Rocker bogie car

Abstract

To provide a rocker bogie car capable of readily and stably climbing and passing a step devoid of an upright plate.SOLUTION: A rocker bogie car 1A includes a vehicle body 2 and a control unit. The vehicle body 2 includes a bogie linkage 20 that supports and links a front wheel 11 and an intermediate wheel 12, a rocker linkage 30 that supports and links an intermediate part 20c of the bogie linkage 20 between the front wheel 11 and intermediate wheel 12, and a rear wheel 13, and a motor 37 that rotates the bogie linkage 20 with respect to the rocker linkage 30 with a rotation shaft 35, via which the rocker linkage 30 supports the bogie linkage 20, as a center. When the rocker bogie car climbs and passes a step, the control unit controls the motor 37 to rotate the bogie linkage 20, and thus raises or lowers one wheel 10 out of the front wheel 11 and rear wheel 13. This causes the one wheel 10 to separate from a road surface F1 or F11. At this time, a load balance of the vehicle body 2 in a fore-and-aft direction is varied in order to augment a load of the vehicle body 2 on an opposite side in the fore-and-aft direction of the one wheel 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rocker bogie vehicle. [Background technology]

[0002] Vehicles that run on wheels generally do not have high running performance when running on rough ground or traversing steps. For this reason, vehicle technology has been developed to improve running performance on rough ground and steps. One such vehicle with high running performance on rough ground is the rocker bogie vehicle, which has three pairs of driving wheels connected by rocker links and bogie links. For example, Patent Document 1 discloses a rocker bogie car with a total of six wheels, with a pair of front, middle, and rear wheels on each side. This rocker bogie car includes bogie links on which the front and middle wheels are supported, a rocker link on which the rear wheels are supported, and a main body connected to the rocker link, where the bogie link is supported by the main body or the rocker link and can rotate freely or dynamically, and the rocker link is fixed to the main body.

[0003] In a rocker bogie car as described in Patent Document 1, when climbing a step, it is necessary to rotate the bogie link and raise the front wheel away from the road surface on which the rocker bogie car is currently located to the height of the step located above. However, since a certain load acts on the front wheel, in order to raise the front wheel against this, it is necessary to make the torque to rotate the bogie link large. For this reason, by abutting the front wheel against a vertical surface (a riser in a staircase, hereinafter referred to as a standing plate) between the road surface on which the rocker bogie car is currently located and the step located above and rotating it, a frictional force is generated between the front wheel and the standing plate, and by this, a part of the force to raise the front wheel is borne, and the torque to rotate the bogie link when climbing the step can be reduced. In this case, more specifically, the rocker bogie car climbs the step in the following procedure. First, the front wheels are brought into contact with the vertical plate, and the bogie link is rotated relative to the rocker link to lift the front wheels while rotating the front wheels in the forward direction, and the front wheels are lifted up onto the step by the frictional force generated between the front wheels and the vertical plate. Next, the rocker bogie car is moved forward to bring the middle wheels into contact with the vertical plate, and in this state, the bogie link is rotated to lift the middle wheels while rotating the middle wheels in the forward direction, and the middle wheels are lifted up onto the step by the frictional force generated between the middle wheels and the vertical plate. Finally, the rocker bogie car is moved forward to bring the rear wheels into contact with the vertical plate, and in this state, the bogie link is rotated to lift the rear wheels while rotating the rear wheels in the forward direction, and the rear wheels are lifted up onto the step by the frictional force generated between the rear wheels and the vertical plate. In this way, the wheels can be raised by the frictional force between the wheels and the vertical plate in addition to the torque to rotate the bogie link, so the torque to rotate the bogie link is reduced and the wheels can be easily raised. Therefore, the rocker bogie vehicle can easily climb steps. When descending a step, the rocker bogie vehicle can easily descend the step by lowering the wheels while rotating and abutting them against the standing board between the road surface on which the rocker bogie vehicle is currently located and the step below.

[0004] Also, for example, when the front wheels are raised when climbing a step, the front wheels are separated from the road surface and positioned in the air, and the rocker bogie car is mainly supported by the middle and rear wheels that are in contact with the road surface, so the rocker bogie car is prone to tipping forward and is in an unstable position, but the front wheels are in contact with the vertical plate, so the forward tipping is prevented and suppressed by the vertical plate. When the rear wheels are raised after the front and middle wheels are raised over the step, the rear wheels are separated from the road surface and positioned in the air, and the rocker bogie car is mainly supported by the front and middle wheels that are in contact with the surface (hereinafter referred to as the step surface) beyond the step (in this case, above the step), so the rocker bogie car is prone to tipping backward and is in an unstable position, but the rear wheels are in contact with the vertical plate, so the backward tipping is prevented and suppressed by the vertical plate. Similarly, when descending a step, the front, middle, and rear wheels are all in contact with either the road surface, the vertical board, or the step surface beyond the step (below the step in this case), so tipping forward or backward is suppressed. In this way, when ascending or descending a step while rotating the wheels in contact with the vertical board, the step can be traversed in a stable state.

[0005] In contrast, when a rocker bogie vehicle attempts to traverse a step that does not have a standing board, the wheels that are raised or lowered cannot be brought into contact with the standing board. In this case, when raising the wheels over the step, the frictional force between the standing board and the wheels cannot be used, and the wheels must be raised only by the torque that rotates the bogie link, making it difficult to climb the step. In addition, when the front wheels are lifted off the road surface to ascend or descend the step, the front wheels are not in contact with either the road surface, the vertical board, or the step surface, and the rocker bogie car is supported only by the middle and rear wheels that are in contact with the road surface, so the rocker bogie car may tip over forward. Alternatively, if the position of the center of gravity of the rocker bogie car is biased forward, even if you try to lift the front wheels off the road surface when climbing a step, the front wheels may not rise, and instead the rear wheels may rise. Similarly, when the front and middle wheels go up or down the step and the rear wheels are lifted off the road surface to go up or down the step, the rear wheels are not in contact with either the road surface, the vertical board, or the step surface, and the rocker bogie car is supported only by the front and middle wheels that are in contact with the step surface, so the rocker bogie car may tip over backwards. Alternatively, if the position of the center of gravity of the rocker bogie car is biased toward the rear, even if you try to lift the rear wheels off the road surface when going up a step, the rear wheels may not rise, and instead the front wheels may rise. In this way, if there is no standing board on the step, the rocker bogie vehicle may not be able to traverse the step stably. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2023-6068 A Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a rocker bogie vehicle that can easily and stably traverse steps that are not provided with standing plates. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following means. That is, the rocker bogie vehicle of the present invention is a rocker bogie vehicle in which a pair of front wheels, middle wheels, and rear wheels are provided on the left and right sides, and includes a body section and a control unit that controls the operation of the body section. The body section supports each of the front wheels and the middle wheels and connects them, a bogie link that supports the intermediate portion between the front wheel and the middle wheel of the bogie link and the rear wheel and connects them, and a motor that rotates the bogie link relative to the rocker link around the rotation axis on which the rocker link supports the bogie link. When traversing a step, the control unit controls the motor to rotate the bogie link and raise or lower one of the front and rear wheels, thereby separating the one wheel from the road surface, and at that time, the load balance of the body section in the fore-and-aft direction is changed, and the load of the body section on the opposite side of the one wheel in the fore-and-aft direction is increased. The rocker bogie vehicle can travel on rough ground by providing a bogie link that supports and connects the front and middle wheels, and a rocker link that supports and connects the intermediate part between the front and middle wheels of the bogie link and the rear wheels. In particular, when traveling up a step, for example from the road surface on which the rocker bogie vehicle is currently located to a step surface higher than the road surface, the control unit first controls the motor that rotates the bogie link relative to the rocker link around the rotation axis on which the rocker link supports the bogie link so that the bogie link rotates in the front wheel upward direction so that the front wheels rise above the middle and rear wheels, and the front wheels are separated from the road surface, and the vehicle moves forward in this state, so that the front wheels are grounded on the step surface above the step. Next, while the front and rear wheels are in contact with the step surface and the road surface, respectively, the control unit controls the motor so that the bogie link rotates in the front wheel downward direction, which is the opposite direction to the front wheel upward direction, and the middle wheel is raised and separated from the road surface, and in that state, the vehicle moves forward further, and in addition to the front wheels, the middle wheel is also grounded on the step surface. Then, while the front and middle wheels are in contact with the step surface, the control unit controls the motor so that the bogie link rotates in the front wheel upward direction, and the rear wheel is raised and separated from the road surface and grounded on the step surface. This allows the rocker bogie car to climb the step. It is also possible to descend the step in a similar procedure, and in this way the rocker bogie car can traverse the step and run. Here, in the above configuration, when the control unit controls the motor to rotate the bogie link to raise or lower one of the front and rear wheels to separate from the road surface when traversing a step, the control unit changes the load balance of the vehicle body in the front-rear direction and increases the load of the vehicle body on the opposite side in the front-rear direction from the one wheel to be raised or lowered. Therefore, when the rocker bogie vehicle climbs a step, when the front wheel as one of the wheels is lifted off the road surface to rise to the step surface, the control unit can be configured to increase the load of the vehicle body on the opposite side in the front-rear direction from the front wheel to be raised, i.e., the rear side. Also, when the front wheel and the middle wheel climb up to the step surface, when the rear wheel as one of the wheels is lifted off the road surface to rise to the step surface, the control unit can be configured to increase the load of the vehicle body on the opposite side in the front-rear direction from the rear wheel to be raised, i.e., the front side. Similarly, when the rocker bogie vehicle descends a step, when the front wheel, as one of the wheels, is separated from the road surface and lowered to the step surface, the control unit can be configured to increase the load on the vehicle body part on the opposite side in the fore-and-aft direction from the front wheel to be lowered, i.e., the rear wheel, as one of the wheels, is lowered to the step surface after the front and middle wheels have descended from the road surface to the step surface, the control unit can be configured to increase the load on the vehicle body part on the opposite side in the fore-and-aft direction from the rear wheel to be lowered, i.e., the front wheel. In this way, when the load of the body of the rocker bogie car increases on the opposite side in the front-rear direction from the one wheel to be raised or lowered, the load of the rocker bogie car is mainly supported by the center wheel and the wheel located on the opposite side in the front-rear direction from the one wheel, so the load acting on the one wheel to be raised or lowered is reduced. Therefore, the torque of the motor for rotating the rocker link can be reduced. Therefore, even if a standing plate is not provided on the step and the wheel cannot be raised or lowered by using the friction force between the standing plate and the wheel, the step can be easily traversed. In addition, when traversing a step, the load of the body of the rocker bogie car increases on the opposite side in the front-rear direction from the one wheel that is to be moved away from the road surface, so that the wheel located on the opposite side is prevented from moving away from the road surface or the step surface instead of the one wheel that is to be moved away from the road surface. Furthermore, when the load of the body of the rocker bogie car increases on the opposite side in the front-rear direction from the one wheel that is to be raised or lowered, the load acting on the one wheel is reduced, so that even if the one wheel rises or falls and moves away from the road surface, the rocker bogie car is prevented from tipping over in the front-rear direction toward the one wheel. Therefore, the stability of the rocker bogie car is improved when traversing a step. In this way, it becomes possible to easily and stably traverse steps that do not have standing boards.

[0009] In one aspect of the present invention, the rocker bogie vehicle of the present invention further includes a center of gravity shifting mechanism that shifts the position of the center of gravity in the fore-and-aft direction, and when the one wheel is raised or lowered, the control unit controls the center of gravity shifting mechanism to shift the position of the center of gravity to the opposite side of the one wheel in the fore-and-aft direction, thereby increasing the load on the vehicle body section on the opposite side of the one wheel in the fore-and-aft direction. According to the above configuration, the rocker bogie car is equipped with a center of gravity shifting mechanism that shifts the position of the center of gravity in the front-rear direction, and when one of the front and rear wheels is raised or lowered to separate from the road surface when traversing a step, the control unit controls the center of gravity shifting mechanism to move the position of the center of gravity to the opposite side in the front-rear direction from the one wheel that is raised or lowered. Therefore, when the rocker bogie car climbs a step, when the front wheel as one wheel is lifted off the road surface to raise it to the step surface, the control unit can be configured to control the center of gravity shifting mechanism to move the position of the center of gravity to the opposite side in the front-rear direction from the front wheel that is to be raised, that is, backward. In addition, when the front wheel and the middle wheel climb up to the step surface, when the rear wheel as one wheel is lifted off the road surface to raise it to the step surface, the control unit can be configured to control the center of gravity shifting mechanism to move the position of the center of gravity to the opposite side in the front-rear direction from the rear wheel that is to be raised, that is, forward. Similarly, when the rocker bogie vehicle descends a step, when the front wheel, which is one of the wheels, is separated from the road surface and descended to the step surface, the control unit can be configured to control the center of gravity shifting mechanism to move the position of the center of gravity to the opposite side in the fore-and-aft direction from the front wheel to be descended, i.e., backward. In addition, when the front wheel and the middle wheel descend from the road surface to the step surface, and the rear wheel, which is one of the wheels, is descended to the step surface, the control unit can be configured to control the center of gravity shifting mechanism to move the position of the center of gravity to the opposite side in the fore-and-aft direction from the rear wheel to be descended, i.e., forward. In this way, when the center of gravity of the rocker bogie car moves to the opposite side in the front-rear direction from the one wheel to be raised or lowered, the load of the rocker bogie car is mainly supported by the center wheel and the wheel located opposite the one wheel in the front-rear direction, so the load acting on the one wheel to be raised or lowered is reduced. Therefore, the torque of the motor for rotating the rocker link can be reduced. Therefore, even if a standing plate is not provided on the step and the wheel cannot be raised or lowered by using the friction force between the standing plate and the wheel, the step can be easily traversed. In addition, when traversing a step, the center of gravity of the rocker bogie car moves in the front-rear direction to the opposite side of the one wheel that is to be moved away from the road surface, so that the wheel located on the opposite side is prevented from moving away from the road surface or the step surface instead of the one wheel that is to be moved away from the road surface. Furthermore, when the center of gravity of the rocker bogie car moves in the front-rear direction to the opposite side of the one wheel that is to be raised or lowered, the load acting on the one wheel is reduced, so that even if the one wheel rises or falls and moves away from the road surface, the rocker bogie car is prevented from tipping over in the front-rear direction toward the one wheel. Therefore, the stability of the rocker bogie car is improved when traversing a step.

[0010] In another aspect of the present invention, the center of gravity moving mechanism includes a rail portion extending in the fore-and-aft direction, a mass body movable in the fore-and-aft direction on the rail portion, and a drive portion for moving the mass body on the rail portion, and the control portion controls the drive portion to move the mass body in the fore-and-aft direction, thereby moving the position of the center of gravity in the fore-and-aft direction. According to the above-mentioned configuration, the center of gravity shifting mechanism includes a rail section provided to extend in the front-rear direction, a mass body provided to be movable in the front-rear direction on the rail section, and a drive section that moves the mass body on the rail section. In this configuration, the control section controls the drive section to move the mass body forward, thereby moving the position of the center of gravity forward. Also, the control section controls the drive section to move the mass body rearward, thereby moving the position of the center of gravity rearward. In this way, it is possible to appropriately realize a center of gravity shifting mechanism that moves the position of the center of gravity in the front-rear direction.

[0011] In another aspect of the present invention, the rocker bogie vehicle of the present invention further includes a drive motor arranged to drive each of the front wheels, the middle wheels, and the rear wheels, and the control unit rotates each of the front wheels, the middle wheels, and the rear wheels forward or backward using the drive motor, and then rotates each of the front wheels, the middle wheels, and the rear wheels in the opposite direction, thereby changing the load balance of the vehicle body in the fore-and-aft direction. According to the above configuration, when the control unit rotates each of the front wheels, middle wheels, and rear wheels by the drive motor so as to move forward, and then rotates each of the front wheels, middle wheels, and rear wheels in the opposite direction, i.e., in the backward direction, the load balance of the vehicle body in the front-rear direction fluctuates due to the inertial force of the rocker bogie car moving forward, and the load of the vehicle body in the front increases. This makes it possible to achieve a state equivalent to when the center of gravity moves forward. In addition, when the control unit rotates each of the front wheels, middle wheels, and rear wheels by the drive motor so as to move backward, and then rotates each of the front wheels, middle wheels, and rear wheels in the opposite direction, i.e., in the forward direction, the load balance of the vehicle body in the front-rear direction fluctuates due to the inertial force of the rocker bogie car moving backward, and the load of the vehicle body in the rear increases. This makes it possible to achieve a state equivalent to when the center of gravity moves backward. In this way, it is possible to appropriately achieve the same action as the above-mentioned center of gravity moving mechanism that moves the position of the center of gravity in the forward-rear direction, without structurally moving the position of the center of gravity.

[0012] In another aspect of the present invention, the rocker bogie vehicle of the present invention further includes a drive motor arranged to drive each of the front wheels, the middle wheels, and the rear wheels, and the control unit rotates each of the front wheels, the middle wheels, and the rear wheels by the drive motor to accelerate forward or backward, thereby varying the load balance of the vehicle body in the fore-and-aft direction. According to the above configuration, the control unit rotates the front wheels, middle wheels, and rear wheels by the drive motor so that they move forward while accelerating, so that the load balance of the vehicle body in the front-rear direction changes due to the forward acceleration, and the load of the vehicle body in the rear increases. This makes it possible to achieve a state equivalent to when the center of gravity moves backward. In addition, the control unit rotates the front wheels, middle wheels, and rear wheels by the drive motor so that they move backward while accelerating, so that the load balance of the vehicle body in the front-rear direction changes due to the backward acceleration, and the load of the vehicle body in the front increases. This makes it possible to achieve a state equivalent to when the center of gravity moves forward. In this way, it is possible to appropriately achieve an action similar to that of the above-mentioned center of gravity moving mechanism, which moves the position of the center of gravity in the front-rear direction, without structurally moving the position of the center of gravity.

[0013] In another aspect of the present invention, when climbing the step upward, the control unit controls the vehicle to increase the load on the rear of the vehicle body portion, raise the front wheels to move them away from the road surface, move the middle and rear wheels forward to ground the front wheels on the step surface above the step, rotate the bogie link around the rotation axis to ground the front and rear wheels on the step surface and the road surface while raising the middle wheels to move them away from the road surface, move the front and rear wheels forward to ground the middle wheels on the step surface, increase the load on the vehicle body portion at the front, then rotate the bogie link around the rotation axis to ground the front and middle wheels on the step surface while raising the rear wheels to move them away from the road surface, and move the front and middle wheels forward to ground the rear wheels on the step surface. With this configuration, when climbing an upward step, one of the wheels, the front wheel, is raised and lifted off the road surface, and when the middle and rear wheels are moved forward to bring the front wheel into contact with the step surface above the step, the load on the rear body section is increased, making it easy to lift the front wheel. By rotating the bogie link around the rotation axis, the front and rear wheels are brought into contact with the step surface and the road surface while the middle wheel is raised and lifted away from the road surface, and when the front and rear wheels are moved forward to bring the middle wheel into contact with the step surface, the front and rear wheels are in contact with the step surface and the road surface, so the middle wheel can be lifted stably. In addition, by rotating the bogie link around the rotation axis to bring the front and middle wheels into contact with the step surface while lifting the rear wheels (as one of the wheels) away from the road surface, and by moving the front and middle wheels forward to bring the rear wheels into contact with the step surface, the load on the front body section is increased, so that the rear wheels can be stably lifted away from the road surface. In this way, the upward step can be climbed easily and stably.

[0014] In another aspect of the present invention, when descending the step downward, the control unit controls the vehicle to increase the load on the rear body part, move the middle and rear wheels forward while rotating the bogie link around the rotation axis, lower the front wheels to touch the step surface below the step, move the front and rear wheels forward while rotating the bogie link around the rotation axis, lower the middle wheels to touch the step surface, and increase the load on the front body part, move the front and middle wheels forward while rotating the bogie link around the rotation axis, lower the rear wheels to touch the step surface. With this configuration, when descending a downward step, the middle and rear wheels are moved forward while the bogie link is rotated around the axis of rotation, and the front wheel is lowered as one of the wheels to touch the step surface below the step. By increasing the load on the rear body section, the front wheel can be prevented from descending suddenly and causing the rocker bogie vehicle to tip forward, and the front wheel can be lowered stably. In addition, by rotating the bogie link around the axis of rotation while moving the front and rear wheels forward, the middle wheels can be stably lowered to the step surface and made to touch the ground. In addition, when the front and middle wheels are moved forward and the bogie link is rotated around the axis of rotation to lower the rear wheels as one of the wheels and bring them into contact with the step surface, the load on the front body section is increased, thereby increasing the load acting on the step surface by the front and middle wheels, allowing the rear wheels to stably touch the step surface. Effect of the Invention

[0015] According to the present invention, it is possible to provide a rocker bogie vehicle that can easily and stably traverse steps that are not provided with standing plates. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a side view showing the configuration of a rocker bogie vehicle according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing the configuration of the body of a rocker bogie vehicle. [Diagram 3] FIG. 2 is a front view of the rocker bogie vehicle. [Figure 4] FIG. 2 is a block diagram showing the functional configuration of a control unit of the rocker bogie vehicle in this embodiment. [Diagram 5] 4 is a flowchart showing the traveling operation of the rocker bogie vehicle according to the present embodiment. [Figure 6] FIG. 1 is a diagram showing a state in which a rocker bogie vehicle is running on a level road surface. [Figure 7] This figure shows the state in which the mass body is moved rearward to increase the load on the rear body section when a rocker bogie vehicle climbs a step. [Figure 8] This figure shows the state in which a rocker bogie vehicle is climbing a step, with the front wheels raised and touching the step surface beyond the step. [Figure 9] This figure shows the state in which the mass body is moved forward to increase the load on the front body section when a rocker bogie vehicle climbs a step. [Figure 10] This figure shows the state in which the rear wheels are in contact with the step when the rocker bogie vehicle is climbing the step. [Figure 11] This figure shows the state in which the mass body has been moved to the center in the fore-and-aft direction after the rocker bogie vehicle has climbed a step. [Figure 12] This is a diagram showing the state in which a rocker bogie vehicle is running on a road surface before descending a step. [Figure 13] This figure shows the state in which the mass body is moved rearward when a rocker bogie vehicle descends a step, increasing the load on the rear vehicle body section. [Figure 14] This figure shows the state in which a rocker bogie vehicle descends a step with its front wheels extending forward over the step and lowering. [Figure 15] This figure shows the state in which a rocker bogie vehicle descends a step, with the front wheels lowered and touching the step surface beyond the step. [Figure 16] This figure shows the state in which the middle wheel protrudes forward from the step when the rocker bogie vehicle descends the step. [Figure 17] This figure shows the state in which the middle wheel is lowered onto the step surface beyond the step when the rocker bogie vehicle descends the step. [Figure 18] This figure shows the state in which the rear wheels are in contact with the step surface when the rocker bogie vehicle descends a step. [Figure 19] This figure shows the state in which the mass body has been moved to the center in the fore-and-aft direction after the rocker bogie vehicle has descended a step. [Figure 20] FIG. 11 is a side view showing the configuration of a rocker bogie vehicle according to a second embodiment of the present invention. [Figure 21] FIG. 2 is a block diagram showing the functional configuration of a control unit of the rocker bogie vehicle in this embodiment. [Figure 22] This figure shows the state in which the rocker bogie vehicle is temporarily moved backwards to increase the load on the rear body portion when the rocker bogie vehicle climbs a step. [Diagram 23] FIG. 13 shows the state in which the rocker bogie vehicle is first moved backward and then moved forward in order to increase the load on the rear body section when climbing a step with the rocker bogie vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, with reference to the accompanying drawings, an embodiment for implementing a rocker bogie vehicle according to the present invention will be described based on the drawings. (First embodiment) A side view showing the configuration of a rocker bogie car according to an embodiment of the present invention is shown in Fig. 1. Fig. 2 is a plan view showing the configuration of a car body of a rocker bogie car. The rocker bogie vehicle 1A includes a vehicle body section 2 and a control section 60A (see FIG. 4). The vehicle body 2 mainly includes a main body 2a, a bogie link 20, a rocker link 30, a plurality of wheels 10, a motor 37, and a center-of-gravity shifting mechanism 50. The vehicle body 2 is provided with front wheels 11, center wheels 12, and rear wheels 13 as the plurality of wheels 10.

[0018] The main body 2a is the main body of the rocker bogie car 1A. For example, the control unit 60A described later can be installed in this main body 2a. The main body 2a is formed, for example, in a rectangular shape when viewed from above. The front wheels 11, the middle wheels 12, and the rear wheels 13 are each provided in pairs on the left and right sides of the main body 2a in the vehicle width direction of the rocker bogie car 1A. The main body 2a is provided with a battery unit 40 that supplies power to each part of the rocker bogie car 1A. The battery unit 40 is provided, for example, on the lower side of the main body 2a.

[0019] A pair of bogie links 20 are provided on the left and right sides of the main body 2a. The pair of bogie links 20 includes a right bogie link 20R provided on the right side and a left bogie link 20L provided on the left side. The right bogie link 20R and the left bogie link 20L have a symmetrical configuration. In the following description, except when it is necessary to distinguish between the right bogie link 20R and the left bogie link 20L, each of the right bogie link 20R and the left bogie link 20L will be simply referred to as the bogie link 20. The bogie link 20 supports each of the front wheels 11 and the middle wheels 12 so as to be rotatable around an axis extending in the left-right direction. The bogie link 20 extends in the front-rear direction of the vehicle body 2. The front wheels 11 are rotatably supported at a front end 20f of the bogie link 20. The middle wheels 12 are rotatably supported at a rear end 20r of the bogie link 20. In this manner, the bogie link 20 axially supports each of the front wheels 11 and the middle wheels 12 and connects them together.

[0020] A pair of rocker links 30 are provided on the left and right sides of the vehicle body 2 in the vehicle width direction. The pair of rocker links 30 are provided on the left and right sides of the vehicle body 2. The pair of rocker links 30 includes a right rocker link 30R provided on the right side and a left rocker link 30L provided on the left side. The right rocker link 30R and the left rocker link 30L are configured symmetrically. In the following description, except where it is necessary to distinguish between the right rocker link 30R and the left rocker link 30L, each of the right rocker link 30R and the left rocker link 30L will be simply referred to as the rocker link 30.

[0021] The rocker link 30 extends in the front-rear direction. In this embodiment, the intermediate portion 30c in the front-rear direction of the rocker link 30 is rotatably supported by the main body 2a around the rocker link shaft 31 extending in the left-right direction, but the rocker link 30 may be rigidly joined to the main body 2a so as not to rotate relative to the main body 2a. In this specification, the "intermediate portion" in the front-rear direction of the rocker link 30 refers to the portion "between" the front end and the rear end in the front-rear direction of the rocker link 30, and does not mean the "center" of the rocker link 30. The rocker link 30 extends obliquely downward from the intermediate portion 30c in the front-rear direction. The front end portion 30f of the rocker link 30 is rotatably supported by the intermediate portion 20c in the front-rear direction of the bogie link 20 around the central axis of the rotation shaft 35 extending in the left-right direction. This allows the rocker link 30 to swing about a rotation axis 35 relative to the bogie link 20. The rear wheel 13 is rotatably supported at the rear end 30r of the rocker link 30. In this manner, the rocker link 30 journals and connects an intermediate portion 20c between the front wheel 11 and the center wheel 12 of the bogie link 20 and the rear wheel 13, which will be described later.

[0022] The bogie links 20 (right bogie link 20R, left bogie link 20L) are driven by the motor 37 to rotate relatively around the central axis of the rotation shaft 35 with respect to the rocker link 30 (right rocker link 30R, left rocker link 30L). In other words, the bogie link 20 is dynamically rotatable with respect to the rocker link 30 by the motor 37. The relative angle between the bogie link 20 and the rocker link 30 around the rotation shaft 35 is controllable. In addition, the bogie link 20 and the rocker link 30 are placed in a state in which they can freely rotate around the rotation shaft 35 by turning off the drive by the motor 37. Such a motor 37 can be realized by an actuator that can freely control the rotational driving force, for example, a torque motor or a Harmonic Drive (registered trademark), etc.

[0023] As shown in Fig. 2, a pair of front wheels 11 are provided on the left and right at the front end of the rocker bogie vehicle 1A. The pair of front wheels 11 includes a right front wheel 11R provided on the right side and a left front wheel 11L provided on the left side. The pair of middle wheels 12 are provided on the left and right sides in the middle of the rocker bogie vehicle 1A in the front-rear direction. The pair of middle wheels 12 includes a right middle wheel 12R provided on the right side and a left middle wheel 12L provided on the left side. A pair of rear wheels 13 is provided on the left and right at the rear end of the rocker bogie vehicle 1A. The pair of rear wheels 13 includes a right rear wheel 13R provided on the right side and a left rear wheel 13L provided on the left side.

[0024] Each of the front wheels 11 (right front wheel 11R, left front wheel 11L) and the rear wheels 13 (right rear wheel 13R, right rear wheel 13R) is a Mecanum wheel (registered trademark). Each of the front wheels 11 and the rear wheels 13 has a main wheel and a plurality of free wheels arranged in the circumferential direction, which are provided on the outer periphery of the main wheel, rotatably supported at an inclination of 45 degrees to the axle, and arranged in the circumferential direction. The middle wheels 12 (right middle wheel 12R, left middle wheel 12L) are Omniwheels (registered trademark). The middle wheels 12 have a main wheel and a plurality of barrel-shaped free wheels arranged in the circumferential direction, which are provided on the outer periphery of the main wheel, supported rotatably at 90° to the axle, and aligned in the circumferential direction.

[0025] The main wheel of the right front wheel 11R is driven to rotate by a drive motor 14R. The main wheel of the left front wheel 11L is driven to rotate by a drive motor 14L. The main wheel of the right middle wheel 12R is driven to rotate by a drive motor 15R. The main wheel of the left middle wheel 12L is driven to rotate by a drive motor 15L. The main wheel of the right rear wheel 13R is driven to rotate by a drive motor 16R. The main wheel of the left rear wheel 13L is driven by a drive motor 16L. These drive motors 14R, 14L, 15R, 15L, 16R, and 16L can be controlled independently. That is, the front wheel 11, the middle wheel 12, and the rear wheel 13 can be controlled to drive independently. The vehicle body 2 controls the front wheels 11 (right front wheel 11R, left front wheel 11L), middle wheels 12 (right middle wheel 12R, left middle wheel 12L), and rear wheels 13 (right rear wheel 13R, right rear wheel 13R) to rotate in a forward or backward direction, respectively. This allows the vehicle body 2 to travel forward, backward, sideways, diagonally, or make spin turns.

[0026] The rocker bogie vehicle 1A is equipped with an obstacle detection unit 18 to control the traveling of the vehicle body 2. The obstacle detection unit 18 is provided, for example, in the main body 2a of the vehicle body 2. The obstacle detection unit 18 detects obstacles including steps, inclines, etc. located ahead of the vehicle body 2 in the traveling direction, and measures the distance to the detected obstacles. The obstacle detection unit 18 is, for example, a 3DLiDAR (Light Detection and Ranging or Laser Imaging Detection and Ranging). The obstacle detection unit 18 is not limited to a 3DLiDAR, and may be, for example, a depth sensor that acquires distance information by ToF (Time of Flight), an ultrasonic sensor, an infrared sensor, a radar, or the like. The obstacle detection unit 18 may also have a CCD (Charge Coupled Device) camera and acquire two-dimensional images and depth data using near infrared rays (IR). The obstacle detection unit 18 outputs information on the distance to the detected obstacle to a control unit 60A, which will be described later.

[0027] FIG. 3 is a front view of the rocker bogie vehicle. The center of gravity shifting mechanism 50 is configured to be able to shift the position of the center of gravity of the rocker bogie car 1A in the front-rear direction. When one of the wheels 10, the front wheels 11 and the rear wheels 13, is raised or lowered by the control of the control unit 60A described later, the center of gravity shifting mechanism 50 shifts the position of the center of gravity of the rocker bogie car 1A to the opposite side in the front-rear direction from the one wheel 10 that is raised or lowered. The center of gravity shifting mechanism 50 includes a rail unit 51, a mass body 52, and a drive unit 53.

[0028] The rail portion 51 is provided, for example, on the lower surface of the main body 2a of the vehicle body 2. The rail portion 51 is provided so as to extend in the front-rear direction. The rail portion 51 is, for example, a linear guide. The mass body 52 is provided so as to be movable in the front-rear direction along the rail portion 51. When one of the wheels 10, the front wheels 11 and the rear wheels 13, is raised or lowered, the mass body 52 has a mass that can sufficiently contribute to moving the position of the center of gravity of the rocker bogie vehicle 1A to the opposite side in the front-rear direction from the one wheel 10 that is raised or lowered. In this embodiment, the battery unit 40 is used as the mass body 52. ​​As the mass body 52, something other than the battery unit 40 may be used. Also, in addition to the battery unit 40, the mass body 52 may be provided with a weight (weight) or the like.

[0029] The driving unit 53 moves the mass body 52 along the rail portion 51. In this embodiment, the driving unit 53 has a rack gear 54, a pinion gear 55, and a gear motor 56. The rack gear 54 is provided on the lower surface of the main body 2a in parallel with the rail portion 51. The rack gear 54 is fixed to the main body 2a, for example, by being joined to an L-shaped steel 54a joined to the lower surface of the main body 2a so as to extend in the front-rear direction. The rack gear 54 has a plurality of gear teeth (not shown) arranged in the front-rear direction. The pinion gear 55 is disk-shaped when viewed from the top-bottom direction, and has gear teeth (not shown) on its outer periphery that mesh with the rack gear 54. The gear motor 56 is fixed to the mass body 52. ​​The gear motor 56 drives the pinion gear 55 to rotate around its central axis. In such a drive unit 53, when the pinion gear 55 is rotationally driven by the gear motor 56, the gear teeth of the pinion gear 55 mesh with the gear teeth of the rack gear 54, so that the pinion gear 55, together with the gear motor 56, tries to move in the front-rear direction relative to the rack gear 54. Here, the gear motor 56 is fixed to the mass body 52, and the mass body 52 is provided so as to be movable in the front-rear direction along the rail portion 51, so that when the gear motor 56 tries to move in the front-rear direction, the mass body 52 also moves in the front-rear direction together with the gear motor 56. In this way, the mass body 52 is movable in the front-rear direction along the rail portion 51. In addition, the drive unit 53 may have any other appropriate configuration as long as it is capable of moving the mass body 52 along the rail portion 51. For example, the drive unit 53 may be configured by a ball screw mechanism, a hydraulic cylinder, etc.

[0030] As shown in FIG. 1, the rocker bogie vehicle 1A described above shares the load of its own weight among the front wheels 11, the middle wheels 12, and the rear wheels 13. Here, if the load shared by the front wheels 11 is R1, the load shared by the middle wheels 12 is R2, and the load shared by the rear wheels 13 is R3, then: R1=R2=R3 By so doing, the load of the rocker bogie vehicle 1A is shared in a well-balanced manner by the front wheels 11, the middle wheels 12, and the rear wheels 13. Here, the distance in the fore-and-aft direction (horizontal direction) between the center axis of the front wheel 11 and the rotation axis 35 of the bogie link 20 is L1, the distance in the fore-and-aft direction between the center axis of the middle wheel 12 and the rotation axis 35 of the bogie link 20 is L2, the distance in the fore-and-aft direction between the rotation axis 35 of the bogie link 20 and the center of gravity G of the rocker bogie car 1A is LR, and the distance in the fore-and-aft direction between the center axis of the rear wheel 13 and the center of gravity G of the rocker bogie car 1A is L3.

[0031] In such a case, for example, a case where the center of gravity G is located on the middle wheel 12 in the center in the front-rear direction will be considered. In this case, L1 = L2 = LR … (1) LR×2=L3 …(2) It must be as follows. Here, from the balance of the moment on the rotation axis 35, R1×L1=R2×L2 However, since L1 = L2 according to equation (1), R1 = R2 … (3) Also, from the balance of the moment at the center of gravity G, LR×(R1+R2)=L3×R3 However, according to equation (2), L3 / 2×(R1+R2)=L3×R3 This is transformed into the following equation (4). R3 = (R1 + R2) / 2 … (4) From equations (3) and (4), R1 = R2 = R3. In other words, when the center of gravity G is located on the center wheel 12, the load balance in the front-rear direction is considered to be the best.

[0032] Basically, it is desirable to design the rocker bogie car 1A with good load balance by making the loads R1, R2, and R3 shared by the front wheels 11, middle wheels 12, and rear wheels 13 equal. However, in reality, since it is necessary to attach various structures when constructing the rocker bogie car 1A, the center of gravity G may shift in the front-rear direction. Alternatively, even if a rocker bogie car 1A with good load balance can be constructed, the load balance of the rocker bogie car 1A may be shifted in the front-to-rear direction by loading some kind of item onto the rocker bogie car 1A. For example, in a state where the load balance is shifted forward, as will be described later, when the rocker bogie vehicle 1A is going over a step, for example, when the bogie link 20 is rotated to raise the front wheels 11 and separate them from the road surfaces F1 and F11, the rear wheels 13 may rise instead of the front wheels 11. Also, when the front wheels 11 do not touch the ground and are suspended in the air while going over a step, and the vehicle body 2 is not supported by the front wheels 11, the vehicle body 2 may tilt toward the front wheels 11 suspended in the air and fall over. Similarly, when the load balance is shifted backward, when the rear wheels 13 do not touch the ground and are suspended in the air while going over a step, and the vehicle body 2 is not supported by the rear wheels 13, the vehicle body 2 may tilt toward the rear wheels 13 suspended in the air and fall over. In order to prevent such a situation, in this embodiment, the load balance of the rocker bogie vehicle 1A is changed by the control in the control unit 60A as described below.

[0033] FIG. 4 is a block diagram showing the functional configuration of the control unit of the rocker bogie vehicle in this embodiment. The control unit 60A controls the operation of the rocker bogie vehicle 1A based on a preset program. The control unit 60A functionally includes a travel control unit 61A and a load control unit 62.

[0034] The travel control unit 61A controls the travel operation of the vehicle body 2. The travel control unit 61A controls the drive motors 14R, 14L, 15R, 15L, 16R, and 16L to rotate and drive the front wheels 11, middle wheels 12, and rear wheels 13, and to self-propel the vehicle body 2. When a step is detected ahead in the traveling direction by the obstacle detection unit 18 while traveling, the travel control unit 61A controls the motor 37 to swing and rotate the bogie link 20 relative to the rocker link 30, thereby raising and lowering the wheels 10 and causing the vehicle body 2 to traverse the step.

[0035] The load control unit 62 works in conjunction with the travel control unit 61A, and when the obstacle detection unit 18 detects a step ahead in the travel direction while traveling, the travel control unit 61A controls the motor 37 to rotate the bogie link 20 to raise or lower either one of the wheels 10, the front wheels 11 and the rear wheels 13, thereby varying the load balance of the vehicle body unit 2 in the front-rear direction. When raising or lowering either one of the wheels 10, the front wheels 11 and the rear wheels 13, the load control unit 62 increases the load of the vehicle body unit 2 on the opposite side in the front-rear direction to the wheel 10 being raised or lowered by moving the battery unit 40, which is the mass body 52, in the front-rear direction using the gear motor 56. Specifically, when the front wheel 11, which is one of the wheels 10, is raised or lowered, the load control unit 62 moves the mass body 52 rearward to move the position of the center of gravity G of the entire vehicle body 2, including the mass W2 of the mass body 52, rearward, thereby decreasing the load acting on the front wheel 11 and increasing the load acting on the middle wheel 12 and the rear wheel 13. In addition, when the rear wheel 13, which is one of the wheels 10, is raised or lowered, the load control unit 62 moves the mass body 52 forward to move the position of the center of gravity G of the entire vehicle body 2, including the mass W2 of the mass body 52, forward, thereby decreasing the load acting on the rear wheel 13 and increasing the load acting on the front wheel 11 and the middle wheel 12.

[0036] FIG. 5 is a flowchart showing the traveling operation of the rocker bogie vehicle according to this embodiment. As shown in FIG. 5, when the rocker bogie car 1A starts traveling, the control unit 60A repeatedly executes the following processing until the rocker bogie car 1A arrives at a preset target value. First, the traveling control unit 61A controls the drive motors 14R, 14L, 15R, 15L, 16R, and 16L to cause the body unit 2 to travel along a preset route toward a target position (step S1). The traveling control unit 61A determines, at every preset time interval, whether or not there is a step ahead in the traveling direction of the body unit 2, based on the information detected by the obstacle detection unit 18 (step S2). As a result, if there is no step ahead in the traveling direction (No in step S2), the process returns to step S1 and the traveling along the route is continued. On the other hand, if it is determined in step S2 that there is a step ahead in the direction of travel (Yes in step S2), the traveling control unit 61A controls the motor 37 to swing and rotate the bogie link 20 relative to the rocker link 30, causing the car body unit 2 to traverse the step (step S3).

[0037] The operation of the rocker bogie vehicle 1A when traversing a step, which is realized by the control unit 60A executing the process according to the above-mentioned flowchart, will be described below with a specific example. In the following description, when it is described that the control unit 60A controls, it indicates that either the traveling control unit 61A or the load control unit 62 of the control unit 60A controls according to its role. FIG. 6 is a diagram showing a state in which a rocker bogie vehicle is traveling on a level road surface. As shown in FIG. 6, when the rocker bogie car 1A runs on a flat, level road surface F1, the car body 2 has all of the front wheels 11, middle wheels 12, and rear wheels 13 in contact with the flat road surface F1. In this state, the control unit 60A places the mass body 52 in the center in the front-rear direction. In this state, if the mass of the car body 2 excluding the mass body 52 of the rocker bogie car 1A is W1 and the mass of the mass body 52 is W2, the mass (W1+W2) of the car body 2 excluding the mass body 52 and the mass W2 of the mass body 52 act on the center of gravity G. Therefore, the entire front wheels 11, the entire middle wheels 12, and the entire rear wheels 13 are subjected to the same load of (W1+W2) / 3. From this state, the control unit 60A controls the drive motors 14R, 14L, 15R, 15L, 16R, and 16L to rotate and drive each of the front wheels 11, middle wheels 12, and rear wheels 13, thereby causing the body unit 2 to run along a predetermined route on the road surface F1.

[0038] FIG. 7 is a diagram showing a state in which the mass body is moved rearward to increase the load on the rear body portion when the rocker bogie vehicle climbs a step. First, as shown in Fig. 7, there is a step D1 between the rocker bogie car 1A and a step surface F2 located above the road surface F1 in the forward direction of the rocker bogie car 1A, and a case where the rocker bogie car 1A climbs this step D1 will be described. Here, the step D1 does not have a standing plate (vertical surface) rising upward from the road surface F1, and the front wheel 11 cannot climb from the road surface F1 to the step surface F2 due to the friction force between the front wheel 11 and the standing plate by pressing the front wheel 11 against the standing plate. In such a case, the control unit 60A controls the gear motor 56 to move the mass body 52 rearward, thereby reducing the load on the front part of the vehicle body 2 and increasing the load on the rear part of the vehicle body 2. Specifically, mass body 52 moves rearward, and the load of mass body 52 is almost not supported by front wheel 11, so the share of the load of mass body 52 on front wheel 11 becomes infinitesimally small. As a result, the load supported by the entire front wheel 11 decreases from (W1+W2) / 3 to a value close to W1 / 3. In addition, mass body 52 is mostly supported by middle wheel 12 and rear wheel 13, so the loads supported by the entire middle wheel 12 and the entire rear wheel 13 increase from (W1+W2) / 3 to values ​​close to W1 / 3+W2 / 2, respectively.

[0039] FIG. 8 is a diagram showing a state in which, when a rocker bogie vehicle goes up a step, the front wheels are raised and placed on the surface of the step beyond the step. Next, as shown in FIG. 8, the rocker bogie car 1A first moves the front wheels 11 upwards to climb the step surface F2 with the middle wheels 12 and the rear wheels 13 in contact with the road surface F1. To do this, the motor 37 first rotates the bogie link 20 around the rotation shaft 35 journaled by the rocker link 30 in the front wheel rising direction, which is the direction in which the front wheels 11 rise. As shown in FIG. 8, when the rocker bogie car 1A is provided so that the front side is located on the left side of the paper, the front wheel rising direction is the direction in which the bogie link 20 is rotated clockwise. As a result, the front wheels 11 are raised from the road surface F1 to a position higher than the middle wheels 12 and the rear wheels 13. At this time, since the mass body 52 has moved rearward of the car body 2, the position of the center of gravity of the car body 2 as a whole moves rearward as already described, and the load of the car body 2 in the front portion is reduced, and the load of the car body 2 in the rear portion is increased. Therefore, when attempting to lift the front wheels 11 off the road surface F1 and into the air, the rear wheels 13 are prevented from lifting off the road surface F1 instead of the front wheels 11. Moreover, even if the front wheels 11 are lifted off the road surface F1 and into the air, the vehicle body 2 is prevented from tilting forward and tipping over. Furthermore, because the load on the vehicle body 2 at the front is reduced, the torque of the motor 37 required to rotate the bogie link 20 and lift the front wheels 11 is reduced. In this way, the front wheels 11 can be lifted easily and stably.

[0040] Here, the front wheels 11 are raised to a position higher than the step surface F2. After that, the middle wheels 12 and the rear wheels 13 are driven forward to move the vehicle body 2 forward as it is, and the front wheels 11 are positioned above the step surface F2. Then, the motor 37 rotates the bogie link 20 around the rotation shaft 35 journaled by the rocker link 30 in the front wheel descending direction, which is the direction in which the front wheels 11 descend. As shown in FIG. 8, when the rocker bogie vehicle 1A is provided so that the front side is located on the left side of the drawing, the front wheel descending direction is the direction in which the bogie link 20 is rotated counterclockwise. In this way, the front wheels 11 are grounded on the step surface F2 located beyond the step D1.

[0041] Next, by continuing to rotate the bogie link 20 in the front wheel downward direction by the motor 37, the middle wheel 12 is raised to a position higher than the step surface F2 while the front wheel 11 remains in contact with the step surface F2 and the rear wheel 13 remains in contact with the road surface F1. Thereafter, the front wheels 11 and the rear wheels 13 are driven forward to move the vehicle body 2 forward as it is, and the middle wheels 12 are positioned above the step surface F2 located beyond the step D1. Then, the bogie link 20 is rotated by the motor 37 about the rotation shaft 35 journaled on the rocker link 30 in the direction in which the front wheels are raised, and the middle wheels 12 are lowered and brought into contact with the step surface F2.

[0042] FIG. 9 is a diagram showing a state in which the mass body is moved forward to increase the load on the front part of the vehicle body when the rocker bogie vehicle climbs a step. 9, the control unit 60A controls the gear motor 56 to move the mass body 52 forward. This reduces the load on the rear part of the vehicle body 2 and increases the load on the front part of the vehicle body 2. Specifically, mass body 52 moves forward, and the load of mass body 52 is almost not supported by rear wheel 13, so the share of the load of mass body 52 on rear wheel 13 becomes extremely small. As a result, the load supported by rear wheel 13 as a whole decreases to a value close to W1 / 3. Also, mass body 52 is mostly supported by front wheel 11 and middle wheel 12, so the loads supported by front wheel 11 as a whole and middle wheel 12 as a whole increase to values ​​close to W1 / 3+W2 / 2.

[0043] FIG. 10 is a diagram showing a state in which the rear wheels are in contact with the step when the rocker bogie vehicle is climbing the step. Then, the rocker bogie car 1A moves the rear wheels 13 upward with the front wheels 11 and the middle wheels 12 in contact with the step surface F2, and makes the rear wheels 13 move upward to the step surface F2. To do this, first, the motor 37 rotates the bogie link 20 in the front wheel upward direction around the rotation shaft 35 supported by the rocker link 30. At this time, since the mass body 52 moves forward of the car body 2, the position of the center of gravity of the car body 2 as a whole moves forward as already described, and the load of the car body 2 at the rear is reduced and the load of the car body 2 at the front is increased. Therefore, when the rear wheels 13 are lifted off the road surface F1 and floated in the air, the front wheels 11 are prevented from lifting off the step surface F2 instead of the rear wheels 13. Furthermore, even if the rear wheels 13 are lifted off the road surface F1 and floated in the air, the car body 2 is prevented from tilting backward and falling over. Furthermore, since the load of the vehicle body 2 at the rear is reduced, the torque of the motor 37 required to rotate the bogie link 20 and lift the rear wheels 13 is reduced. In this way, the rear wheels 13 can be lifted easily and stably.

[0044] Here, the rear wheels 13 are raised to a position higher than the step surface F2. Thereafter, the front wheels 11 and the middle wheels 12 are driven forward to move the vehicle body 2 forward as is, and the rear wheels 13 are positioned above the step surface F2. Then, the bogie link 20 is rotated by the motor 37 in the front wheel descending direction to lower the rear wheels 13. In this manner, the rear wheels 13 are brought into contact with the step surface F2.

[0045] FIG. 11 is a diagram showing a state in which the mass body 52 has been moved to the center in the front-rear direction after the rocker bogie vehicle has climbed a step. After climbing the step D1, as shown in Fig. 11, the control unit 60A controls the gear motor 56 to move the mass body 52 to the center in the front-rear direction. As a result, the position of the center of gravity of the rocker bogie car 1A returns to the original state before the rocker bogie car 1A climbs the step D1.

[0046] FIG. 12 is a diagram showing a state in which the rocker bogie vehicle is traveling on a road surface before descending a step. As shown in Fig. 12, when the rocker bogie vehicle 1A is traveling on a road surface F11, the vehicle body 2 has all of the front wheels 11, middle wheels 12, and rear wheels 13 in contact with the road surface F11 without any steps. In this state, the control unit 60A places the mass body 52 in the center in the fore-and-aft direction. In this state, an equal load of (W1+W2) / 3 acts on the entire front wheels 11, the entire middle wheels 12, and the entire rear wheels 13, respectively.

[0047] FIG. 13 is a diagram showing a state in which the mass body 52 is moved rearward to increase the load on the rear part of the vehicle body when the rocker bogie vehicle descends a step. As shown in Fig. 13, there is a step D2 between the rocker bogie car 1A and a step surface F12 located below the road surface F11 in the forward direction of the rocker bogie car 1A, and a case where the rocker bogie car 1A descends this step D2 will be described. Here, the step D2 does not have a vertical plate (vertical surface) extending downward from the road surface F11, and the front wheel 11 cannot be lowered from the road surface F11 to the step surface F12 due to the frictional force between the front wheel 11 and the vertical plate by pressing the front wheel 11 against the vertical plate. In such a case, the control unit 60A controls the gear motor 56 to move the mass body 52 rearward, thereby reducing the load on the front part of the vehicle body 2 and increasing the load on the rear part of the vehicle body 2. Specifically, as in the case of climbing step D1, mass body 52 moves rearward, and the load of mass body 52 is almost not supported by front wheels 11, so the share of the load of mass body 52 on front wheels 11 becomes infinitesimally small. As a result, the load supported by the entire front wheels 11 decreases from (W1+W2) / 3 to a value close to W1 / 3. In addition, mass body 52 is mostly supported by middle wheels 12 and rear wheels 13, so the loads supported by the entire middle wheels 12 and rear wheels 13 increase from (W1+W2) / 3 to values ​​close to W1 / 3+W2 / 2, respectively.

[0048] FIG. 14 is a diagram showing a state in which, when a rocker bogie vehicle descends a step, the front wheels are extended forward from the step and lowered. Next, the rocker bogie car 1A lowers the front wheels 11 from the road surface F11 to the step surface F12 with the middle wheels 12 and the rear wheels 13 in contact with the road surface F11. For this, as shown in FIG. 14, the front wheels 11 are extended forward from the step D2, and in this state, the motor 37 rotates the bogie link 20 in the front wheel lowering direction so that the front wheels 11 are lowered. At this time, since the mass body 52 has moved rearward from the car body 2, the position of the center of gravity of the entire car body 2 has moved rearward as already described, and the load of the car body 2 in the front has decreased and the load of the car body 2 in the rear has increased. Therefore, even if the front wheels 11 are separated from the road surface F11 and suspended in the air, the car body 2 is prevented from tilting forward and falling. In this way, the front wheels 11 can be lowered stably.

[0049] FIG. 15 is a diagram showing a state in which, when a rocker bogie vehicle descends a step, the front wheels are lowered to make contact with the step surface beyond the step. 15, the bogie link 20 is rotated by the motor 37 so that the front wheels 11 are further lowered. As a result, the front wheels 11 contact the step surface F12 that is lower than the middle wheels 12 and the rear wheels 13.

[0050] FIG. 16 is a diagram showing a state in which the middle wheel protrudes forward from the step when the rocker bogie vehicle descends the step. After that, the rocker bogie vehicle 1A is further advanced, and when the middle wheel 12 goes forward from the step D2, the bogie link 20 is rotated by the motor 37 in the front wheel ascending direction so that the middle wheel 12 descends, while lowering the middle wheel 12 to the step surface F12. When the middle wheel 12 contacts the step surface F12, the control unit 60A controls the gear motor 56 to move the mass body 52 forward. Specifically, mass body 52 moves forward, and the load of mass body 52 is almost not supported by rear wheel 13, so the share of the load of mass body 52 on rear wheel 13 becomes extremely small. As a result, the load supported by rear wheel 13 as a whole decreases to a value close to W1 / 3. Also, mass body 52 is mostly supported by front wheel 11 and middle wheel 12, so the loads supported by front wheel 11 as a whole and middle wheel 12 as a whole increase to values ​​close to W1 / 3+W2 / 2.

[0051] FIG. 17 is a diagram showing a state in which, when a rocker bogie vehicle descends a step, the middle wheel is lowered onto the step surface beyond the step. After the middle wheel 12 reaches the step surface F12 and moves the mass body 52 forward, the front wheel 11 and the middle wheel 12 are grounded on the step surface F12, and the rear wheel 13 is in contact with the road surface F11, and the rocker bogie car 1A is moved forward. Then, the rear wheel 13 reaches the step D2. In this case, the bogie link 20 is rotated by the motor 37 in the front wheel descending direction so that the rear wheel 13 descends, and the rear wheel 13 is lowered to the step surface F12. At this time, since the mass body 52 has moved forward of the car body 2, the position of the center of gravity of the car body 2 as a whole moves forward as already described, and the load of the car body 2 at the rear is reduced and the load of the car body 2 at the front is increased. Therefore, even if the rear wheel 13 is separated from the road surface F11 and suspended in the air, the car body 2 is prevented from tilting backward and falling over. In this way, the rear wheel 13 can be stably lowered. FIG. 18 is a diagram showing a state in which the rear wheels are in contact with the surface of a step when the rocker bogie vehicle descends the step. Thereafter, as shown in FIG. 18, the rear wheels 13 reach the step surface F12, and the rocker bogie car 1A traverses the step D2.

[0052] FIG. 19 is a diagram showing a state in which the mass body 52 has been moved to the center in the front-rear direction after the rocker bogie vehicle has descended a step. After descending the step D2, as shown in Fig. 19, the control unit 60A controls the gear motor 56 to move the mass body 52 to the center in the front-rear direction. As a result, the position of the center of gravity of the rocker bogie car 1A returns to the original state before the rocker bogie car 1A descends the step D2.

[0053] The rocker bogie car 1A as described above is a rocker bogie car 1A in which a pair of front wheels 11, middle wheels 12, and rear wheels 13 are provided on the left and right sides, and includes a car body section 2 and a control section 60A that controls the operation of the car body section 2. The car body section 2 includes a bogie link 20 that supports each of the front wheels 11 and middle wheels 12 and connects them, a rocker link 30 that supports an intermediate portion between the front wheels 11 and middle wheels 12 of the bogie link 20 and the rear wheel 13 and connects them, and a rotating shaft 3 on which the rocker link 30 supports the bogie link 20. and a motor 37 which rotates the bogie link 20 relative to the rocker link 30 around 5. When negotiating steps D1, D2, the control unit 60A controls the motor 37 to rotate the bogie link 20 and raise or lower one of the wheels 10, either the front wheel 11 or the rear wheel 13, thereby moving the one wheel 10 away from the road surface F1, F11, and at that time, the load balance of the body unit 2 in the fore-and-aft direction is changed, and the load on the body unit 2 on the opposite side of the one wheel 10 in the fore-and-aft direction is increased. According to this configuration, the rocker bogie vehicle 1A can travel on rough ground by being equipped with a bogie link 20 that supports each of the front wheels 11 and the middle wheels 12 and connects them, and a rocker link 30 that supports the intermediate portion between the front wheels 11 and the middle wheels 12 of the bogie link 20 and the rear wheels 13 and connects them. In particular, when the rocker bogie vehicle 1A travels up a step D1, for example from a road surface F1 on which the vehicle is currently located to a step surface F2 that is higher than the road surface F1, first, while the middle wheels 12 and rear wheels 13 are placed in contact with the road surface F1, the control unit 60A controls the motor 37 that rotates the bogie link 20 relative to the rocker link 30 around the rotation axis 35 on which the rocker link 30 supports the bogie link 20 so that the bogie link 20 rotates in the front wheel upward direction in which the front wheels 11 rise, thereby raising the front wheels 11 higher than the middle wheels 12 and rear wheels 13 and separating the front wheels 11 from the road surface F1, and by moving forward in this state, the front wheels 11 are placed in contact with the step surface F2 above the step D1. Next, while the front wheels 11 and the rear wheels 13 are respectively grounded on the step surface F2 and the road surface F1, the control unit 60A controls the motor 37 so that the bogie link 20 rotates in the front wheel downward direction, which is the opposite direction to the front wheel upward direction, in which the front wheels 11 descend, and the middle wheels 12 are raised and separated from the road surface F1, and in that state, the vehicle moves forward further, so that in addition to the front wheels 11, the middle wheels 12 are also grounded on the step surface F2. Then, while the front wheels 11 and the middle wheels 12 are grounded on the step surface F2, the control unit 60A controls the motor 37 so that the bogie link 20 rotates in the front wheel upward direction, and the rear wheels 13 are raised and separated from the road surface F1, and grounded on the step surface F2. This allows the rocker bogie car 1A to climb the step D1. It is also possible to descend the step D2 in a similar procedure, and in this way the rocker bogie car 1A can traverse the steps D1 and D2 and run. Here, in the above configuration, when the step D1, D2 is traversed, the control unit 60A controls the motor 37 to rotate the bogie link 20 to raise or lower one of the wheels 10, the front wheel 11 and the rear wheel 13, to separate from the road surface F1, F11, to vary the load balance of the vehicle body 2 in the front-rear direction, and increase the load of the vehicle body 2 on the opposite side in the front-rear direction from the one wheel 10 to be raised or lowered. Therefore, when the rocker bogie vehicle 1A climbs the step D1, when the front wheel 11 as one wheel 10 is separated from the road surface F1 and raised to the step surface F2, the control unit 60A can be configured to increase the load of the vehicle body 2 on the opposite side in the front-rear direction from the front wheel 11 to be raised, that is, the rear side. In addition, after the front wheels 11 and the middle wheels 12 climb up to the step surface F2, when the rear wheels 13 as one of the wheels 10 are lifted off the road surface F1 to rise to the step surface F2, the control unit 60A can be configured to increase the load of the vehicle body 2 on the opposite side in the front-to-rear direction from the rear wheels 13 to be raised, i.e., the front side. Similarly, when the rocker bogie vehicle 1A descends the step D2, when the front wheels 11 as one of the wheels 10 are lifted off the road surface F11 to descend to the step surface F12, the control unit 60A can be configured to increase the load of the vehicle body 2 on the opposite side in the front-to-rear direction from the front wheels 11 to be lowered, i.e., the rear side. In addition, when the rear wheel 13 is lowered as one of the wheels 10 onto the step surface F12 after the front wheel 11 and middle wheel 12 have descended from the road surface F11 onto the step surface F12, the control unit 60A can be configured to increase the load on the body section 2 on the opposite side in the fore-and-aft direction to the rear wheel 13 that is being lowered, i.e., in front. In this way, when the load of the car body 2 of the rocker bogie car 1A increases on the opposite side in the front-rear direction from the one wheel 10 to be raised or lowered, the load of the rocker bogie car 1A is mainly supported by the middle wheel 12 and the wheel 10 located on the opposite side in the front-rear direction from the one wheel 10, so that the load acting on the one wheel 10 to be raised or lowered is reduced. Therefore, the torque of the motor 37 for rotating the rocker link 30 can be reduced. Therefore, even if the steps D1 and D2 are not provided with a standing plate and the wheel 10 cannot be raised or lowered by using the friction force between the standing plate and the wheel 10, the steps D1 and D2 can be easily traversed. In addition, when traversing the steps D1 and D2, the load of the body 2 of the rocker bogie car 1A increases on the opposite side in the front-rear direction from the one wheel 10 to be separated from the road surface F1 and F11, so that the wheel 10 located on the opposite side is prevented from separating from the road surface F1 and F11 or the step surface F2 and F12 instead of the one wheel 10 to be separated from the road surface F1 and F11. Furthermore, when the load of the body 2 of the rocker bogie car 1A increases on the opposite side in the front-rear direction from the one wheel 10 to be raised or lowered, the load acting on the one wheel 10 is reduced, so that even if the one wheel 10 rises or falls and separates from the road surface F1 and F11, the rocker bogie car 1A is prevented from tipping over in the front-rear direction toward the one wheel 10. Therefore, the stability of the rocker bogie car 1A is improved when traversing the steps D1 and D2. In this way, it becomes possible to easily and stably traverse the steps D1, D2 that are not provided with standing boards.

[0054] In addition, the rocker bogie vehicle 1A further includes a center of gravity shifting mechanism 50 that shifts the position of the center of gravity in the fore-and-aft direction. When raising or lowering either one of the wheels 10, the front wheels 11 or the rear wheels 13, the control unit 60A controls the center of gravity shifting mechanism 50 to shift the position of the center of gravity to the opposite side of the one wheel 10 in the fore-and-aft direction, thereby increasing the load on the vehicle body section 2 on the opposite side of the one wheel 10 in the fore-and-aft direction. According to this configuration, the rocker bogie car 1A is equipped with a center of gravity shifting mechanism 50 that shifts the position of the center of gravity in the front-rear direction, and when the control unit 60A traverses the steps D1 and D2, when either the front wheel 11 or the rear wheel 13 is raised or lowered to separate from the road surface F1 and F11, the center of gravity shifting mechanism 50 is controlled to move the position of the center of gravity to the opposite side in the front-rear direction from the one wheel 10 that is raised or lowered. Therefore, when the rocker bogie car 1A climbs the step D1, when the front wheel 11 as one wheel 10 is lifted off the road surface F1 and raised to the step surface F2, the control unit 60A controls the center of gravity shifting mechanism 50 to move the position of the center of gravity to the opposite side in the front-rear direction from the front wheel 11 that is to be raised, that is, backward. In addition, after the front wheels 11 and the middle wheels 12 climb up to the step surface F2, when the rear wheels 13 as one of the wheels 10 are lifted off the road surface F1 to rise to the step surface F2, the control unit 60A controls the center of gravity shifting mechanism 50 to move the position of the center of gravity to the opposite side in the front-rear direction from the rear wheels 13 to be raised, that is, forward. Similarly, when the rocker bogie car 1A descends the step D2, when the front wheels 11 as one of the wheels 10 are lifted off the road surface F11 to descend to the step surface F12, the control unit 60A controls the center of gravity shifting mechanism 50 to move the position of the center of gravity to the opposite side in the front-rear direction from the front wheels 11 to be lowered, that is, backward. In addition, when the rear wheel 13 is lowered as one of the wheels 10 onto the step surface F12 after the front wheel 11 and the middle wheel 12 have descended from the road surface F11 onto the step surface F12, the control unit 60A can be configured to control the center of gravity moving mechanism 50 to move the position of the center of gravity to the opposite side in the fore-and-aft direction from the rear wheel 13 that is being lowered, i.e., forward. In this way, when the center of gravity of the rocker bogie car 1A moves to the opposite side in the front-rear direction from the one wheel 10 to be raised or lowered, the load of the rocker bogie car 1A is mainly supported by the middle wheel 12 and the wheel 10 located opposite the one wheel 10 in the front-rear direction, so that the load acting on the one wheel 10 to be raised or lowered is reduced. Therefore, the torque of the motor 37 for rotating the rocker link 30 can be reduced. Therefore, even if the steps D1 and D2 are not provided with a standing plate and the wheel 10 cannot be raised or lowered by using the friction force between the standing plate and the wheel 10, the steps D1 and D2 can be easily traversed. In addition, when traversing the steps D1 and D2, the center of gravity of the rocker bogie car 1A moves to the opposite side in the front-rear direction from the one wheel 10 to be separated from the road surface F1 and F11, so that the wheel 10 located on the opposite side is prevented from being separated from the road surface F1 and F11 or the step surface F2 and F12 instead of the one wheel 10 to be separated from the road surface F1 and F11. Furthermore, when the center of gravity of the rocker bogie car 1A moves to the opposite side in the front-rear direction from the one wheel 10 to be raised or lowered, the load acting on the one wheel 10 is reduced, so that even if the one wheel 10 rises or falls and separates from the road surface F1 and F11, the rocker bogie car 1A is prevented from falling in the front-rear direction toward the one wheel 10. Therefore, the stability of the rocker bogie car 1A when traversing the steps D1 and D2 is improved.

[0055] The center of gravity moving mechanism 50 also includes a rail section 51 extending in the front-to-rear direction, a mass body 52 movable in the front-to-rear direction on the rail section 51, and a drive section 53 that moves the mass body 52 on the rail section 51. The control section 60A controls the drive section 53 to move the mass body 52 in the front-to-rear direction, thereby moving the position of the center of gravity in the front-to-rear direction. According to this configuration, the center-of-gravity shifting mechanism 50 includes a rail portion 51 provided to extend in the front-rear direction, a mass body 52 provided to be movable in the front-rear direction on the rail portion 51, and a drive portion 53 that moves the mass body 52 on the rail portion 51. In this configuration, the control portion 60A controls the drive portion 53 to move the mass body 52 forward, thereby moving the position of the center of gravity forward. The control portion 60A also controls the drive portion 53 to move the mass body 52 rearward, thereby moving the position of the center of gravity rearward. In this manner, the center-of-gravity shifting mechanism 50 that moves the position of the center of gravity in the front-rear direction can be appropriately realized.

[0056] In addition, when climbing an upward step D1, the control unit 60A increases the load of the vehicle body unit 2 at the rear, raises the front wheels 11 to separate them from the road surface F1, moves the middle wheels 12 and the rear wheels 13 forward to bring the front wheels 11 into contact with the step surface F2 above the step D1, rotates the bogie link 20 about the rotation axis 35, and brings the front wheels 11 and the rear wheels 13 into contact with the step surface F2 and the road surface F1 while raising the middle wheels 12 to contact the road surface F2. 1, the front wheels 11 and the rear wheels 13 are moved forward so that the middle wheels 12 contact the step surface F2, the load on the front of the vehicle body section 2 is increased, and then the bogie link 20 is rotated about the rotation axis 35 so that the front wheels 11 and the middle wheels 12 contact the step surface F2 while the rear wheels 13 are raised and moved away from the road surface F1, and the front wheels 11 and the middle wheels 12 are moved forward so that the rear wheels 13 contact the step surface F2. With this configuration, when climbing an upward step D1, the front wheel 11, as one of the wheels 10, is raised and moved away from the road surface F1, and the middle wheel 12 and rear wheel 13 are moved forward to bring the front wheel 11 into contact with the step surface F2 above the step D1, the load on the rear body section 2 is increased, making it easy to raise the front wheel 11. When the bogie link 20 is rotated around the rotating shaft 35, the front wheels 11 and rear wheels 13 are brought into contact with the step surface F2 and the road surface F1 while the middle wheel 12 is raised and moved away from the road surface F1, and the front wheels 11 and rear wheels 13 are moved forward to bring the middle wheel 12 into contact with the step surface F2, the middle wheel 12 can be raised stably because the front wheels 11 and rear wheels 13 are in contact with the step surface F2 and the road surface F1. In addition, by rotating the bogie link 20 around the rotating shaft 35, the front wheels 11 and middle wheels 12 are brought into contact with the step surface F2 while the rear wheels 13, which is one of the wheels 10, are raised and moved away from the road surface F1, and the front wheels 11 and middle wheels 12 are moved forward to bring the rear wheels 13 into contact with the step surface F2, by increasing the load on the front part of the body section 2, the rear wheels 13 can be stably raised and moved away from the road surface F1. In this way, the upward step D1 can be climbed easily and stably.

[0057] In addition, when descending the downward step D2, the control unit 60A controls the vehicle so that: the load on the rear body section 2 is increased, the middle wheels 12 and rear wheels 13 are moved forward while rotating the bogie link 20 around the rotating shaft 35, causing the front wheel 11 to descend and touch the step surface F12 below the step D2; the front wheels 11 and rear wheels 13 are moved forward while rotating the bogie link 20 around the rotating shaft 35, causing the middle wheel 12 to descend and touch the step surface F12; the load on the front body section 2 is increased, the front wheels 11 and middle wheels 12 are moved forward while rotating the bogie link 20 around the rotating shaft 35, causing the rear wheel 13 to descend and touch the step surface F12. According to this configuration, when descending the downward step D2, the middle wheel 12 and the rear wheel 13 are moved forward while the bogie link 20 is rotated around the rotating shaft 35, and the front wheel 11 is lowered as one of the wheels to touch the step surface F12 below the step D2. By increasing the load on the rear body section 2, the front wheel 11 can be prevented from descending suddenly and causing the rocker bogie vehicle 1A to tip forward, and the front wheel 11 can be lowered stably. In addition, by rotating the bogie link 20 about the rotation axis 35 while moving the front wheels 11 and the rear wheels 13 forward, the middle wheels 12 can be stably lowered to the step surface F12 and made to touch the ground. In addition, when the front wheels 11 and middle wheels 12 are moved forward and the bogie link 20 is rotated around the rotating shaft 35 to lower the rear wheel 13 as one of the wheels and bring it into contact with the step surface F12, the load on the front body section 2 is increased, thereby allowing the rear wheel 13 to stably come into contact with the step surface F12 while increasing the load acting on the step surface F12 by the front wheels 11 and middle wheels 12.

[0058] (Modification of the first embodiment) In the above embodiment, when climbing the step D1, the front wheels 11 are first raised to a position higher than the step surface F2, the middle wheels 12 and the rear wheels 13 are driven forward, the vehicle body 2 is moved forward as it is, the front wheels 11 are positioned above the step surface F2, and then the front wheels 11 are lowered to make the front wheels 11 touch the step surface F2. The same is true for the middle wheels 12 and the rear wheels 13, and the rocker bogie car 1A is moved forward with these wheels 10 once raised to a position higher than the step surface F2, and the wheels 10 are positioned above the step surface F2 and then lowered to make the front wheels 11 touch the step surface F2. In this way, rather than raising the wheel 10 to a position above the step surface F2, the wheel 10 may be raised to a height equivalent to the step surface F2, and then the rocker bogie vehicle 1A may be moved forward so that the wheel 10 touches the step surface F2.

[0059] In the above embodiment, when climbing the step D1, the middle wheel 12 is raised and grounded on the step surface F2, the mass body 52 is moved forward, and then the rear wheel 13 is raised and grounded on the step surface F2, but this is not limited to the above. When climbing the step D1, the front wheel 11 may be raised, the mass body 52 may be moved forward, and then the middle wheel 12 and the rear wheel 13 may be raised in sequence and grounded on the step surface F2. Alternatively, in the above embodiment, when descending the step D2, the middle wheel 12 is lowered to touch the step surface F12, the mass body 52 is moved forward, and then the rear wheel 13 is lowered to touch the step surface F2, but this is not limited to the above. When descending the step D2, the front wheel 11 may be lowered, the mass body 52 may be moved forward, and then the middle wheel 12 and the rear wheel 13 may be sequentially lowered to touch the step surface F12.

[0060] Second embodiment In the above first embodiment, a center of gravity shifting mechanism 50 is provided, and by moving the mass body 52 in the fore-and-aft direction, the position of the center of gravity G of the vehicle body section 2 is shifted in the fore-and-aft direction, thereby varying the load balance of the vehicle body section 2 in the fore-and-aft direction. In the second embodiment described below, the center of gravity shifting mechanism 50 is not provided, and the load of the body 2 on the opposite side in the fore-aft direction to the wheel 10 being lifted is increased by the movement of the body 2 in the fore-aft direction. FIG. 20 is a side view showing the configuration of a rocker bogie vehicle according to an embodiment of the present invention. The rocker bogie car 1B includes a body section 2 and a control section 60B (see FIG. 21). The body section 2 of the rocker bogie car 1B according to this embodiment has a similar configuration to the body section 2 of the rocker bogie car 1A in the first embodiment, except that it does not include a center of gravity moving mechanism 50. For this reason, in the following description, the control section 60B, which is different from the first embodiment, will be described, and the description of the common configuration will be omitted. In this case, the battery unit 40 used as the mass body 52 in the first embodiment may be provided on the lower side of the main body 2a, as in the first embodiment, or the battery unit 40 may be provided inside the main body 2a.

[0061] FIG. 21 is a block diagram showing the functional configuration of the control unit of the rocker bogie vehicle in this embodiment. As shown in FIG. 21, the control unit 60B functionally includes a traveling control unit 61B. When the obstacle detection unit 18 detects a step D1 (see FIG. 22) ahead in the traveling direction while traveling, the traveling control unit 61B controls the motor 37 to rotate the bogie link 20, and when one of the wheels 10, the front wheels 11 and the rear wheels 13, is lifted and separated from the road surface F1, the traveling control unit 61B varies the load balance of the vehicle body unit 2 in the front-rear direction. The traveling control unit 61B rotates each of the front wheels 11, the middle wheels 12, and the rear wheels 13 by the drive motors 14R, 14L, 15R, 15L, 16R, and 16L so as to move forward or backward, and then rotates each of the front wheels 11, the middle wheels 12, and the rear wheels 13 in the opposite direction, thereby varying the load balance of the vehicle body unit 2 in the front-rear direction. Specifically, the traveling control unit 61B rotates each of the front wheels 11, the middle wheels 12, and the rear wheels 13 to move forward, and then rotates each of the front wheels 11, the middle wheels 12, and the rear wheels 13 to move backward. Then, due to the inertial force of the rocker bogie car 1B moving forward, the load balance of the car body part 2 in the front-rear direction changes, and the load of the car body part 2 in the front increases. Also, each of the front wheels 11, the middle wheels 12, and the rear wheels 13 is rotated to move backward, and then each of the front wheels 11, the middle wheels 12, and the rear wheels 13 is rotated to move forward. Then, due to the inertial force of the rocker bogie car 1B moving backward, the load balance of the car body part 2 in the front-rear direction changes, and the load of the car body part 2 in the rear increases.

[0062] Fig. 22 is a diagram showing a state in which the rocker bogie car is once moved backward in order to increase the load on the rear body part when climbing a step with the rocker bogie car. Fig. 23 is a diagram showing a state in which the rocker bogie car is once moved backward and then moved forward in order to increase the load on the rear body part when climbing a step with the rocker bogie car. As shown in FIG. 22, when there is a step D1 in front of the rocker bogie car 1B in the traveling direction, the control unit 60B rotates each of the front wheels 11, the middle wheels 12, and the rear wheels 13 so as to move backward. Then, as shown in FIG. 23, each of the front wheels 11, the middle wheels 12, and the rear wheels 13 is suddenly rotated in the forward direction in the opposite direction. As a result, the load balance of the car body 2 in the front-rear direction fluctuates due to the inertial force of the rocker bogie car 1B moving backward, and the load of the car body 2 in the rear increases and the load of the car body 2 in the front decreases. In this state, the motor 37 rotates the bogie link 20 in the front wheel upward direction so that the front wheels 11 rise. As a result, the front wheels 11 are raised from the road surface F1 to a position higher than the middle wheels 12 and the rear wheels 13. Thereafter, the middle wheel 12 and the rear wheel 13 are driven forward to move the vehicle body 2 forward as is, and the front wheel 11 is brought into contact with the step surface F2 located beyond the step D1. Thereafter, the vehicle body 2 is moved forward, and the bogie link 20 is operated to lift the middle wheel 12 in the same manner as in the first embodiment, whereby the middle wheel 12 can be caused to climb up onto the step surface F2.

[0063] After the middle wheel 12 touches the step surface F2, the control unit 60B rotates each of the front wheel 11, the middle wheel 12, and the rear wheel 13 to move forward. Then, the front wheel 11, the middle wheel 12, and the rear wheel 13 are suddenly rotated in the reverse direction, that is, the backward direction. As a result, the load balance of the vehicle body 2 in the front-rear direction fluctuates due to the inertial force of the rocker bogie car 1B moving forward, the load of the vehicle body 2 in the front part increases, and the load of the vehicle body 2 in the rear part decreases. In this state, the motor 37 rotates the bogie link 20 in the front wheel upward direction so that the rear wheel 13 rises. As a result, the rear wheel 13 rises away from the road surface F1. Then, the front wheel 11 and the middle wheel 12 are driven forward to move the vehicle body 2 forward as it is, and the rear wheel 13 touches the step surface F2.

[0064] In the above, it has been described that when the step D1 is ascended, the load of the rear body 2 is increased when the front wheels 11 are lifted off the road surface F1, and the load of the front body 2 is increased when the rear wheels 13 are lifted off the road surface F1. However, for example, when the center of gravity of the rocker bogie vehicle 1B is biased forward in the front-to-rear direction, it is necessary to increase the load of the rear body 2 when the front wheels 11 are lifted off the road surface F1 when ascending the step D1, but it is not necessary to further increase the load of the front body 2 by using inertia force when the rear wheels 13 are lifted off the road surface F1. Alternatively, for example, if the center of gravity of the rocker bogie vehicle 1B is biased rearward in the fore-and-aft direction, when climbing the step D1, it is necessary to increase the load on the front of the vehicle body section 2 when lifting the rear wheels 13 away from the road surface F1, but when lifting the front wheels 11 away from the road surface F1, it is not necessary to use inertia force to further increase the load on the rear of the vehicle body section 2. However, for example, in a case where the center of gravity is located near the center in the fore-and-aft direction, if the load balance is controlled to vary using inertia force in both cases where the front wheels 11 are lifted away from the road surface F1 and where the rear wheels 13 are lifted away from the road surface F1, the rocker bogie vehicle 1B can climb the step D1 more stably.

[0065] When the rocker bogie vehicle 1B descends the step D2 (see FIG. 12, etc.), the front wheels 11 are lowered from the road surface F11 to the step surface F12 with the middle wheels 12 and rear wheels 13 in contact with the road surface F11. Specifically, the bogie link 20 is rotated by the motor 37 so that the front wheels 11 are further lowered. As a result, the front wheels 11 come into contact with the step surface F12, which is lower than the middle wheels 12 and rear wheels 13. After that, the rocker bogie car 1B is further advanced, and when the middle wheel 12 goes forward from the step D2, the bogie link 20 is rotated by the motor 37 in the front wheel upward direction so that the middle wheel 12 descends, and the middle wheel 12 is lowered to the step surface F12. After the middle wheel 12 reaches the step surface F12, the front wheel 11 and the middle wheel 12 are grounded on the step surface F12, and the rear wheel 13 is in contact with the road surface F11, and the rocker bogie car 1B is moved forward. Then, the rear wheel 13 reaches the step D2. In this case, the motor 37 rotates the bogie link 20 in the front wheel descending direction so that the rear wheel 13 descends, while lowering the rear wheel 13 to the step surface F12. After that, the rear wheel 13 reaches the step surface F12, and the rocker bogie car 1B traverses the step D2.

[0066] The rocker bogie car 1B as described above is a rocker bogie car 1B in which the front wheels 11, the middle wheels 12, and the rear wheels 13 are each provided in pairs on the left and right, and is equipped with a car body section 2 and a control section 60B that controls the operation of the car body section 2. The car body section 2 is equipped with a bogie link 20 that supports each of the front wheels 11 and the middle wheels 12 and connects them, a rocker link 30 that supports an intermediate portion between the front wheels 11 and the middle wheels 12 of the bogie link 20 and the rear wheels 13 and connects them, and the rocker link 30 supports the bogie link 20. and a motor 37 which rotates the bogie link 20 relative to the rocker link 30 around a rotation axis 35 which rotates the bogie link 20. When negotiating a step D1, the control unit 60B controls the motor 37 to rotate the bogie link 20 and lift one of the wheels 10, either the front wheel 11 or the rear wheel 13, thereby moving the one wheel 10 away from the road surface F1, thereby varying the load balance of the body unit 2 in the fore-and-aft direction and increasing the load on the body unit 2 on the opposite side of the one wheel 10 in the fore-and-aft direction. According to this configuration, the rocker bogie vehicle 1B can travel on rough ground by being equipped with a bogie link 20 that supports each of the front wheels 11 and the middle wheels 12 and connects them, and a rocker link 30 that supports the intermediate portion between the front wheels 11 and the middle wheels 12 of the bogie link 20 and the rear wheels 13 and connects them. In particular, when traveling up a step D1, for example from the road surface F1 on which the rocker bogie vehicle 1B is currently located to a step surface F2 that is higher than the road surface F1, first, while the middle wheels 12 and rear wheels 13 are placed in contact with the road surface F1, the control unit 60B controls the motor 37 that rotates the bogie link 20 relative to the rocker link 30 around the rotation axis 35 on which the rocker link 30 supports the bogie link 20 so that the bogie link 20 rotates in the front wheel upward direction in which the front wheels 11 rise, thereby raising the front wheels 11 higher than the middle wheels 12 and rear wheels 13 and separating the front wheels 11 from the road surface F1, and by moving forward in that state, the front wheels 11 are placed in contact with the step surface F2 above the step D1. Next, while the front wheels 11 and the rear wheels 13 are respectively grounded on the step surface F2 and the road surface F1, the control unit 60B controls the motor 37 so that the bogie link 20 rotates in the front wheel downward direction, which is the opposite direction to the front wheel upward direction, in which the front wheels 11 descend, and the middle wheels 12 are raised and separated from the road surface F1, and in that state, the vehicle moves forward further, so that in addition to the front wheels 11, the middle wheels 12 are also grounded on the step surface F2. Then, while the front wheels 11 and the middle wheels 12 are grounded on the step surface F2, the control unit 60B controls the motor 37 so that the bogie link 20 rotates in the front wheel upward direction, and the rear wheels 13 are raised and separated from the road surface F1, and grounded on the step surface F2. This allows the rocker bogie car 1B to climb the step D1. It is also possible to descend the step D2 in a similar procedure, and in this way the rocker bogie car 1B can traverse the steps D1 and D2 and run. Here, in the above configuration, when the step D1 is traversed, the control unit 60B controls the motor 37 to rotate the bogie link 20 to raise either the front wheel 11 or the rear wheel 13 to separate from the road surface F1, thereby varying the load balance of the vehicle body 2 in the front-rear direction and increasing the load of the vehicle body 2 on the opposite side in the front-rear direction from the one wheel 10 to be raised. Therefore, when the rocker bogie vehicle 1B climbs the step D1, when the front wheel 11 as one wheel 10 is lifted off the road surface F1 to be lifted to the step surface F2, the control unit 60B can be configured to increase the load of the vehicle body 2 on the opposite side in the front-rear direction from the front wheel 11 to be lifted, that is, the rear side. In addition, when the front wheel 11 and middle wheel 12 climb up to the step surface and then the rear wheel 13, as one of the wheels 10, is lifted away from the road surface F1 and raised up to the step surface F2, the control unit 60B can be configured to increase the load on the body unit 2 on the opposite side in the fore-and-aft direction to the rear wheel 13 that is to be raised, i.e., in front of it. In this way, when the load of the car body 2 of the rocker bogie car 1B increases on the opposite side in the front-rear direction from the one wheel 10 to be raised, the load of the rocker bogie car 1B is mainly supported by the middle wheel 12 and the wheel 10 located on the opposite side in the front-rear direction from the one wheel 10, so the load acting on the one wheel 10 to be raised is reduced. Therefore, the torque of the motor 37 for rotating the rocker link 30 can be reduced. Therefore, even if a standing plate is not provided on the step D1 and the wheel 10 cannot be raised by using the friction force between the standing plate and the wheel 10, the step D1 can be easily traversed. In addition, when traversing the step D1, the load of the body 2 of the rocker bogie car 1B increases on the opposite side in the front-rear direction from the one wheel 10 to be separated from the road surface F1, so that the wheel 10 located on the opposite side is prevented from being separated from the road surface F1 or the step surface F2 instead of the one wheel 10 to be separated from the road surface F1. Furthermore, when the load of the body 2 of the rocker bogie car 1B increases on the opposite side in the front-rear direction from the one wheel 10 to be raised, the load acting on the one wheel 10 is reduced, so that even if the one wheel 10 rises and separates from the road surface F1, the rocker bogie car 1B is prevented from tipping over in the front-rear direction toward the one wheel 10. Therefore, the stability of the rocker bogie car 1B when traversing the step D1 is improved. In this way, it becomes possible to easily and stably traverse the step D1 that is not provided with a standing board.

[0067] In addition, the rocker bogie vehicle 1B further includes drive motors 14R, 14L, 15R, 15L, 16R, and 16L arranged to drive the front wheels 11, middle wheels 12, and rear wheels 13, respectively, and the control unit 60B rotates the front wheels 11, middle wheels 12, and rear wheels 13 forward or backward using the drive motors 14R, 14L, 15R, 15L, 16R, and 16L, and then rotates the front wheels 11, middle wheels 12, and rear wheels 13 in the opposite direction, thereby varying the load balance of the vehicle body section 2 in the fore-and-aft direction. According to this configuration, when the control unit 60B rotates the front wheels 11, middle wheels 12, and rear wheels 13 forward using the drive motors 14R, 14L, 15R, 15L, 16R, and 16L, and then rotates the front wheels 11, middle wheels 12, and rear wheels 13 in the opposite direction, that is, in the backward direction, the load balance of the vehicle body 2 in the front-rear direction fluctuates due to the inertial force of the rocker bogie vehicle 1B moving forward, and the load of the vehicle body 2 in the front and rear direction increases. This makes it possible to achieve a state equivalent to when the center of gravity moves forward. In addition, when the control unit 60B rotates each of the front wheels 11, the middle wheels 12, and the rear wheels 13 to move backwards by the drive motors 14R, 14L, 15R, 15L, 16R, and 16L, and then rotates each of the front wheels 11, the middle wheels 12, and the rear wheels 13 in the opposite direction, i.e., in the forward direction, the load balance of the vehicle body 2 in the front-rear direction fluctuates due to the inertial force of the rocker bogie vehicle 1B moving backwards, and the load of the vehicle body 2 in the rear increases. This makes it possible to achieve a state equivalent to when the center of gravity moves backwards. In this way, it is possible to appropriately realize the same action as the center of gravity moving mechanism 50 of the first embodiment, which moves the position of the center of gravity in the front-rear direction, without structurally moving the position of the center of gravity.

[0068] In addition, when climbing an upward step D1, the control unit 60B increases the load of the vehicle body unit 2 at the rear, raises the front wheels 11 to separate them from the road surface F1, moves the middle wheels 12 and the rear wheels 13 forward to bring the front wheels 11 into contact with the step surface F2 above the step D1, rotates the bogie link 20 around the rotation axis 35, and brings the front wheels 11 and the rear wheels 13 into contact with the step surface F2 and the road surface F1 while raising the middle wheels 12 to contact the road surface F2. 1, the front wheels 11 and the rear wheels 13 are moved forward so that the middle wheels 12 contact the step surface F2, the load on the front of the vehicle body section 2 is increased, and then the bogie link 20 is rotated about the rotation axis 35 so that the front wheels 11 and the middle wheels 12 contact the step surface F2 while the rear wheels 13 are raised and moved away from the road surface F1, and the front wheels 11 and the middle wheels 12 are moved forward so that the rear wheels 13 contact the step surface F2. With this configuration, when climbing an upward step D1, the front wheel 11, as one of the wheels 10, is raised and moved away from the road surface F1, and the middle wheel 12 and rear wheel 13 are moved forward to bring the front wheel 11 into contact with the step surface F2 above the step D1, the load on the rear body section 2 is increased, making it easy to raise the front wheel 11. When the bogie link 20 is rotated around the rotating shaft 35, the front wheels 11 and rear wheels 13 are brought into contact with the step surface F2 and the road surface F1 while the middle wheel 12 is raised and moved away from the road surface F1, and the front wheels 11 and rear wheels 13 are moved forward to bring the middle wheel 12 into contact with the step surface F2, the middle wheel 12 can be raised stably because the front wheels 11 and rear wheels 13 are in contact with the step surface F2 and the road surface F1. In addition, by rotating the bogie link 20 around the rotating shaft 35, the front wheels 11 and middle wheels 12 are brought into contact with the step surface F2 while the rear wheels 13, which is one of the wheels 10, are raised and moved away from the road surface F1, and the front wheels 11 and middle wheels 12 are moved forward to bring the rear wheels 13 into contact with the step surface F2, by increasing the load on the front part of the body section 2, the rear wheels 13 can be stably raised and moved away from the road surface F1. In this way, the upward step D1 can be climbed easily and stably.

[0069] (Modification of the second embodiment) In the above second embodiment, the front wheels 11, the middle wheels 12, and the rear wheels 13 are each rotated to move forward or backward, and then the front wheels 11, the middle wheels 12, and the rear wheels 13 are each rotated in the opposite direction, thereby varying the load balance of the vehicle body 2 in the fore-and-aft direction; however, this is not limited to this. For example, the control unit 60B may vary the load balance of the vehicle body 2 in the fore-and-aft direction by rotating each of the front wheels 11, middle wheels 12, and rear wheels 13 using the drive motors 14R, 14L, 15R, 15L, 16R, and 16L to accelerate and move forward or backward. For example, the control unit 60C of the rocker bogie car 1C in this modified example shown in FIG. 21 rotates each of the front wheels 11, the middle wheels 12, and the rear wheels 13 so as to accelerate and move forward, so that the load balance of the car body 2 becomes rearward, the load of the car body 2 at the rear increases, and the load of the car body 2 at the front decreases. In this state, the front wheels 11 can be easily raised by operating the bogie link 20 so as to lift the front wheels 11. In addition, the control unit 60C of the rocker bogie car 1C in this modified example rotates each of the front wheels 11, the middle wheels 12, and the rear wheels 13 so as to accelerate and move backward, so that the load balance of the car body 2 becomes frontward, the load of the car body 2 at the front increases, and the load of the car body 2 at the rear decreases. In this state, the bogie link is operated so as to lift the rear wheels 13, so that the rear wheels 13 can be easily raised.

[0070] The rocker bogie vehicle 1C as described above further includes drive motors 14R, 14L, 15R, 15L, 16R, and 16L arranged to drive the front wheels 11, middle wheels 12, and rear wheels 13, respectively, and the control unit 60C rotates the front wheels 11, middle wheels 12, and rear wheels 13, respectively, by the drive motors 14R, 14L, 15R, 15L, 16R, and 16L so as to accelerate and move forward or backward, thereby varying the load balance of the vehicle body section 2 in the fore-and-aft direction. According to this configuration, the control unit 60C rotates the front wheels 11, the middle wheels 12, and the rear wheels 13 by the drive motors 14R, 14L, 15R, 15L, 16R, and 16L so that the wheels move forward while accelerating, and the load balance of the body unit 2 in the front-rear direction changes due to the forward acceleration, and the load of the body unit 2 at the rear increases. This makes it possible to achieve a state equivalent to when the center of gravity moves backward. In addition, the control unit 60C rotates the front wheels 11, the middle wheels 12, and the rear wheels 13 by the drive motors 14R, 14L, 15R, 15L, 16R, and 16L so that the wheels move backward while accelerating, and the load balance of the body unit 2 in the front-rear direction changes due to the backward acceleration, and the load of the body unit 2 at the front increases. This makes it possible to achieve a state equivalent to when the center of gravity moves forward. In this way, a function similar to that of the center-of-gravity shifting mechanism 50 of the first embodiment, which shifts the position of the center of gravity in the front-rear direction, can be appropriately achieved without structurally shifting the position of the center of gravity.

[0071] (Other variations) In the above-mentioned embodiments and their modified examples, the steps D1, D2 do not have a standing plate, but this is not limited to the above. Even if the steps D1, D2 have a standing plate, it goes without saying that the steps D1, D2 can be traversed by changing the load balance of the body 2 to separate the wheels 10 from the road surfaces F1, F11, as explained in the above-mentioned embodiments and modified examples. Here, when the above-mentioned embodiments and modifications are applied, even if a standing board is present, each wheel 10 traverses the steps D1 and D2 without contacting the standing board. Alternatively, if a standing board is present, each wheel 10 may traverse the steps D1 and D2 by contacting the standing board and ascending or descending. In this case, for example, when the wheel 10 is raised from the road surface F1, the bogie link 20 is rotated while the wheel 10 is in contact with the vertical plate, and the wheel 10 is rotated in the forward direction, so that the wheel 10 can be raised by both the torque for rotating the bogie link 20 and the frictional force between the wheel 10 and the vertical plate. Therefore, the step D1 can be traversed efficiently.

[0072] Further, the rocker bogie vehicles 1A to 1C according to the present embodiment are premised on autonomous driving, but may be configured to be not only autonomous but also remotely operable. In addition, the configurations described in the above embodiments can be selected or changed as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0073] 1A~1C Rocker bogie car 2 Body 10 wheels 11 Front wheel 12 Middle wheel 13 Rear wheel 14L, 14R, 15L, 15R, 16L, 16R Drive motor 20 Bogie Link 20c middle part 30 Locker Link 35 Rotational Axis 37 Motor 50 Center of gravity movement mechanism 51 Rail section 52 mass body 53 Drive unit 60A~60C Control section D1, D2 steps F1, F11 road surface F2, F12 step surface G center of gravity

Claims

1. A rocker bogie car in which the front wheels, the middle wheels, and the rear wheels are each provided in pairs on the left and right, A vehicle body part, A control unit that controls the operation of the vehicle body unit, The vehicle body portion includes: a bogie link that pivotally supports the front wheels and the center wheels and connects them; a rocker link that pivotally supports an intermediate portion between the front wheel and the center wheel of the bogie link and the rear wheel and connects them; a motor that rotates the bogie link relative to the rocker link about a rotation axis on which the rocker link supports the bogie link; Equipped with When negotiating a step, the control unit controls the motor to rotate the bogie link and raise or lower one of the front and rear wheels, thereby moving the one wheel away from the road surface, and in so doing, changes the load balance of the vehicle body part in the fore-and-aft direction and increases the load on the vehicle body part on the opposite side in the fore-and-aft direction to the one wheel. Rocker bogie vehicle.

2. Further comprising a center of gravity moving mechanism for moving the position of the center of gravity in the front-rear direction, When the one wheel is raised or lowered, the control unit controls the center of gravity moving mechanism to move the position of the center of gravity to the opposite side of the one wheel in the fore-and-aft direction, thereby increasing the load on the vehicle body part on the opposite side of the one wheel in the fore-and-aft direction. The rocker bogie car according to claim 1.

3. The center of gravity shifting mechanism includes: A rail portion provided so as to extend in the front-rear direction; a mass body provided on the rail portion so as to be movable in the front-rear direction; a drive unit that moves the mass body on the rail portion; Equipped with The rocker bogie vehicle according to claim 2, wherein the control unit controls the drive unit to move the mass body in the fore-and-aft direction, thereby moving the position of the center of gravity in the fore-and-aft direction.

4. Further comprising a drive motor configured to drive each of the front wheels, the middle wheels, and the rear wheels; The control unit rotates each of the front wheels, the middle wheels, and the rear wheels to move forward or backward by the drive motor, and then rotates each of the front wheels, the middle wheels, and the rear wheels in the opposite direction, thereby varying the load balance of the vehicle body in the fore-and-aft direction. The rocker bogie car according to claim 1.

5. Further comprising a drive motor configured to drive each of the front wheels, the middle wheels, and the rear wheels; The control unit rotates each of the front wheels, the middle wheels, and the rear wheels to move forward or backward while accelerating by the drive motor, thereby varying the load balance of the vehicle body in the fore-and-aft direction. The rocker bogie vehicle according to claim 1.

6. The control unit, when climbing the step upward, Increasing the load of the vehicle body portion at the rear to lift the front wheels away from the road surface; The middle wheel and the rear wheel are moved forward so that the front wheel contacts a step surface above the step; Rotating the bogie link around the rotation axis to bring the front wheels and the rear wheels into contact with the step surface and the road surface while lifting the middle wheels away from the road surface; The front wheels and the rear wheels are moved forward so that the middle wheels contact the step surface; After increasing the load of the vehicle body portion at the front, the bogie link is rotated about the rotation axis to bring the front wheels and the middle wheels into contact with the step surface while raising the rear wheels to separate them from the road surface; The front and middle wheels are moved forward so that the rear wheels contact the step surface. The rocker bogie vehicle according to any one of claims 1 to 5, wherein the rocker bogie vehicle is controlled as follows.

7. When descending the step downward, the control unit Increasing the load on the vehicle body portion at the rear, While moving the middle wheel and the rear wheel forward, the bogie link is rotated about the rotation axis to lower the front wheel and make it touch the step surface below the step, While moving the front wheels and the rear wheels forward, the bogie link is rotated about the rotation axis to lower the middle wheel and make it contact with the step surface; Increasing the load on the vehicle body portion at the front, While moving the front wheels and the middle wheels forward, the bogie link is rotated about the rotation axis, and the rear wheels are lowered to make contact with the step surface. The rocker bogie vehicle according to any one of claims 1 to 3, wherein the rocker bogie vehicle is controlled as follows.

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