Mobile cargo handling equipment

Abstract

To provide a cargo handling vehicle that can prevent the vehicle body from tipping over due to the displacement of the cargo being handled. [Solution] The attitude control unit of the cargo handling mobile body 10 controls the right wheel drive unit and the left wheel drive unit in accordance with the center of gravity G which fluctuates according to the displacement of the load W accompanying the movement of the forks 45 from the forward position FP to the rear position BP.

Description

【Technical Field】 【0001】 The present invention relates to a mobile body for cargo handling. 【Background Art】 【0002】 For example, Patent Document 1 discloses a mobile body for cargo handling. The mobile body for cargo handling disclosed in Patent Document 1 is of a two-wheeled inverted wheel type. The mobile body for cargo handling includes a pair of left and right drive wheels, a vehicle body swingable about an axis coaxial with the axles of the pair of left and right drive wheels as a swing center, and a cargo handling device supported by the vehicle body. The cargo handling device includes a support member for supporting a load. The support member swings in the vertical direction. 【0003】 Further, the mobile body for cargo handling includes a drive unit for driving a pair of left and right drive wheels and a control device for controlling the drive unit. The control device includes an attitude control unit. The attitude control unit controls the attitude of the vehicle body by swinging the vehicle body in the front-rear direction by controlling the drive of the pair of left and right drive units. Specifically, the attitude control unit tilts the vehicle body to move the center of gravity of the mobile body for cargo handling in the front-rear direction in order to invert the mobile body for cargo handling with a load supported by the support member. At this time, the mobile body for cargo handling utilizes the weight of the vehicle body itself as a balance weight to enable the inversion of the mobile body for cargo handling. 【0004】 By the way, in the mobile body for cargo handling disclosed in Patent Document 1, in order to displace the position of the load supported by the support member, for example, from a front position of the vehicle body to a rear position, it is necessary to drive the mobile body for cargo handling to turn. In order to displace the position of the load with respect to the vehicle body without driving the mobile body for cargo handling, for example, as disclosed in Patent Document 2, it is conceivable to move the support member to displace the position of the load by rotating the support member with respect to the vehicle body or the like. 【Prior Art Documents】 【Patent Documents】 【0005】 【Patent Document 1】 Japanese Unexamined Patent Application Publication No. 2024-88228 【Patent Document 2】 Japanese Patent Publication No. 2015-11384 [Overview of the Initiative] [Problems that the invention aims to solve] 【0006】 However, when the vehicle body is inverted while a load is supported by a support member, moving the support member to change the position of the load relative to the vehicle body will cause the center of gravity to shift as the load moves, resulting in the vehicle body tipping over. [Means for solving the problem] 【0007】 A cargo handling mobile body for solving the above problems is an inverted wheel type cargo handling mobile body for handling cargo, comprising: a pair of left and right drive wheels; a drive unit for driving the pair of left and right drive wheels; a vehicle body that swings in the front-rear direction around an axis coaxial with the axles of the pair of left and right drive wheels as a pivot point by the drive unit; a cargo handling device provided on the vehicle body and equipped with a support member for supporting the cargo; a moving mechanism for moving the support member to displace the position of the cargo supported by the support member from a first position relative to the vehicle body to a second position different from the first position; and a posture control unit that controls the drive unit to control the vehicle body's posture by swinging the vehicle body in the front-rear direction around the axis as a pivot point, wherein the posture control unit controls the drive unit in accordance with the center of gravity which fluctuates according to the displacement of the cargo accompanying the movement of the support member from the first position to the second position. 【0008】 According to this, while the load to be handled is supported by a support member, the vehicle's posture is controlled by the posture control unit to keep it inverted. In this state, the load to be handled may be displaced from a first position to a second position by the operation of the moving mechanism. The center of gravity also changes in accordance with the displacement of the load to be handled caused by the operation of the moving mechanism, and the posture control unit oscillates the vehicle in response to the change in the center of gravity. As a result, the vehicle can be kept inverted even if the center of gravity changes in accordance with the displacement of the load to be handled. Consequently, the vehicle can be prevented from tipping over in accordance with the displacement of the load to be handled. 【0009】 With respect to the cargo handling vehicle, the attitude control unit may acquire the position of the center of gravity multiple times while the cargo being handled moves from the first position to the second position, and each time the center of gravity is acquired, it may control the drive unit to swing the vehicle body. 【0010】 According to this, the cargo handling vehicle can gradually change its body posture in accordance with the displacement of the object being handled. Therefore, compared to a case where the body is swung only once by the posture control unit when the object being handled moves from the first position to the second position, the amount of fluctuation of the body due to the swinging of the body can be kept small, so that the displacement of the object being handled from the first position to the second position can be performed in a stable state. 【0011】 With respect to the cargo handling mobile body, the moving mechanism is preferably a mechanism that rotates the support member laterally around a moving rotation axis that extends vertically in the vehicle body as the center of rotation. According to this, when the support member supporting the cargo to be handled rotates around the pivot axis, the center of gravity shifts towards the second position, accompanied by the lateral displacement of the cargo to the vehicle body. Taking this shift in the center of gravity into account, the attitude control unit swings the vehicle body, thus preventing the vehicle body from tipping over, even if the cargo handling vehicle is equipped with a mechanism that displaces the cargo to the side of the vehicle body. 【0012】 Regarding the cargo handling mobile body, the cargo handling device is equipped with a rocking device that rocks the movable rotating shaft in the front-rear direction, and the moving mechanism is preferably interposed between the rocking device and the support member. 【0013】 According to this, the forward and backward oscillation of the pivot axis for movement by the oscillating device allows the upper surface of the support member to be kept horizontal. Furthermore, since the moving mechanism is interposed between the oscillating device and the support member, the support member can be rotated by the moving mechanism while the upper surface of the support member is kept horizontal. As a result, the cargo handling mobile body can displace the cargo object from a first position to a second position while supporting the cargo object horizontally. In other words, the oscillating device can serve both the function of oscillating the support member and the function of tilting the support member. 【0014】 Regarding the cargo handling mobile body, it is preferable to operate the movement mechanism while the cargo handling mobile body is stopped. According to this, the cargo handling vehicle can perform cargo handling in a stable state. [Effects of the Invention] 【0015】 This invention can suppress the tilting of the vehicle body due to the displacement of the cargo being handled. [Brief explanation of the drawing] 【0016】 [Figure 1] Figure 1 is a side view showing a cargo handling mobile vehicle and a cargo handling platform. [Figure 2] Figure 2 is a cross-sectional view showing a mobile cargo handling vehicle. [Figure 3] Figure 3 is a perspective view showing the load handling mechanism on the forks in the forward-extending and backward-extending positions. [Figure 4] Figure 4 is a side view showing a cargo handling mobile body in a forward-tilted and backward-tilted position. [Figure 5] Figure 5 is a block diagram of the control device. [Figure 6] Figure 6 is a side view showing the cargo handling vehicle before the load is removed. [Figure 7] Figure 7 is a side view showing a cargo handling vehicle after the load has been removed. [Figure 8] Figure 8 is a flowchart showing the processing of the attitude control unit. [Figure 9] Figure 9 is a side view showing the fork in a rotated state. [Figure 10] FIG. 10 is a side view showing the transfer vehicle at the front position and the rear position forks. [Figure 11] FIG. 11 is a side view showing a modified example of the transfer device. [Figure 12] FIG. 12 is a perspective view showing another modified example of the transfer device. 【BEST MODE FOR CARRYING OUT THE INVENTION】 【0017】 Hereinafter, an embodiment in which the transfer vehicle is embodied will be described. <Overall of the transfer vehicle> As shown in FIG. 1, the transfer vehicle 10 is of an inverted wheel type. The transfer vehicle 10 performs the transfer of the load W as the transfer target on the transfer platform 100. The transfer platform 100 is a platform on which the load W to be transferred by the transfer vehicle 10 is placed. On the placement surface 100a of the transfer platform 100, although only one is shown in FIG. 1, the pallet 101 is placed via a pair of pallet placement tables 102. Below the pallet 101, a pair of forks 45 can be inserted and removed between the pair of pallet placement tables 102. The load Wa is placed on the pallet 101. The load W is composed of the pallet 101 and the load Wa placed on the pallet 101. Note that the transfer target may be only the load Wa. In this case, the load Wa is directly supported by the forks 45 without going through the pallet 101. 【0018】 As shown in Figures 1 to 3, the cargo handling mobile vehicle 10 comprises a vehicle body 11, a pair of drive wheels (right drive wheel 31 and left drive wheel 32), a pair of drive units (right wheel drive unit 21 and left wheel drive unit 25), a cargo handling device 40, a control device 50, and a moving mechanism 70. In the following description, front, rear, left, and right refer to the front, rear, left, and right relative to the cargo handling mobile vehicle 10. The front-rear direction X is the direction of travel of the cargo handling mobile vehicle 10. The cargo handling mobile vehicle 10 has a front surface 11a on one side of the vehicle body 11 in the front-rear direction X, and a rear surface 11b on the other side. The front surface 11a and the rear surface 11b are located opposite each other in the front-rear direction X. The cargo handling mobile vehicle 10 moves forward when moving in the direction facing the front surface 11a, and moves backward when moving in the direction facing the rear surface 11b. The left-right direction Y is the vehicle width direction of the cargo handling mobile vehicle 10. Note that, as shown in Figure 2, the left and right sides are defined when viewing the vehicle body 11 from the front 11a side. The vertical direction Z is the height direction of the cargo handling mobile body 10. 【0019】 <Vehicle body> The vehicle body 11 comprises a base 12, a housing 35, and a secondary battery 60. The base 12 is plate-shaped. The 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 opposite to each other in the thickness direction of the base 12. 【0020】 The housing 35 is positioned on the second main surface 122. The housing 35 is box-shaped. The top plate of the housing 35 is the mounting surface 351 for the cargo handling device 40 via the moving mechanism 70. The front 11a of the vehicle body 11 is one of the four sides of the housing 35, and the rear 11b is the opposite side of the housing 35 from the front 11a. The control device 50 and the secondary battery 60 are housed inside the housing 35. 【0021】 <Right-wheel drive unit and left-wheel drive unit> The right wheel drive unit 21 drives the right drive wheel 31, and the left wheel drive unit 25 drives the left drive wheel 32. 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 comprises 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 housed inside 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 to the outside of the right cover 29a. The right drive wheel 31 is fixed to the protrusion from the right cover 29a on the right axle 23. 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, which is the amount of rotation of the right drive wheel 31. 【0022】 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, separated in the left-right direction Y. The left wheel drive unit 25 comprises 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 housed inside the left cover 29b. The left axle 26 is connected to the rotation axis 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 to the outside of the left cover 29b. The left drive wheel 32 is fixed to the protrusion from the left cover 29b on the left axle 26. 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, which is the amount of rotation of the left drive wheel 32. 【0023】 <Right-hand drive wheel and left-hand drive wheel> The right drive wheel 31 is in contact with the running surface F. The left drive wheel 32 is in contact with the running surface F. The right drive wheel 31 and the left drive wheel 32 rotate in contact with the running surface F. 【0024】 The central axis of the right axle 23 and the central axis of the left axle 26 lie on the same axis L. Therefore, the axles 23 and 26 of the pair of left and right drive wheels 31 and 32 lie on the same axis. The vehicle body 11 oscillates around axis L as its pivot point by the drive of the right wheel drive unit 21 and the left wheel drive unit 25. The right wheel drive unit 21 and the left wheel drive unit 25 are driven by power supplied from the secondary battery 60. 【0025】 <Cargo handling equipment> As shown in Figures 2 and 3, the cargo handling device 40 is mounted on the vehicle body 11. The cargo handling device 40 is rotatably supported by a moving mechanism 70 installed on the mounting surface 351 of the housing 35. 【0026】 The cargo handling device 40 comprises a tilt motor 42, a tilt encoder 43, a bar 44, and a pair of forks 45 as support members. The tilt motor 42 is supported by a moving mechanism 70. The tilt encoder 43 detects the rotation angle as the amount of rotation of the tilt motor 42. The bar 44 extends from the tilt motor 42 in the left-right direction Y. The first end of the bar 44 is connected to one fork 45, and the second end of the bar 44 is connected to the other fork 45. The bar 44 extends coaxially with the rotation axis (not shown) of the tilt motor 42. When the rotation axis of the tilt motor 42 rotates due to the drive of the tilt motor 42, the bar 44 rotates, and the pair of forks 45 swing with the bar 44 as the pivot point. 【0027】 The fork 45 can take on a reference position, a tilt-up position, and a tilt-down position by being driven by the tilt motor 42. The reference position is the position where the upper surface 45a of the fork 45 is horizontal. Although not shown in the diagram, the tilt-up position is the position where the tip of the fork 45 is higher than the reference position. The tilt-down position is the position where the tip of the fork 45 is lower than the reference position. These changes in the position of the fork 45 are performed by driving the tilt motor 42. 【0028】 <Movement mechanism> The moving mechanism 70 is located in the center of the mounting surface 351 of the housing 35 in the front-rear direction X and the left-right direction Y. The moving mechanism 70 comprises a moving motor 71, a moving rotating shaft 72, a moving encoder 73, and a tilt adjustment device 74. The lower end of the moving rotating shaft 72 is connected to the moving motor 71 via the tilt adjustment device 74, and a tilt motor 42 is connected to the upper end of the moving rotating shaft 72. The moving rotating shaft 72 extends coaxially with the rotating shaft of the moving motor 71 (not shown). When the rotating shaft of the moving motor 71 rotates due to the drive of the moving motor 71, the moving rotating shaft 72 rotates and the tilt motor 42 rotates. As a result, the fork 45 rotates laterally to the side of the vehicle body 11 via the tilt motor 42 and the bar 44. Therefore, the moving mechanism 70 rotates the fork 45 laterally relative to the vehicle body 11, with the moving rotation shaft 72, which extends vertically from the vehicle body 11, as the center of rotation. The direction of rotation of the moving rotation shaft 72, which is rotated by the moving motor 71, can be either forward or reverse, or it can be in only one direction. 【0029】 The mobile encoder 73 detects the rotation angle of the mobile motor 71. The tilt adjustment device 74, although not shown in detail, adjusts the angle of the tilt motor 42 via the moving rotation shaft 72 so that a reference position can be maintained in which the upper surface 45a of the fork 45 is on the horizontal plane. The tilt adjustment device 74 is connected to the lower end of the moving rotation shaft 72. The tilt adjustment device 74 oscillates the moving rotation shaft 72 in the ZX plane with the lower end of the moving rotation shaft 72 as the pivot point, adjusting the inclination of the moving rotation shaft 72 so that the central axis of the moving rotation shaft 72 extends in the vertical direction Z. The tilt adjustment device 74 adjusts the central axis of the moving rotation shaft 72 so that it extends in the vertical direction Z even when the vehicle body 11 is in a tilted position. Therefore, the fork 45 can rotate to the side of the vehicle body 11 while maintaining the reference position, i.e., the upper surface 45a is horizontal. 【0030】 As shown in Figure 3, the fork 45, which is rotated by the moving mechanism 70, moves between a forward-extending position P1 that extends forward from the front surface 11a of the vehicle body 11 and a rearward-extending position P2 that extends rearward from the rear surface 11b of the vehicle body 11. The forward-extending position P1 and the rearward-extending position P2 are positions where the direction of extension of the fork 45 is 180 degrees opposite. When the moving motor 71 rotates the moving rotation shaft 72 in the positive direction, the fork 45 rotates, for example, clockwise to move from the forward-extending position P1 to the rearward-extending position P2, or from the rearward-extending position P2 to the forward-extending position P1. Conversely, when the moving motor 71 rotates the moving rotation shaft 72 in the opposite direction, the fork 45 rotates, for example, counterclockwise to move from the forward-extending position P1 to the rearward-extending position P2, or from the rearward-extending position P2 to the forward-extending position P1. 【0031】 Furthermore, the fork 45 can move between the forward-extending position P1 and the backward-extending position P2 while maintaining its reference position by swinging the movable rotation shaft 72 by the tilt adjustment device 74 described above. When the fork 45 is in the forward-extending position P1, the load W supported on the upper surface 45a of the fork 45 is in the forward position FP, which is the first position relative to the vehicle body 11. When the fork 45 is in the backward-extending position P2, the load W supported on the upper surface 45a of the fork 45 is in the rearward position BP, which is a second position different from the forward position FP. In the forward position FP, the load W is located in front of the vehicle body 11. In the rearward position BP, the load W is located behind the vehicle body 11. Therefore, the moving mechanism 70 of the cargo handling mobile body 10 moves the fork 45 to displace the position of the load W supported by the fork 45 from the forward position FP relative to the vehicle body 11 to the rearward position BP, which is different from the forward position FP. 【0032】 <Vehicle posture> The vehicle body 11 of the cargo handling mobile body 10 can assume a standard posture T1, a forward-tilted posture T2, and a backward-tilted posture T3, whether the load W is supported by the forks 45 or not. 【0033】 As shown in Figure 1, in a side view of the cargo handling mobile body 10, the standard posture T1 is a posture in which the mounting surface 351 is parallel to the travel surface F. As shown by the dashed line in Figure 4, in a side view of the cargo handling mobile body 10, the forward-tilted posture T2 is a posture in which the vehicle body 11 is tilted forward more than in the standard posture T1. In the forward-tilted posture T2, the upper part of the vehicle body 11 is located in front of the lower part of the vehicle body 11. In a side view of the cargo handling mobile body 10, the mounting surface 351 in the forward-tilted posture T2 is downward at the front. [Downward at the front] means that the front side 11a of the mounting surface 351 is lower than the rear side 11b. The cargo handling mobile body 10 can assume the forward-tilted posture T2 while the forks 45 are in any of the following positions: the standard position, the tilt-up position, or the tilt-down position. 【0034】 As shown by the solid line in Figure 4, in a side view of the cargo handling mobile body 10, the rearward tilt posture T3 is a posture in which the vehicle body 11 is tilted further back than the standard posture T1. Also, in the rearward tilt posture T3, the upper part of the vehicle body 11 is located behind the lower part of the vehicle body 11. In a side view of the cargo handling mobile body 10, the mounting surface 351 in the rearward tilt posture T3 is downward at the rear. Note that "downward at the rear" means that the rear surface 11b side of the mounting surface 351 is lower than the front surface 11a side. The cargo handling mobile body 10 can assume the rearward tilt posture T3 while the forks 45 are in any of the following positions: standard position, tilt-up position, or tilt-down position. 【0035】 The control device 50 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, thereby allowing the vehicle body 11 to be in a standard posture T1, a forward-leaning posture T2, or a rearward-leaning posture T3, whether the load W is supported by the forks 45 or not. Furthermore, the control device 50 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, thereby allowing the position of the center of gravity G of the cargo handling mobile body 10 to be moved in the longitudinal direction X. Whether the load W is supported by the forks 45 or not, the posture control unit 51 can move the position of the center of gravity G in the longitudinal direction X. The center of gravity G is the combined center of gravity of the cargo handling mobile body 10 and the load W when the load W is supported by the forks 45, and the center of gravity of the cargo handling mobile body 10 when the load W is not supported by the forks 45. The weight of the forks 45 will be ignored for the sake of simplicity. The position of the center of gravity G in the longitudinal direction X is determined based on the weight of the vehicle body 11, the cargo handling device 40, the moving mechanism 70 and the load W, the posture of the vehicle body 11, and the rotation angle of the forks 45 with the moving rotation axis 72 as the center of rotation. 【0036】 In a side view of the cargo handling mobile vehicle 10, a virtual line M is defined as the reference line passing through the axis L in the vertical direction Z and extending in the vertical direction of the vehicle body 11. The smaller of the angles formed between the reference line M and the center line N of the vehicle body 11 in the longitudinal direction X is defined as the inclination angle θ of the vehicle body 11. The center line N is a straight line perpendicular to the axis L and extending in the vertical direction of the vehicle body 11. 【0037】 As shown in Figure 1, in the reference posture T1 when the load W is not supported by the forks 45, the center line N coincides with the reference line M, and the center of gravity G is located on the reference line M. In this case, the inclination angle θ is zero. 【0038】 As shown in Figure 4, in the forward-leaning posture T2 when the load W is not supported by the forks 45, the center line N is located in front of the reference line M, so the inclination angle θ is formed in front of the reference line M. Even when the load W is supported by the forks 45, in the forward-leaning posture T2, the center line N is located in front of the reference line M, so the inclination angle θ is formed in front of the reference line M. 【0039】 In the rearward tilted position T3, when the load W is not supported by the forks 45, the center line N is located behind the reference line M, so the inclination angle θ is formed behind the reference line M. Even when the load W is supported by the forks 45, in the rearward tilted position T3, the center line N is located behind the reference line M, so the inclination angle θ is formed behind the reference line M. 【0040】 In the cargo handling mobile body 10, when the forks 45 supporting the load W are rotated around the movable rotation axis 72 as the center of rotation, the position where the load on the load W is generated changes as the forks 45 rotate. For example, if the load W, which is located at the front position FP, is displaced to the rear position BP by the clockwise rotation of the forks 45, the position where the load on the load W is generated also moves clockwise from the front position FP to the rear position BP. As a result, the position of the center of gravity G shifts to the right and rear. 【0041】 The control device 50 controls the posture of the vehicle body 11 in order to adjust the tilt angle θ according to the posture of the vehicle body 11 and the position of the forks 45 supporting the load W in the rotational direction. As a result, the posture of the vehicle body 11 is controlled and the cargo handling mobile body 10 is inverted. The adjustment of the tilt angle θ by the control device 50 is described below. 【0042】 <Control device> The control device 50 controls the entire cargo handling mobile body 10. The control device 50 also controls the right wheel drive unit 21 and the left wheel drive unit 25, the cargo handling device 40, and the moving mechanism 70. 【0043】 The control device 50 comprises a processor and a memory unit. Examples of processors include a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a DSP (Digital Signal Processor). The memory unit includes RAM (Random Access Memory) and ROM (Read Only Memory). The memory unit stores program code or instructions configured to cause the processor to execute processing. The memory unit, i.e., the computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer. The control device 50 may be composed of hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). 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 FPGA, or a combination thereof. 【0044】 As shown in Figure 5, the control device 50 includes an attitude control unit 51, a position control unit 52, a tilt control unit 53, and a movement mechanism control unit 54. The control device 50 is also connected to a measurement unit 51a, an input unit 55, and a communication unit 56. 【0045】 <Input section> The input unit 55 outputs various commands for driving the cargo handling mobile body 10. The input unit 55 inputs the various commands to the control device 50. 【0046】 <Communications Department> The communication unit 56 receives information regarding the weight of the load W to be transported by the cargo handling mobile body 10 as a load command from a higher-level control device (not shown). The communication unit 56 outputs the received load command to the attitude control unit 51. 【0047】 <Position Control Unit> The input unit 55 inputs a position command to the position control unit 52. The position command is a command for moving the cargo handling mobile body 10, such as the movement path and movement speed of the cargo handling mobile body 10. For example, the position command related to the movement path commands the position from the initial standby position of the cargo handling mobile body 10 to the position where the load W is unloaded, via the loading platform 100. According to this position command, the cargo handling mobile body 10 moves forward from the initial standby position to near the loading platform 100, and then supports the load W with the forks 45 at the forward extension position P1. The cargo handling mobile body 10 rotates the forks 45 to the backward extension position P2, and then, according to the position command, moves backward from the loading platform 100 to the position where the load W is unloaded. Then, according to the position command, the cargo handling mobile body 10 unloads the load W at the unloading position. Note that the position command related to the movement path may be changed as needed. 【0048】 The position control unit 52 calculates the acceleration and target speed of the cargo handling mobile body 10 according to the position command 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 according to the calculated acceleration and target speed. As a result, the cargo handling mobile body 10 travels along the travel path at the travel speed. 【0049】 The position control unit 52 receives 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 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 by both the right wheel encoder 24 and the left wheel encoder 28. Based on the acquired detection signals, the position control unit 52 detects the rotational angular velocity of the right drive wheel 31 and acquires the rotational angular velocity of the left drive wheel 32. Based on the acquired rotational angular velocity, the position control unit 52 drives the right wheel drive motor 22 and the left wheel drive motor 27. Under the control of the position control unit 52, the cargo handling mobile body 10 moves along the movement path at the movement speed according to the position command. 【0050】 <Tilt Control Unit> The input unit 55 inputs a tilt command value to the tilt control unit 53. The tilt command value is a command value for controlling the fork 45 to the reference position, tilt-up position, and tilt-down position. The tilt control unit 53 is connected to the tilt motor 42 and the tilt encoder 43. The tilt encoder 43 detects the rotation angle of the tilt motor 42 and outputs a detection signal related to the detected rotation angle to the tilt control unit 53. The tilt control unit 53 drives the tilt motor 42 according to the tilt command value and based on the detection signal related to the rotation angle detected by the tilt encoder 43, and controls the fork 45 to the reference position, tilt-up position, or tilt-down position. 【0051】 When lifting the load W from the loading platform 100, the tilt control unit 53 controls the drive of the tilt motor 42 according to the tilt command value, thereby moving the fork 45 from the reference position to the tilt-up position. 【0052】 The tilt control unit 53 moves the load W to the reference position by controlling the drive of the tilt motor 42 according to the tilt command value, from the time the load W is supported by the forks 45 until it is transported and unloaded. When unloading the load, the tilt control unit 53 moves the forks 45 to the tilt-down position by controlling the drive of the tilt motor 42 according to the tilt command value. 【0053】 <Movement mechanism control unit> The input unit 55 inputs fork position commands to the movement mechanism control unit 54. The fork position commands are commands for controlling the position of the forks 45. Specifically, the input unit 55 inputs commands related to the forward extension position P1 and the backward extension position P2, as well as commands related to the tilt-up position, reference position, and tilt-down position to the movement mechanism control unit 54. 【0054】 The mobile mechanism control unit 54 is connected to the mobile motor 71, the mobile encoder 73, and the tilt adjustment device 74. The mobile encoder 73 detects the rotational degree of the mobile motor 71 and outputs a detection signal related to the detected rotation angle to the mobile mechanism control unit 54. Specifically, the mobile encoder 73 outputs a detection signal related to the rotation angle of the fork 45, which is rotated around the mobile rotation shaft 72 as the center of rotation, to the mobile mechanism control unit 54. The mobile mechanism control unit 54 drives the mobile motor 71 based on the detection signal output by the mobile encoder 73. 【0055】 In cargo handling using the cargo handling mobile body 10, as described above, when the load W is supported by the fork 45 at the forward-extending position P1 and then the fork 45 is rotated to move it to the backward-extending position P2, the movement mechanism control unit 54 controls the drive of the movement motor 71. Also, when the fork 45 supporting the load W is moved from the forward-extending position P1 to the backward-extending position P2, the inclination angle θ of the vehicle body 11 changes as the center of gravity G changes, and this is controlled by the attitude control unit 51, which will be described later. The movement mechanism control unit 54 controls the drive of the inclination adjustment device 74 according to the inclination angle θ, and controls the central axis of the moving rotation shaft 72 to extend in the vertical direction Z, thereby making it possible to maintain the fork 45 in the reference position, that is, the upper surface 45a of the fork 45 in a horizontal plane. As a result, the fork 45 moves from the forward-extending position P1 to the backward-extending position P2 while maintaining the reference position, under the control of the movement mechanism control unit 54. 【0056】 <Posture Control Unit> The attitude control unit 51 controls the drive of the right wheel drive unit 21 and the left wheel drive unit 25, thereby causing the vehicle body 11 to oscillate around the axis L as the pivot point, and thereby controlling the attitude of the vehicle body 11. 【0057】 The attitude control unit 51 is connected to a measurement unit 51a, a right-wheel drive motor 22, a left-wheel drive motor 27, a communication unit 56, and a motion encoder 73. The measurement unit 51a is an IMU (Inertial Measurement Unit). The measurement unit 51a detects three-dimensional inertial motion. Inertial motion consists of translational and rotational motion in the three orthogonal axes. The measurement unit 51a detects translational motion using a built-in acceleration sensor and rotational motion using a built-in gyro sensor. 【0058】 The measurement unit 51a measures the inclination angle θ of the vehicle body 11 at any time, such as when the load W is supported by the forks 45, when the load W is lowered from the forks 45, or more specifically, when the load W is in the forward position FP, when the load W is in the rear position BP, when the forks 45 are rotating, etc. The inclination angle θ is a change that changes according to the position of the center of gravity G. The measurement unit 51a detects the change in the inclination angle θ of the vehicle body 11 in the longitudinal direction X. 【0059】 Whether the load W is supported by the forks 45 or not, the attitude control unit 51 acquires the inclination angle θ from the measurement unit 51a. Based on the detection signal related to the acquired inclination angle θ, the attitude 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. As a result, the attitude of the vehicle body 11 is controlled to a standard attitude T1, a forward-tilted attitude T2, or a backward-tilted attitude T3 depending on the position of the center of gravity G, and the cargo handling mobile body 10 inverts in that controlled attitude. When the cargo handling mobile body 10 stops, whether the load W is supported by the forks 45 or not, the inclination angle θ when the vehicle body 11 is inverted is the equilibrium angle θm. 【0060】 The attitude control unit 51 derives an equilibrium angle θm in order to invert the cargo handling mobile body 10, and then uses the right wheel drive unit 21 and the left wheel drive unit 25 to swing the vehicle body 11 in the longitudinal direction X so that the equilibrium angle θm is achieved, thereby moving the position of the center of gravity G in the longitudinal direction X. Therefore, the attitude control unit 51 controls the attitude of the vehicle body 11 by controlling the drive of the right wheel drive unit 21 and the left wheel drive unit 25 to swing the vehicle body 11 in the longitudinal direction X with the axis L as the pivot point. 【0061】 The attitude control unit 51 acquires the load signal output by the communication unit 56. This load signal is input to the attitude control unit 51 before the cargo handling mobile body 10 is inverted while the load W is supported by the forks 45 at the forward extension position P1. Based on the acquired load signal, the attitude control unit 51 derives the moment generated when the load W is supported by the forks 45. The moment may be derived by calculation by the attitude control unit 51, or it may be derived using a map or table stored in the attitude control unit 51. In short, as long as the attitude control unit 51 can derive the moment from the acquired load signal, the method of derivation is arbitrary. The derived moment is a moment that acts in a direction that rotates the tip of the forks 45 downwards. 【0062】 When such a moment occurs in the cargo handling mobile body 10, the cargo handling mobile body 10 attempts to move forward by lowering the tips of its forks 45. In other words, when the load W is supported by the forks 45 at the forward extension position P1, the center of gravity G moves forward of the reference line M, and therefore the cargo handling mobile body 10 attempts to move forward in order to maintain its inverted state. 【0063】 In light of the generation of the moment described above, the attitude control unit 51, before inverting the cargo handling mobile body 10 with the load W supported by the forks 45 at the forward-extending position P1, derives an equilibrium angle θm based on the derived moment, and synchronously drives the right wheel drive motor 22 and the left wheel drive motor 27 to achieve that equilibrium angle θm, rotating the right drive wheel 31 and the left drive wheel 32 so that the cargo handling mobile body 10 tilts backward. In other words, when the load W is not supported by the forks 45, the attitude 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 to the rear of the reference line M. As a result, as shown in Figure 6, the attitude control unit 51 moves the center of gravity G to the rear of the reference line M. When the center of gravity G moves to the rear of the reference line M, the vehicle body 11 tilts backward due to the artificially formed balance weight before the load W is supported by the forks 45. In other words, the attitude control unit 51 causes the vehicle body 11 to swing, so that the cargo handling mobile body 10 assumes a posture with the vehicle body 11 tilted backward, i.e., a backward tilt posture T3. As a result, when the load W is not supported by the forks 45, the attitude control unit 51 can create a state in which a balance weight is artificially formed on the cargo handling mobile body 10. 【0064】 In order to control the vehicle body 11 to a balance angle θm while the load W is supported by the forks 45, when the right drive wheel 31 and left drive wheel 32 are rotated, the attitude control unit 51 derives the amount to drive the right wheel drive motor 22 and the left wheel drive motor 27 at the same time as deriving the moment. The amount of drive of the right wheel drive motor 22 and the left wheel drive motor 27 is also the amount of rotation of the right drive wheel 31 and the left drive wheel 32. Note that the amount of drive of the right wheel drive motor 22 and the left wheel drive motor 27 may be derived by calculation by the attitude control unit 51, or may be derived using a map or table that links the amount of drive to the moment. 【0065】 Furthermore, if the forks 45 that are not supporting the load W are in the extended position P2, when the attitude control unit 51 receives the load signal output by the communication unit 56, before inverting the cargo handling mobile body 10 with the load W supported by the forks 45 in the extended position P2, the attitude control unit 51 synchronously drives the right wheel drive motor 22 and the left wheel drive motor 27 to rotate the right drive wheel 31 and the left drive wheel 32 so that the cargo handling mobile body 10 tilts forward. 【0066】 When the fork 45 is in the forward-extending position P1 and a balance weight is artificially formed on the cargo handling mobile body 10, a load W is generated when the load W is supported by the fork 45. As a result of the generation of the load W, the position of the center of gravity G shifts. Specifically, as the load W is generated, a moment acts on the center of gravity G in the direction that moves it closer to the reference line M (the direction in which it transitions from tilting backward to tilting forward). However, since the center of gravity G before the load W is generated is located behind the reference line M, when the load W is generated, the position of the center of gravity G moves onto the reference line M, and the vehicle body 11 remains in the tilted backward position T3. In other words, even when the load W is supported by the fork 45 and a load W is generated by the artificially formed balance weight, the center of gravity G remains on the reference line M, so the vehicle body 11 is maintained in the tilted backward position T3. 【0067】 <When the fork is rotated> When a load W is supported by the fork 45 at the forward position P1, the load W is positioned at the forward position FP. When the load W at this forward position FP is displaced to the rear position BP by the clockwise rotation of the fork 45, the position where the load of the load W is generated moves clockwise from the forward position FP to the rear position BP. As a result, the position of the center of gravity G shifts to the rear side of the vehicle body 11 with the rotation of the fork 45, but this shift of the center of gravity G does not shift linearly in the longitudinal direction X, but rather shifts in the longitudinal direction X while shifting in the lateral direction Y. For this reason, the attitude control unit 51 takes the rotation of the fork 45 into account when deriving the equilibrium angle θm of the vehicle body 11. 【0068】 <Vehicle body attitude control> Next, the attitude control of the vehicle body 11 by the attitude control unit 51 will be explained according to the flowchart in Figure 8. 【0069】 Specifically, as shown in Figure 7, when the cargo handling mobile body 10 is inverted in a rearward tilted posture T3, the control performed by the attitude control unit 51 will be described when the load W is supported by the forks 45 positioned at the forward extension position P1, the load W is positioned at the forward position FP, the mobile body moves backward and stops, the forks 45 are rotated to the rearward extension position P2, and the load W is displaced to the rearward position BP. The attitude control unit 51 acquires detection signals from the mobile encoder 73 at predetermined time intervals and executes the processing shown in the flowchart in Figure 8. 【0070】 Next, the movement mechanism control unit 54 drives the movement motor 71, and the rotation of the fork 45 supporting the load W from the forward extension position P1 to the rear extension position P2 begins. At this time, the movement mechanism control unit 54 controls the drive of the tilt adjustment device 74 to rotate the movement rotation shaft 72 so that it extends in the vertical direction Z, and at the same time, the tilt control unit 53 controls the drive of the tilt motor 42 to maintain the fork 45 in the reference position. As a result, the load W is displaced from the forward position FP to the rear position BP while being horizontally supported by the upper surface 45a of the fork 45. 【0071】 The attitude control unit 51 acquires the detection signal from the moving encoder 73 to obtain the rotation angle of the fork 45 (step S11). Next, the attitude control unit 51 acquires the position of the center of gravity G corresponding to the rotation angle of the fork 45 supporting the load W (step S12). The position of the center of gravity G corresponding to the rotation angle of the fork 45 is derived by calculation by the attitude control unit 51 based on the weight of the load W, the rotation angle of the fork 45, and the inclination angle θ of the vehicle body 11. The weight of the load W is obtained from the load signal transmitted from the higher-level control unit, and the rotation angle of the fork 45 is obtained from the detection signal from the moving encoder 73. The inclination angle θ of the vehicle body 11 is obtained from the measurement unit 51a. 【0072】 Next, the attitude control unit 51 derives the equilibrium angle θm corresponding to the acquired position of the center of gravity G (step S13). The equilibrium angle θm is linked to the position of the center of gravity G and is pre-stored in the memory unit (not shown) of the control device 50. Specifically, the equilibrium angle θm is obtained by actually supporting the load W on the forks 45 and then rotating the forks 45, calculating the position of the center of gravity G at that rotation angle. Multiple types of equilibrium angles θm are set for each weight of the load W. Note that the equilibrium angle θm may be derived by calculation by the attitude control unit 51 based on the position of the center of gravity G, or it may be derived by referring to a map or table. In short, as long as the equilibrium angle θm corresponding to the position of the center of gravity G can be obtained from the weight of the load W and the rotation angle of the forks 45, the method of derivation is arbitrary. 【0073】 Next, the attitude 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 that the inclination angle θ of the vehicle body 11 becomes the derived equilibrium angle θm (step S14). As a result, the attitude control unit 51 controls the right wheel drive unit 21 and the left wheel drive unit 25 in accordance with the center of gravity G which fluctuates according to the displacement of the load W due to the movement of the fork 45. Then, the vehicle body 11 is controlled to the equilibrium angle θm derived by the attitude control unit 51 and stands upright. At this time, the movement mechanism control unit 54 controls the drive of the inclination adjustment device 74 in accordance with the equilibrium angle θm so that the movement rotation shaft 72 maintains the vertical direction Z. 【0074】 Next, the attitude control unit 51 determines whether or not the fork 45 is rotating based on the detection signal from the movement encoder 73 (step S15). If the fork 45 has not reached the rearward-extending position P2 since starting to move from the forward-extending position P1, then the fork 45 is rotating. In other words, if the fork 45 is in the process of rotating, the determination in step S15 is YES. On the other hand, if the fork 45 has reached the rearward-extending position P2 since starting to move from the forward-extending position P1, then the fork 45 is not rotating, and the determination in step S15 is NO. If the determination in step S15 is YES, the attitude control unit 51 proceeds to step S11 and continues processing. If the determination in step S15 is NO, the attitude control unit 51 terminates processing. 【0075】 Therefore, as the position of the load W moves from the forward position FP to the rear position BP, the attitude control unit 51 acquires the position of the center of gravity G multiple times, and each time the position of the center of gravity G is acquired, it controls the right wheel drive unit 21 and the left wheel drive unit 25 to swing the vehicle body 11. In detail, as the position of the load W moves from the forward position FP to the rear position BP, the attitude control unit 51 continues to execute the process shown in Figure 8 at predetermined time intervals to continuously derive the equilibrium angle θm, and swings the vehicle body 11 to that equilibrium angle θm. As a result, when the fork 45 is in the rearward extension position P2, the vehicle body 11 is controlled to an equilibrium angle θm that matches the center of gravity G corresponding to the rear position BP, and it stands upright. 【0076】 <Operation of cargo handling equipment> Next, the operation of the cargo handling mobile unit 10 will be explained. 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 vehicle body 11. The cargo handling mobile body 10 moves along the movement path and moves close to the loading platform 100. When the cargo handling mobile body 10 moves to the loading position relative to the loading platform 100, the pair of forks 45 are inserted between the pair of pallet loading platforms 102. Subsequently, the higher control unit transmits a stop command to the cargo handling mobile body 10 to stop it at the loading position. The position control unit 52 then controls the right wheel drive motor 22 and the left wheel drive motor 27 to decelerate and stop the cargo handling mobile body 10. 【0077】 Next, the attitude control unit 51 drives the right wheel drive motor 22 and the left wheel drive motor 27 in synchronous motion using the drive amounts derived from the load signal. In other words, when the load W is not supported by the forks 45, the attitude control unit 51 moves the center of gravity G to the rear of the reference line M. 【0078】 As shown in Figure 7, when the center of gravity G moves behind the reference line M, the vehicle body 11 tilts backward due to the artificially formed balance weight before the load W is supported by the forks 45. As a result, the cargo handling vehicle 10 stands upright in a backward-tilted position T3 when the load W is not supported by the forks 45. The vehicle body 11 is kept upright either because the forks 45 contact the load W before the vehicle body 11 tips over, or because the backward-tilted position T3 lasts for a very short time. 【0079】 Next, the tilt control unit 53 drives the tilt motor 42 to support the load W on the upper surface 45a of the pair of forks 45. This generates the load of the load W. Next, the position control unit 52 slightly reverses the cargo handling mobile body 10, moving it away from the cargo handling platform 100. While reversing, the forks 45 are in the forward extension position P1, so the load W is in the forward position FP, and the center of gravity G is positioned slightly to the rear 11b side of the vehicle body 11 from the reference line M in order to maintain balance during reversing. When reversing is complete, the cargo handling mobile body 10 comes to a stop. 【0080】 Next, the moving mechanism control unit 54, following the flowchart in Figure 8, moves the fork 45 from the forward-extending position P1 to the backward-extending position P2, and also moves the load W from the forward position FP to the rearward position BP by controlling the moving motor 71 to rotate the fork 45 clockwise. The moving mechanism control unit 54 also controls the drive of the tilt adjustment device 74 to maintain the fork 45 in the reference position. 【0081】 Figure 9 shows the fork 45 supporting the load W rotated by 90°. As shown in Figure 9, the fork 45 rotates toward the side of the vehicle body 11 while supporting the load W with its upper surface 45a remaining horizontal. If the inclination angle θ of the vehicle body 11 remains unchanged while the fork 45 rotates, the position of the center of gravity G will shift toward the rear surface 11b of the vehicle body 11 as the fork 45 rotates. However, the attitude control unit 51 updates the inclination angle θ of the vehicle body 11 to the equilibrium angle θm as needed. As a result, the vehicle body 11 maintains an inverted state while oscillating around the axis L and changing its attitude from a rearward tilted attitude T3 to a forward tilted attitude T2. 【0082】 As shown by the dashed line in Figure 10, when the forks 45 move to the rearward extension position P2 and the load W is displaced to the rearward position BP, the vehicle body 11 inverts in a forward-leaning posture T2. Subsequently, the position control unit 52 calculates the acceleration and target speed of the cargo handling mobile body 10 based on the movement speed included in the movement command value input from the input unit 55. Next, the attitude 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 backward while maintaining the forward-leaning posture T2. 【0083】 [Effects of the Embodiment] According to the above embodiment, the following effects can be obtained. (1) In the cargo handling mobile body 10, when the load W is supported by the forks 45 at the forward position P1 and the vehicle body 11 is inverted in a rearward tilt position T3, when the position of the load W is displaced from the forward position FP to the rearward position BP, the center of gravity G also changes in accordance with the displacement of the load W. In response to the change in the center of gravity G, the attitude control unit 51 swings the vehicle body 11. As a result, even if the center of gravity G changes in accordance with the displacement of the load W, the vehicle body 11 can be kept inverted. 【0084】 (2) In the cargo handling mobile body 10, as the load W moves from the forward position FP to the rear position BP, the attitude control unit 51 acquires the center of gravity G multiple times, and each time the center of gravity G is acquired, it derives the equilibrium angle θm and swings the vehicle body 11. As a result, the cargo handling mobile body 10 can gradually change the attitude of the vehicle body 11 in accordance with the displacement of the load W. Therefore, compared to the case where the vehicle body 11 is swung only once by the attitude control unit 51 as the load W moves from the forward position FP to the rear position BP, for example, the amount of fluctuation of the vehicle body 11 due to the swinging of the vehicle body 11 can be kept small, so that the movement of the load W from the forward position FP to the rear position BP can be performed in a stable state. 【0085】 (3) The moving mechanism 70 consists of a mechanism that rotates the forks 45 laterally to the side of the vehicle body 11 with the moving rotation axis 72 as the center of rotation. When the forks 45 supporting the load W are rotated by the moving mechanism 70, the position of the center of gravity G shifts to the rear of the vehicle body 11, accompanied by the displacement of the load W laterally to the side of the vehicle body 11. Taking this shift in the center of gravity G into account, the attitude control unit 51 derives an equilibrium angle θm and swings the vehicle body 11, so that even if the cargo handling mobile vehicle 10 is equipped with a moving mechanism 70 that displaces the load W laterally to the side of the vehicle body 11, the vehicle body 11 can be prevented from tipping over. 【0086】 (4) The cargo handling mobile unit 10 can rotate the forks 45 while swinging the vehicle body 11, thereby preventing the vehicle body 11 from tipping over. As a result, it is no longer necessary for the cargo handling mobile unit 10 to travel in a turning motion in order to displace the load W from the forward position FP to the rear position BP. As a result, the cargo handling mobile unit 10 can reduce the travel time for cargo handling and improve the efficiency of transporting the load W by the cargo handling mobile unit 10. 【0087】 (5) For example, if the cargo handling mobile body 10 is not equipped with an inclination adjustment device 74, there is a condition in which the forks 45 are rotated with the moving rotation axis 72 inclined with respect to the vertical Z. In this case, the upper surface 45a of the forks 45 becomes inclined. The larger the load of the load W, the larger the equilibrium angle θm becomes, and the greater the inclination of the upper surface 45a. In this embodiment, the moving mechanism 70 is equipped with an inclination adjustment device 74 for maintaining the forks 45 in a reference position. Therefore, the cargo handling device 40 can displace the position of the load W from the forward position FP to the rear position BP while supporting the load W horizontally on the upper surface 45a of the forks 45. With this configuration, the cargo handling mobile body 10 can stably displace the load W from the forward position FP to the rear position BP even when supporting a load W with a large load on the forks 45, such that the equilibrium angle θm becomes large. 【0088】 [Example of changes] This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically. 【0089】 ○In this embodiment, the moving mechanism 70 was operated with the cargo handling mobile body 10 stopped (the position control unit 52 outputs a command value to stop at the current position, so that the right drive wheel 31 and the left drive wheel 32 are substantially immobile relative to the travel surface F). However, the moving mechanism 70 may also be operated while the cargo handling mobile body 10 is moving (for example, while moving in reverse). 【0090】 As shown in Figure 11, the support member of the cargo handling device 40 may consist of an endless belt 81 and a pair of circumferential rollers 82 that make the belt 81 rotate, instead of the forks 45. Although not shown, the cargo handling device 40 is equipped with a tilt motor 42 for swinging the support member and a tilt encoder 43, as in the embodiment. The moving mechanism 80 may consist of a roller drive motor 83 that rotates the circumferential rollers 82. 【0091】 The outer surface of the belt 81 that is located above the pair of circumferential rollers 82 and faces upward is designated as the support surface 81a. The load W is supported by the support surface 81a of the belt 81. In the cargo handling device 40, one of the pair of circumferential rollers 82 is positioned at a location forward of the front surface 11a of the vehicle body 11, and the other of the pair of circumferential rollers 82 is positioned at a location backward of the rear surface 11b of the vehicle body 11. 【0092】 When the load W is supported on the support surface 81a near the top of the circulating roller 82 positioned in front of the vehicle body 11, the load W is positioned at a forward position FP relative to the vehicle body 11. Also, when the load W is supported on the support surface 81a near the top of the circulating roller 82 positioned behind the vehicle body 11, the load W is positioned at a rearward position BP relative to the vehicle body 11. 【0093】 As the roller drive motor 83 rotates a pair of circumferential rollers 82 and the support surface 81a moves toward the rear of the vehicle body 11, the position of the load W supported by the belt 81 is displaced from a forward position FP to a rear position BP relative to the vehicle body 11. When the position of the load W is displaced from a forward position FP to a rear position BP, the position of the center of gravity G of the cargo handling mobile body 10 changes linearly in the longitudinal direction X. 【0094】 In this case, the attitude control unit 51 controls the right wheel drive unit 21 and the left wheel drive unit 25 in accordance with the center of gravity G which fluctuates according to the displacement of the load W accompanying the movement of the belt 81 from the forward position FP to the rear position BP, thereby causing the vehicle body 11 to swing and invert. 【0095】 As shown in Figure 12, the cargo handling device 40 includes a rotating mechanism 85 connected to a bar 44 that is connected to a pair of forks 45. The bar 44 is non-rotatably connected to the rotating mechanism 85. The upper end of a rotating shaft 86 is connected to the lower end of the rotating mechanism 85. The rotating mechanism 85 rotates about the rotating shaft 86 as its center of rotation. When the rotating mechanism 85 rotates, the pair of forks 45 also rotate. The rotating mechanism 85 is a moving mechanism that moves the forks 45 to displace the position of the load W supported by the forks 45 from a forward position FP to a rearward position BP relative to the vehicle body 11. 【0096】 A rocking device 87 is connected to the lower end of the rotating shaft 86. The rocking device 87 causes the rotating shaft 86 to rock in the front-rear direction X in the ZX plane around the lower end of the rotating shaft 86. When the rotating shaft 86 is rocked in the front-rear direction X by the rocking device 87, the rotating mechanism 85 connected to the rotating shaft 86 also rocks in the front-rear direction X, causing the tips of the pair of forks 45 connected to the rotating mechanism 85 to swing up and down. 【0097】 Therefore, when the fork 45 is oscillated by the oscillating device 87 to make the upper surface 45a of the fork 45 horizontal, the fork 45 is positioned in the reference position. Then, when the rotating mechanism 85 is rotated while the fork 45 is maintained in the reference position by the oscillating device 87, the fork 45 rotates while maintaining the reference position. 【0098】 Therefore, the cargo handling device 40 is equipped with a swinging device 87 that swings the movable rotating shaft 72 in the front-rear direction X, and the rotation mechanism 85 is interposed between the swinging device 87 and the fork 45. With this configuration, the swinging of the fork 45 by the swinging device 87 keeps the upper surface 45a of the fork 45 horizontal. Furthermore, because the rotation mechanism 85 is interposed between the swinging device 87 and the fork 45, the fork 45 can be rotated by the rotation mechanism 85 while keeping the upper surface 45a of the fork 45 horizontal. As a result, the cargo handling mobile body 10 can displace the load W from the forward position FP to the rear position BP while supporting the load W horizontally. In other words, the swinging device 87 can combine the functions of the tilt motor 42 and the tilt adjustment device 74 of the embodiment. 【0099】 ○The attitude control unit 51 may acquire the position of the center of gravity G when the load W is in the forward position FP and when the load W is in the rear position BP, and may control the right wheel drive unit 21 and the left wheel drive unit 25 to oscillate the vehicle body 11 only when the center of gravity G is acquired. In other words, the attitude control unit 51 may acquire the equilibrium angle θm of the vehicle body 11 when the position of the load W switches to the rear position BP, and control the attitude of the vehicle body 11. 【0100】 ○The position of the load W when the forks 45 extend in the left-right direction Y of the vehicle body 11, or when the forks 45 extend diagonally with respect to the front-rear direction X, is defined as the lateral position. When the forks 45 are rotated to displace the position of the load W from the forward position FP or the rear position BP to the lateral position, the attitude control unit 51 may control the right wheel drive unit 21 and the left wheel drive unit 25 in accordance with the change in the center of gravity G that occurs in response to the displacement of the load W. As the load W is displaced to the lateral position, the attitude control unit 51 may swing the vehicle body 11 to invert it. In this case, the forward position FP or the rear position BP becomes the first position, and the lateral position becomes a second position that is different from the first position. 【0101】 ○The support members of the cargo handling device 40 may be replaced with suction devices for picking up the load W or hand devices for gripping the load W, instead of the forks 45. ○The drive unit may be an actuator other than a motor. 【0102】 ○The cargo handling mobile body 10 may be equipped with auxiliary wheels or the like to prevent the vehicle body 11 from tipping over. In this case, the auxiliary wheels may be used to stabilize the posture of the vehicle body 11 when the forks 45 are rotating. In other words, the posture control unit 51 should control the right wheel drive unit 21 and the left wheel drive unit 25 in accordance with the fluctuation of the center of gravity G, so that the vehicle body 11 maintains a stable posture using the auxiliary wheels during the fluctuation. 【0103】 ○The cargo handling mobile body 10 may use a spherical motor instead of the mobile motor 71 and the tilt adjustment device 74. ○If the balance angle θm is small, or if there is little slippage between the upper surface 45a of the fork 45 and the load W, and the load W does not fall while the moving rotating shaft 72 is rotating, the cargo handling mobile body 10 does not need to be equipped with an inclination adjustment device 74. [Explanation of symbols] 【0104】 FP... Forward position as the first position, BP... Rear position as the second position, G... Center of gravity, L... Axis, X... Front-rear direction, W... Load as the object to be handled, 10... Mobile body for handling cargo, 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, 40... Cargo handling device, 45... Fork as support member, 51... Posture control unit and drive wheel control unit, 70, 80... Moving mechanism, 72... Rotating shaft for movement, 81... Belt as support member, 85... Rotating mechanism, 87... Swivel device.

Claims

[Claim 1] An inverted wheel type cargo handling mobile vehicle for handling objects, A pair of left and right drive wheels, A drive unit that drives the pair of left and right drive wheels, A vehicle body that, by the drive of the aforementioned drive unit, swings in the front-rear direction with an axis coaxial with the axles of the pair of left and right drive wheels as the pivot point, A cargo handling device provided on the vehicle body and equipped with a support member for supporting the object to be handled, A moving mechanism for moving the support member to displace the position of the object to be handled, which is supported by the support member, from a first position relative to the vehicle body to a second position different from the first position, The vehicle comprises a posture control unit that controls the drive of the drive unit and controls the posture of the vehicle body by causing the vehicle body to swing in the front-rear direction with the axis as the pivot point, The attitude control unit controls the drive unit in accordance with the movement of the object to be handled, which is caused by the movement of the support member from the first position to the second position. [Claim 2] The cargo handling mobile body according to claim 1, wherein, while the object to be handled moves from the first position to the second position, the attitude control unit acquires the position of the center of gravity multiple times, and controls the drive unit to swing the vehicle body each time the center of gravity is acquired. [Claim 3] The cargo handling mobile body according to claim 1 or claim 2, wherein the moving mechanism is a mechanism that rotates the support member laterally around a moving rotation axis that extends vertically in the vehicle body as the rotation center. [Claim 4] The cargo handling device includes a rocking device that swings the movable rotating shaft in the forward and backward direction, The cargo handling mobile body according to claim 3, wherein the moving mechanism is interposed between the rocking device and the support member. [Claim 5] The cargo handling mobile body according to claim 1 or claim 2, wherein the mobile mechanism is operated while the cargo handling mobile body is stopped.

Images