Mobile device

Abstract

The invention provides a moving device which can travel on a moving path with less irregularities. A mobile device (10) is provided with: a deformation mechanism (14) capable of changing the relative arrangement relationship of a plurality of wheels (16); and a control unit (30) that selects a movement path on the basis of the amount of deformation of the deformation mechanism (14).

Description

Technical Field

[0001] The present invention relates to a mobile device. Background Art

[0002] In Patent Document 1, a traveling device capable of climbing a wall surface using four wheels is disclosed.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2021 / 247275 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] When a mobile device travels on a curved surface, there is sometimes a requirement to move along a path that avoids unevenness as much as possible. An object of the present invention is to provide a mobile device that can travel on a mobile path with fewer unevennesses.

[0008] Means for Solving the Technical Problem

[0009] The mobile device according to the present invention includes: a deformation mechanism capable of changing the relative arrangement relationship of a plurality of wheels; and a control unit that selects a movement path based on the deformation amount of the deformation mechanism.

[0010] Effect of the Invention

[0011] According to the present invention, it is possible to provide a mobile device that travels on a mobile path with fewer unevennesses. Brief Description of the Drawings

[0012] Figure 1A It is a top view showing the mobile device according to the embodiment of the present invention.

[0013] Figure 1B It is a perspective view showing the mobile device according to the embodiment of the present invention.

[0014] Figure 2A It shows Figure 1A and Figure 1B A partial cross-sectional front view of the wheel structure, showing the state when the surface parallel to the upper surface Su of the frame is in contact with the ground.

[0015] Figure 2B It shows Figure 1A and Figure 1B A partial cross-sectional front view of the wheel structure, showing the state when the left upper inclined surface is in contact with the ground.

[0016] Figure 3A It shows Figure 1A andFigure 1B Partial cross-sectional side view of the wheel structure, showing the state when the surface parallel to the upper surface Su of the frame touches the ground.

[0017] Figure 3B It represents Figure 1A and Figure 1B Partial cross-sectional side view of the wheel structure, showing the state when it touches an inclined surface.

[0018] Figure 4 It is a diagram for explaining the principle of the deformation amount calculation process of the suspension mechanism.

[0019] Figure 5 It is a diagram for explaining the deformation amount calculation process of the suspension mechanism.

[0020] Figure 6 It is a diagram showing an example of the moving path along which the mobile device travels.

[0021] Figure 7 It is a flowchart showing the travel control process executed by the control unit. Detailed implementation mode

[0022] Hereinafter, with reference to the accompanying drawings, the implementation modes of the present invention will be described in detail. Figure 1A and Figure 1B are respectively a top view and a perspective view of the mobile device according to the implementation mode of the present invention.

[0023] The mobile device 10 of the present implementation mode is a device that tries to avoid traveling over unevenness. In this specification, the unevenness refers to the shape of the traveling surface that can maintain the adsorption of the wheels 16 to the traveling surface by passively changing the direction of the magnet 19 described later. In a traveling surface where the second traveling surface intersects the first traveling surface perpendicularly, for the mobile device 10 to move from the first traveling surface to the second traveling surface, it is necessary to actively change the direction of the magnet 19 (that is, change it by an external control instruction), and such a traveling surface shape that requires changing the direction of the magnet 19 does not include unevenness. This traveling surface shape is different from unevenness and can be called an obstacle.

[0024] The mobile device 10 of the present implementation mode is a device that can travel on surfaces such as a wall surface or a top surface and can also travel on a curved surface. The mobile device 10 includes: a plurality of wheels 16 (the first wheel 16a to the fourth wheel 16d); a first frame 20A and a second frame 20B that support the plurality of wheels 16; a suspension mechanism (equivalent to a deformation mechanism) 14 that can change the configuration relationship of the plurality of wheels 16; a drive unit 21 that drives the plurality of wheels 16; and a measuring instrument 24 that measures the orientation (for example, the normal direction) of the contact surface of each wheel 16.

[0025] The mobile device 10 has four wheels 16. The four wheels 16 are respectively supported so as to be rotatable about rotation axes a1 to a4. Each wheel 16 is spherical and configured to be able to transmit driving force to driving surfaces in various directions. Additionally, the number of wheels 16 may be three or five or more. Also, the wheels 16 do not necessarily have to be spherical, and may be of any shape such as a drum shape as long as the wheels 16 can adapt to driving surfaces in various directions and can transmit driving force to the driving surface.

[0026] The first wheel 16a and the third wheel 16c are rotatably supported by the first frame 20A. That is, the rotation axis a1 supporting the first wheel 16a and the rotation axis a3 supporting the third wheel 16c are supported by the first frame 20A. The rotation axes a1, a3 may be mounted on the first frame 20A in a displaceable manner via a spring or the like. The rotation axes a1, a3 may be arranged substantially parallel.

[0027] The second wheel 16b and the fourth wheel 16d are rotatably supported by the second frame 20B. That is, the rotation axis a2 supporting the second wheel 16b and the rotation axis a4 supporting the fourth wheel 16d are supported by the second frame 20B. The rotation axes a2, a4 may be mounted on the second frame 20B in a displaceable manner via a spring or the like. The rotation axes a2, a4 may be arranged substantially parallel.

[0028] The suspension mechanism 14 is a mechanism capable of changing the configuration relationship between the first frame 20A and the second frame 20B in the torsional direction At. The torsional direction At is the rotational direction about an axis a14 extending along the direction in which the first frame 20A and the second frame 20B are arranged. This mechanism is also called a rocker suspension mechanism.

[0029] A measuring instrument 141 such as an encoder for measuring the degree of deformation thereof is provided on the suspension mechanism 14. Additionally, various methods such as analyzing an image of the mobile device 10 taken from the outside can be applied to measure the deformation amount of the suspension mechanism 14.

[0030] Moreover, the suspension mechanism 14 is not limited to the above example. For example, the suspension mechanism 14 may be a mechanism that enables relative displacement between the frame rotatably supporting the first wheel 16a and the frames rotatably supporting the second wheel 16b to the fourth wheel 16d. Or, the suspension mechanism 14 may be a structure in which the frames supporting each wheel 16 can be displaced relative to each of the multiple frames supporting other wheels 16. The structure enabling the frames to be displaced is not limited to a structure variable in the torsional direction, and may also adopt a structure enabling each frame to be translated in the direction in which the frames are arranged, a structure enabling each frame to be translated in a direction perpendicular or inclined to the direction in which the frames are arranged, a structure enabling one or both of the angles and distances between two frames to be variable via various link mechanisms, and a combined structure of two or more of these structures.

[0031] Figure 2A and Figure 2B is a partial cross-sectional front view showing the wheel structure of Figure 1A and Figure 1B When the surface parallel to the upper surface Su of the frame is in contact with the ground, Figure 2A it shows the state. Figure 2B It shows the state when in contact with the upper left inclined surface. Figure 3A and Figure 3B is a partial cross-sectional side view showing the wheel structure of Figure 1A and Figure 1B When the surface parallel to the upper surface Su of the frame is in contact with the ground, Figure 3A it shows the state. Figure 3B It shows the state when in contact with the inclined surface.

[0032] Inside the first wheel 16a, a magnet 19 and a link mechanism 192 that supports the magnet 19 so as to be displaceable are provided. The link mechanism 192 rotatably supports the magnet 19 in the rotational direction about the rotation axis a1 and in the rotational direction about an axis a5 that intersects (for example, is orthogonal to) the rotation axis a1. The magnet 19 can be a permanent magnet or an electromagnet. According to this structure, when the first wheel 16a comes into contact with a contact surface such as iron, the magnet attracts the contact surface, causing the first wheel 16a to be adsorbed to the contact surface. Therefore, the moving device 10 can be adsorbed against gravity even on a wall surface or a top surface and travel on that surface. Moreover, according to the above link mechanism 192, even when the first wheel 16a comes into contact with contact surfaces of various orientations, the magnet 19 faces the contact surface, and a strong attraction force to the contact surface can be obtained.

[0033] The measuring instrument 24 that measures the orientation (for example, the normal direction) of the contact surface of the first wheel 16a is, for example, a biaxial encoder that measures the orientation of the magnet 19. Since the magnet 19 faces the contact surface, the orientation of the contact surface can be determined based on the orientation of the magnet 19.

[0034] In addition, the structure for measuring the orientation of the contact surface of each wheel 16 is not limited to the above example. For example, various structures such as a structure that can measure the orientation of the contact surface by measuring the distance to the contact surface by a plurality of distance sensors around each wheel 16 can be applied.

[0035] The drive unit 21 rotationally drives the first wheel 16a. The drive unit 21 is a motor capable of controlling the rotation amount or rotational speed.

[0036] Similar to the first wheel 16a, magnets 19, link mechanisms 192, and gauges 24 are also provided inside the second wheel 16b to the fourth wheel 16d. Moreover, a plurality of drive units 21 for rotating and driving the second wheel 16b to the fourth wheel 16d respectively are provided in the mobile device 10. In addition, the drive unit 21 may have a structure that can drive at least two wheels 16 with independent rotation amounts or rotation speeds.

[0037] According to the mobile device 10 configured as described above, by controlling the rotation amounts of the first wheel 16a to the fourth wheel 16d respectively, various-directional movements such as steering, left turning, right turning, and straight-ahead movement of the mobile device 10 can be achieved. Moreover, through the suspension mechanism 14, even when the traveling surface is a curved surface, the mobile device 10 can travel in a state where the first wheel 16a to the fourth wheel 16d are all in contact with the traveling surface.

[0038] <Path Selection Control>

[0039] The mobile device 10 includes a control unit 30 that selects which direction to advance, that is, selects a movement path, for an arbitrary traveling surface. The control unit 30 is mounted on the mobile device 10. In addition, the control unit 30 may have a structure that is separately provided from the mobile device 10 and controls the drive unit 21 via communication. The control unit 30 receives measurement data from the gauge 24 that measures the orientation of the magnet 19 of each wheel 16 and the gauge 141 of the suspension mechanism 14.

[0040] The control unit 30 selects a movement path that reduces the deformation amount of the suspension mechanism 14. In the present embodiment, the following process for calculating the deformation amount of the suspension mechanism 14 is performed, and the traveling route with the reduced deformation amount of the suspension mechanism 14 calculated is determined, thereby selecting a movement path.

[0041] In addition, the control unit 30 may not perform the following calculation process, but actually make the mobile device 10 repeatedly move slightly forward in each direction and then return, and maintain and compare the deformation amounts of the respective suspension mechanisms 14 when moving slightly forward, thereby determining the movement path with the reduced deformation amount.

[0042] Generally, the more uneven the traveling surface is, the more the configuration relationship of the first wheel 16a to the fourth wheel 16d changes, and thus the deformation amount θ of the suspension mechanism 14 becomes larger. On the contrary, by advancing along a movement path that reduces the deformation amount θ of the suspension mechanism 14, it is possible to achieve traveling that avoids unevenness as much as possible.

[0043] Therefore, through the selection of the movement path by the control unit 30 described above, it is possible to achieve traveling of the mobile device 10 that avoids unevenness as much as possible.

[0044] In addition, in order for the mobile device 10 to avoid the above-mentioned obstacles, in addition to the above-mentioned control for avoiding unevenness, processing for avoiding obstacles can also be performed through other controls. As the processing for avoiding obstacles, control that detects obstacles using a sensor such as a three-dimensional scanner and selects a movement path for avoiding the obstacles can be adopted.

[0045] <Estimation process of the deformation amount of the suspension mechanism 14>

[0046] Figure 4 It is a diagram for explaining the principle of the estimation process of the deformation amount of the suspension mechanism. Figure 5 It is a diagram for explaining the estimation process of the deformation amount of the suspension mechanism.

[0047] As Figure 4 shown, when the mobile device 10 is located on an arbitrary curved surface, the first wheel 16a to the fourth wheel 16d are respectively in contact with contact surfaces Sa to Sd facing a certain direction. Here, the directions of the contact surfaces Sa to Sd are represented by normal directions na to nd.

[0048] The actual driving surface includes a plurality of unevennesses of different sizes, and it is assumed that the surfaces contacted by the first wheel 16a to the fourth wheel 16d are curved surfaces. On the other hand, when focusing on the small areas in contact with the first wheel 16a to the fourth wheel 16d, the contact surfaces of the respective small areas can be approximately regarded as small planes obtained by flatly expanding the surfaces in contact with the first wheel 16a to the fourth wheel 16d. Figure 4 The contact surfaces Sa to Sd represent the planes of the small areas. The directions of the respective contact surfaces Sa to Sd can be calculated based on the measurement data of a plurality of measuring instruments 24 respectively provided on the first wheel 16a to the fourth wheel 16d. Moreover, the positional relationship of the respective contact surfaces Sa to Sd can be calculated based on the measurement data of the measuring instrument 141 of the suspension mechanism 14 and the dimension data of the first frame 20A, the second frame 20B, and the four wheels 16.

[0049] For such contact surfaces Sa to Sd, the mobile device 10 can move along a plurality of travel routes such as straight ahead, right turn, and left turn. And when it is assumed that the mobile device 10 moves forward along one of the travel routes, the trajectories of the first wheel 16a to the fourth wheel 16d can be calculated. Each trajectory corresponds to the trajectory of the first wheel 16a to the fourth wheel 16d moving along the planar contact surfaces Sa to Sd so that the mobile device 10 moves forward along the assumed one travel route, and thus can be uniquely calculated. And if the trajectories of the first wheel 16a to the fourth wheel 16d are calculated, the orientation (vector A) of the first frame 20A and the orientation (vector B) of the second frame 20B can be calculated, and thus the deformation amount θ of the suspension mechanism 14 in the torsional direction can be calculated.

[0050] For example, as Figure 5As shown, when the deformation amount (angle in the torsional direction) of the current suspension mechanism 14 is θ 1 , if turning right, the deformation amount is θ 2a , if going straight, the deformation amount is θ 2b , if turning left, the deformation amount is θ 2c , from which the deformation amount θ when advancing along each travel route can be deduced 2a , θ 2b , θ 2c . In Figure 5 , Δθ a , Δθ b , Δθ c represents the change amount of the deformation amount θ when only advancing a specified amount on each travel route.

[0051] Therefore, the control unit 30 can determine on which travel route the deformation amount θ of the suspension mechanism 14 will become smaller when advancing, and can select a movement path that makes the deformation amount θ smaller based on this determination.

[0052] <Second selection condition for movement path>

[0053] Figure 6 is a diagram showing an example of the movement path along which the mobile device travels.

[0054] The control unit 30 can make the mobile device 10 travel by only performing the selection control of the above movement path. This control is equivalent to the selection control of the movement path based on the first selection condition of avoiding unevenness as much as possible.

[0055] On the other hand, the control unit 30 can also perform the selection of the movement path based on the above first selection condition and the selection of the movement path based on a second selection condition different from it. For example, as Figure 6 shown, the second selection condition is to move from the starting point Q1 to the ending point Q2 as short a distance as possible. In addition, any other condition can be applied as the second selection condition.

[0056] The control unit 30 includes an input unit 31 capable of inputting data ( Figure 1A and Figure 1B ). The input unit 31 is, for example, a data reading device that inputs data via a memory card, but the data input method is not particularly limited. For example, it can be a method of inputting data via communication, a method of inputting data via input devices such as a keyboard and a mouse, etc. In order to perform the selection of the movement path based on the above second selection condition, the control unit 30 inputs the second selection condition from the outside via the input unit 31.

[0057] In order to select a movement path based on two selection conditions, the control unit 30 can use two evaluation functions. That is, as the first evaluation function, the control unit 30 prepares a function in which the smaller the deformation amount θ of the suspension mechanism 14, the higher the evaluation value, and the larger the deformation amount θ, the lower the evaluation value. And, as the second evaluation function, the control unit 30 prepares a function in which the closer the travel route is to the end point Q2, the higher the evaluation value, and the farther the travel route is from the end point Q2, the lower the evaluation value. And, the control unit 30 weights the first evaluation function and the second evaluation function according to the importance of the first selection condition and the second selection condition. The evaluation functions and the weighting can be provided to the control unit 30 by the operator.

[0058] And, the control unit 30 calculates the sum of the first evaluation function with weighting and the second evaluation function, selects the movement path with the larger value, and causes the mobile device 10 to travel. Through such processing, it is possible to select a movement path corresponding to both the first selection condition of avoiding unevenness as much as possible and the second selection condition of moving to the end point Q2 as short a distance as possible, and cause the mobile device 10 to travel.

[0059] Through such processing, as Figure 6 shown, the mobile device 10 can avoid the movement paths p1 and p2 passing through areas with large unevenness and areas with many unevenness, and avoid the movement path p3 that has no unevenness but is very roundabout. And, by the control unit 30 selecting the movement path p4 with few unevenness and capable of reaching the end point Q2 in a short distance, the mobile device 10 can achieve movement that conforms to the first selection condition and the second selection condition.

[0060] <Travel control process>

[0061] Figure 7 is a flowchart showing the travel control process executed by the control unit. Next, the travel control process of the control unit 30 will be described. First, the control unit 30 inputs the second selection condition for selecting a movement path before starting to travel (step S1). This second selection condition can be the second evaluation function itself described above.

[0062] Next, the control unit 30 receives the outputs of the measuring instrument 141 and the measuring instrument 24, calculates the orientations and positions of the contact surfaces of the first wheel 16a to the fourth wheel 16d (step S2), and estimates the deformation amount of the suspension mechanism 14 when advancing in multiple directions (step S3). And, the estimated values of the deformation amount are respectively substituted into the first evaluation function, and a plurality of first evaluation values corresponding to a plurality of directions are calculated (step S4).

[0063] Moreover, the control unit 30 evaluates the situation of moving in multiple directions using the second evaluation function, and calculates multiple second evaluation values corresponding to the multiple directions respectively (step S5). In addition, the control unit 30 selects the direction with the highest sum of the weighted first evaluation value and the second evaluation value as the direction of the movement path (step S6), and causes the mobile device 10 to move forward by a specified amount in this direction (step S7).

[0064] Furthermore, the control unit 30 determines whether it is a travel end condition (step S8). If the result is "no", it returns to step S2 and repeats the loop process of steps S2 to S6. If, for example, the mobile device 10 reaches the end point Q2 or the like that meets the travel end condition through the repetition of this loop process, the determination result in step S8 becomes "yes", and the control unit 30 ends the travel control process.

[0065] As described above, according to the mobile device 10 of the present embodiment, the movement path is selected based on the deformation amount of the suspension mechanism 14. Therefore, the situation of selecting a movement path including unevenness that causes a large deformation of the suspension mechanism 14 is reduced, and the mobile device 10 can travel along the movement path with less unevenness as described above. And since the movement path can be selected as described above, even when moving along a curved surface, it is easy to achieve traveling in which values of desired parameters such as the speed and yaw angular velocity of the mobile device 10 are suppressed within the target values.

[0066] Moreover, according to the mobile device 10 of the present embodiment, the suspension mechanism 14 is configured to be able to change the configuration relationship between the first wheel 16a and the second wheel 16b in the torsion direction. When there are unevenness with different phases on the left and right of the mobile device 10, such a suspension mechanism 14 will be greatly deformed. Therefore, a movement path that further avoids this unevenness can be selected. In addition, the central axis a14 in the torsion direction of the suspension mechanism 14 may also be an axis in the same direction as the rotation axis a1 of the first wheel 16a and the rotation axis a2 of the second wheel 16b. The same direction means that they are parallel to each other or within the range of ±15° on the basis of being parallel. Since the suspension mechanism 14 is a structure that deforms along the above torsion direction, the suspension mechanism 14 will be frequently deformed due to random unevenness. Therefore, a movement path that further avoids the unevenness as described above can be selected.

[0067] Moreover, according to the mobile device 10 of the present embodiment, the multiple wheels 16 are spherical. Therefore, it is possible to achieve stable traveling on a curved surface including unevenness, and it is easy to measure the orientation of the contact surface with each wheel 16 on this curved surface.

[0068] Further, for the mobile device 10 according to the present embodiment, by comparing the deformation amounts of the suspension mechanism 14 when moving forward in multiple traveling directions respectively, the traveling direction with a smaller deformation amount is selected. When moving forward in multiple traveling directions respectively as described above, the case of turning may be included. According to the above structure, even when the state of the traveling route is unknown, the mobile path with a smaller deformation amount can be selected, enabling the mobile device 10 to travel along a mobile path with fewer unevennesses.

[0069] Further, for the mobile device 10 according to the embodiment, measuring instruments 24 for measuring the orientation of the contact surface are respectively provided on the multiple wheels 16, and the control unit 30 calculates the deformation amounts of the suspension mechanism 14 when moving forward in multiple traveling directions respectively based on the measurement results of the measuring instruments 24. According to this structure, an appropriate mobile path can be selected without attempting to move the mobile device 10. Therefore, efficient movement of the mobile device 10 can be achieved.

[0070] Further, for the mobile device 10 according to the embodiment, it includes an input unit 31 that inputs a second selection condition for selecting a mobile path. And the control unit 30 selects a mobile path based on at least a first selection condition based on the deformation amount of the suspension mechanism 14 and the second selection condition described above. Therefore, for example, according to other conditions such as the direction towards the end point Q2, the mobile device 10 can be made to travel along a mobile path with fewer unevennesses.

[0071] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. For example, in the above embodiments, an example is shown in which the control unit 30 selects a movement path that reduces the deformation amount θ of the suspension mechanism 14. However, the control unit 30 may also select a movement path that reduces the change amount Δθ of the deformation amount of the suspension mechanism 14 (the change amount Δθ of the deformation amount θ per unit travel distance or the change amount Δθ of the deformation amount θ per unit time, etc.). By such control, it is possible to reduce traveling through sharp unevenness. And, in the above embodiments, a structure is shown in which the mobile device can move on a wall surface, a top surface, etc. by the adsorption of a magnet, but the mobile device may also have a structure that does not have such an adsorption effect. And, the magnet can be arranged outside the wheels. And, the drive structure of the plurality of wheels is not limited to the examples of the above embodiments. For example, it may be a structure in which the plurality of wheels can be independently driven respectively, a structure in which turning is performed by setting a rotational speed difference between the left and right wheels, etc. For example, a steering mechanism that turns the orientation of the rotation axis of one or more wheels may be provided, and it may be configured to be able to change the traveling direction by the steering mechanism. And, the plurality of wheels may include wheels that generate driving force and driven wheels. And, the mobile device of the present invention can also be used as a mobile robot that moves on each part of a building, etc. in fields such as shipbuilding and heavy industry fields, construction and building fields, infrastructure inspection and maintenance fields, etc. In addition, within the scope not departing from the gist of the invention, the details shown in the embodiments can be appropriately changed.

[0072] The disclosures of the specification, drawings, and abstract included in the Japanese application of Japanese Patent Application No. 2022-195316 filed on December 7, 2022 are incorporated herein by reference.

[0073] Industrial Applicability

[0074] The present invention can be used for mobile devices.

[0075] Reference Signs

[0076] 10 - Mobile device, 14 - Suspension mechanism (deformation mechanism), 16 - Wheel, 16a - First wheel, 16b - Second wheel, 16c - Third wheel, 16d - Fourth wheel, 19 - Magnet, 192 - Linkage mechanism, 20A - First frame, 20B - Second frame, 21 - Drive unit, 24, 141 - Measuring instrument, 30 - Control unit, 31 - Input unit, Sa to Sd - Contact surface, At - Torsion direction, θ, θ 1 、θ 2a 、θ 2b 、θ 2c - Deformation amount.

Claims

1. A mobile device, comprising: A deformation mechanism capable of changing the relative arrangement relationship of a plurality of wheels; and A control unit that selects a movement path according to the deformation amount of the deformation mechanism.

2. The mobile device according to claim 1, wherein, The plurality of wheels include a first wheel and a second wheel, The deformation mechanism can change the arrangement relationship between the first wheel and the second wheel in the torsional direction.

3. The mobile device according to claim 1, wherein, The plurality of wheels are spherical.

4. The mobile device according to claim 1, wherein, The control unit compares the deformation amounts when moving forward in a plurality of traveling directions respectively, and selects the traveling direction in which the deformation amount becomes smaller.

5. The mobile device according to claim 4, further comprising: A measuring instrument that measures the orientation of the contact surface of each of the plurality of wheels, The control unit estimates the deformation amounts when moving forward in the plurality of traveling directions respectively according to the measurement results of the measuring instrument.

6. The mobile device according to claim 1, comprising: An input unit that inputs a second selection condition for the movement path, The control unit selects the movement path according to the deformation amount of the deformation mechanism and the second selection condition.

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