Unmanned carrier vehicle

Abstract

To provide an unmanned carrier vehicle which enables downsizing and multiple functions to be achieved easily.SOLUTION: An unmanned carrier vehicle (91) comprises: four wheels (2L, 2R, 3L, 3R) that include driving wheels (2L, 2R) and are in contact with a floor (FL); a first arm (61) that couples and supports two wheels (2L, 3L) among the four wheels; a second arm (71) that couples and supports the remaining two wheels (2R, 3R) among the four wheels; and a frame (12) that supports the first arm (61) in a manner which prevents swinging, and that supports the second arm (71) in a manner which enables swinging between the two wheels (2R, 3R).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an automated guided vehicle. [Background technology]

[0002] Patent Document 1 describes a wheel structure for a four-wheeled automated guided vehicle that does not have a suspension structure and allows all four wheels to always stay in contact with the ground regardless of unevenness of the ground surface. The wheel structure described in Patent Document 1 places the center of gravity of the automated guided vehicle on the two drive wheels, and connects the remaining two driven wheels with an eccentric shaft to allow them to oscillate freely. This wheel structure is designed so that even if the heights of the grounded parts of the two driven wheels that should be in contact with the ground are different, the eccentric shaft automatically rotates to automatically adjust the height position of the shaft of each driven wheel so that a ground reaction force can be generated from the two driven wheels. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-338145 Summary of the Invention [Problem to be solved by the invention]

[0004] The wheel structure of the four-wheeled automated guided vehicle described in Patent Document 1 has two driven wheels connected by an eccentric shaft, which means that there is no space between the driven wheels to place other components. This reduces the degree of freedom in the layout of the components that make up the automated guided vehicle, which hinders miniaturization and multi-functionality, leaving room for improvement. [Means for solving the problem]

[0005] In order to solve the above problems, one aspect of one or more embodiments of the present invention is to The automated guided vehicle is equipped with four wheels including drive wheels that contact the floor, a first arm that connects and supports two of the four wheels, a second arm that connects and supports the remaining two of the four wheels, and a frame that supports the first arm so that it cannot swing and supports the second arm so that it can swing at a position between the two wheels. [Effects of the Invention]

[0006] According to one or more embodiments of the automatic guided vehicle of the present invention, it is possible to obtain the effect that it is easy to make it smaller and more multifunctional. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of an automated guided vehicle 91 according to one embodiment of the present invention, viewed obliquely from above and front left. [Figure 2] FIG. 2 is a bottom view of the automatic guided vehicle 91. FIG. [Figure 3] FIG. 3 is a right side view of the automatic guided vehicle 91. FIG. [Figure 4] FIG. 4 is a left side view of the automatic guided vehicle 91. FIG. [Figure 5A] FIG. 5A is a schematic right side view for explaining the operation of the automatic guided vehicle 91. FIG. [Figure 5B] FIG. 5B is a schematic left side view for explaining the operation of the automatic guided vehicle 91. FIG. [Figure 6] FIG. 6 is a schematic left side view for explaining the operation of the automatic guided vehicle P91 of the comparative example. [Figure 7] FIG. 7 is a schematic front view for explaining the operation of the automatic guided vehicle 91. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] The configuration of an automated guided vehicle 91 according to one embodiment of the present invention will be described with reference to Figs. 1 to 4. Fig. 1 is a perspective view of an automated guided vehicle 91 according to one embodiment of the present invention, seen from diagonally above and to the left front. Fig. 2 is a bottom view of the automated guided vehicle 91. Fig. 3 is a right side view of the automated guided vehicle 91. Fig. 4 is a left side view of the automated guided vehicle 91. For ease of explanation, the up / down, left / right, front / rear directions are defined as the directions of the arrows shown in Fig. 1. The up / down direction is the vertical direction.

[0009] As shown in Figures 1 and 2, the automated guided vehicle 91 has a main body 1 that is a rectangular parallelepiped and thin in appearance. The main body 1 has a frame 12 inside that serves as a skeleton. The lower part of the main body 1 has drive wheels 2, which are wheels driven by motors 5, at each of the front corners, and driven wheels 3, which are wheels, at each of the rear corners. Specifically, the drive wheels 2 are a pair of left and right drive wheels 2L, 2R, which are independently driven by motors 5L, 5R, respectively. The driven wheels 3 are a pair of left and right driven wheels 3L, 3R, which are so-called swivel casters. Note that the appearance shown in Figure 1 is a design treatment, and the shape and dimensional proportions do not necessarily match those of the structural drawings shown in Figures 2 to 4.

[0010] The main body 1 is equipped with a control unit 11 that controls the operation of the automatic guided vehicle 91. The control unit 11 independently controls the rotation speed and rotation direction of the motors 5L and 5R based on a pre-stored travel program or the like.

[0011] The main body 1 appears to have a horizontal groove cut into its vertical center. Openings (not shown) are formed in the front left and rear right of the groove, and sensors 41 and 42 are disposed inside the openings. As shown in FIG. 3, the sensors 41 and 42 are optical sensors that detect the presence and distance of an object on monitoring surfaces SF41 and SF42 that are horizontal to the floor FL through the openings and transmit the detection results to the control unit 11. Based on the detection results, the control unit 11 controls the operation of the main body 1, including the operation to avoid the detected object.

[0012] As shown in Figures 2 and 4, the left drive wheel 2L and driven wheel 3L are connected and supported by a plate-shaped or pipe-shaped left arm 61. The left arm 61 is rotatably supported by the frame 12 at a left shaft 62 located approximately in the center between the drive wheel 2L and driven wheel 3L. As shown in Figure 4, fixed plates 611 and 612 are fixed to the left side of the frame 12, respectively, on the front and rear sides of the left shaft 62. The fixed plates 611 and 612 abut against each other to restrict rotation of the left arm 61 about the left shaft 62. In other words, the left arm 61 is integrated with the frame 12 so as not to swing.

[0013] 2 and 3, the right drive wheel 2R and driven wheel 3R are connected and supported by a plate-shaped or pipe-shaped right arm 71. The right arm 71 is supported by a right shaft portion 72 located approximately in the center between the drive wheel 2R and the driven wheel 3R so as to be rotatable about an axis line CL7 relative to the frame 12. In other words, the right arm 71 is swingable relative to the frame 12.

[0014] Swing restricting plates 712, 711 are fixed to the right side of the frame 12, one at the front and one at the back of the right shaft 72. The swing restricting plates 711, 712 abut against each other to restrict the rotation angle range of the right shaft 72 of the right arm 71 about the axis CL7. In this example, when the drive wheel 2R and the driven wheel 3R are in contact with the floor FL and the loading unit 1a is in a reference position parallel to the floor FL, the allowable rotation angle α about the axis CL7 shown in FIG. 3 is set to 1.5° on both sides. This allowable angle α is set appropriately based on the longitudinal pitch of the drive wheel 2 and the driven wheel 3 and the unevenness of the floor FL where the automated guided vehicle 91 travels.

[0015] With the above-described configuration, the automated guided vehicle 91 travels under the control of the control unit 11 with four wheels, namely a pair of drive wheels 2 and a driven wheel 3, in contact with a flat floor FL. The control unit 11 autonomously controls the automated guided vehicle 91 to move forward and backward in a straight line and forward and backward on a curve, based on a pre-stored travel program and real-time detection results of the sensors 41 and 42.

[0016] In order for the automated guided vehicle 91 to accurately detect objects ahead in the traveling direction that may become obstacles, it is desirable that the monitoring surfaces SF41, SF42 of the sensors 41, 42 be as parallel as possible to the surface of the floor FL. For example, it is desirable that the monitoring surfaces SF41, SF42 be maintained parallel or nearly parallel to the floor FL while being as little affected by unevenness in the floor FL as possible. In other words, it is desirable to suppress changes in the inclination of the frame 12 of the main body 1 as much as possible. This will be described with reference to FIGS. 5A and 5B.

[0017] 5A shows an example of the right side view of the automated guided vehicle 91 when the right drive wheel 2R runs over a protruding step FLa in the floor FL, and FIG. 5B shows the left side view. The protruding height of the protruding step FLa in this case is set so that the rotation angle of the right arm 71 falls within the range of the allowable angle α.

[0018] The right arm 71 tilts so that the drive wheel 2R side rides up on the protruding step FLa and is raised, and the driven wheel 3R side lowers. This allows not only the drive wheel 2R but also the driven wheel 3R to maintain contact with the floor FL. This tilt of the right arm 71 does not substantially affect the tilt of the frame 12.

[0019] On the other hand, as shown in FIG. 5B, the left drive wheel 2L and driven wheel 3L are both in contact with the floor FL, so that the frame 12 as a whole with the four wheels maintains a posture in which the loading portion 1a is generally parallel to the floor FL. As a result, the monitoring surfaces SF41 and SF42 of the sensors 41 and 42 are maintained as surfaces that are generally parallel to the floor FL, and no problems occur in detecting obstacles related to travel.

[0020] Furthermore, the automated guided vehicle 91 has one of its left and right arms non-swingable, and a sensor is located at the front of the non-swingable arm, which is primarily the front of the vehicle when traveling. In the example described above, the left arm 61 on the left side is non-swingable, and the sensor 41 is located at the front left. On the non-swingable arm (left arm 61), even when the drive wheels 2L and driven wheels 3L are inclined on the floor FL, they do not swing and contact the ground along the inclination, so the monitoring surface SF41 of the sensor 41 can easily follow the inclination of the floor FL. This maintains a high level of accuracy in detecting obstacles that may be involved in the vehicle's travel.

[0021] This is maintained regardless of the position of the center of gravity of the load loaded on the loading section 1a. A more detailed description will be given with reference to an automated guided vehicle P91 of a comparative example. FIG. 6 is a schematic left side view showing the automated guided vehicle P91 of the comparative example. The automated guided vehicle P91 is different from the automated guided vehicle 91 in that both the left and right arms are swingable. That is, in FIG. 6, the drive wheel 2L and the driven wheel 3L are connected by a swingable left arm P61. The right arm on the right side (not shown) is also swingable.

[0022] In the comparative example of automated guided vehicle P91 in which both the left and right arms are swingable, when the center of gravity of the load on loading section 1a is center of gravity G1 that is biased forward, frame 12 tilts downward at the front as shown by the solid line, and the monitoring surface SF41 of sensor 41 also becomes a plane that tilts downward at the front and is significantly tilted relative to floor FL. On the other hand, when the center of gravity of the load on loading section 1a is center of gravity G3 that is biased rearward, frame 12 tilts downward at the rear as shown by the dashed-dotted line, and the monitoring surface SF41 of sensor 41 also becomes a plane that tilts downward at the rear and is significantly tilted relative to floor FL.

[0023] In contrast, in an automated guided vehicle 91 according to one embodiment of the present invention, the left arm 61 is non-swingable. Therefore, as shown in Fig. 5B, even if the center of gravity of the load placed on the loading section 1a is G1, which is biased forward, or G3, which is biased rearward, or even if it is in a position corresponding to the left shaft section 62, the monitoring surface SF41 follows the inclination of the floor FL and is maintained approximately parallel, in part because the sensor 41 is disposed on the non-swingable side. Therefore, the automated guided vehicle 91 maintains a high level of accuracy in detecting obstacles related to its travel, regardless of the position of the center of gravity of the load in the fore-and-aft direction.

[0024] 7, in one embodiment of the automated guided vehicle 91, even if the drive wheel 2R rides over the protruding step FLa and the frame 12 and loading section 1a tilt left and right so that the right side is higher than the floor FL at an angle β (see arrow DR7), the sensor 41 is disposed near the left edge where it cannot swing, so the vertical displacement is significantly smaller than when it is disposed on the right side (dashed line). Therefore, in the automated guided vehicle 91, the fluctuation in height of the monitoring surface SF41 of the sensor 41 is extremely small, and the accuracy of detecting obstacles involved in travel is maintained at a high level, substantially unchanged from when the floor FL is flat.

[0025] As described above in detail, in one embodiment of the automated guided vehicle 91, the pair of left and right (widthwise) driven wheels 3L, 3R are not connected by an eccentric shaft or the like, so components can be placed between the pair of driven wheels 3L, 3R. In this example, the control unit 11 is placed, but other components may also be placed there. In this way, there is a high degree of freedom in the layout of the components that make up the automated guided vehicle 91, making it easy to reduce the size and make it multifunctional.

[0026] In one embodiment of the automated guided vehicle 91, one of the arms connecting the left and right drive wheels 2 and driven wheels 3 (in this example, the left arm 61) is made non-swingable, while the other (in this example, the right arm 71) is made swingable. This minimizes the effects of unevenness in the floor FL and the position of the center of gravity of the cargo in the front-to-rear direction of the automated guided vehicle 91, and maintains good parallelism of the monitoring surface SF41 of the sensor 41 to the floor FL, thereby maintaining a high level of accuracy in detecting obstacles related to travel.

[0027] One aspect of one or more embodiments of the present invention is not limited to the configurations described above, and may be modified without departing from the spirit of the present invention.

[0028] The non-swingable arm and the swingable arm may be reversed. In this case, the sensor on the side that is mainly in the traveling direction (the front side in this example) is placed on the non-swingable arm. The motors 5L, 5R that drive the drive wheels 2 may be of a type housed within the wheels, and any member may be disposed between the drive wheels 2L, 2R. Although the example has been described in which the left arm 61, which cannot swing, is prevented from swinging by abutting against the fixed plates 611, 612, the left arm 61 may be fixed to the frame 12 with the left shaft portion 62 as a non-rotatable shaft. Because the driven wheel 3 is a swivel caster, the pitch between the drive wheel 2 and the driven wheel 3 changes to a certain extent depending on its orientation. It is preferable that the right axle 72 is positioned in the front-to-rear direction so that the ground reaction forces acting on the drive wheel 2 and the driven wheel 3 are as close as possible to each other. For example, it is preferable to match the caster posture when moving forward, which accounts for the majority of the traveling mode.

[0029] As described above in detail, one aspect of one or more embodiments of the present invention is an automated guided vehicle 91 equipped with four wheels 2L, 2R, 3L, 3R including drive wheels 2L, 2R that are in contact with a floor FL, a first arm 61 that connects and supports two of the four wheels 2L, 3L, a second arm 71 that connects and supports the remaining two of the four wheels 2R, 3R, and a frame 12 that supports the first arm 61 so that it cannot swing and supports the second arm 71 so that it can swing at a position between the two wheels 2R, 3R.

[0030] As a result, the pair of left and right (widthwise) driven wheels 3L, 3R are not connected by an eccentric shaft or the like, so components can be placed between the pair of driven wheels 3L, 3R. In this example, a control unit 11 is placed, but other components may also be placed there. In this way, there is a high degree of freedom in the layout of the components that make up the automated guided vehicle 91, making it easy to reduce the size and make it multifunctional.

[0031] This embodiment also includes a sensor 41 that detects the presence or absence of a surrounding object, and the sensor 41 is disposed at a position closer to the first arm 61 than the second arm 71.

[0032] This reduces the degree of tilt of the monitoring surface SF41 of the sensor 41 caused by unevenness of the floor FL and differences in the position of the center of gravity of the load, thereby maintaining a high level of accuracy in detecting obstacles related to travel.

[0033] In addition, in this embodiment, when the floor FL is flat, the sensor 41 detects the presence or absence of an object on a plane parallel to the floor FL.

[0034] This allows the robot to quickly detect an object located far away in the traveling direction and reliably execute an avoidance or detour operation, thereby improving the efficiency of transporting goods.

[0035] In this embodiment, the first arm 61 is rotatably supported by the frame 12, and includes fixed plates 611 and 612 that abut against the first arm 61 so as to prevent it from swinging.

[0036] As a result, by replacing the fixed plates 611, 612 with the swing restriction plates 711, 712, the first arm 61 can be made swingable and the second arm 71 can be made non-swingable, thereby improving the versatility of the automatic guided vehicle 91.

[0037] In addition, in this embodiment, one of the two wheels 2L, 3L supported by the first arm 61 and one of the two wheels 2R, 3R supported by the second arm 71 are driving wheels, and the remaining two wheels are driven wheels.

[0038] This allows the automatic guided vehicle 91 to smoothly move forward and backward on a straight line, as well as on a curved line. [Explanation of symbols]

[0039] 1 Main body 1a Loading section 11 Control section 12 frames 2, 2L, 2R drive wheels 3,3L,3R Driven wheel 4,41,42 Sensors 5,5L,5R motor 61 Left Arm 62 Left shaft 611,612 Fixing plate 71 Right Arm 711,712 Swing control plate 72 Right shaft section CR7 axis FL floor G1,G3 Center of gravity SF41,SF42 Monitoring surface α Acceptable angle β angle

Claims

1. Four wheels including drive wheels that contact the floor; a first arm that connects and supports two of the four wheels; a second arm that connects and supports the remaining two wheels of the four wheels; a frame that supports the first arm so that it cannot swing and that supports the second arm so that it can swing at a position between the two wheels; An automated guided vehicle equipped with

2. A sensor is provided to detect the presence or absence of surrounding objects, 2. The automated guided vehicle according to claim 1, wherein the sensor is disposed at a position closer to the first arm than to the second arm.

3. 3. The automated guided vehicle according to claim 2, wherein when the floor is flat, the sensor detects the presence or absence of an object on a plane parallel to the floor.

4. the first arm is rotatably supported by the frame, 2. The automatic guided vehicle according to claim 1, further comprising a fixed plate that abuts against the first arm so as to prevent the first arm from swinging.

5. one of the two wheels supported by the first arm; one of the two wheels supported by the second arm is a drive wheel; 5. The automated guided vehicle according to claim 1, wherein the remaining two wheels are driven wheels.

Images