JP7304553B2 - Traveling mobile body, its control method, and its control program - Google Patents

Description

Article 30, Paragraph 2 of the Patent Act applies The 23rd Ota Industrial Fair Dates: January 31 and February 1, 2019 Venue: Ota Ward Industrial Plaza PiO (1-20-20 Minami-Kamata, Ota-ku, Tokyo)

The present invention relates to mobile robots, astronomical exploration robots, wheeled robots, traveling mobile bodies including wheeled mobile bodies, control methods thereof, and control programs thereof.

2. Description of the Related Art For example, Patent Document 1 describes a traveling vehicle for space exploration as a traveling vehicle that travels on rough terrain for the purpose of exploring planets other than the earth. This vehicle for space exploration includes front and rear driving motors for individually driving each wheel, and a differential gear interposed in a power transmission system from each driving motor to each wheel. A large reduction gear provided on the output shaft of the differential gear is engaged with a transmission member to which a mounted object is connected so as to be driven by the large reduction gear. Thereby, the mounted object is held so as to be movable in the longitudinal direction of the vehicle body.

While the space exploration vehicle described in Patent Document 1 is running, the front and rear running motors are rotated in opposite directions to each other, so the large reduction gear of the differential does not rotate. On the other hand, when changing the position of the center of gravity for traveling on rough terrain, the front and rear traveling motors are rotated in the same direction. As a result, since the large reduction gear in the differential gear rotates, the transmission member rotates, the mounted object moves, and the position of the center of gravity changes.

JP-A-8-183499

For example, when traveling over a step, it is conceivable to change the position of the center of gravity while traveling in order to run the vehicle body over the step. However, in the traveling mobile body described in Patent Literature 1, it is not possible to change the position of the center of gravity while driving the wheels. That is, in order to change the position of the center of gravity, it is necessary to change the rotation directions of the front and rear driving motors. Therefore, when changing the position of the center of gravity, the front and rear wheels are locked. Therefore, it is impossible to change the position of the center of gravity while driving the wheels.

Further, the main purpose of the suspension mechanism for a wheel-type traveling mobile body is to improve the grounding property of the wheels and to absorb traveling vibrations. That is, in this traveling mobile body, all the wheels are in contact with the ground so that the driving force can be more reliably transmitted to the ground surface. Therefore, when the vehicle travels on rough terrain, the load acting on each wheel is important. In particular, when overcoming obstacles such as steps and slopes, it is desirable to distribute a large amount of load to the rear wheels when the front wheels go over the steps, and to distribute a large amount of load to the front wheels when the rear wheels subsequently go over the steps. However, in order to distribute the load in this way, a driving section for distributing the load is required in addition to the driving section for driving the wheels.

A traveling mobile body according to an aspect of the present invention includes front wheels and rear wheels, a suspension mechanism that suspends the front wheels and the rear wheels so that a wheel interval between the front wheels and the rear wheels can be increased or decreased, and the wheels A center-of-gravity moving mechanism that moves the center-of-gravity position in conjunction with an increase or decrease in the distance, a front-wheel drive section that drives the front wheels, a rear-wheel drive section that drives the rear wheels, and the front-wheel drive section and the rear-wheel drive section. a controller that controls and differentiates the torque applied to the front wheels by the front wheel drive and the torque applied to the rear wheels by the rear wheel drive so as to increase or decrease the wheel spacing.

Further, a control method for a traveling mobile body according to an aspect of the present invention includes front wheels and rear wheels, and a suspension for suspending the front wheels and the rear wheels so that a wheel interval between the front wheels and the rear wheels can be increased or decreased. a center-of-gravity moving mechanism that moves a center-of-gravity position in conjunction with an increase or decrease in the wheel spacing; a front-wheel drive unit that drives the front wheels; a rear-wheel drive unit that drives the rear wheels; a control unit for controlling a rear wheel drive unit, wherein the control unit controls torque applied to the front wheels by the front wheel drive unit and the rear wheel drive unit so as to increase or decrease the wheel gap; The torque applied to the rear wheels by the wheel drive is different.

A control program for a traveling mobile body according to an aspect of the present invention includes front wheels and rear wheels, and a suspension mechanism that suspends the front wheels and the rear wheels so that a wheel interval between the front wheels and the rear wheels can be increased or decreased. a center-of-gravity moving mechanism for moving a center-of-gravity position in conjunction with an increase or decrease in the wheel spacing; a front-wheel drive unit for driving the front wheels; a rear-wheel drive unit for driving the rear wheels; A control program for a traveling mobile body, comprising: a control unit for controlling a driving unit, wherein the control program instructs the control unit to apply torque to the front wheels by the front wheel driving unit so as to increase or decrease the wheel gap; , the torque applied to the rear wheels by the rear wheel drive.

As a result, when traveling on uneven ground with obstacles such as steps and slopes, the center of gravity position of the traveling mobile body can be changed by controlling the driving force of the wheels of the traveling mobile body. As a result, it is possible to arbitrarily distribute the load to each wheel when traveling on rough terrain. Also, by controlling the driving force of the wheels, the load can be distributed to the front and rear wheels without providing an additional drive unit.

FIG. 2 is a schematic perspective view of a traveling mobile body according to the first embodiment; FIG. 2 is a schematic plan view of a portion of the traveling mobile body; 1 is a schematic block diagram of a traveling mobile body; FIG. 3A and 3B are schematic diagrams for explaining the movement of the position of the center of gravity, where A indicates a backward tilting state, B indicates a normal state, and C indicates a forward tilting state. 1 is a schematic diagram for explaining the climbing process, where A indicates a normal state, B indicates a backward tilted state, C indicates a state in which the front wheels are overridden, D indicates a forward state, E indicates a forward tilted state, F indicates a state in which the rear wheels have run over the vehicle, and G indicates a state in which the traveling vehicle has risen. Flowchart of rising process. 1 is a schematic diagram for explaining a descending process, where A indicates a normal state, B indicates a backward tilting state, C indicates a state in which the front wheels are lowered, D indicates a forward state, E indicates a forward tilting state, F indicates the state in which the rear wheels are lowered, and G indicates the state in which the traveling vehicle is lowered. Flowchart of descending process. Explanatory drawing of the state which hold|grips an obstacle. Explanatory drawing of the normal state of the traveling mobile body which concerns on 2nd Embodiment. FIG. 2 is a schematic plan view of a portion of the traveling mobile body; FIG. 4 is an explanatory diagram of a backward tilting state of a traveling moving body; Explanatory drawing of the forward tilting state of the traveling mobile body.

Exemplary embodiments for carrying out the present invention will now be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of components described in the following embodiments can be arbitrarily set, and can be changed according to the configuration of the apparatus to which the present invention is applied or various conditions. Also, unless otherwise stated, the scope of the invention is not limited to the embodiments specifically described below.

In this specification, up and down respectively correspond to upward and downward directions in the direction of gravity. Further, front and rear correspond to the forward direction (forward direction) in the running direction of the traveling mobile body 100 and the rearward direction (backward direction) opposite to the forward direction.

[First embodiment]
As shown in FIG. 1 , the traveling body 100 includes a substantially rectangular parallelepiped main body 10 and front and rear wheels suspended below the main body 10 . Specifically, the traveling vehicle 100 of FIG. 1 includes a first front wheel 21 and a second front wheel 22 as a pair of front wheels, and a first rear wheel 31 and a second rear wheel 32 as a pair of rear wheels. Note that the traveling mobile body 100 may have front wheels and rear wheels, and may have two, three, or four or more wheels. For example, the traveling vehicle 100 may have one front wheel and two rear wheels.

As will be described later, the traveling mobile body 100 can increase or decrease the wheel gap between the front wheels and the rear wheels according to the difference in driving force (torque) applied to the front wheels and the rear wheels arranged side by side in the traveling direction. is configured to Further, the traveling vehicle 100 includes a center-of-gravity moving mechanism 97 (FIG. 3) that moves the center-of-gravity position in conjunction with the increase or decrease of the wheel interval. For example, the center-of-gravity moving mechanism 97 is mechanically connected to a link mechanism, which will be described later, so as to move the center-of-gravity position in conjunction with changes in the wheel spacing. Alternatively, the center-of-gravity moving mechanism 97 may move the center-of-gravity position via a hydraulic system as a suspension mechanism for suspending the front and rear wheels, or a mechanism including a belt and pulleys.

The main body 10 has a carrier 11 on which articles to be conveyed are mounted. In addition to or instead of the carrier 11, the main body 10 may be provided with devices such as an agricultural robot, an exploration robot, an inspection robot, a robot arm, and a communication robot. The main body 10 also includes a link mechanism as a suspension mechanism for suspending the front and rear wheels so that the wheel interval between the front and rear wheels can be increased or decreased. This link mechanism has a front link connected to the front wheel and a rear link connected to the rear wheel. Specifically, the pair of front links has a first front link 61 and a second front link 62 , and the pair of rear links has a first rear link 63 and a second rear link 64 . The first front wheel 21, the second front wheel 22, the first rear wheel 31 and the second rear wheel 32 are connected by the first front link 61, the second front link 62, the first rear link 63 and the second rear link 64, respectively. suspended.

In addition, the traveling moving body 100 includes a first front wheel driving section 71 and a second front wheel driving section 72 as front wheel driving sections that drive the front wheels, and a first rear wheel driving section 73 and a second front wheel driving section 73 as rear wheel driving sections that drive the rear wheels. 2 rear wheel drive 74 . Specifically, the first front link 61, the second front link 62, the first rear link 63, and the second rear link 64 are provided with a first front wheel drive section 71, a second front wheel drive section 72 (FIG. 2), and a second front wheel drive section 72 (FIG. 2). A first rear wheel drive section 73 and a second rear wheel drive section 74 (FIG. 2) are attached. As an example, the front link and the rear link are attached with forward and reverse motors that function as a front wheel drive and a rear wheel drive.

Specifically, the front wheel drive section and the rear wheel drive section are attached to each link so that the drive shaft (rotating shaft of the motor) extends along the direction in which the links extend. Thereby, the drive shaft does not protrude between the front wheels and between the rear wheels. Therefore, between the front wheels and between the rear wheels, contact between the drive shaft and the obstacle can be suppressed. Each drive is located on the opposite side of the link from the wheel, i.e. on the inside. Therefore, in FIG. 1, the second front wheel drive section 72 and the second rear wheel drive section 74 are not shown. Alternatively, the first front wheel drive section 71 may be attached to the rear side of the first front link 61 and the second front wheel drive section 72 may be attached to the rear side of the second front link 62 . Similarly, the first rear wheel drive section 73 may be attached to the front side of the first rear link 63 and the second rear wheel drive section 74 may be attached to the front side of the second rear link 64 . Thereby, each driving part does not protrude between the front wheels and between the rear wheels. Therefore, between the front wheels and between the rear wheels, it is possible to suppress contact between the drive units and obstacles.

As an example of a rotation transmission mechanism interposed between each drive section and a wheel, a drive section side bevel gear that rotates together with the output shaft is connected to the output shaft of each drive section. The driving section side bevel gear meshes with the wheel side bevel gear. The wheel-side bevel gear is connected to the rotating shaft of the wheel so as to rotate together with the rotating shaft of the wheel. Therefore, when each drive unit rotates forward or backward, torque is applied to the wheels according to the direction of rotation of the drive unit, and the wheels are rotationally driven. Instead of these bevel gears, a mechanism including a belt and pulleys may be used as the rotation transmission mechanism. In addition, when the drive units are attached so as not to protrude between the front wheels and between the rear wheels, a worm gear may be used as the rotation transmission mechanism.

Each drive can arbitrarily drive the corresponding wheel. That is, any torque can be applied to each wheel. For example, when going straight on level ground, the torque applied to each wheel is controlled so that the wheels rotate at the same number of revolutions. Also, when turning to the right, the torque applied to the left wheel is controlled so that the left wheel rotates more than the right wheel. Conversely, when turning left, the torque applied to the right wheel is controlled such that the right wheel rotates more than the left wheel.

FIG. 2 is a plan view showing a state in which part of the traveling mobile body 100, specifically, the cover of the main body 10 and the loading platform 11 are removed. The traveling moving body 100 includes a differential gear 50 as a differential device as part of the center-of-gravity moving mechanism 97 . Both the first link mechanism 13 and the second link mechanism 14, which are a pair of link mechanisms, have the same configuration. Therefore, the first link mechanism 13 will be described below, and the description of the second link mechanism 14 will be omitted.

The first link mechanism 13 suspends the first front wheel 21 and the first rear wheel 31 . The first link mechanism 13 also has a first front link 61 rotatably connected to the shaft 55 and a first rear link 63 fixed to the shaft 55 . That is, the first front link 61 and the first rear link 63 are relatively rotatably connected via the shaft 55 . Also, the first front link 61 and the first rear link 63 are connected by a spring 65 for balancing their own weights. The spring 65 is connected to the first front link 61 and the first rear link 63 and applies tension in the direction in which the first front wheel 21 and the first rear wheel 31 approach each other. The spring 65 may be connected to the first front link 61 and the first rear link 63 via another member.

Alternatively, first front link 61 may be fixed relative to shaft 55 and first rear link 63 may be rotatably coupled to shaft 55 . Alternatively, a shaft member coaxial with the shaft 55 may be further provided to connect the first front link 61 and the first rear link 63 via the shaft member. When the first rear link 63 moves relative to the first front link 61, if the shaft 55 rotates in conjunction with the movement, the first link mechanism 13 may employ another structure. good. For example, the shaft 55 and the rotating shaft of the first link mechanism 13 may be connected via a gear train.

The traveling mobile body 100 also includes a substantially rectangular support frame 15 that supports the loading platform 11 via a plurality of support columns (not shown). Further, the traveling vehicle 100 has, as a part of the center of gravity moving mechanism 97, a shaft 55 connected to the first rear link 63 of the first link mechanism 13 so as to rotate in conjunction with the increase or decrease of the wheel interval. there is The center-of-gravity moving mechanism 97 also has a differential gear 50 connected to the shaft 55 . This shaft 55 is inserted into a bearing provided in the support frame 15 and is rotatable with respect to the support frame 15 . Therefore, even if the shaft 55 rotates, the support frame 15 and the loading platform 11 do not rotate. 1, the shaft 55 is fixed so as to rotate together with the first rear link 63. As shown in FIG. However, the shaft 55 may be rotated by another rotation transmission member (eg gear) that rotates together with the first rear link 63 .

A differential gear 50 functioning as a differential device has a differential case 51 and a pair of ring gears 52 fixed to the outside of the differential case 51 . The differential gear 50 also has a pair of pinion gears 53 pivotally supported by the differential case 51 and a pair of side gears 54 pivotally supported by the differential case 51 . A shaft 55 is connected to each of the pair of side gears 54 . Note that only one pinion gear 53 may be provided.

A first wheel spacing between the first front wheel 21 and the first rear wheel 31 and a second wheel spacing between the second front wheel 22 and the second rear wheel 32 decrease, and the pair of shafts 55 rotate in the same direction. Then, the pinion gear 53 , the differential case 51 and the ring gear 52 integrally rotate about the shaft 55 . As a result, differential case 51 tilts rearward, and the center of gravity of traveling body 100 moves rearward due to its mass.

When the first wheel spacing and the second wheel spacing increase and the pair of shafts 55 rotate in the same direction, the pinion gear 53, the differential case 51 and the ring gear 52 rotate integrally around the shaft 55. As a result, the differential case 51 tilts forward, so that the center of gravity of the traveling vehicle 100 moves forward. Alternatively, the center-of-gravity moving mechanism 97 may further have a rotating member connected to a spur gear meshing with the ring gear 52 . By tilting the rotating member rearward, the center of gravity of the traveling body 100 can be moved rearward or forward due to its mass.

On the other hand, when the pair of shafts 55 rotate in mutually different directions, the pinion gear 53 meshing with the side gear 54 rotates around the axis of the pinion gear 53 . As a result, the differential case 51 and the ring gear 52 do not rotate. Therefore, the inclination of the differential case 51 does not change, and the center of gravity position is maintained.

The traveling vehicle 100 includes a seesaw mechanism 80 connected to the first rear link 63 of the first link mechanism 13 and the second rear link 64 of the second link mechanism 14 . Specifically, one end 81 of the seesaw mechanism 80 is rotatably supported by the first rear link 63 , and the other end 82 of the seesaw mechanism 80 is rotatably supported by the second rear link 64 . there is Further, the seesaw mechanism 80 is rotatable around a rotation shaft located in its center. Thus, the first rear link 63, the second rear link 64, and the seesaw mechanism 80 constitute a link structure.

The seesaw mechanism 80 relatively lowers one of the first rear link 63 and the second rear link 64 when the other rises. That is, the seesaw mechanism 80 maintains the position of the center of gravity so as not to move when the traveling body 100 is tilted in the horizontal direction perpendicular to the traveling direction. For example, when any one of the first front wheel 21, the second front wheel 22, the first rear wheel 31, and the second rear wheel 32 is vertically displaced by the seesaw mechanism 80, the center of gravity position is maintained by the seesaw mechanism 80. be.

That is, when the first rear wheel 31 rides over an obstacle and the first rear link 63 rises, the seesaw mechanism 80 rotates around the center rotation shaft. Then, one end portion 81 of the seesaw mechanism 80 rises and the other end portion 82 descends. Therefore, the second rear link 64 connected to the seesaw mechanism 80 descends relative to the first rear link 63 . As a result, the second rear wheel 32 suspended on the second rear link 64 will not rise. Also, since the first rear link 63 and the second rear link 64 move in opposite directions, the first front link 61 and the second front link 62 also move in opposite directions. As a result, the shaft 55 connected to the first front link 61 and the shaft 55 connected to the second front link 62 rotate in different directions.

Therefore, the side gear 54 rotates the pinion gear 53 , and the pinion gear 53 rotates about the axis of the pinion gear 53 . Accordingly, since the differential case 51 and the ring gear 52 do not rotate, the center of gravity moving mechanism 97 does not move the center of gravity. That is, the movement of the link mechanism by the seesaw mechanism 80 and the movement of the link mechanism by the center-of-gravity moving mechanism 97 are separated so that the center-of-gravity position is maintained when the traveling body 100 is tilted. Similarly, when one of the centrally symmetrically arranged first front wheel 21 and second rear wheel 32 and the second front wheel 22 and first rear wheel 31 runs over the center of gravity, the center of gravity movement mechanism 97 shifts the center of gravity. do not.

Further, when one of the first front link 61 and the second front link 62 rises, such as when riding on an obstacle, the first front link 61 and the second front link 62 are moved by the seesaw mechanism 80 functioning as a differential suspension mechanism. relative to the other. Similarly, when one of the first front link 61 and the second front link 62 descends, such as when descending from an obstacle, the seesaw mechanism 80 raises the other of the first front link 61 and the second front link 62 .

As shown in FIG. 3, the traveling mobile body 100 includes a first distance detector 91 that detects the first wheel distance and a second distance detector 92 that detects the second wheel distance. As an example, the first distance detector 91 and the second distance detector 92 are sensors that detect the distance between the front wheels and the rear wheels. The traveling mobile body 100 also includes a measuring unit 93 that measures the wheel interval. The measurement unit 93 measures the first and second wheel intervals based on the positions of the front wheels and the rear wheels detected by the first interval detection unit 91 and the second interval detection unit 92 .

Furthermore, the traveling mobile body 100 includes a rotation speed detection sensor, a rotation speed detection sensor, an angular velocity sensor, an acceleration sensor, a weight sensor, an obstacle sensor, a wheel speed sensor, a contact detection sensor, an inclination sensor, and a detection unit 94 including a camera and the like. have. As an example, the detection unit 94 detects an image of an obstacle such as a step approaching the moving body 100, the distance to the obstacle, the moving speed of the moving body 100, and the like. The detection unit 94 then transmits the acquired information and image to the control unit 95 . Furthermore, the detection unit 94 may detect contact with an obstacle and transmit a contact detection signal to the control unit 95 . The traveling mobile body 100 also has a power source (not shown) that supplies electric power to each electric component.

The traveling mobile body 100 also includes a control unit 95 as a computer and a storage unit 96 . As an example, the control unit 95 is a processor, and the storage unit 96 is a memory that stores control programs. The processor is, for example, a CPU (Central Processing Unit) or MPU (Micro-Processing Unit), and controls the entire apparatus based on a program stored in a memory, and also controls various processes in an integrated manner. The memory includes RAM (Random Access Memory), which is system work memory for the processor to operate, ROM (Read Only Memory), HDD (Hard Disc Drive), and SSD (Solid State Drive) for storing programs and system software. ) and other storage devices.

Alternatively, the control unit 95 may be a portable recording medium such as a CD (Compact Disc), a DVD (Digital Versatile Disc), a CF (Compact Flash) card, and a USB (Universal Serial Bus) memory, or a server on the Internet. Control can also be performed according to a program stored in an external storage medium. In the following description, it is assumed that the CPU executes processing operations such as various calculations, controls, and determinations according to control programs stored in the ROM or HDD.

The control unit 95 acquires the rotation state of each wheel (the rotation state of the output shaft of the driving unit) from the detection unit 94 . Then, the rotational speed of each wheel (torque applied by each drive unit) is controlled so that the wheels rotate at the required number of revolutions. For example, when traveling straight on leveled ground, the control unit 95 controls each drive unit so that the wheel rotation speeds match. Furthermore, when traveling straight on leveled ground, the control unit 95 controls the torque applied by each driving unit based on the first and second wheel intervals acquired from the measuring unit 93 so that the first and second wheel intervals are constant. A spring 65 exerts tension between the first front link 61 and the first rear link 63 and the second front link 62 and the second rear link 64, respectively. In addition to torque control, the tension of spring 65 keeps the first and second wheel spacing constant.

Furthermore, based on the information acquired from the detection unit 94, the control unit 95 determines whether or not it is possible to climb the steps that are obstacles. Then, when it is determined that it is possible to go up, the control unit 95 performs a climbing process, which will be described later. For example, the control unit 95 refers to the climbable height recorded in the storage unit 96 and compares it with the height of the obstacle calculated from the image. Then, when the obstacle is lower than the climbable height, it is determined that the obstacle can be climbed.

On the other hand, the control unit 95 refers to the climbable height recorded in the storage unit 96 and compares it with the height of the obstacle calculated from the image. Then, when the obstacle is higher than the climbable height, it is determined that the obstacle cannot be climbed. When it is determined that it cannot climb, the control unit 95 controls the first front wheel drive unit 71, the second front wheel drive unit 72, the first rear wheel drive unit 73, and the second rear wheel drive unit to bypass the obstacle. 74. As an example, when making a right turn to avoid an obstacle, the controller 95 sets the rotational speeds of the first front wheel 21 and the first rear wheel 31 to be higher than the rotational speeds of the second front wheel 22 and the second rear wheel 32. also increase. Similarly, the control unit 95 determines whether or not it is possible to go down the step, which is an obstacle, based on the information acquired from the detection unit 94 .

Although one detection unit 94 is illustrated in FIG. 3, a plurality of detection units 94 may be provided. For example, the traveling moving body 100 has a rotation speed detection unit, a rotation speed detection unit, a moving speed detection unit, an acceleration detection unit, a weight detection unit, an obstacle detection unit, etc. as the plurality of detection units 94. good too. These detection units 94 can also be configured as functional units that are logically implemented as various functions in a control unit 95 (processor) that acquires information from detection sensors. This functional unit is realized as various functions by the control unit 95 executing various processes corresponding to the programs recorded in the storage unit 96 .

The control unit 95 acquires the first and second wheel intervals from the measurement unit 93 and determines the center of gravity position of the traveling mobile body 100 . For example, when the distance between the first and second wheels is narrow, the center-of-gravity moving mechanism 97 is tilted backward, so the controller 95 determines that the center-of-gravity position is behind the reference position. Further, when the distance between the first and second wheels is large, the center-of-gravity moving mechanism 97 is tilted forward, so the control unit 95 determines that the center-of-gravity position is ahead of the reference position. Furthermore, when the first and second wheel intervals are initial values, the control unit 95 determines that the center of gravity position is at the reference position.

Further, the control unit 95 controls each driving unit so that the center-of-gravity vertical line (perpendicular line extending from the center of gravity to the ground surface) is not located behind the rotation center line connecting the rotation axes of the rear wheels. Specifically, when determining that the center-of-gravity vertical line is behind the rotation center line, the control unit 95 controls each driving unit so that the first and second wheel intervals are increased. Further, the control unit 95 controls each drive unit so that the vertical line of the center of gravity is not positioned forward of the rotation center line of the front wheels. Specifically, when determining that the position of the center of gravity is ahead of the center line of rotation, the control section 95 controls each driving section so that the first and second wheel intervals are reduced. In other words, the control unit 95 controls each drive unit so that the center of gravity is positioned between the line connecting the rotation axes of the front wheels and the line connecting the rotation axes of the rear wheels.

Also, when both the first front link 61 and the second front link 62 are raised, the control unit 95 controls the first and second wheel gaps to decrease. In this case, since the first front link 61 and the second front link 62 move in the same direction, the differential case 51 and the ring gear 52 rotate. As a result, the center of gravity moves forward. On the other hand, when both the first front link 61 and the second front link 62 descend, the controller 95 controls the first and second wheel gaps to increase. In this case, since the first front link 61 and the second front link 62 move in the same direction, the differential case 51 and the ring gear 52 rotate. As a result, the center of gravity moves rearward.

[Control method]
4A to C, FIGS. 5A to G, FIG. 6, FIGS. 7A to G, and FIG. 8, a control method for the traveling mobile body 100 will be described. In addition, in FIGS. 4A to 4C, the position of the center of rotation of the rear wheel is indicated by a two-dot chain line. Also, the center of gravity vertical line drawn from the center of gravity to the ground surface is indicated by a dotted line. Note that the traveling mobile body 100 has a substantially symmetrical configuration. Therefore, the first link mechanism 13 will be described below, and the description of the second link mechanism 14 will be omitted.

When it is determined that the obstacle can be overcome, the control unit 95 controls each drive unit so that the first and second wheel gaps obtained from the measurement unit 93 reach predetermined target values. That is, the control unit 95 controls the torque applied to the front wheels by the front wheel drive unit (the first front wheel drive unit 71 and the second front wheel drive unit 72) and the torque applied to the front wheels by the rear wheel drive unit (the first rear wheel drive unit) so as to increase or decrease the wheel interval. The torque applied to the rear wheels by the portion 73 and the second rear wheel drive portion 74) is made different. As a result, the first and second wheel intervals are controlled to a predetermined length.

Specifically, increasing the torque applied by the rear wheel drive to the torque applied by the front wheel drive reduces the first and second wheel spacing. That is, since the rotational speeds are different, one of the front wheels and the rear wheels relatively moves toward the other. Then, the first front link 61 and the first rear link 63 rotate about the rotation axis A. As shown in FIG. Also, if the torque applied by the rear wheel drive is less than the torque applied by the front wheel drive, the first and second wheel spacing is increased. That is, one of the front wheels or the rear wheels relatively moves away from the other because of the difference in rotation speed. Then, the first front link 61 and the first rear link 63 rotate about the rotation axis A. As shown in FIG. As a result of the rotation of the first rear link 63 in conjunction with the increase or decrease in the length of the first and second wheel spacings, the position of the center of gravity of the traveling vehicle 100 changes. Note that the torque may be varied so that one of the front wheel drive section and the rear wheel drive section rotates in a different direction from the other, or one of them stops rotating.

As the wheel spacing decreases, as shown in FIG. 4A, the center of gravity position moves rearward relative to the central reference position shown in FIG. 4B. Also, as shown in FIG. 4C, when the length of the wheel interval increases, the center of gravity position moves forward with respect to the reference position. A change in the position of the center of gravity causes a change in load distribution to the wheels. Specifically, when the center of gravity moves rearward, the load applied to the rear wheels increases and the load applied to the front wheels decreases. On the other hand, when the center of gravity moves forward, the load applied to the rear wheels decreases and the load applied to the front wheels increases. The reference position is the position of the center of gravity during normal running shown in FIG. 4B, that is, when running on a level surface that is substantially flat. This reference position may be a position other than the center of the traveling mobile body 100 . The lengths of the first and second wheel gaps can be increased or decreased with reference to the wheel gap when the center of gravity position is at the reference position.

As will be described with reference to FIGS. 5A to 5G, when the front wheels (first front wheels 21) run over an obstacle, the control unit 95 controls the front wheel drive unit so that the position of the center of gravity is located behind the reference position. (first front wheel drive section 71) and rear wheel drive section (first rear wheel drive section 73) respectively control the torque applied to the front wheels and rear wheels. Further, the control unit 95 controls the front wheel drive unit and the rear wheel drive unit so that the center of gravity position is located forward of the reference position when the rear wheel (first rear wheel 31) runs over an obstacle. Each controls the torque applied to the wheels.

Furthermore, the control unit 95 controls the torques applied to the front wheels and the rear wheels by the front wheel drive unit and the rear wheel drive unit so that the center of gravity is located behind the reference position when the front wheels are lowered from the obstacle. . In addition, the control unit 95 controls the torque applied to the front wheels and the rear wheels by the front wheel drive unit and the rear wheel drive unit so that the center of gravity is located forward of the reference position when the rear wheels are lowered from the obstacle. do.

Specifically, when detecting, for example, a step as an obstacle as shown in FIG. 5A, the control unit 95 determines whether or not the step can be climbed (S601 in FIG. 6). Then, when it is determined that it is possible to go up (YES in S601), the control unit 95 reduces the first and second wheel gaps as shown in FIG. ). At this time, the control unit 95 may reduce the first and second wheel gaps in the running state. Furthermore, the control unit 95 may stop the traveling mobile body 100 at the contact timing and reduce the first and second wheel gaps in the stopped state. As an example, the control unit 95 acquires an image of a step relatively approaching the traveling body 100 from the detection unit 94 . Then, the control unit 95 predicts the contact timing with the step based on the distance to the step, the traveling speed of the traveling mobile body 100, and the like. Alternatively, the control unit 95 may determine the timing of receiving the contact detection signal as the contact timing. On the other hand, when determining that it is impossible to climb (NO in S601), the control unit 95 terminates the climbing process and bypasses the step.

Decreasing the first and second wheel spacing moves the center of gravity rearward as shown in FIG. 5B. In this state, the control unit 95 drives each driving unit to advance the traveling mobile body 100, and the front wheels run on the step as shown in FIG. 5C (S603). At this time, the control unit 95 may move the traveling body 100 forward while decreasing the distance between the first and second wheels. When the center of gravity moves rearward, the load applied to the rear wheels increases and the load applied to the front wheels decreases. As a result, a large frictional force (driving force) is generated between the rear wheel with increased load and the ground contact surface, so that the front wheel of the traveling mobile body 100 can be easily run over. Subsequently, the control unit 95 drives each drive unit to move the traveling body 100 forward until the rear wheels come into contact with the side surface of the step as shown in FIG. 5D (S604).

Then, the control unit 95 increases the distance between the first and second wheels at the contact timing when the front wheels contact the side surface of the step (S605). At this time, the control unit 95 may increase the first and second wheel gaps in either the running state or the stopped state. Increasing the first and second wheel spacing moves the center of gravity forward as shown in FIG. 5E. In this state, the control unit 95 drives each driving unit to advance the traveling mobile body 100, and the rear wheels run on the step as shown in FIG. 5F (S606). When the center of gravity moves forward, the load applied to the rear wheels decreases and the load applied to the front wheels increases. As a result, a large frictional force (driving force) is generated between the front wheel with increased load and the ground contact surface, so that the rear wheel of the traveling body 100 can be easily ridden. Additionally, increasing the wheel spacing as shown in FIG. 5E stores energy in a spring 65 (not shown) between the first front link 61 and the first rear link 63 . As a result, tension corresponding to the deflection (elongation) of the spring 65 is applied to the first front wheel 21 and the first rear wheel 31 . Therefore, when the first rear wheel 31 rides on the step, the first rear wheel 31 is pressed against the side surface of the step, and the pressing force (normal force) can be compensated. As a result, it is possible to prevent the first rear wheel 31 from slipping (idling) and losing the propulsive force (the force to ride on the first rear wheel 31). Further, since the reaction force of the pressing force against the first rear wheel 31 is applied to the first front wheel 21, the slip of the first front wheel 21 can be suppressed. Furthermore, even if the first front wheel 21 slips or stops rotating, the propulsive force of the first rear wheel 31 is maintained during the period in which energy is stored in the spring 65, that is, until the deflection of the spring 65 is eliminated. . This advantageously contributes to the running of the first rear wheel 31 over the step. In addition, the controller 95 can apply torques in opposite directions to the first and second front wheel drives 72 and the first and second rear wheel drives 74 so as to provide a gripping function to be described later. Alternatively, the rotational speeds of the front and rear wheels can be different so as to achieve a gripping function. This gripping function creates a force that pulls the sides and top of the step between the front and rear wheels. Therefore, like the pressing force of the spring 65, the pressing force against the first rear wheel 31 can be compensated, and the driving force can be maintained.

After the rear wheels run up the step, the control unit 95 restores the first and second wheel intervals to the normal length as shown in FIG. 5G (S607), ends the climbing process, and starts normal running. do. For example, the control unit 95 acquires the inclination of the traveling moving body 100 from the detection unit 94, and determines that the rear wheels have run up when the inclination reaches a predetermined range. It should be noted that the control unit 95 may control so that only one of the front wheel drive unit and the rear wheel drive unit (for example, the one with the larger load) applies torque when moving forward in the climbing process.

When the traveling mobile body 100 detects the edge of the step as shown in FIG. 7A, the control unit 95 determines whether or not it is possible to get off from the edge of the step (S801 in FIG. 8). For example, the control unit 95 refers to the climbable height recorded in the storage unit 96 and compares it with the height of the step calculated from the image. Then, if the step is lower than the climbable height, it is determined that it is possible to descend. On the other hand, when determining that it is not possible to get off (NO in S801), the control unit 95 terminates the process of getting off and bypasses the edge of the step. If it is determined that it is possible to get off (YES in S801), the control unit 95 reduces the first and second wheel gaps at the timing when the front wheels reach the edge of the step (S802). At this time, the control unit 95 may increase the first and second wheel gaps in either the running state or the stopped state. For example, the control unit 95 can determine the arrival timing based on the image of the end of the step, the distance to the step, the traveling speed of the traveling moving body 100, and the like.

Decreasing the first and second wheel spacing moves the center of gravity rearward as shown in FIG. 7B, thereby reducing the load applied to the front wheels. In this state, the control unit 95 drives each driving unit to move the traveling body 100 forward, and as shown in FIG. 7C, the front wheels are lowered from the step (S803). As a result, the impact when the front wheels land on the ground can be suppressed by reducing the load. Subsequently, the control unit 95 drives each driving unit to move the traveling body 100 forward until the rear wheels reach the end of the step as shown in FIG. 7D (S804). Then, the control unit 95 increases the first and second wheel gaps at the timing when the rear wheels reach the end of the step (S805). At this time, the control unit 95 may reduce the first and second wheel gaps in either the running state or the stopped state. Increasing the distance between the first and second wheels moves the center of gravity forward as shown in FIG. 7E, thus reducing the load on the rear wheels.

In this state, the control unit 95 drives each driving unit to move the traveling body 100 forward, and as shown in FIG. 7F, lowers the rear wheels from the step (S806). As a result, the impact when the rear wheels land on the ground can be suppressed by reducing the load. After the rear wheels get off the step, the control unit 95 restores the first and second wheel gaps to the normal length (S807) as shown in FIG. 7G, ends the descending process, and starts normal running. . For example, the control unit 95 acquires the inclination of the traveling moving body 100 in the traveling direction from the detection unit 94, and determines that the rear wheels have descended from the step when the inclination reaches a predetermined range. Then, the control unit 95 returns the first and second wheel intervals to the normal length. It should be noted that the control unit 95 may perform control so that only one of the front wheel drive unit and the rear wheel drive unit (for example, the one with the larger load) applies torque when moving forward in the descending process.

Furthermore, in the ascending process and descending process, the control unit 95 can control each driving unit so that the center-of-gravity vertical line extending from the center of gravity to the running surface does not extend outside the line connecting the rotation axes of the wheels. Specifically, the control unit 95 controls the vertical line of the center of gravity to be positioned between a line connecting the rotation axes of the first and second front wheels 22 and a line connecting the rotation axes of the first and second rear wheels 32 . to control each drive. For example, when the center-of-gravity vertical line is in front of the line connecting the rotation axes of the first and second front wheels 22, the controller 95 increases the wheel interval to move the center-of-gravity position behind the line. Also, when the center-of-gravity vertical line appears behind the line connecting the rotation axes of the first and second rear wheels 32, the controller 95 reduces the wheel interval to move the center-of-gravity position behind the line.

In this way, the controller 95 causes the torque applied by the front wheel drive section to the front wheels to differ from the torque applied by the rear wheel drive section to the rear wheels so as to increase or decrease the wheel spacing. For this purpose, the traveling mobile body 100 includes a suspension mechanism that suspends the front and rear wheels and a center-of-gravity shift mechanism that moves the center-of-gravity position in conjunction with the increase and decrease of the wheel interval so that the wheel interval between the front and rear wheels can be increased or decreased. A mechanism 97, a front wheel drive section for driving the front wheels, a rear wheel drive section for driving the rear wheels, and a control section 95 for controlling the front wheel drive section and the rear wheel drive section. The control program for the traveling mobile body 100 causes the control unit 95 to execute the ascending process and descending process described above. Specifically, the control program causes the controller 95 to vary the torque applied to the front wheels by the front wheel drive and the torque applied to the rear wheels by the rear wheel drive so as to increase or decrease the wheel spacing. The control program is recorded in the storage unit 96 or a computer-readable internal or external recording medium.

[Gripping function]
A grasping function of the traveling mobile body 100 will be described with reference to FIG. 9 . Note that the traveling mobile body 100 has a substantially symmetrical configuration. Therefore, the first link mechanism 13 will be described below, and the description of the second link mechanism 14 will be omitted. The traveling moving body 100 is provided with a spring 65 in order to travel on rough terrain that is difficult to travel as shown in FIG. This spring 65 is connected to the front and rear links of the link mechanism. Springs 65 also apply tension to the front and rear wheels to pinch an obstacle between the front and rear wheels.

As a result, the springs 65 press the front and rear wheels against a running surface such as uneven ground, and the frictional force between the front and rear wheels and the running surface can be increased. That is, the spring 65 applies tension to the first front link 61 and the first rear link 63 in a direction in which they approach each other. As a result, force is applied to the first front wheel 21 and the first rear wheel 31 in the direction of approaching each other. Therefore, with respect to the running surface on the obstacle, which is a convex portion between the first front wheel 21 and the first rear wheel 31, an arrow is drawn in the direction in which the first front wheel 21 and the first rear wheel 31 grip the obstacle. Forces are generated as indicated by F1 and arrow F2. As a result, the first front wheel 21 and the first rear wheel 31 are pressed against the running surface, thereby increasing the frictional force between the first front wheel 21 and the first rear wheel 31 and the running surface.

Furthermore, the traveling moving body 100 can perform a gripping function by applying torque in opposite directions to the first and second front wheel drive units 72 and the first and second rear wheel drive units 74 by the control unit 95. good. Specifically, the control unit 95 controls to apply forward rotation torque to one of the first front wheel drive unit 71 and the first rear wheel drive unit 73 and to apply reverse rotation torque to the other. As a result, a force indicated by an arrow F2 is applied to the first front wheel 21 and the first rear wheel 31 in the direction of approaching each other. Therefore, the arrow F1 and the arrow F2 move in the direction in which the obstacle is gripped by the first front wheel 21 and the first rear wheel 31 with respect to the running surface above the obstacle between the first front wheel 21 and the first rear wheel 31. A force shown by is generated. In other words, a pulling force acts between the first front wheel 21 and the first rear wheel 31 on the running surface. As a result, the first front wheel 21 and the first rear wheel 31 are pressed against the running surface, thereby increasing the frictional force between the first front wheel 21 and the first rear wheel 31 and the running surface.

In this case, the control unit 95 makes the torque in the forward rotation direction higher than the torque in the reverse rotation direction, so that the traveling body 100 can move forward. Conversely, the control unit 95 makes the torque in the reverse rotation direction higher than the torque in the forward rotation direction, so that the traveling body 100 can move backward. As a result, the traveling vehicle 100 can travel with the first front wheels 21 and the first rear wheels 31 pressed against the travel surface. It should be noted that the convex portion formed by the running surface is not limited to the convex portion having a right angle as shown in FIG. The convex portion formed by the running surface may be a convex portion having an obtuse angle or an acute angle, a curved convex portion, or a convex portion having a plurality of vertices.

According to the traveling vehicle 100 according to the first embodiment described above, the center-of-gravity position of the traveling vehicle 100 can be controlled by increasing or decreasing the wheel interval using the driving force of the wheels. Further, when traveling on uneven ground, particularly when overcoming obstacles such as steps, by controlling the driving force of the wheels of the traveling mobile body 100, the position of the center of gravity can be arbitrarily moved in the longitudinal direction of the traveling mobile body 100. can. This makes it easier for the traveling mobile body 100 to climb over the obstacle. Furthermore, since the center-of-gravity position is changed by controlling the driving force of the wheels, no other drive unit (actuator) is required to change the center-of-gravity position. As a result, it is possible to suppress an increase in size, complexity, and weight of the traveling mobile body 100 .

The position of the center of gravity can be changed at any rate with respect to the increase/decrease of the wheel interval by connecting members such as gears, belts, wires, and links. Further, when the traveling mobile body 100 is tilted in the horizontal direction, for example, when one wheel gets over an obstacle, the differential suspension mechanism functions. That is, the operation can be separated so that the center-of-gravity moving mechanism 97 does not operate when the traveling body 100 is tilted. Furthermore, the first link mechanism 13 and the second link mechanism 14 operate in the same manner as a normal suspension mechanism for wheels when traveling on a level road.

[Second embodiment]
A traveling mobile body 200 according to the second embodiment will be described with reference to FIGS. 10 to 13 . 10 shows the traveling mobile body 200 in the normal state, FIG. 12 shows the traveling mobile body 200 in the backward inclined state, and FIG. 13 shows the traveling mobile body 200 in the forward inclined state. FIG. 11 is a plan view of part of the center-of-gravity moving mechanism 297 as seen from above. 10, 11 and 12, one side surface and bottom surface of the main body 210 are omitted for convenience of explanation.

A traveling body 200 according to the second embodiment includes a center-of-gravity moving mechanism 297 having a structure different from that of the first embodiment. In addition, in the description of the second embodiment, differences from the first embodiment will be described, and the same reference numerals will be given to the components that have already been described, and the description thereof will be omitted. Components with the same reference numerals have substantially the same operations and functions, and have substantially the same effects, unless otherwise specified.

As shown in FIG. 10 , the traveling body 200 includes a substantially rectangular parallelepiped main body 210 and front and rear wheels suspended below the main body 210 . Specifically, the traveling mobile body 200 includes a first front wheel 221 and a second front wheel 222 as front wheels, and a first rear wheel 231 and a second rear wheel 232 as rear wheels. As in the first embodiment, the traveling mobile body 200 changes the wheel gap between the front and rear wheels by the difference in driving force applied to the front and rear wheels arranged side by side in the traveling direction. can be done. Further, the traveling mobile body 200 includes a center-of-gravity moving mechanism 297 that moves the center-of-gravity position by changing the distance between the wheels.

The main body 210 suspends the front wheels and the rear wheels via a link mechanism as a suspension mechanism. This link mechanism has a front link connected to the front wheel and a rear link connected to the rear wheel. Specifically, the link mechanism has a first front link 261 and a second front link 262 as front links, and a first rear link 263 and a second rear link 264 as rear links. The first front wheel 221, the second front wheel 222, the first rear wheel 231, and the second rear wheel 232 are connected to a first front link 261, a second front link 262, a first rear link 263, and a second rear link 264, respectively. suspended by

Each wheel is equipped with a motor (not shown) capable of forward and reverse rotation, which functions as a drive unit for the wheel. Specifically, a first front wheel drive section 71, a second front wheel drive section 72, and a first rear wheel drive section are provided to the first front wheel 221, the second front wheel 222, the first rear wheel 231, and the second rear wheel 232, respectively. 73 and a second rear wheel drive unit 74 (both not shown) are attached. Each driving unit can arbitrarily drive the corresponding wheel. Specifically, increasing the torque applied by the rear wheel drive to the torque applied by the front wheel drive reduces the first and second wheel spacing. Then, the first front link 261 and the first rear link 263 rotate about their rotation axes. Also, if the torque applied by the rear wheel drive is less than the torque applied by the front wheel drive, the first and second wheel spacing is increased. Then, the first front link 261 and the first rear link 263 rotate about their rotation axes.

The traveling moving body 200 of the second embodiment has a center-of-gravity moving mechanism 297 different from that of the first embodiment. As shown in FIG. 11, the center-of-gravity moving mechanism 297 has a link gear 256 that rotates together with the front link as a gear connected to the front link. Note that the link gear 256 may be connected to the front link by another rotation transmission member (for example, a gear) that rotates together with the front link. The center-of-gravity moving mechanism 297 also has a side gear 254 that meshes with the link gear 256 .

Furthermore, the center-of-gravity moving mechanism 297 has a shaft 255 that is connected to the side gear 254 and rotates together with the side gear 254 . In addition, the shaft 255 may be connected to the side gear 254 by another rotation transmission member (for example, a gear) that rotates together with the side gear 254 . The center-of-gravity moving mechanism 297 also has a cylindrical gear 252 that rotates together with the shaft 255 as a gear connected to the shaft 255 . It should be noted that the cylindrical gear 252 may be a gear having another shape such as a disk shape or a ring shape. Also, the cylindrical gear 252 may be connected to the shaft 255 by another rotation transmission member (eg, gear) that rotates together with the shaft 255 .

Returning to FIG. 10 , the center-of-gravity moving mechanism 297 includes a substantially rectangular parallelepiped rotating member 257 fixed to the lower surface of the main body 210 and a gear shaft 258 fixed to the rotating member 257 and meshing with the cylindrical gear 252 . When rotation is transmitted from cylindrical gear 252 to gear shaft 258 , body 210 and rotating member 257 rotate together with gear shaft 258 . 10, the gear shaft 258 is indicated by dotted lines.

When the first wheel spacing and the second wheel spacing decrease, the first front link 261, the second front link 262, and the link gear 256 rotate. Therefore, the side gear 254, the shaft 255 and the cylindrical gear 252 rotate. As a result, the gear shaft 258 rotates, and the rotating member 257 and the main body 210 rotate integrally around the gear shaft 258 . As a result, the rotating member 257 and the main body 210 tilt rearward, so that the center of gravity of the traveling body 200 moves rearward. Conversely, when the first wheel spacing and the second wheel spacing increase, the first front link 261 and the second front link 262 and the link gear 256 rotate. Therefore, the side gear 254, the shaft 255 and the cylindrical gear 252 rotate. As a result, the gear shaft 258 rotates, and the rotating member 257 and the main body 210 rotate integrally around the gear shaft 258 . As a result, the rotating member 257 and the main body 210 are tilted forward, so that the center of gravity of the traveling body 200 is moved forward.

Furthermore, the traveling mobile body 200 includes a seesaw mechanism 280 that is connected to the first rear link 263 and the second rear link 264 . Specifically, one end 281 of the seesaw mechanism 280 is rotatably supported by the first rear link 263 . The other end 282 of the seesaw mechanism 280 is rotatably supported by the second rear link 264 . Furthermore, the seesaw mechanism 280 is configured to be rotatable around a rotation shaft located in the center. Thus, the first rear link 263, the second rear link 264, and the seesaw mechanism 280 constitute a link structure. For example, when the first rear wheel 231 runs over an obstacle and the first rear link 263 rises, the seesaw mechanism 280 rotates around the rotation axis. Therefore, the second rear link 264 connected to the seesaw mechanism 280 descends relative to the first rear link 263 .

Next, movement of the position of the center of gravity will be described with reference to FIGS. 12 and 13. FIG. If it is determined that the obstacle can be overcome, the control unit 95 controls the first and second front wheel drive units 72 and the first and second wheel drive units 72 so that the first and second wheel clearances reach predetermined target values. 2 rear wheel drive unit 74. That is, the control unit 95 makes the torque applied by the first and second front wheel drive units 72 and the torque applied by the first and second rear wheel drive units 74 different. As a result, the first and second wheel intervals are controlled to a predetermined length. Specifically, if the torque applied by the first and second rear wheel drive sections 74 is made greater than the torque applied by the first and second front wheel drive sections 72, the first and second wheel spacing is reduced. Also, if the torque applied by the first and second rear wheel drive units 74 is made smaller than the torque applied by the first and second front wheel drive units 72, the first and second wheel spacing is increased. As a result of the rotation of the front link in conjunction with the increase or decrease in the length of the first and second wheel spacings, the position of the center of gravity of the traveling vehicle 200 changes. It should be noted that the torque may be varied so that the directions of rotation of the drive units are varied, or the rotation of one of the drive units is stopped.

As shown in FIG. 12, when the length of the first and second wheel gaps decreases, the center of gravity position moves rearward with respect to the reference position shown in FIG. Further, when the length increases as shown in FIG. 13, the position of the center of gravity moves forward with respect to the reference position shown in FIG. A change in the position of the center of gravity causes a change in load distribution to the wheels. That is, when the center of gravity moves rearward, the load applied to the rear wheels increases and the load applied to the front wheels decreases. On the other hand, when the center of gravity moves forward, the load applied to the rear wheels decreases and the load applied to the front wheels increases. Note that the lengths of the first and second wheel gaps are increased or decreased with reference to the wheel gap when the center of gravity position is at the reference position.

According to the traveling vehicle 200 according to the second embodiment described above, the center-of-gravity position of the traveling vehicle 200 can be controlled by increasing or decreasing the wheel interval using the driving force of the wheels. Also, when traveling on uneven ground, particularly when overcoming obstacles such as steps, by controlling the driving force of the wheels of the traveling mobile body 200, the position of the center of gravity can be arbitrarily moved in the longitudinal direction of the traveling mobile body 200. can. This makes it easier for the traveling mobile body 200 to climb over the obstacle. Furthermore, since the center-of-gravity position is changed by controlling the driving force of the wheels, no other drive unit (actuator) is required to change the center-of-gravity position. As a result, it is possible to suppress an increase in size, complexity, and weight of the traveling mobile body 200 .

Although the present invention has been described with reference to each embodiment, the present invention is not limited to the above embodiments. Inventions modified within the scope of the present invention and inventions equivalent to the present invention are also included in the present invention. Further, each embodiment and each modification can be appropriately combined within a range not contrary to the present invention.

For example, an internal combustion engine may be used as the drive unit instead of the motor. Moreover, the shafts 55 and 255 of the weighted movement mechanism may be connected to at least one of the front link and the rear link. Further, the center-of-gravity moving mechanisms 97, 297 displace the loading platform 11 or other heavy objects in addition to displacing the differential case 51 or the main body 210 in conjunction with the increase or decrease of the wheel interval, thereby moving the traveling bodies 100, 200. You may move the center-of-gravity position. In addition, the traveling mobile bodies 100 and 200 can climb and descend obstacles of various sizes. As an example, the traveling mobile body 100, 200 can ascend and descend an obstacle that is higher than the wheels or an obstacle that is lower than the wheels.

Moreover, the present invention is applicable to all vehicles and robots that move using wheels. For example, the present invention can be applied to planetary exploration robots that run on rough terrain, unmanned mobile robots that run on urban areas with many steps, electric wheelchairs, agricultural robots, inspection robots, and vehicles for running on rough terrain. As an example, when the present invention is applied to an autonomous mobile body, the mobile body 200 can automatically deliver the product to the destination. Also, the autonomous mobile body may travel together with the purchaser to support the transportation of the product. Furthermore, the autonomous mobile body may transport articles in buildings such as factories, warehouses, and offices.

Some or all of the above-described embodiments can also be described in the following supplementary remarks, but are not limited to the following.

(Appendix 1)
front and rear wheels;
a suspension mechanism that suspends the front wheels and the rear wheels so that the wheel spacing between the front wheels and the rear wheels can be increased or decreased;
a center-of-gravity moving mechanism that moves the center-of-gravity position in conjunction with the increase or decrease of the wheel interval;
a front wheel drive unit that drives the front wheels;
A rear wheel drive unit that drives the rear wheels,
The suspension mechanism has a front link that suspends the front wheel and a rear link that suspends the rear wheel,
The front wheel drive section is arranged such that the drive shaft extends along the direction in which the front link extends,
The traveling mobile body, wherein the rear wheel drive section is arranged such that the drive shaft extends along the direction in which the rear link extends.

13: Suspension mechanism (first link mechanism)
14: Suspension mechanism (second link mechanism)
21: front wheel (first front wheel)
22: Front wheel (second front wheel)
31: Rear wheel (first rear wheel)
32: Rear wheel (second rear wheel)
50: Differential gear 55: Shaft 65: Spring 71: Front wheel drive section (first front wheel drive section)
72: Front wheel drive unit (second front wheel drive unit)
73: Rear wheel drive unit (first rear wheel drive unit)
74: Rear wheel drive unit (second rear wheel drive unit)
80: Seesaw mechanism 93: Measuring unit 95: Control unit 97: Center of gravity moving mechanism 100: Traveling moving body 200: Traveling moving body 221: Front wheel (first front wheel)
222: front wheel (second front wheel)
231: Rear wheel (first rear wheel)
232: Rear wheel (second rear wheel)
252: Cylindrical gear (gear)
254: Side gear 255: Shaft 256: Link gear (gear)
261: Suspension mechanism (first front link)
262: Suspension mechanism (second front link)
263: Suspension mechanism (first rear link)
264: Suspension mechanism (second rear link)
280: seesaw mechanism 297: center-of-gravity movement mechanism

Claims (13)

front and rear wheels;
a suspension mechanism that suspends the front wheels and the rear wheels so that the wheel spacing between the front wheels and the rear wheels can be increased or decreased;
a center-of-gravity moving mechanism that moves the center-of-gravity position forward or backward in conjunction with an increase or decrease in the wheel spacing by displacing a member having mass ;
a front wheel drive unit that drives the front wheels;
a rear wheel drive unit that drives the rear wheels;
controlling the front wheel drive section and the rear wheel drive section, and controlling the torque applied to the front wheels by the front wheel drive section and the torque applied by the rear wheel drive section to the rear wheels so as to increase or decrease the wheel spacing; and a different control unit. The rear wheels include a first rear wheel and a second rear wheel,
2. The traveling vehicle according to claim 1, wherein said suspension mechanism has a first link mechanism that suspends said first rear wheel and a second link mechanism that suspends said second rear wheel. 3. A seesaw mechanism connected to said first link mechanism and said second link mechanism, wherein when one of said first link mechanism and said second link mechanism rises, the other is relatively lowered. The traveling mobile body described in . 4. The center-of-gravity moving mechanism according to claim 1, wherein the center-of-gravity moving mechanism has a shaft connected to the suspension mechanism so as to rotate in conjunction with an increase or decrease in the wheel spacing, and a differential gear connected to the shaft. The traveling mobile body according to any one of the items. The center-of-gravity moving mechanism includes a gear connected to the suspension mechanism so as to rotate in conjunction with an increase or decrease in the distance between the wheels, a side gear meshing with the gear, a shaft connected to the side gear, and a shaft connected to the shaft. 4. The traveling body according to any one of claims 1 to 3, further comprising a gear. 3. The control unit controls the torques applied by the front wheel drive unit and the rear wheel drive unit so that the center of gravity position is positioned rearward of a reference position when the front wheels run over an obstacle. 6. The traveling mobile body according to any one of 1 to 5. wherein the control unit controls torques applied by the front wheel drive unit and the rear wheel drive unit so that the center of gravity position is located forward of a reference position when the rear wheels run over an obstacle. Item 7. The traveling mobile body according to any one of Items 1 to 6. 3. The control unit controls the torques applied by the front wheel drive unit and the rear wheel drive unit so that the center of gravity position is positioned rearward of a reference position when the front wheels are lowered from the obstacle. 8. The traveling mobile body according to any one of 1 to 7. wherein the control unit controls torques applied by the front wheel drive unit and the rear wheel drive unit so that the center of gravity position is positioned forward of a reference position when the rear wheels are lowered from the obstacle. Item 9. The traveling mobile body according to any one of Items 1 to 8. further comprising a spring connected to the suspension mechanism;
10. The traveling body according to any one of claims 1 to 9, wherein said spring applies tension in a direction in which said front wheel and said rear wheel approach each other. Further comprising a measuring unit for measuring the wheel interval,
The traveling mobile body according to any one of claims 1 to 10, wherein the control unit controls the front wheel drive unit and the rear wheel drive unit based on the wheel interval acquired from the measurement unit. A suspension mechanism that suspends the front wheels and the rear wheels so that the wheel gap between the front wheels and the rear wheels can be increased or decreased, and a member having a mass are displaced to reduce the wheel gap. A center-of-gravity moving mechanism that moves the center-of-gravity position forward or backward in conjunction with increase or decrease, a front wheel drive section that drives the front wheels, a rear wheel drive section that drives the rear wheels, the front wheel drive section and the rear wheel drive. A control method for a traveling mobile body, comprising:
The control method, wherein the control unit causes the torque applied to the front wheels by the front wheel drive unit to differ from the torque applied to the rear wheels by the rear wheel drive unit so as to increase or decrease the wheel spacing. A suspension mechanism that suspends the front wheels and the rear wheels so that the wheel gap between the front wheels and the rear wheels can be increased or decreased, and a member having a mass are displaced to reduce the wheel gap. A center-of-gravity moving mechanism that moves the center-of-gravity position forward or backward in conjunction with increase or decrease, a front wheel drive section that drives the front wheels, a rear wheel drive section that drives the rear wheels, the front wheel drive section and the rear wheel drive. A control program for a traveling mobile body comprising a control unit that controls a unit,
The control program causes the control unit to vary the torque applied to the front wheels by the front wheel drive unit and the torque applied to the rear wheels by the rear wheel drive unit so as to increase or decrease the wheel spacing. .

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