to invert the cargo handling vehicle 10, the posture control unit 51 causes the right wheel drive unit 21 and the left wheel drive unit 25 to swing the vehicle body 11, thereby moving the position of the center of gravity G in the fore-and-aft direction X.

[0062] The posture control unit 51 acquires the load signal output by the communication unit 56. This load signal is input to the posture control unit 51 before the load handling vehicle 10 is inverted with the load W supported by the forks 45. The posture control unit 51 derives the moment that will be generated when the load W is supported by the forks 45 based on the acquired load signal. The moment may be derived by calculation by the posture control unit 51, or may be derived using a map or table stored in the posture control unit 51. In short, any method of derivation may be used as long as the posture control unit 51 can derive the moment from the acquired load signal. The derived moment is a moment that is predicted to be generated when the vehicle body 11 is in the reference posture T1 and the forks 45 are in the reference position.

[0063] The derived moment is a moment that acts in a direction that rotates the base ends of the forks 45, which are in the reference position, downward. If such a moment is generated in the cargo handling vehicle 10, the cargo handling vehicle 10 will attempt to move forward by lowering the tips of the forks 45. In other words, when the load W is supported by the forks 45, the center of gravity G will move forward from the line of gravity M, and the cargo handling vehicle 10 will attempt to move forward.

[0064] Before the loading vehicle 10 is turned upside down with the load W supported by the forks 45, the posture control unit 51 synchronously drives the right wheel drive motor 22 and the left wheel drive motor 27 based on the derived moment to rotate the right drive wheel 31 and the left drive wheel 32 so that the loading vehicle 10 moves backward. That is, the posture control unit 51 rotates the right drive wheel 31 and the left drive wheel 32 based on the load signal to move the center of gravity G rearward. As a result, the posture control unit 51 of the loading vehicle 10 moves the center of gravity G rearward compared to when the load W is not supported by the forks 45.

[0065] At the same time as deriving the moment, the posture control unit 51 derives the amount by which to drive the right wheel drive motor 22 and the left wheel drive motor 27. The drive amounts of the right wheel drive motor 22 and the left wheel drive motor 27 are also the rotation amounts of the right drive wheel 31 and the left drive wheel 32. The drive amounts of the right wheel drive motor 22 and the left wheel drive motor 27 may be derived by calculation by the posture control unit 51, or may be derived using a map or table that links drive amounts to moments.

[0066] Therefore, the posture control unit 51 synchronously drives the right wheel drive motor 22 and the left wheel drive motor 27 based on the derived moment and drive amount, thereby rotating the right drive wheel 31 and the left drive wheel 32 so that the cargo handling vehicle 10 moves backward. In other words, the posture control unit 51 moves the center of gravity G of the vehicle body 11 rearward from the state in which the forks 45 are not supporting the load W, specifically, rearward from the line of gravity M.

[0067] When the posture control unit 51 moves the center of gravity G rearward, the vehicle body 11 takes on a rearward tilting posture T3. In other words, before the cargo handling vehicle 10 is inverted with the load W supported by the forks 45, the posture control unit 51 moves the center of gravity G rearward and puts the vehicle body 11 into a rearward tilting posture T3. As a result, the posture control unit 51 can create a state in which a counterweight is formed in the cargo handling vehicle 10. In other words, under the control of the posture control unit 51, the cargo handling vehicle 10 can create a state in which a counterweight is provided in the cargo handling vehicle 10.

[0068] <Load handling control section> The input unit 55 inputs a cargo handling command value to the cargo handling control unit 53. The cargo handling command value is, for example, a command value for controlling the angle of the fork 45. The cargo handling control unit 53 is connected to the cargo handling motor 42 and the cargo handling encoder 43. The cargo handling encoder 43 detects the rotational angular velocity of the cargo handling motor 42 and outputs a detection signal to the cargo handling control unit 53. The cargo handling control unit 53 drives the cargo handling motor 42 based on the detection signal related to the rotation angle detected by the cargo handling encoder 43 in accordance with the cargo handling command value.

[0069] As described above, the fork 45 can be in any one of the reference position, tilt-up position, and tilt-down position. The position of the fork 45, such as the reference position, tilt-up position, or tilt-down position, is controlled in accordance with a cargo handling command value from the cargo handling control unit 53.

[0070] Before the forks 45 support the load W, the load handling control unit 53 controls the drive of the load handling motor 42 to place the forks 45 at a reference position. When lifting the load W from the loading platform 100, the load handling control unit 53 controls the drive of the load handling motor 42 in accordance with a load handling command value to move the forks 45 from the reference position to a tilt-up position. Furthermore, when the load handling mobile body 10 is to be inverted with the load W supported by the forks 45, the load handling control unit 53 controls the drive of the load handling motor 42 in accordance with a load handling command value to move the forks 45 from the reference position to a tilt-down position.

[0071] When transporting the load W, the load handling control unit 53 controls the drive of the load handling motor 42 in accordance with the load handling command value to move the forks 45 to the tilt-up position. When unloading the load, the load handling control unit 53 controls the drive of the load handling motor 42 in accordance with the load handling command value to move the forks 45 to the tilt-down position. Note that the forks 45 may be moved to the reference position when transporting the load W, or may be moved to the reference position when unloading the load.

[0072] <Movement of the cargo handling vehicle> The operation of the cargo handling vehicle 10 is started by the operator after various command values ​​such as the movement route and movement speed are input to the control device 50 by the input unit 55.

[0073] The control device 50 executes the movement process and the cargo handling process. The body 11 of the cargo handling vehicle 10 is controlled to the reference posture T1, and the forks 45 are controlled to the reference positions. Furthermore, before transporting the load W, the control device 50 receives a load signal of the load W in response to a command from a higher-level control unit. The communication unit 56 outputs the input load signal of the load W to the posture control unit 51. The posture control unit 51 acquires the load signal from the communication unit 56 and derives the moment and the drive amounts of the right wheel drive motor 22 and the left wheel drive motor 27 based on the load signal.

[0074] <Cargo handling> When the cargo handling vehicle 10 moves along the movement path to the cargo unloading position, it starts the cargo handling process according to the flowchart shown in Fig. 5. Note that the cargo handling vehicle 10 has the vehicle body 11 in the reference posture T1 and the forks 45 in the reference position. The position control unit 52 controls the drive of the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to move the cargo handling vehicle 10 forward at the cargo unloading position. Then, the cargo handling vehicle 10 inserts the pair of forks 45 into the pallet holes 101a (step S11).

[0075] Next, the posture control unit 51 synchronously drives the right wheel drive motor 22 and the left wheel drive motor 27 with the drive amounts of the right wheel drive motor 22 and the left wheel drive motor 27 calculated based on the load signal. In other words, the posture control unit 51 moves the center of gravity G behind the gravity line M. Then, as shown in FIG. 7, the center of gravity G moves behind the gravity line M in response to the load signal (step S12). As a result, before the load W is supported on the forks 45, the body 11 tilts backward due to the artificially formed counterweight. Note that the upper surfaces 45a of the forks 45 are not in contact with the contact surfaces 101b of the pallet 101. Therefore, the load of the load W is not applied to the forks 45.

[0076] Next, the cargo handling control unit 53 drives the cargo handling motor 42 to place the pair of forks 45 in the tilt-up position (step S13). At this time, the inclination of the vehicle body 11 does not change. Then, as shown in FIG. 8, the contact surfaces 101b of the pallet 101 come into contact with the upper surfaces 45a of the pair of forks 45, and the load W is supported on the upper surfaces 45a of the forks 45 via the pallet 101. Then, when the forks 45 are further tilted up, although not shown, the load W is supported on the forks 45, and the center of gravity G moves forward in the fore-and-aft direction X in accordance with the weight of the load W.

[0077] The measurement unit 51a measures the tilt angle θ of the vehicle body 11. The posture control unit 51 also acquires a detection signal related to the tilt angle θ measured by the measurement unit 51a. The posture control unit 51 determines whether the center of gravity G is located ahead of the gravity line M based on the detection signal from the measurement unit 51a (step S14). If it is determined that the center of gravity G is located ahead of the gravity line M (YES in step S14), the posture control unit 51 synchronously drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to tilt the vehicle body 11 backward (step S15). As a result, the cargo handling vehicle 10 assumes a backward tilt posture T3. At this time, the cargo handling control unit 53 returns the fork 45 to the reference position.

[0078] Next, the posture control unit 51 determines whether the center of gravity G is stable or not based on the detection signal of the measurement unit 51a (step S16). If the posture control unit 51 determines that the center of gravity G is stable (YES in step S16), the posture control unit 51 ends the cargo handling process. The state in which the center of gravity G is stable is a state in which the center of gravity G is located on the gravity line M. As a result, the cargo handling vehicle 10 stands upright in a backward tilt posture T3.

[0079] As a result, as shown in FIG. 9, in a state in which the load W is supported on the upper surfaces 45a of the forks 45 via the pallet 101, the load handling vehicle 10 stands upright in a backward tilted posture T3. On the other hand, as shown in FIG. 5, if the center of gravity G has not moved forward of the gravity line M (NO in step S14), the posture control unit 51 determines whether the center of gravity G is behind the gravity line M (step S17). If the posture control unit 51 determines that the center of gravity G is behind the gravity line M (YES in step S17), it synchronously drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to tilt the vehicle body 11 slightly forward (step S18). As a result, the cargo handling vehicle 10 assumes a rearward tilt posture T3 while reducing the amount of rearward tilt. The cargo handling control unit 53 returns the forks 45 to the reference position.

[0080] Next, the posture control unit 51 determines whether the center of gravity G has stabilized based on the detection signal of the measurement unit 51a (step S16). If the posture control unit 51 determines that the center of gravity G has stabilized (YES in step S16), the loading and unloading process is terminated.

[0081] The state in which the center of gravity G is stable is a state in which the center of gravity G is located on the gravity line M. As a result, the position of the center of gravity G is adjusted, and with the load W supported on the upper surfaces 45a of the forks 45, the cargo handling vehicle 10 comes to rest in a state in which it takes on a backward tilted posture T3. In other words, the cargo handling vehicle 10 stands upright in the backward tilted posture T3.

[0082] On the other hand, if the posture control unit 51 determines that the center of gravity G is not behind the line of gravity M (NO in step S17), the posture control unit 51 proceeds to step S16. If the posture control unit 51 determines that the center of gravity G is stable (YES in step S16), the load handling process ends. In this case, the position of the center of gravity G has been moved behind the line of gravity M in advance, but has moved forward due to loading, so that the center of gravity G is located on the line of gravity M. Therefore, the right wheel drive motor 22 and the left wheel drive motor 27 are not driven synchronously. As a result, the loading vehicle 10 comes to a standstill in a state of tilting backward in a posture T3. In other words, the loading vehicle 10 stands still in a state of tilting backward in a posture T3.

[0083] Therefore, when the loading / unloading process is performed, the center of gravity G of the vehicle body 11 is adjusted in the fore-and-aft direction X. Based on the detection signal from the measurement unit 51a, the posture control unit 51 drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25, or does not drive the right wheel drive motor 22 and the left wheel drive motor 27. In other words, by controlling the posture of the vehicle body 11, which is a heavy object, the position of the center of gravity G can be adjusted, and the loading / unloading vehicle 10 can be made to stand upright.

[0084] <Processing during movement> When the cargo handling vehicle 10 supports the load W on the upper surfaces 45a of the forks 45 via the pallet 101 at the load-receiving position, the cargo handling vehicle 10 executes the movement process in accordance with the flowchart shown in Fig. 11 to move to the unloading position. The movement process is also executed when the cargo handling vehicle 10 moves from the standby position to the load-receiving position.

[0085] The position control unit 52 calculates the acceleration and target speed of the cargo handling vehicle 10 based on the movement speed included in the movement command value input from the input unit 55 (step S21). Next, the posture control unit 51 drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to move the center of gravity G forward and change the vehicle body 11 to a forward-leaning posture T2 (step S22). In other words, when the cargo handling vehicle 10 is moving, the vehicle body 11 leans forward due to acceleration. Therefore, the posture control unit 51 controls the position of the center of gravity G to change the vehicle body 11 to a forward-leaning posture T2 so that the vehicle body 11 can maintain an inverted state at the calculated acceleration and target speed.

[0086] Next, the position control unit 52 drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to move the cargo handling vehicle 10. At this time, as shown in Fig. 10, the cargo handling vehicle 10 moves while accelerating in a forward tilt posture T2. The position control unit 52 accelerates the movement speed of the cargo handling vehicle 10 so that it reaches the target speed, and therefore the movement speed approaches the target speed.

[0087] Next, the position control unit 52 determines whether the acceleration of the cargo handling vehicle 10 has reached the calculated acceleration based on the detection signal from the measurement unit 51a (step S23). If the acceleration has not reached the calculated acceleration in step S23 (NO in step S23), the position control unit 52 returns to step S22. The posture control unit 51 drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to move the center of gravity G further forward and change the vehicle body 11 to a further forward-leaning posture T2 (step S22).

[0088] If the acceleration reaches the calculated acceleration in step S23 (YES in step S23), the position control unit 52 determines whether the moving speed of the cargo handling vehicle 10 exceeds the calculated target speed based on the detection signal from the measurement unit 51a (step S24). If the moving speed exceeds the calculated target speed in step S24 (YES in step S24), the position control unit 52 proceeds to step S25. In step S25, the posture control unit 51 drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to move the center of gravity G backward. This reduces the tilt angle θ of the forward tilt posture T2 in the forward tilt direction. The posture control unit 51 controls the position of the center of gravity G so that the inverted state can be maintained at the moving speed.

[0089] On the other hand, if the moving speed does not exceed the calculated target speed in step S24 (NO in step S24), the position control unit 52 proceeds to step S26. In step S26, the posture control unit 51 drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to move the center of gravity G forward. As a result, the tilt angle θ in the forward tilt direction of the forward tilt posture T2 increases. The posture control unit 51 controls the position of the center of gravity G so that the inverted state can be maintained at the moving speed. Through the above-mentioned movement processing, the cargo handling vehicle 10 moves while maintaining the inverted state. Thereafter, the cargo handling vehicle 10 performs deceleration processing to move the center of gravity G backward in order to reduce the moving speed so that the cargo handling vehicle 10 can stop at the unloading position. When the cargo handling vehicle 10 reaches the unloading position, the control device 50 ends the movement processing. Thereafter, the cargo handling vehicle 10 unloads the load W under the control of the control device 50.

[0090] [Effects of the embodiment] According to the first embodiment, the following effects can be obtained. (1-1) The cargo handling vehicle 10 can stand upright while supporting a load W on the forks 45. Furthermore, before standing upright while supporting a load W on the forks 45, the posture control unit 51 shifts the center of gravity G rearward. This allows the posture control unit 51 to create a state in which a counterweight is virtually formed on the cargo handling vehicle 10. Therefore, compared to a case in which a counterweight separate from the vehicle body 11 is required, the cargo handling vehicle 10 can reduce the torque applied when moving the vehicle body 11, thereby reducing the output required by the right wheel drive motor 22 and the left wheel drive motor 27. Therefore, the cargo handling vehicle 10 does not require a counterweight, and the right wheel drive motor 22 and the left wheel drive motor 27 can be made smaller, allowing the cargo handling vehicle 10 to be made smaller.

[0091] (1-2) The counterweight created artificially by the control of the posture control unit 51 can tilt the vehicle body 11 backward before supporting the load W with the forks 45. When the load W is actually supported by the forks 45, the posture control unit 51 shifts the center of gravity G to invert the load handling vehicle 10. However, the amount of shift of the center of gravity G required to invert the load handling vehicle 10, i.e., the amount by which the right wheel drive motor 22 and the left wheel drive motor 27 are driven, can be reduced. Therefore, even without using a counterweight, the load handling vehicle 10 can be inverted, and the amount by which the right wheel drive motor 22 and the left wheel drive motor 27 are driven to invert the load handling vehicle 10 can also be reduced, i.e., the amount by which the load handling vehicle 10 moves forward. Therefore, when the load handling vehicle 10 supporting the load W is inverted, interference between the load handling vehicle 10 and the platform 100 can be suppressed.

[0092] (1-3) The center of gravity G of the cargo handling vehicle 10 can be moved in the fore-and-aft direction X by swinging the vehicle body 11 itself using the right wheel drive unit 21 and the left wheel drive unit 25. In other words, swinging the vehicle body 11 allows the cargo handling vehicle 10 to stand upright. Therefore, the right wheel drive unit 21 and the left wheel drive unit 25 enable the cargo handling vehicle 10 to stand upright and move without requiring a heavy object such as a counterweight separate from the vehicle body 11. As a result, compared to when a counterweight is required separate from the vehicle body 11, the torque applied when moving the vehicle body 11 can be reduced, and the output required for the right wheel drive motor 22 and the left wheel drive motor 27 can be reduced. Therefore, a counterweight is not required, and the right wheel drive unit 21 and the left wheel drive unit 25 can be made smaller, allowing the cargo handling vehicle 10 to be made smaller.

[0093] (1-4) The posture control unit 51 acquires the load signal output by the communication unit 56 before the load W is supported by the forks 45. Then, the posture control unit 51 derives the moment and the drive amounts of the drive motors 22, 27 before the load W is supported by the forks 45. For example, compared to a case where the posture control unit 51 acquires the load signal and derives the moment and the drive amounts of the drive motors 22, 27 at the same time as the load W is supported by the forks 45, the time required to invert the cargo handling vehicle 10 can be shortened.

[0094] (1-5) The moving process allows the cargo handling vehicle 10 to maintain an inverted state in both a loaded state and a non-loaded state. In particular, in a loaded state, the cargo handling vehicle 10 can move while maintaining a state in which the load W is supported horizontally.

[0095] (1-6) The vehicle body 11 is formed by integrating the battery 33, the control device 50, the housing 35, the right wheel drive unit 21, and the left wheel drive unit 25 into the vehicle base 12. Therefore, the battery 33, the control device 50, the housing 35, the vehicle base 12, the right wheel drive unit 21, and the left wheel drive unit 25 all swing integrally as the vehicle body 11.

[0096] For example, a comparative example will be taken of a case in which the battery 33, the control device 50, the housing 35, and the machine base 12 form a vehicle body, and this vehicle body is swung by the right wheel drive unit 21 and the left wheel drive unit 25. In this comparative example, the vehicle body and the right wheel drive unit 21 and the left wheel drive unit 25 must be connected by joints, and the attitude of the vehicle body must be controlled taking into account the vehicle body and the right wheel drive unit 21 and the left wheel drive unit 25. In contrast to this comparative example, the cargo handling vehicle 10 of this embodiment can reduce the number of joints connecting the vehicle body 11 and the right wheel drive unit 21 and the left wheel drive unit 25. Furthermore, unlike the comparative example, the cargo handling vehicle 10 only needs to swung the vehicle body 11, making attitude control easier than in the comparative example.

[0097] (Second embodiment) Next, a second embodiment of a cargo handling vehicle will be described with reference to Figures 12 to 15. Note that the second embodiment is simply a modified version of the first embodiment, and therefore detailed descriptions of similar parts will be omitted.

[0098] As shown in Figures 12 and 13, the cargo handling vehicle 10 includes a cargo handling device 40 that includes a cargo handling motor 42, a cargo handling encoder 43, a cargo handling bar 44, a fork 45, and a pair of arms 60 on the left and right. The arms 60 are connected to the forks 45. The cargo handling device 40 can freely adjust the height of the forks 45 by adjusting the shape of the arms 60. The cargo handling device 40 supports the load W with the forks 45 by swinging the forks 45 at the adjusted height. Therefore, the cargo handling device 40 includes the forks 45 that support the load W, and the arms 60 that swingably support the forks 45.

[0099] In the second embodiment, the battery 33 and the control device 50 are arranged in the center of the second main surface 122 in the left-right direction Y, stacked in the direction of gravity Z. The housing 35 is arranged in the center of the second main surface 122 in the left-right direction Y. The space surrounded by the second main surface 122 of the machine base 12 and the inner surface of the housing 35 is the storage space S. The stacked battery 33 and the control device 50 are housed in the storage space S.

[0100] Each of the pair of arms 60 includes a first joint 61, a second joint 62, a third joint 63, a first link 64, and a second link 65. That is, each of the pair of arms 60 includes a plurality of links 64, 65, and joints 61, 62 that connect the links 64, 65. Each of the pair of arms 60 is capable of changing the relative angle between the links 64, 65 connected by the joints 61, 62.

[0101] Each of the first joint 61, the second joint 62, and the third joint 63 is a rotatable joint. The first link 64 and the second link 65 are rod-shaped rigid bodies. The first link 64 is shorter than the second link 65.

[0102] One of the pair of first joints 61 is installed on the second main surface 122 outside the housing 35 in the left-right direction Y, and the other of the pair of first joints 61 is installed on the second main surface 122 outside the housing 35 in the left-right direction Y. The pair of first joints 61 sandwich the housing 35 from both sides in the left-right direction Y. The pair of first joints 61 are located closer to the axis L in the direction of gravity Z than the upper surface of the housing 35 in the direction of gravity Z. The first joint 61 includes a first joint motor 61a and a first encoder 61b. A first end 64a of a first link 64 is connected to the first joint 61. When the first joint motor 61a is driven, the first link 64 swings via the first joint 61. This causes the arm 60 to swing.

[0103] A second end 64b of the first link 64 is connected to a first end 65a of a second link 65 via a second joint 62. The second joint 62 includes a second joint motor 62a and a second encoder 62b. When the second joint motor 62a is driven, the second link 65 swings via the second joint 62. When the second link 65 swings, the relative angle between the first link 64 and the second link 65 changes. In this way, by changing the relative angle between the first link 64 and the second link 65, the arm 60 can be extended or bent.

[0104] A second end 65b of the second link 65 is connected to the fork 45 via a third joint 63. The third joint 63 is equipped with a cargo handling motor 42 and a cargo handling encoder 43. When the cargo handling motor 42 is driven, the fork 45 swings via the third joint 63. When the fork 45 swings, the relative angle of the fork 45 with respect to the second link 65 changes. The pair of forks 45 are integrated by a cargo handling bar 44.

[0105] Each of the pair of arms 60 has a tip end 60b and a base end 60a opposite to the tip end 60b. The base end 60a is a first end 64a of a first link 64. The tip end 60b is a second end 65b of a second link 65. Therefore, each of the pair of arms 60 has a second link 65 that forms the tip end 60b of the arm 60, and a first link 64 that forms the base end 60a of the arm 60. Furthermore, a fork 45 is connected to each of the tip ends 60b of the pair of arms 60. Therefore, the fork 45 is swingably connected to the second link 65 that forms the tip end 60b of the arm 60.

[0106] The base end 60a of the arm 60 is disposed closer to the axis L in the direction of gravity Z than the upper surface of the housing 35 in the direction of gravity Z. Specifically, the base end 60a of the arm 60 is disposed immediately adjacent to the second main surface 122 of the machine base 12 and lower in the direction of gravity Z than the upper surface of the housing 35 in the direction of gravity Z.

[0107] In the second embodiment, the operator operates the input unit 55 to input the height of the pallet holes 101a as a position command value. The height of the pallet holes 101a is a height at which the forks 45 can be inserted into the pallet holes 101a. The height of the pallet holes 101a varies depending on the surface on which the pallet 101 is placed. The surface on which the pallet 101 is placed can be a floor surface, the top surface of a shelf, the top surface of a truck bed, etc.

[0108] 14, the control device 50 includes an arm control unit 54 in addition to the configuration of the first embodiment. A first joint motor 61a, a second joint motor 62a, a first encoder 61b, and a second encoder 62b are connected to the arm control unit 54.

[0109] The input unit 55 outputs the input arm command value to the arm control unit 54. The arm command value is a command value for controlling the angle of the arm 60. The arm control unit 54 controls the driving of the first joint motor 61 a and the second joint motor 62 a in accordance with the arm command value, thereby rotating the first joint 61 and the second joint 62, thereby controlling the angle of the arm 60.

[0110] The arm control unit 54 acquires detection signals detected by the first encoder 61b and the second encoder 62b. The arm control unit 54 detects the rotation angles of the first joint motor 61a and the second joint motor 62a based on the acquired detection signals. The arm control unit 54 controls the driving of the first joint motor 61a and the second joint motor 62a based on the height of the pallet hole 101a. As a result, the angle of the pair of arms 60 changes depending on the height of the pallet hole 101a. Specifically, depending on the height of the pallet hole 101a, the arm 60 can take on a shape that extends in a straight line, a shape in which the first link 64 and the second link 65 are folded in two, or a shape in which the arm 60 is bent.

[0111] The cargo handling control unit 53 controls the driving of the cargo handling motor 42 in accordance with the angle of the arm 60 adjusted by the arm control unit 54. In other words, the cargo handling control unit 53 adjusts the fork 45 to the reference position, the tilt-up position, or the tilt-down position.

[0112] When the angle of the arm 60 is adjusted by the arm control unit 54, the position of the center of gravity G of the vehicle body 11 moves. For example, when the arm 60 is bent so that the fork 45 is positioned in front of the vehicle body 11, the center of gravity G moves forward. Then, the posture control unit 51 moves the center of gravity G during loading and unloading work according to the shape of the arm 60 and the position of the fork 45. In other words, the posture control unit 51 moves the center of gravity G by executing the process shown in FIG. 5.

[0113] Then, in the loaded state, the cargo handling vehicle 10 stands inverted in the standard posture T1 as shown in FIG. 15, stands inverted in the forward tilt posture T2 as shown in FIG. 16, or stands inverted in the backward tilt posture T3 (not shown).

[0114] Furthermore, as shown in FIG. 13, when the cargo handling vehicle 10 is in a non-load handling state, the arm control unit 54 can control the arm 60 to be straight in the vertical direction, while the posture control unit 51 can set the vehicle body 11 to the reference posture T1.

[0115] As shown in Fig. 17, a load W may be placed on a pallet 101 placed on the travel surface. In this case, the arm control unit 54 drives the first joint motor 61a, the second joint motor 62a, and the loading motor 42 based on the height of the pallet hole 101a on the travel surface. This controls the position of the fork 45 to a position where it can be inserted into the pallet hole 101a.

[0116] In this case, as a result of the first joint 61 being driven by the first joint motor 61a, the second end 64b of the first link 64 and the first end 65a of the second link 65 are positioned rearward of the housing 35. Furthermore, as a result of the second joint 62 being driven by the second joint motor 62a, the second end 65b of the second link 65 is positioned forward of the housing 35 and near the travel surface. Furthermore, as a result of the swinging of the forks 45 by the cargo handling motor 42, the forks 45 are positioned so that their lower surfaces are aligned with the travel surface. In this way, as the arms 60 are folded in two, the forks 45 can be inserted into the pallet holes 101a of the pallet 101 placed on the travel surface, and the load W can be supported by the forks 45. Then, as the vehicle body 11 is tilted forward in position T2, the cargo handling vehicle 10 is inverted.

[0117] [Effects of the embodiment] Therefore, according to the second embodiment, in addition to the effects (1-1) to (1-6) described in the first embodiment, the following effects can be obtained.

[0118] (2-1) The cargo handling vehicle 10 is equipped with a pair of arms 60 as the cargo handling device 40, so the height of the forks 45 can be adjusted to the height of the pallet holes 101a. Even if the position of the center of gravity G changes depending on the angle of the arms 60, the position of the center of gravity G can be moved by the posture control unit 51, so that the cargo handling vehicle 10 can stand upright.

[0119] (2-2) The cargo handling vehicle 10 can move the forks 45 to a position away from the vehicle body 11 by utilizing the length from the base end 60a to the tip end 60b of the arms 60. Then, by swinging the forks 45, the load W can be supported by the forks 45. Therefore, for example, compared to when the cargo handling device 40 includes only the forks 45, by providing the arms 60, the range around the vehicle body 11 in which the load can be picked up or unloaded by the forks 45 can be expanded in the front-rear direction X, the left-right direction Y, and the direction of gravity Z.

[0120] (2-3) The arm 60 includes a first link 64 and a second link 65, as well as a first joint 61 and a second joint 62. The arm 60 can be bent or extended by changing the relative angle between the first link 64 and the second link 65. The height of the fork 45 can be adjusted by changing the shape of the arm 60, thereby widening the range of heights of the load W that can be supported by the fork 45. The arm 60 can also be folded in two. Therefore, compared to when the arm 60 is a single rigid rod, the overall length can be shortened by folding the arm 60, and the load handling vehicle 10 can be made smaller in size in the forward / backward direction X.

[0121] (2-4) The base end 60a of the arm 60 is disposed closer to the axis L in the direction of gravity Z than the upper surface of the housing 35 in the direction of gravity Z so as to be closer to the second main surface 122 of the machine base 12. Specifically, the base end 60a of the arm 60 is disposed closer to the second main surface 122 so as to be closer to the axis L. This allows the center of gravity G of the cargo handling vehicle 10 to be lower than when the base end 60a of the arm 60 is located higher in the direction of gravity Z than the upper surface of the housing 35 in the direction of gravity Z, thereby stabilizing the cargo handling vehicle 10.

[0122] [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0123] Before changing from a state in which the load W is supported by the forks 45 to a state in which the load W is not supported by the forks 45 by releasing the load W, specifically, before unloading the load, the posture control unit 51 may also move the center of gravity G based on information related to the weight of the load W. In this case, in order to turn the load handling vehicle 10 upside down when the load W is not supported by the forks 45, the posture control unit 51 swings the vehicle body 11 using the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25, thereby moving the center of gravity G of the load handling vehicle 10 in the front-to-rear direction. Specifically, before changing from a state in which the load W is supported by the forks 45 to a state in which the load W is not supported by releasing the load W, the posture control unit 51 moves the center of gravity G forward of the axis L, which is the swing center.

[0124] The posture control unit 51 acquires in advance a load signal as information related to the weight of the load W. Based on the acquired load signal, the posture control unit 51 derives the moment generated when the load W is supported by the forks 45, and also derives the drive amounts of the right wheel drive motor 22 and the left wheel drive motor 27. The load signal may also be acquired at the time of unloading. In other words, the moment generated when the load W is released from the forks 45 may be derived at the time of unloading, and the drive amounts of the right wheel drive motor 22 and the left wheel drive motor 27 may also be derived.

[0125] The cargo handling process during unloading will now be described in detail. When the loading and unloading vehicle 10 moves along the movement path to the unloading position, it starts the loading and unloading process according to the flowchart shown in Fig. 18. Note that the loading and unloading vehicle 10 has the body 11 in the reference posture T1 and the forks 45 in the reference position. The position control unit 52 controls the drive of the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to move the loading and unloading vehicle 10 forward at the unloading position. Then, the loading and unloading vehicle 10 positions the forks 45 above the loading surface 100a of the loading platform 100, which is the unloading position (step S31).

[0126] Next, the posture control unit 51 synchronously drives the right wheel drive motor 22 and the left wheel drive motor 27 with the drive amounts of the right wheel drive motor 22 and the left wheel drive motor 27 derived based on the load signal. In other words, the posture control unit 51 moves the center of gravity G forward from the axis L, which is the center of swing (step S32). As a result, before the state in which the load W is supported by the forks 45 changes to a state in which the load W is not supported, the vehicle body 11 moves forward and tilts forward due to the pseudo-formed counterweight. Note that the underside of the pallet 101 is not in contact with the loading surface 100a of the loading platform 100.

[0127] Next, the cargo handling control unit 53 drives the cargo handling motor 42 to place the pair of forks 45 in the tilt-down position (step S33). At this time, the inclination of the vehicle body 11 does not change. The underside of the pallet 101 comes into contact with the loading surface 100a, and the pallet 101 is placed on the loading surface 100a. Then, the forks 45 no longer support the load W, and the center of gravity G moves backward in the fore-and-aft direction X.

[0128] The measurement unit 51a measures the tilt angle θ of the vehicle body 11. The posture control unit 51 also acquires a detection signal related to the tilt angle θ measured by the measurement unit 51a. The posture control unit 51 determines whether the center of gravity G is behind the axis L based on the detection signal from the measurement unit 51a (step S34). If it is determined that the center of gravity G is behind the axis L (YES in step S34), the posture control unit 51 synchronously drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to tilt the vehicle body 11 forward (step S35). At this time, the loading and unloading control unit 53 returns the fork 45 to the reference position.

[0129] Next, the posture control unit 51 determines whether the center of gravity G has stabilized based on the detection signal from the measurement unit 51a (step S36). If the posture control unit 51 determines that the center of gravity G has stabilized (YES in step S36), the posture control unit 51 ends the cargo handling process. As a result, the position of the center of gravity G is adjusted, and the cargo handling mobile body 10 comes to a standstill with the load W released from the upper surface 45a of the fork 45. In other words, the cargo handling mobile body 10 stands upright in the reference posture T1.

[0130] On the other hand, as shown in FIG. 18, if the center of gravity G has not moved rearward from the axis L, which is the center of swing (NO in step S34), the posture control unit 51 determines whether the center of gravity G is in front of the axis L (step S37). If the posture control unit 51 determines that the center of gravity G is in front of the axis L (YES in step S37), it synchronously drives the right wheel drive motor 22 of the right wheel drive unit 21 and the left wheel drive motor 27 of the left wheel drive unit 25 to tilt the vehicle body 11 backward (step S38). Then, the forward tilt amount of the cargo handling vehicle 10 is reduced. The cargo handling control unit 53 returns the forks 45 to the reference position.

[0131] Next, the posture control unit 51 determines whether the center of gravity G has stabilized based on the detection signal from the measurement unit 51a (step S36). If the posture control unit 51 determines that the center of gravity G has stabilized (YES in step S36), the posture control unit 51 ends the cargo handling process. As a result, the position of the center of gravity G is adjusted, and the cargo handling mobile body 10 comes to a standstill with the load W released from the upper surface 45a of the fork 45. In other words, the cargo handling mobile body 10 stands upright in the reference posture T1.

[0132] On the other hand, if the posture control unit 51 determines that the center of gravity G is not in front of the axis L (NO in step S37), the posture control unit 51 proceeds to step S36. Then, if the posture control unit 51 determines that the center of gravity G is stable (YES in step S36), the load handling process ends. In this case, the position of the center of gravity G has been moved in front of the axis L in advance, but has now moved backward due to unloading, so that the center of gravity G is located directly above the axis L. Therefore, the loading vehicle 10 comes to a standstill. In other words, the loading vehicle 10 stands upright in the reference posture T1.

[0133] Therefore, even during unloading, a state in which the expected movement of the center of gravity G when the state changes between a state in which the load W is supported by the forks 45 and a state in which the load W is not supported by the forks 45 can be offset can be simulated by the control of the posture control unit 51. In other words, the cargo handling vehicle 10 can simulate a state in which the cargo handling vehicle 10 is equipped with a counterweight by the control of the posture control unit 51.

[0134] Then, when the load W is actually released, the posture control unit 51 shifts the center of gravity G to make the load handling vehicle 10 inverted while not supporting the load W, but the amount of shift of the center of gravity G required for this inversion can be reduced. Therefore, the load handling vehicle 10 can be inverted without using a counterweight, and the amount of drive of the right wheel drive motor 22 and the left wheel drive motor 27 required for inversion can also be reduced.

[0135] Therefore, the right wheel drive motor 22 and the left wheel drive motor 27 enable the loading / unloading vehicle 10 to stand upright and move without the need for a heavy object such as a counterweight separate from the vehicle body 11. As a result, compared to the case where a counterweight separate from the vehicle body 11 is required, the torque applied to the right wheel drive motor 22 and the left wheel drive motor 27 when moving the vehicle body 11 can be reduced, and the output required by the right wheel drive motor 22 and the left wheel drive motor 27 can be reduced. This allows the loading / unloading vehicle 10 to be made smaller.

[0136] The cargo handling device 40 may include a load sensor disposed on the cargo handling motor 42 or the cargo handling bar 44. This load sensor comes into contact with the load W simultaneously with or before the load W is supported on the forks 45. The load sensor is also signal-connected to the posture control unit 51. The load W may be brought into contact with the load sensor simultaneously with or before the load W is supported on the forks 45, causing the load sensor to output a load signal related to the weight of the load W. The load signal output by the load sensor is acquired by the posture control unit 51. The posture control unit 51 may then move the center of gravity G of the cargo handling vehicle 10 in accordance with the load signal. In this case, the control device 50 does not need to include the communication unit 56.

[0137] When the weight of the load W repeatedly transported by the load handling vehicle 10 is the same, the moment generated when the load W is supported by the forks 45 is approximately constant during the repeated transport. In this case, the generated moment may be derived from the weight of the load W, which is uniquely determined, and the drive amounts of the drive motors 22, 27 for moving the center of gravity G may be derived and input in advance to the posture control unit 51. In this case, the control device 50 does not need to be equipped with the communication unit 56.

[0138] When the weight of the loads W repeatedly transported by the load handling vehicle 10 falls within a certain range, the average value of the weights of the loads W is calculated. Then, the generated moment is calculated from the average value, and the drive amounts of the drive motors 22, 27 for moving the center of gravity G are calculated and input in advance to the posture control unit 51. In this case, the control device 50 does not need to be equipped with the communication unit 56.

[0139] In steps S14, S16, and S17 of the first embodiment, the posture control unit 51 may determine whether the center of gravity G is located in front of or behind the axis L. As shown in FIG. 19 , the loading device 40 of the loading vehicle 10 may include only one arm 60. In this case, the battery 33 and the control device 50 are separately arranged on both sides of the second main surface 122 in the left-right direction Y. The battery 33 and the control device 50 are each housed in a separate housing 35. The arm 60 is installed between the housing 35 housing the battery 33 and the housing 35 housing the control device 50. A slit 12a for passing the arm 60 is formed in the center of the machine base 12 in the left-right direction Y. The arm 60 includes a first joint 61, a second joint 62, a first link 64, and a second link 65, similar to one arm 60 of the second embodiment. A loading motor 42 is supported on a second end 65b of the second link 65, similar to the first embodiment. A pair of loading bars 44 extend from the loading motor 42, and forks 45 are connected to the loading bars 44.

[0140] In this configuration, when the arm 60 is bent by the second joint 62 and the fork 45 is brought closer to the traveling surface, the second link 65 enters the slit 12a. As a result, even if the arm 60 is provided in the center of the machine base 12 in the left-right direction Y, the load W placed on the traveling surface can be supported by the fork 45.

[0141] 20, an arm 60 may include a first joint 61, a second joint 62, a third joint 63, a fourth joint 67, a first link 64, a second link 65, and a third link 66. Each of the first joint 61, the second joint 62, the third joint 63, and the fourth joint 67 is a freely rotatable joint.

[0142] A first end 66a of the third link 66 is connected to a second end 65b of the second link 65 via a third joint 63. The second end 66b of the third link 66 is connected to the fork 45 via a fourth joint 67. Each of the pair of arms 60 has a tip end 60b and a base end 60a opposite to the tip end 60b. The base end 60a is a first end 64a of the first link 64. The tip end 60b is a second end 66b of the third link 66.

[0143] Therefore, each of the pair of arms 60 includes a third link 66 that forms the tip end 60b of the arm 60, and a first link 64 that forms the base end 60a of the arm 60. Furthermore, a fork 45 is connected to each of the tip ends 60b of the pair of arms 60. Therefore, the fork 45 is connected to the tip end 60b of the arm 60 so as to be able to swing.

[0144] In this configuration, by swinging the third link 66 relative to the second link 65, the height of the fork 45 can be set to a placement surface that is one step lower than the travel surface.

[0145] 19 and 20, the link forming the tip 60b may be configured by connecting a plurality of link forming members that can slide relative to one another. In this configuration, the plurality of link forming members can be extended or retracted relatively at the tip 60b of the arm 60, allowing for finer adjustment of the height of the fork 45.

[0146] The arm control unit 54 may control the angle of the arm 60 based on the position of the fork 45, while the cargo handling control unit 53 may control the position of the fork 45 based on the angle of the arm 60. In this case, the input unit 55 acquires a detection signal related to the rotation angle detected by the cargo handling encoder 43, as well as a detection signal related to the rotation angle detected by the first encoder 61b and the second encoder 62b. Based on the acquired detection signals related to the rotation angles, the input unit 55 inputs an arm command value to the arm control unit 54 and inputs a cargo handling command value to the cargo handling control unit 53.

[0147] The length of the links forming the arm 60 can be changed as desired. In the arm 60, the joint connected to the fork 45 may support the fork 45 so as to be rotatable 360 ​​degrees.

[0148] The fork 45 may be equipped with a conveyor that can freely transport the load W in the longitudinal direction of the fork 45. It is also preferable that the fork 45 is connected to the arm 60 at the center in the longitudinal direction. In this configuration, the load W can be moved in the longitudinal direction of the fork 45 by the conveyor.

[0149] In each embodiment, the housing 35 may be omitted. In the second embodiment, the base end 60a of the right arm 60 may be connected to a side surface of the right cover 29a, and the base end 60a of the left arm 60 may be connected to a side surface of the left cover 29b. Even in this configuration, the base end 60a of the arm 60 is positioned closer to the axis L in the direction of gravity Z than the upper surface of the housing 35 in the direction of gravity Z.

[0150] The right drive wheel 31 and the left drive wheel 32 may be driven by a single drive motor. In this case, a single cover is installed on the first main surface 121 of the machine base 12, and the drive motor and the encoder are housed in the cover. Thus, the body 11 is provided with a single drive unit.

[0151] The right wheel drive unit 21 and the left wheel drive unit 25 may be housed in a single cover. The storage space S of the housing 35 may store a heavy object other than the battery 33 and the housing 35 .

[0152] The support members of the cargo handling device 40 may be, instead of the forks 45, suction devices that suck the load W or hand devices that grip the load W. In short, as long as the load W can be transported, the configuration of the support members of the cargo handling device 40 can be changed as appropriate.

[0153] The load W may be supported directly by the forks 45 without using the pallet 101. The drive unit may be an actuator other than a motor. [Note] <Appendix 1> an inverted wheel type loading and unloading vehicle comprising: a pair of left and right drive wheels; a vehicle body capable of swinging around an axis coaxial with the axles of the pair of left and right drive wheels as a swing center; and a loading and unloading device supported on the vehicle body, the loading and unloading device comprising a support member for supporting a load; the vehicle body comprising: a drive unit that drives the pair of left and right drive wheels; a control device that controls the drive of the drive unit and the loading and unloading device; and a power source for the drive unit and the loading and unloading device; the control device comprising: an attitude control unit that controls the drive of the drive unit to swing the vehicle body around the axis as a swing center, thereby controlling the attitude of the vehicle body; and the attitude control unit causes the drive unit to swing the vehicle body to move the center of gravity of the loading and unloading vehicle in the longitudinal direction in order to invert the loading and unloading vehicle.

[0154] <Appendix 2> The cargo handling device includes an arm connected to the support member, the arm having a tip end and a base end opposite the tip end, and the support member is swingably connected to the tip end of the arm.

[0155] <Appendix 3> The arm comprises a plurality of links and joints connecting the links together, the arm is capable of changing the relative angle between the links connected by the joints, the links include a link forming the tip end of the arm and a link forming the base end of the arm, and the support member is swingably connected to the link forming the tip end of the arm.

[0156] <Appendix 4> The loading and unloading vehicle according to <Appendix 2> or <Appendix 3>, wherein the vehicle body includes a housing that houses the control device and the power source, and the base end of the arm is positioned closer to the axle in the direction of gravity than the upper surface of the housing in the direction of gravity. [Explanation of symbols]

[0157] G...center of gravity, L...axis as swing center, 10...load handling vehicle, 11...vehicle body, 21...right wheel drive unit, 23...right axle, 25...left wheel drive unit, 26...left axle, 31...right drive wheel, 32...left drive wheel, 33...battery as power source, 40...load handling device, 45...fork as support member, 50...control device, 51...posture control unit.

Claims

1. An inverted wheel type cargo handling vehicle, A pair of left and right drive wheels; a vehicle body that can swing about an axis that is coaxial with the axles of the pair of left and right drive wheels; a loading device supported on the vehicle body, the loading device including a support member for supporting a load; the vehicle body includes a drive unit that drives the pair of left and right drive wheels, a control device that controls the drive of the drive unit and the cargo handling device, and a power source for the drive unit and the cargo handling device, the control device includes an attitude control unit that controls driving of the drive unit to swing the vehicle body around the axis line as a swing center, thereby controlling the attitude of the vehicle body; the attitude control unit causes the drive unit to swing the vehicle body and move the center of gravity of the cargo handling mobile body in a front-to-rear direction so as to invert the cargo handling mobile body while the cargo handling device supports the load; The posture control unit is characterized in that, before inverting the loading vehicle with the load supported by the loading device, the center of gravity of the loading vehicle is moved further back than when the load is not supported by the loading device.

2. An inverted wheel type cargo handling vehicle, A pair of left and right drive wheels; a vehicle body that can swing about an axis that is coaxial with the axles of the pair of left and right drive wheels; a loading device supported on the vehicle body, the loading device including a support member for supporting a load; the vehicle body includes a drive unit that drives the pair of left and right drive wheels, a control device that controls the drive of the drive unit and the cargo handling device, and a power source for the drive unit and the cargo handling device, the control device includes an attitude control unit that controls driving of the drive unit to swing the vehicle body around the axis line as a swing center, thereby controlling the attitude of the vehicle body; the attitude control unit causes the drive unit to swing the vehicle body and move the center of gravity of the cargo handling mobile body in a front-to-rear direction so as to invert the cargo handling mobile body in a state where the cargo handling device is not supporting the load, The posture control unit is characterized in that, before changing a state in which the load is supported by the loading device to a state in which the load is not supported by releasing the load, the center of gravity of the loading device is moved forward from a state in which the load is supported by the loading device.

3. 3. The cargo handling vehicle according to claim 1, wherein the attitude control unit acquires a load signal relating to the load in advance before the load is supported by the cargo handling device.

Images