Mobile apparatus

Abstract

A mobile apparatus (1) includes a crawler mobile body (11) including a crawler belt (111), a drive wheel (113) to apply driving force to the crawler belt (111), and an upstream road wheel (115a) and a downstream road wheel (115b) below the drive wheel (113) and positioned upstream and downstream from each other in a travel direction of the crawler mobile body (11), and an assist member (20) at an upstream position of the crawler mobile body (11) in the travel direction, to prevent the crawler mobile body (11) from falling. The crawler mobile body (11) travels with rotation of the crawler belt (111) wound around the drive wheel (113), the upstream road wheel (115a), and the downstream road wheel (115b). The center of gravity of the mobile apparatus (1) is downstream in the travel direction from a vertical line extending from a contact point between the end of the assist member (20) and a travel road surface when the mobile apparatus (1) is tilted such that the upstream road wheel (115a) of the mobile apparatus (1) is in contact with an upper level of a step via the crawler belt (111), and an end of the assist member (20) is in contact with the travel road surface. The step is located downstream from the crawler mobile body (11) in the travel direction, and has a predetermined height from the travel road surface.

Description

FN202501185[DESCRIPTION][Title of Invention]MOBILE APPARATUS[Technical Field]

[0001] The present disclosure relates to a mobile apparatus.[Background Art]

[0002] One of mobile robots is a mobile apparatus equipped with a crawler mobile body that travels using a crawler belt wound around wheels.

[0003] Patent Literature (PTL) 1 discloses a mobile apparatus that includes a flipper crawler and shifts the center of gravity of the body to smooth climb over steps even when the pulling force of the crawler is weak.[Citation List][Patent Literature]

[0004] [PTL 1]Japanese Unexamined Patent Application Publication No. 2012-061963[Summary of Invention][Technical Problem]

[0005] However, PTL 1 proposes the use of multiple drivers to shift the center of gravity of the body to smoothly climb over steps, which results in a complicated design. The present disclosure aims to provide a mobile apparatus that is prevented from falling backward with a simple structure when climbing a step.[Solution to Problem]

[0006] The present disclosure described herein provides a mobile apparatus that includes a crawler mobile body including a crawler belt, a drive wheel to apply driving force to the crawler belt, and an upstream road wheel and a downstream road wheel below the drive wheel and positioned upstream and downstream from each other in a travel direction of the crawler mobile body, and an assist member at an upstream position of the crawler mobile body in the travel direction, to prevent the crawler mobile body from falling. The crawler mobile body travels with rotation of the crawler belt wound around the drive wheel, the upstream road wheel, and the downstream road wheel. The center of gravity of the mobile apparatus is downstream in the travel direction from a vertical line extending from a contact point between the end of the assist member and a travel road surface when the mobile apparatus is tilted such that the upstream road wheel of the mobile apparatus is in contact with an upper level of a step via the crawler belt, and an end of the assist member is in contact with the travel roadFN202501185surface. The step is located downstream from the crawler mobile body in the travel direction, and has a predetermined height from the travel road surface.[Advantageous Effects of Invention]

[0007] According to one aspect of the present disclosure, the mobile apparatus is prevented from falling backward with a simple structure when climbing a step.[Brief Description of Drawings]

[0008] A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings.FIG. 1 is an exterior perspective view of a mobile apparatus according to a first embodiment. FIG. 2 is a side view of a crawler mobile body.FIG. 3 is a diagram of assist members.FIG. 4A is a diagram illustrating the relationship between the height of the center of a road wheel of a mobile apparatus and the height of a step.FIG. 4B is a diagram illustrating the relationship between the height of the center of a road wheel of a mobile apparatus and the height of a step.FIGS. 5 A, 5B 1, 5B2, and 5C are diagrams each illustrating a behavior pattern of a mobile apparatus.FIGS. 6A, 6B, and 6C are diagrams each illustrating a behavior of a mobile apparatus climbing a step having climbable height.FIG. 7 is a perspective view of a mobile apparatus according to a second embodiment.FIG. 8 is an enlarged view of a portion around an assist member of the mobile apparatus illustrated in FIG. 7.FIG. 9 is a perspective view of a mobile apparatus according to a modification.FIG. 10 is a side view of a mobile apparatus according to a third embodiment.FIGS. 11A, 1 IB 1, 11B2, and 11C are diagrams each illustrating a behavior pattern of a mobile apparatus.FIG. 12 is a diagram illustrating a position of a bumper.FIGS. 13 A and 13B are side views of a mobile apparatus according to a fourth embodiment. FIGS. 14A and 14B are diagrams each illustrating a behavior pattern of the mobile apparatus illustrated in FIGS. 13 A and 13B.The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views.[Description of Embodiments]

[0009] FN202501185In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.Referring now to the drawings, embodiments of the present disclosure are described below. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0010] First EmbodimentFIG. 1 is an exterior perspective view of a mobile apparatus 1 according to a first embodiment.

[0011] In the present specification, the Y direction matches the lateral width direction of the mobile apparatus 1. The X direction matches the travel direction (advancing direction) of the mobile apparatus 1, and the Z direction matches the height direction of the mobile apparatus 1.

[0012] The mobile apparatus 1 includes crawler mobile bodies 1 la and 1 lb and a main body 10.

[0013] The crawler mobile bodies Ila and 1 lb are units serving as drivers of the mobile apparatus 1. Each of the crawler mobile bodies Ila and 1 lb employs a crawler belt that is a metallic or rubber belt.

[0014] The crawler mobile bodies Ila and 1 lb have a wider contact area with the ground compared to mobile vehicles that travel with tires, such as automobiles, and can travel more stably even in, for example, a bad footing environment.While the mobile vehicle that travels with tires requires space to make a turn, the mobile apparatus 1 equipped with crawler mobile bodies Ila and 1 lb can perform a so-called spin turn (turning around a pivot point between the two crawler mobile bodies) or a so-called pivot turn (pivoting about one of the crawler mobile bodies). Accordingly, the mobile apparatus 1 can smoothly turn even in a limited space. The mobile apparatus 1 is not limited to an apparatus that performs both spin turn and pivot turn but may be an apparatus that performs at least one of spin turn and pivot turn. Spin turn and pivot turn are examples of turning.

[0015] In this disclosure, spin turn refers to turning on the spot with the center of the vehicle body as an axis by rotating the left and right crawler belts in opposite directions at a constant speed. Additionally, pivot turn refers to rotating only one crawler belt with the other crawler belt kept stopped, using the stopped crawler belt as the axis for the turn.

[0016] FN202501185The two crawler mobile bodies 1 la and 1 lb are installed across the main body 10 such that the mobile apparatus 1 can travel. The number of crawler mobile bodies is not limited to two and may be three or more. For example, the mobile apparatus 1 may include three crawler mobile bodies arranged in parallel such that the mobile apparatus 1 can travel. Alternatively, the mobile apparatus 1 may include four crawler mobile bodies arranged on the front, rear, right, and left sides like the tires of an automobile.

[0017] The crawler mobile bodies Ila and 1 lb each have a substantially triangular shape. The crawler mobile bodies Ila and 11b may be collectively referred to as the crawler mobile bodies 11” in the following description. The substantially triangular crawler mobile bodies 11 are advantageous in that, when a constraint is imposed on the length of the traveling body in the front-rear direction, the contact area of the crawler mobile body with the ground is maximized within the constraint. Such a configuration can increase the stability in traveling as described above. In the case of a so-called tank crawler in which the upper side (drive wheel side) is longer than the lower side (road wheel side), when a constraint is imposed on the front-rear direction length, the contact area with the ground is typically small, making traveling unstable. As described above, the crawler mobile bodies 11 are effective in increasing traveling performance, especially when applied to the mobile apparatus 1 that is relatively small.

[0018] The main body 10 supports the crawler mobile bodies 1 la and 1 lb to travel and includes a controller to control the driving of the mobile apparatus 1. The main body 10 also includes a battery to supply electric power for driving the crawler mobile bodies Ila and 1 lb.

[0019] The main body 10 of the mobile apparatus 1 includes a power button 12, a start button 13, an emergency stop button 14, a state indicator lamp 15, and two assist members 20.

[0020] The power button 12 is an operation device to be pressed by a person near the mobile apparatus 1 to turn on or off the power of the mobile apparatus 1. The start button 13 is an operation device to be pressed by a person near the mobile apparatus 1 to start the two crawler mobile bodies 1 la and 1 lb. The emergency stop button 14 is an operation device to be pressed by a person near the mobile apparatus 1 to stop the mobile apparatus 1 being traveling.

[0021] The state indicator lamp 15 is a notification means for indicating the state of the mobile apparatus 1. When the state of the mobile apparatus 1 changes, for example, due to a decrease in the remaining battery charge, the state indicator lamp 15 lights up to notify persons nearby of the state change of the mobile apparatus 1. The state indicator lamp 15 lights up also when a possible abnormality, such as an obstacle to the travel of the mobile apparatus 1, is detected.FN202501185

[0022] The mobile apparatus 1 may include one state indicator lamp 15, or two or more state indicator lamps 15. In alternative to or in addition to the state indicator lamp 15, the notification means may include, for example, a speaker to output an alert sound indicating the state of the mobile apparatus 1.

[0023] The two assist member 20 are disposed at the upstream position of the main body 10 of the mobile apparatus 1 in the travel direction (X direction), as illustrated in FIG. 3. Although the two assist members 20 are disposed at the upstream position of the main body 10 of the mobile apparatus 1 in the travel direction (X direction), the number of the assist members 20 is not limited to this but may be one or three or more. The details of the assist members 20 are described later.

[0024] The mobile apparatus 1 includes a range sensor 152 for horizontal detection, which is disposed at a height of 0.5 meter. The range sensor 152 is oriented in the travel direction of the main body 10. The range sensor 152 for horizontal detection performs detection with laser light and two-dimensional range finding. The range sensor 152 is, for example, a laser range finder (LRF) or a two-dimensional (2D) light detection and ranging (LiDAR).Examples of 2D LiDAR sensors include micro-electro-mechanical systems (MEMS)-based sensors and rotating-mirror sensors.

[0025] The range sensor 152 irradiates an object with laser light, measures the time for the laser light to be reflected back from the object, and calculates the distance to the object and the direction of the object based on the measured time. The range sensor 152 has the capability of measuring a 270-degree range with the front X direction as the center.The mobile apparatus 1 measures the distance to an object in a wide horizontal range using the range sensor 152 and uses the distance as obstacle information.

[0026] The mobile apparatus 1 further includes a range sensor 153 for oblique direction detection. The range sensor 153 is disposed at a height of 0.9 meter and a depression angle of 30 degrees, and is oriented in the travel direction of the main body 10. This installation position is determined to enable the detection of the road surface up to the front of the mobile apparatus 1. The road surface on which the mobile apparatus 1 travels may be referred to as the “travel road surface” in the following description. The range sensor 153 for oblique direction detection is, for example, an LRF or a three-dimensional (3D) LiDAR that perform three-dimensional range finding. Examples of 3D LiDAR sensors include MEMS -based sensors and rotating-mirror sensors.

[0027] As the 3D LiDAR, a non-repetitive scanning sensor that measures a conical range of 70.4 degrees as viewed from the center of the sensor detection surface and measures the distanceFN202501185up to 90 meters is used. The non-repetitive scanning method is scanning in a flower-like pattern while shifting the phase little by little in the horizontal and vertical directions, and is characterized in that the point cloud coverage in the measurement range is increased by the accumulation of time. The range sensor 153 is installed at an angle inclined down from the horizontal surface so as to be inclined down by a predetermined angle relative to a horizontal road surface.

[0028] The range sensor 153 irradiates an object, such as an obstacle on the road surface, with laser light, measures the distance to the object and the direction of the object based on the time for the laser light to be reflected from the object, and obtains the result of measurement as data. For the installation position of the range sensor 153, the appropriate value depends on the widths and lengths of the crawler belts of the crawler mobile bodies Ila and 1 lb, and the sizes, widths, depths, and heights of objects to be detected.

[0029] The mobile apparatus 1 further includes multiple cameras 151 oriented in the travel direction of the main body 10.

[0030] The crawler mobile bodies 11 (Ila, 1 lb) are described below.

[0031] FIG. 2 is a side view of the crawler mobile body 11. As illustrated in FIG. 1, the mobile apparatus 1 includes two crawler mobile bodies Ila and 1 lb. The mobile bodies Ila and 1 lb have the identical structure, and their structures are described as the structure of the crawler mobile body 11 in the following description.

[0032] As illustrated in FIG. 2, the crawler mobile body 11 includes a crawler belt 111, a drive wheel 113, an in-wheel motor 114, road wheels 115a and 115b, an auxiliary mechanism 118, a side plate 120, and a tensioner 125. The auxiliary mechanism 118 includes idlers 118a and 118b, and a link 119. The crawler mobile body 11 further includes another side plate (inner side plate) positioned inside the side plate 120, and a support that supports the side plate 120 and the inner side plate. The inner side plate sandwiches the drive wheel 113 and related components together with the side plate 120.

[0033] The crawler belt 111 is also called a crawler, and is made of metal or rubber. The crawler belt 111 is wound around the drive wheel 113 and the road wheels 115a and 115b. The crawler belt 111 drives the road wheels 115a and 115b while moving in the rotation direction of the drive wheel 113, thereby rotating the crawler mobile body 11. The crawler belt 111 has multiple projections Illa and 11 lb on its faces. The projections 11 la on the outer face of the crawler belt 111 allow the crawler mobile body 11 to ride over a small obstacle, such as a stone on the road surface, to stably travel. The projections 11 lb on the inner face prevent theFN202501185crawler belt 111 from coming off, for example, the drive wheel 113 or the road wheels 115a and 115b.

[0034] The drive wheel 113 transmits driving force to the crawler belt 111 to roll the crawler mobile body 11. In the crawler mobile body 11, the driving force (rotational force) transmitted to the drive wheel 113 by the in- wheel motor 114 is transmitted to the road wheels 115a and 115b through the crawler belt 111.

[0035] The in-wheel motor 114 is built in the drive wheel 113 and transmits the rotational force to the drive wheel 113. The in- wheel motor 114 rotates about a motor shaft 114a that is the rotary shaft (drive shaft). The rotary shaft (the motor shaft 114a) of the in- wheel motor 114 serves as the rotary shaft (the drive shaft) of the drive wheel 113, and the drive wheel 113 is rotated by the rotational force of the in- wheel motor 114. The rotational force of the in-wheel motor 114 is transmitted to the crawler belt 111 as the driving force. Specifically, the inwheel motor 114 gives the drive wheel 113 positive rotational force to move the mobile apparatus 1 forward or negative rotational force to move the mobile apparatus 1 backward.

[0036] Building the in- wheel motor 114 in the drive wheel 113 simplifies the structure of the crawler mobile body 10. When power transmission components such as a drive chain and gears are not used, risks such as a failure caused by such components can decrease. In addition, since the in- wheel motor 114 built in the drive wheel 113 generates the driving force near the outer periphery of the crawler mobile body 11, the in- wheel motor 114 generates a large torque.

[0037] The road wheels 115a and 115b are attached to the crawler mobile body 11 to rotate. The road wheels 115a and 115b are rotated about road-wheel rotary shafts 116a and 116b, as rotation axes, by the driving force (rotational force) transmitted from the drive wheel 113 via the crawler belt 111, respectively.

[0038] The drive wheel 113 and the road wheels 115a and 115b form a substantially triangular shape in a side view. The crawler belt 111 is wound around the drive wheel 113 and the road wheels 115a and 115b, and the portion of the crawler belt 111 between the road wheels 115a and 115b contacts the ground. In other words, the drive wheel 113, in which the in-wheel motor 114 is built, does not contact the road surface. With this configuration, the in-wheel motor 114 does not sink in the water even when, for example, the crawler mobile body 11 travels in a puddle. It is thus not necessary to provide a special waterproof mechanism for the in- wheel motor 114.

[0039] As illustrated in FIG. 2, the drive wheel 113 is different in diameter from the road wheels 115a and 115b. The component layout of a mobile vehicle is designed considering, for example, size limitations and the traveling performance. Typically, the torque per unit widthFN202501185of a motor tends to decrease as the diameter of the motor decreases. Accordingly, the diameter of the drive wheel 113 incorporating the in-wheel motor 114 is made equal to or larger than the diameter of the motor that exhibits the intended torque performance.Accordingly, the crawler mobile body 11 is designed such that the diameter of the drive wheel 113 installed at the upper section is made larger than the diameters of the road wheels 115a and 115b, to satisfy the size limitations of the mobile apparatus 1 or the crawler mobile body 11, as well as the intended traveling performance. When the size of the mobile apparatus is limited, increasing the diameters of the road wheels reduces the ground contact area and accordingly, reduces the traveling stability.In this regard, the crawler mobile body 11 has an advantage by adopting the road wheels 115a and 115b having a relatively small diameter taking into account the diameter of the drive wheel 113.

[0040] In the auxiliary mechanism 118, the idlers 118a and 118b (auxiliary wheels) rotate following the crawler belt 111, and swing around a link shaft 119a as the swing axis. The auxiliary mechanism 118 may be referred to as, for example, a swing mechanism, a balance-type auxiliary mechanism, a balance-type swing mechanism, a balance-type swing wheel, or a balance-type swing road wheel. The auxiliary mechanism 118 is installed at the bottom of the triangular shape formed by the drive wheel 113 and the road wheels 115a and 115b in a side view.

[0041] The auxiliary mechanism 118 includes the idlers 118a and 118b, and the link 119. The idlers 118a and 118b are auxiliary wheels disposed between the two road wheels 115a and 115b and are rotated by the crawler belt 111. The idlers 118a and 118b rotate about idler shafts 181a and 181b, respectively. The link 119 supports the idlers 118a and 118b.

[0042] In the crawler mobile body 11, the side plate 120 is a structural component that supports the drive wheel 113, the road wheels 115a and 115b, and the auxiliary mechanism 118, together with the inner side plate. The crawler mobile body 11 has a double- supported structure that supports the drive wheel 113, the road wheels 115a and 115b, and the auxiliary mechanism 118 using two side plates, namely, the side plate 120 and the inner side plate. The side plate 120 and the inner side plate are suspended by multiple side plate supports. The side plate 120 and the inner side plate support the drive wheel 113 using the motor shaft 114a. The side plate 120 and the inner side plate support the road wheels 115a and 115b by using the roadwheel rotary shafts 116a and 116b, respectively. Further, the side plate 120 and the inner side plate support the auxiliary mechanism 118 via the link shaft 119a of the link 119 that supports the idlers 118a and 118b.

[0043] The tensioner 125 is an elastic member, such as a spring, and is coupled to the motor shaft 114a, which is the rotary shaft of the in-wheel motor 114 and the drive wheel 113. TheFN202501185tensioner 125 biases the drive wheel 113 to press against the inner face of the crawler belt 111 to apply tension to the crawler belt 111. The crawler mobile body 11 includes the tensioner 125 to adjust the sagging of the crawler belt 111 so that the crawler belt 111 keeps transmitting a proper level of driving force.

[0044] As illustrated in FIG. 2, the crawler mobile body 11 has a substantially symmetrical structure in the travel direction with respect to the drive wheel 113 as the center. More specifically, the crawler mobile body 11 is substantially symmetrical in the horizontal direction (in the Y direction) in which the two road wheels 115a and 115b are aligned, with respect to the motor shaft 114a of the in- wheel motor 114 as the center. In other words, the crawler mobile body 11 is substantially symmetrical with respect to a line perpendicular to the motor shaft 114a of the in-wheel motor 114.

[0045] A mobile apparatus that travels in, for example, a narrow space frequently moves forward or backward, or makes spin turn. If the mobile apparatus is asymmetrical in the shape of the crawler belt; or the arrangement of the drive wheel, the road wheels, and the tensioner in the travel direction, the driving characteristics may differ between the forward travel and the backward travel. As a result, the mobile apparatus may fail to rotate about the center of the mobile apparatus in spin turn. In view of this, the crawler mobile body 11 has a symmetrical structure (or the symmetrical layout) in the travel direction to increase the stability of travel of the mobile apparatus 1 and simplify the control of the mobile apparatus 1. Since the crawler mobile body 11 is attachable to the mobile apparatus 1 without regard to the left and right sides of the mobile apparatus 1, the number of parts is reduced.

[0046] The details of the assist members 20 are described below.

[0047] FIG. 3 is a diagram of the assist members 20. FIG. 3 illustrates the assist members 20 in an enlarged manner and illustrates the installation position of the assist members 20 in the mobile apparatus 1.

[0048] A crawler mobile body may fall down and fail to travel stably due to level differences, such as the unevenness of the rough road surface or steps (stairs). In view of this, the mobile apparatus 1 is designed to travel stably without falling backward, with a simple structure, when climbing the highest step that the mobile apparatus 1 may climb over even if the possibility is slight. Specifically, the mobile apparatus 1 includes the assist members 20 disposed at the rear position (upstream position) in the travel direction, and the center of gravity thereof is determined to prevent the mobile apparatus 1 from falling backward.

[0049] The assist members 20 are attached to the main body 10 of the mobile apparatus 1 to prevent the mobile apparatus 1 from falling over and enhance the performance of climbing over a stepFN202501185on the road surface. As illustrated in FIG. 3, the assist members 20 each include a base 21 and a ground-contact end 22 (contact portion) that contacts the ground. Since the assist members 20 are similar in shape, one assist member 20 is described below.

[0050] The base 21 is a main body of the assist member 20. The base 21 is a rigid body having strength (rigidity) to support the weight of the mobile apparatus 1 during traveling. The base 21 is made of, for example, metal such as stainless steel. The base 21 of the assist member 20 is attached to the main body 10 of the mobile apparatus 1.

[0051] The base 21 is an elongated flat plate bent into a crank shape to increase the strength (rigidity). The base 21 includes a rectangular attachment portion 21a to be attached to the main body 10 of the mobile apparatus 1, and a ground-contact portion 21b integral with the ground-contact end 22.

[0052] The assist member 20 is attached to the main body 10 of the mobile apparatus 1 such that the attachment portion 21a of the base 21 is substantially parallel to the road surface or the bottom of the crawler belt 111 when the mobile apparatus 1 is stationary. The ground-contact portion 21b of the base 21 extends obliquely downward when the mobile apparatus 1 is stationary, with the attachment portion 21a attached to the main body 10 substantially parallel to the road surface or the bottom of the crawler belt 111.

[0053] In the assist member 20, the attachment portion 21a of the base 21 has multiple holes 24 for attaching the assist member 20 to the main body 10. The assist member 20 is attached to the main body 10 of the mobile apparatus 1 by, for example, screwing with screws 25 through the holes 24 in the base 21.

[0054] The ground-contact end 22 is at the tip of the ground-contact portion 21b of the base 21. The ground-contact end 22 is substantially circular so that the assist member 20 contacts the ground at a point irrespective of the contact position thereof. The ground-contact end 22 at the tip of the assist member 20 allows the mobile apparatus 1 to smoothly travel even when the ends of the assist members 20 are grounded.

[0055] If the substantially circular portion of the ground-contact end 22 is caught in road surface irregularities such as a recess while the mobile apparatus 1 travels, the mobile apparatus 1 becomes immovable. Accordingly, the diameter of the substantially circular portion of the ground-contact end 22 is preferably, for example, about twice the size of the assumed road surface irregularities in order to prevent the circular portion from being caught. When the road surface irregularities are unpredictable, the diameter of the substantially circular portion of the ground-contact end 22 may be, for example, approximately the same as or slightlyFN202501185smaller than the diameter of the idlers 118a and 118b considering the size of the crawler mobile body 11.

[0056] The relationship between the mobile apparatus 1 and the height of the step will be described below.

[0057] FIGS. 4A and 4B are diagrams each illustrating the relationship between a height hO of the center of the road wheel 115b of the mobile apparatus 1 and a height H of a step. FIG. 4A illustrates an overall configuration of the mobile apparatus 1. FIG. 4B is an enlarged view of the portion around the road wheel 115b on the downstream side in the travel direction of the mobile apparatus 1. The road wheel 115a and the road wheel 115b, which are upstream and downstream from each other in the travel direction, may be referred to as the upstream road wheel 115a and the downstream road wheel 115b, respectively, in the following description. FIGS. 5 A to 5C are diagrams each illustrating a behavior pattern of the mobile apparatus 1.

[0058] As illustrated in FIGS. 4A and 4B, the height from the horizontal ground surface (lower level) to the center of the downstream road wheel 115b in the travel direction of the mobile apparatus 1 via the horizontal portion of the crawler belt 111 is a height hO. When there is a step having a height H in front of (downstream from) the mobile apparatus 1 in the travel direction, the road wheel 115b on the downstream side of the travel direction of the mobile apparatus 1 exhibits one of three behavior patterns A, B, and C illustrated in FIGS. 5A, 5B 1, 5B2, and 5C, depending on the relationship between the height H of the step and the height hO to the center of the road wheel 115b. It is assumed that the driving force of the mobile apparatus 1 is sufficient.

[0059] The height h illustrated in FIGS. 5 A to 5C is the height of the highest step that the mobile apparatus 1 may climb, even if the possibility is slight. This height h may be referred to as the climbable height h in the following description. It is assumed that the mobile apparatus 1 cannot climb over a step height H greater than the maximum climbable height h under any condition.

[0060] FIG. 5A illustrates the behavior pattern A when the step height H is equal to or lower than the height hO to the center of the road wheel 115b.As illustrated in FIG. 5 A, the road wheel 115b on the downstream side in the travel direction of the mobile apparatus 1 climbs over the step having the height H. The mobile apparatus 1 climbs over the step, for example, in the following state. The road wheel 115a is grounded via the crawler belt 111, the assist member 20 is grounded, and the projection 11 la on the outer face of the portion of the crawler belt 111 wound around the road wheel 115b is caught on the apex of the step.

[0061] FN202501185FIGS. 5B 1 and 5B2 illustrate the behavior pattern B when the step height H is higher than the height hO to the center of the road wheel 115b and equal to or lower than the climbable height h.As illustrated in FIGS. 5B 1 and 5B2, the road wheel 115b on the downstream side in the travel direction of the mobile apparatus 1 climbs over the step having the height H in some cases, and keeps idling on the spot and fails to climb over the step having the height H in other cases. Whether the road wheel 115b on the downstream side in the travel direction of the mobile apparatus 1 can climb over the step having the height H varies depending on the surface unevenness and the friction coefficient of the crawler belt 111 and the step, and the differences in shape of the step.

[0062] FIG. 5C illustrates the behavior pattern C when the step height H is higher than the climbable height h.As illustrated in FIG. 5C, the road wheel 115b on the downstream side in the travel direction of the mobile apparatus 1 idles on the spot and fails to climb over the step having the height H.

[0063] Accordingly, in order for the mobile apparatus 1 to travel stably, the mobile apparatus 1 is devised to stably climb over steps having the climbable height h without falling over considering the above-described behavior patterns A, B, and C. The climbable height h is the height of the highest step that the mobile apparatus 1 may climb even if the possibility is slight.

[0064] FIGS. 6A to 6C are diagrams each illustrating a behavior when the mobile apparatus 1 climbs over a step having the climbable height h. The mobile apparatus 1 behaves as described below when the mobile apparatus 1 climbs over a step having the climbable height h, present in the travel direction.

[0065] As illustrated in FIG. 6A, when the mobile apparatus 1 advances toward the step having the climbable height h, the road wheel 115b on the downstream side in the travel direction first climbs over the step having the climbable height h.

[0066] As illustrated in FIG. 6B, the mobile apparatus 1 starts to tilt backward when the mobile apparatus 1 climbs over the step having the climbable height h. As the mobile apparatus 1 further advances, the tilt angle increases. As the tilt angle of the mobile apparatus 1 increases, the ground-contact end 22 of the assist member 20 contacts the lower level of the step (road surface). The mobile apparatus 1 continues to increase its tilt angle around the contact point with the ground-contact end 22 of the assist member 20.

[0067] FN202501185As illustrated in FIG. 6C, when the mobile apparatus 1 further advances, the upstream road wheel 115a in the travel direction starts climbing the step having the climbable height h. With time, the road wheel 115a of the mobile apparatus 1 climbs onto the upper level of the step. In the state illustrated in FIG. 6C in which the road wheel 115a is on the upper level of the step, the mobile apparatus 1 has the maximum tilt angle.

[0068] In view of this, considerations are given to the center of gravity of the mobile apparatus 1 when the mobile apparatus 1 is in a tilted posture with the upstream road wheel 115a (rear wheel) in contact with the upper level of the step having the height h via the crawler belt 111 and the ground-contact end 22 of the assist member 20 in contact with the lower level of the step. Specifically, as illustrated in FIG. 6C, the center of gravity of the mobile apparatus 1 in this posture is located downstream in the travel direction from a vertical line extending from the point of contact between the ground-contact end 22 of the assist member 20 and the lower level of the step.

[0069] Thus, with a simple structure, the mobile apparatus 1 is prevented from falling backward and allowed to travel stably even when the mobile apparatus 1 climbs the step having the climbable height h that the mobile apparatus 1 may climb, even if the possibility is slight.

[0070] Second EmbodimentA second embodiment will be described below.

[0071] The mobile apparatus 1 according to the second embodiment differs from that according to the first embodiment in the structure of the assist member 20. Specifically, the assist member 20 according to the second embodiment includes, in addition to the ground-contact end 22 that contacts the horizontal ground surface as the lower level of the step, a second groundcontact portion 23 positioned between the ground-contact end 22 and the upstream road wheel 115a in the travel direction. In the following description of the second embodiment, descriptions of elements identical or similar to those in the first embodiment are omitted, and differences from the first embodiment are described.

[0072] FIG. 7 is a perspective view of the mobile apparatus 1 according to the second embodiment. FIG. 7 illustrates the assist members 20 in an enlarged manner and illustrates the installation position of the assist members 20 in the mobile apparatus 1.

[0073] As illustrated in FIG. 7, the assist member 20 includes the second ground-contact portion 23 positioned between the ground-contact end 22 and the road wheel 115a (see FIG. 8) on the upstream side in the travel direction, in addition to the ground-contact end 22 that contacts the horizontal ground surface as the lower level of the step. More specifically, the assist member 20 includes the second ground-contact portion 23 at the attachment portion 21a of the base 21.FN202501185

[0074] The second ground-contact portion 23 is disposed below the rectangular attachment portion 21a. The second ground-contact portion 23 is substantially semicircular so that the second ground-contact portion 23 contacts the ground at a point irrespective of the contact position thereof. The diameter of the substantially circular portion of the second ground-contact portion 23 is, for example, approximately the same as or slightly smaller than the diameter of the substantially circular portion of the ground-contact end 22.

[0075] FIG. 8 is an enlarged view of the portion around the assist member 20 of the mobile apparatus 1. FIG. 8 is an enlarged view of the lower level and the upper level of the step in a state similar to that illustrated in FIG. 6C.

[0076] As illustrated in FIG. 8, when the mobile apparatus 1 is in a tilted posture with the upstream road wheel 115a in contact with the upper horizontal surface (upper level) of the step via the crawler belt 111 and the second ground-contact portion 23 in contact with the upper horizontal surface, the center of gravity of the mobile apparatus 1 is positioned downstream in the travel direction from the vertical line extending from the contact point between the second ground-contact portion 23 and the upper horizontal surface of the step.

[0077] With this configuration, in the mobile apparatus 1, the direction of the moment about the contact point between the upper horizontal surface of the step and the second ground-contact portion 23 (another contact portion) acts in the forward direction (downstream) even when the ground-contact end 22 of the assist member 20 is separated from the horizontal ground surface (lower level of the step). As a result, the mobile apparatus 1 restores its posture forward without falling over backward and has a horizontal posture to stably travel.

[0078] ModificationFIG. 9 is a perspective view of the mobile apparatus 1 according to a modification. FIG. 9 illustrates the assist members 20 in an enlarged manner and illustrates the installation position of the assist members 20 in the mobile apparatus 1.

[0079] As illustrated in FIG. 9, the assist member 20 may include a rotatable first wheel 31 as the ground-contact end 22 (see FIG. 3) and a rotatable second wheel 32 as the second groundcontact portion 23.The first wheel 31 and the second wheel 32 are mounted on the base 21 and are small wheels that freely rotate when the assist member 20 contacts the ground.

[0080] The assist member 20 including the first wheel 31 and the second wheel 32 allows the mobile apparatus 1 to smoothly travel even when the assist member 20 is grounded. Additionally,FN202501185the assist member 20 including the first wheel 31 and the second wheel 32 prevents the assist member 20 from damaging the road surface.

[0081] The diameter of the first wheel 31 and that of the second wheel 32 are preferably, for example, about twice the size of the anticipated road surface irregularities in order to prevent the wheels from being caught and immovable due to road surface irregularities while traveling. When the road surface irregularities are unpredictable, the diameter of the first wheel 31 and that of the second wheel 32 may be, for example, approximately the same as or slightly smaller than the diameter of the idlers 118a and 118b considering the size of the crawler mobile body 11.

[0082] With the above-described structure, since the wheels that rotate freely contact the lower level and the upper level of the step, the mobile apparatus 1 experiences less snagging and resistance against the road surface, the traveling stability is enhanced.

[0083] One of or both the ground-contact end 22 and the second ground-contact portion 23 of the assist member 20 may be replaced with a wheel as mentioned above.

[0084] Third EmbodimentA third embodiment will be described below.

[0085] The third embodiment is different from the first embodiment and the second embodiment in that the mobile apparatus 1 further includes a bumper 16 (shock absorber) at the climbable height h from the horizontal ground surface, at the downstream end in the travel direction. In the following description of the third embodiment, descriptions of the same parts as those in the first and second embodiments are omitted, and differences from the first and second embodiments are described.

[0086] FIG. 10 is a side view of the mobile apparatus 1 according to the third embodiment. FIGS.11A to 11C are diagrams each illustrating a behavior pattern of the mobile apparatus 1.

[0087] As illustrated in FIG. 10, the mobile apparatus 1 according to the third embodiment includes the bumper 16 as a shock absorber to absorb and relieve a shock. The bumper 16 is disposed at the climbable height h from a horizontal ground surface and at the downstream end of the mobile apparatus 1 in the travel direction when the mobile apparatus 1 is in a horizontal posture on the horizontal ground surface that is the lower level of a step. The climbable height h is the height of the highest step that the mobile apparatus 1 may climb even if the possibility is slight, as described above.

[0088] FN202501185Also in the mobile apparatus 1 including the bumper 16 illustrated in FIG. 10, when there is a step having a height H in front of (downstream from) the mobile apparatus 1 in the travel direction, the road wheel 115b on the downstream side of the travel direction of the mobile apparatus 1 exhibits one of three behavior patterns A, B, and C illustrated in FIGS. 11A, 1 IB 1, 11B2, and 11C, depending on the relationship between the height H of the step and the height hO to the center of the road wheel 115b similar to FIGS. 5A to 5C. It is assumed that the driving force of the mobile apparatus 1 is sufficient, and the height from the horizontal ground surface to the center of the downstream road wheel 115b in the travel direction of the mobile apparatus 1 via the horizontal portion of the crawler belt 111 is the height hO.

[0089] The climbable height h is the height of the highest step that the mobile apparatus 1 may climb even if the possibility is slight. It is assumed that the mobile apparatus 1 cannot climb over a step height H greater than the maximum climbable height h under any condition.

[0090] FIG. 11 A illustrates the behavior pattern A when the step height H is equal to or lower than the height hO to the center of the road wheel 115b.As illustrated in FIG. 11A, the road wheel 115b on the downstream side in the travel direction of the mobile apparatus 1 climbs over the step having the height H. The mobile apparatus 1 climbs over the step, for example, in the following state. The road wheel 115a is grounded via the crawler belt 111, the assist member 20 is grounded, and the projection 11 la on the outer face of the portion of the crawler belt 111 wound around the road wheel 115b is caught on the apex of the step.

[0091] FIGS. 1 IB 1 and 11B2 illustrate the behavior pattern B when the step height H is higher than the height hO to the center of the road wheel 115b and equal to or lower than the climbable height h.As illustrated in FIGS. 1 IB 1 and 11B2, the downstream road wheel 115b in the travel direction of the mobile apparatus 1 climbs over the step having the height H in some cases, and keeps idling on the spot and fails to climb over the step in other cases.

[0092] FIG. 11C illustrates the behavior pattern C when the step height H is higher than the climbable height h.As illustrated in FIG. 11C, the bumper 16 of the mobile apparatus 1 hits the step, and the mobile apparatus 1 is prevented from climbing the step having the height H.

[0093] Although the behavior patterns of the mobile apparatus 1 are almost similar to those illustrated in FIGS. 5 A to 5C as described above, the height H of the unclimbable step higher than the climbable height h is a fixed value and quantitative value when the bumper 16 is added as illustrated in FIG. 10. By contrast, in the structure illustrated in FIG. 1, in which the height H of the unclimbable step varies depending on the surface unevenness and the frictionFN202501185coefficient of the crawler belt 111 and the step, and the differences in shape of the step.Accordingly, the structure and the position of the assist member 20 can be determined quantitatively so that the mobile apparatus 1 can climb over the step without falling backward when climbing a step having the climbable height h.

[0094] FIG. 12 is a diagram illustrating a position of the bumper 16. When determining the positional and the structure of the assist member 20, for example, as illustrated in FIG. 12, first it is ensured that the center of gravity is downstream in the travel direction from the line vertical to the axis of the first wheel 31 and the line vertical to the axis of the second wheel 32 when the mobile apparatus 1 is tilted at a step height having the climbable h, and the bumper 16 is attached at the climbable height h.

[0095] Further, the mobile apparatus 1 may further include a shock sensor 17 within the bumper 16 to detect the collision of the bumper 16 with some object. For example, the shock sensor 17 includes a pair of sensors disposed on the left and the right of the bumper 16. The shock sensor 17 detects acceleration (shock or vibration) applied from the outside and generates an electrical signal. For example, a piezoelectric ceramic-based acceleration sensor is used as the shock sensor 17. As illustrated in FIG. 11C, when the bumper 16 of the mobile apparatus 1 hits a step, the shock sensor 17 emits a signal indicating that a collision of the bumper 16 with an object has been detected. The mobile apparatus 1 may have a control process, triggered by a signal indicating the detection of a collision with an object, to stop its driving and notify the remote operator of the collision, or to autonomously select a route to avoid a step and continue to travel.

[0096] Fourth EmbodimentThe fourth embodiment will be described below.

[0097] The fourth embodiment differs from the third embodiment in that the mobile apparatus 1 includes a guide 30 below the bumper 16. In the following description of the fourth embodiment, descriptions of the same parts as those in the third embodiment are omitted, and differences from the third embodiment are described.

[0098] FIGS. 13 A and 13B are side views of a mobile apparatus 1 according to the fourth embodiment. FIG. 13 A illustrates an overall configuration of the mobile apparatus 1. FIG.13B is an enlarged view of the portion around the road wheel 115b on the downstream side in the travel direction of the mobile apparatus 1. FIGS. 14A and 14B are diagrams each illustrating a behavior pattern of the mobile apparatus 1.

[0099] As illustrated in FIGS. 13 A and 13B, the mobile apparatus 1 according to the fourth embodiment includes the guide 30 disposed below the bumper 16. As illustrated in FIGS.FN20250118513 A and 13B, the guide 30 is inclined down from the front end of the bumper 16 toward the crawler belt 111 in the mobile apparatus 1 in a horizontal posture. More specifically, the guide 30 has an inclined shape extending down to a position lower than the height hO of the center of the road wheel 115b on the downstream side in the travel direction.

[0100] As illustrated in FIGS. 13 A and 13B, with the guide 30 disposed below the bumper 16, when a step having the height H is present in front of (downstream from) the mobile apparatus 1 in the travel direction, the road wheel 115b on the downstream side of the mobile apparatus 1 in the travel direction exhibits one of two behavior patterns A and B illustrated in FIGS. 14A and 14B depending on the relationship between the height H of the step and the height hO of the center of the road wheel 115b.

[0101] FIG. 14A illustrates the behavior pattern A when the step height H is equal to or lower than the height hO of the center of the road wheel 115b.As illustrated in FIG. 14A, when the mobile apparatus 1 is horizontal, the road wheel 115b on the downstream side in the travel direction of the mobile apparatus 1 is guided to the comer of the upper level of the step having the height H. More specifically, the guide 30 guides the road wheel 115b on the downstream side of the mobile apparatus 1 in the travel direction to a position of the crawler belt 111 equal to or lower than the height hO of the center of the road wheel 115b, and climbs over the step having the height H.

[0102] When the road wheel 115b on the downstream side in the travel direction of the mobile apparatus 1 climbs over the step having the height H, the mobile apparatus 1 can travel stably over the step without falling down.

[0103] Thus, when the mobile apparatus 1 includes the guide 30, the mobile apparatus 1 can reliably climb over a step whose height is equal to or lower than the climbable height h and continue to travel without falling down.

[0104] Accordingly, the height h of a step that the mobile apparatus 1 can climb can be indicated in the specifications.

[0105] FIG. 14B illustrates the behavior pattern B when the step height H is higher than the height hO of the center of the road wheel 115b.As illustrated in FIG. 14B, when the height H of the step is higher than the height hO of the center of the road wheel 115b, the bumper 16 of the mobile apparatus 1 hits the step, and the mobile apparatus 1 is prevented from climbing the step having the height H.

[0106] In this case, the mobile apparatus 1 may have a control process triggered by a signal from a shock sensor 17, indicating the detection of a collision with an object, to stop its driving andFN202501185notify the remote operator of the collision, or to autonomously select a route to avoid a step and continue to travel.

[0107] As described above, the guide 30 allows the mobile apparatus 1 to climb over a step whose height is equal to or lower than the height h or less and travel without falling over. When the step is higher than the height h, the bumper 16 hits the step, and the mobile apparatus 1 can commence a pre-programmed action based on the signal from the shock sensor 17.

[0108] Aspects of the present disclosure are, for example, as follows.According to Aspect 1, a mobile apparatus includes a crawler belt, a drive wheel to apply driving force to the crawler belt, at least two road wheels positioned below the drive wheel, a crawler mobile body that travels with the rotation of the crawler belt wound around the drive wheel and the road wheels, and an assist member disposed at an upstream position of the crawler mobile body in a travel direction of the crawler mobile body, to prevent the crawler mobile body from falling. At least two road wheels mentioned above include an upstream road wheel and a downstream road wheel positioned upstream and downstream from each other in the travel direction.The center of gravity of the mobile apparatus is downstream in the travel direction of the crawler mobile body from a vertical line extending from a contact point between the end of the assist member and a travel road surface when the mobile apparatus is in a tilted posture with the upstream road wheel in contact, via the crawler belt, with an upper level of a step located downstream from the crawler mobile body in the travel direction and having a predetermined height from the travel road surface, and with an end of the assist member in contact with the travel road surface.According to Aspect 2, in the mobile apparatus according to Aspect 1, the assist member includes a rigid base disposed at the crawler mobile body, and a contact portion at an end of the base. The contact portion contacts the travel road surface.According to Aspect 3, in the mobile apparatus according to Aspect 2, the assist member includes a second contact portion disposed between the contact portion and the upstream road wheel in the travel direction. The center of gravity of the mobile apparatus is downstream in the travel direction from a vertical line extending from a contact point between the second contact portion and the upper level of the step when the mobile apparatus in a tilted posture with the upstream road wheel in contact with the upper level of the step via the crawler belt and the second contact portion in contact with the upper level of the step.According to Aspect 4, in the mobile apparatus according to Aspect 3, at least one of the contact portion and the second contact portion of the assist member includes a rotatable wheel.According to Aspect 5, the mobile apparatus according to any one of Aspects 1 to 4 further includes a shock absorber disposed at a downstream end of the crawler mobile body in the travel direction and at the predetermined height from the travel road surface.FN202501185According to Aspect 6, the mobile apparatus according to Aspect 5 further includes a shock sensor 17 to emit a signal indicating that a collision of the shock absorber with an object has been detected.According to Aspect 7, the mobile apparatus according to Aspect 5 or 6 further includes a guide disposed below the shock absorber, and the guide has a shape inclined down from an end of the shock absorber toward the downstream road wheel.According to Aspect 8, in the mobile apparatus according to any one of Aspects 1 to 7, the predetermined height is the height of the highest step that the crawler mobile body climbs over.

[0109] The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and / or features of different illustrative embodiments may be combined with each other and / or substituted for each other within the scope of the present invention.

[0110] This patent application is based on and claims priority to Japanese Patent Application No. 2024-231416, filed on December 26, 2024, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.[Reference Signs List]

[0111] 1 Mobile apparatus11, Ila, 11b Crawler mobile body16 Shock absorber20 Assist member21 Base22 Ground-contact end23 Second ground-contact portion30 Guide31, 32 Wheel111 Crawler belt113 Drive wheel115a, 115b Road wheel

Claims

FN202501185[CLAIMS]1. A mobile apparatus comprising:a crawler mobile body including:a crawler belt;a drive wheel configured to apply driving force to the crawler belt; and an upstream road wheel and a downstream road wheel positioned below the drive wheel and positioned upstream and downstream from each other in a travel direction of the crawler mobile body, the crawler mobile body being configured to travel with rotation of the crawler belt wound around the drive wheel, the upstream road wheel, and the downstream road wheel; andan assist member disposed at an upstream position of the crawler mobile body in the travel direction and configured to prevent the crawler mobile body from falling, wherein the center of gravity of the mobile apparatus is downstream in the travel direction from a vertical line extending from a contact point between the end of the assist member and a travel road surface when the mobile apparatus is tilted such thatthe upstream road wheel of the crawler mobile body is in contact with an upper level of a step via the crawler belt, the step being located downstream from the crawler mobile body in the travel direction, and an end of the assist member is in contact with the travel road surface, andthe step has a predetermined height from the travel road surface.

2. The mobile apparatus according to claim 1,wherein the assist member includes:a rigid base disposed at the crawler mobile body; anda contact portion disposed at an end of the base to contact the travel road surface.

3. The mobile apparatus according to claim 2, whereinthe assist member further includes another contact portion disposed between the contact portion and the upstream road wheel in the travel direction, andthe center of gravity of the mobile apparatus is downstream in the travel direction from a vertical line extending from a contact point between the another contact portion and the upper level of the step when the mobile apparatus is tilted such thatthe upstream road wheel is in contact with the upper level of the step via the crawler belt, and the another contact portion is in contact with the upper level of the step.

4. The mobile apparatus according to claim 3,wherein at least one of the contact portion and the another contact portion of the assist member includes a rotatable wheel.FN2025011855. The mobile apparatus according to any one of claims 1 to 4, further comprising a shock absorber disposed at a downstream end of the crawler mobile body in the travel direction and at the predetermined height from the travel road surface.

6. The mobile apparatus according to claim 5, further comprising a shock sensor configured to emit a signal indicating that a collision of the shock absorber with an object has been detected.

7. The mobile apparatus according to claim 5 or 6, further comprising a guide below the shock absorber,wherein the guide has a shape inclined down from an end of the shock absorber toward the downstream road wheel.

8. The mobile apparatus according to any one of claims 1 to 7,wherein the predetermined height is a height of a highest step that the crawler mobile body climbs over.

Images