JP2016033010A - Mobile robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile robot capable of surely moving without falling off from a cylindrical body.SOLUTION: A mobile robot according to the present invention that moves on a cylindrical body whose surface is made of metal and along its axial direction comprises a body part, at least a pair of wheel parts arranged on both sides of the body part and rotationally driven, and a holding part mounted to the body part and having a pair of holding members mounted to the body part and sandwiching the cylindrical body from radially outward. Each of the wheel parts comprises a base, a plurality of bar-like members radially projecting from the base, and a magnet mounted on a tip of each bar-like member. A contact angle of the magnet with respect to the surface of the cylindrical body can be adjusted.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mobile robot.

  Conventional inspection work for a conventional bridge has been performed after a work scaffold is installed below the bridge. That is, a working scaffold is laid down below the bridge, and an environment in which workers can come and go is constructed, and the worker inspects the lower part of the bridge from the scaffold. In addition, when the road below the bridge is a road, an aerial work vehicle is installed on the road to inspect the lower part of the bridge. In addition, inspection work may be performed using a crane type inspection vehicle.

  However, in such work, there is a problem that it takes time to prepare for installation of a working scaffold, installation of a special vehicle, etc., and the burden on the operator is heavy. In order to solve this problem, for example, Non-Patent Document 1 discloses a robot equipped with an endless track and a permanent magnet, and the bridge steel plate with the endless track while adsorbing the robot to the bridge plate with the permanent magnet. It is comprised so that it may move along. The bridge is inspected with the camera mounted on the robot.

  Incidentally, the bridge to be inspected includes not only a flat inspection object but also an inspection object made of a cylindrical body. Such a cylindrical inspection object is difficult to maintain a contact state with the robot, and thus it is difficult to move on the cylindrical body. On the other hand, for example, Patent Document 1 discloses a traveling vehicle having a pair of wheels provided with magnets. In this traveling vehicle, both wheels are in contact with the surface of the cylindrical body vertically. The wheel angle can be changed. Thereby, a wheel can be firmly fixed to the surface of a cylindrical body.

Japanese Utility Model Publication No. 62-35211

iXs Research Corp., “Ultrasonic flaw detection robot for bridge steel floor slab”, [online], [Search date on November 22, 2012] Internet <http://www.ixs.co.jp/products/robot/saut -robot-j.html>

  However, since the mobile robot of the above-mentioned Patent Document 1 simply holds the cylindrical body between the wheels, the movement in the axial direction is still unstable and it is difficult to use it for inspection of the bridge.

  Thus, since the inspection robot currently proposed has a problem in practical use and cannot be used for a cylindrical inspection object, improvement has been demanded. In addition to inspecting bridges, such problems are problems that can occur in general robots that move on a cylindrical target surface made of metal, and are not limited to cylinders, but are formed into cylinders. This is also a problem that can occur when inspecting the target surface.

  Accordingly, the present invention has been made to solve such a problem, and an object thereof is to provide a mobile robot that can move reliably without dropping from the cylinder.

  The present invention is a mobile robot that moves along the axial direction on a cylinder whose surface is made of metal, and is provided with a main body portion and at least a pair of wheel portions that are arranged on both sides of the main body portion and are driven to rotate. And a clamping part having a pair of clamping members that are attached to the main body part and sandwich the cylindrical body from the outside in the radial direction, and each wheel part includes a base part and a plurality of radially projecting parts from the base part A rod-shaped member and a magnet attached to the tip of each of the rod-shaped members are provided so that the contact angle of the magnet with respect to the surface of the cylindrical body can be adjusted.

  According to this structure, each wheel part is comprised by the several rod-shaped member attached radially and the magnet attached to the front-end | tip part. Thereby, the mobile robot can be attracted to the target surface made of metal by the magnet. Since any of the magnets is always attracted to the target surface as the wheel portion rotates, it can be prevented that the mobile robot moves away from the target surface even if the mobile robot moves. In addition, since the rod-shaped members are arranged radially, for example, even when a step is provided on the surface of the cylinder, the step enters between adjacent rod-shaped members, so that the step can be overcome. .

  Moreover, it is comprised so that adjustment of the contact angle of the magnet of a wheel part is possible with respect to the surface of a cylinder. Therefore, since the contact angle of the magnet can be optimally adjusted in accordance with the diameter of the cylinder, it is possible to prevent dropping from the target surface.

  Furthermore, since it has a clamping part having a pair of clamping members that clamp the cylindrical body from the outside in the radial direction, the main body part can be prevented from being displaced from the cylindrical body, and the main body part is in the axial direction of the cylindrical body. It can be ensured that it can move along. For example, when there is no clamping part, if one wheel part is deficient, such as idle rotation, the main body part turns by driving the other wheel part and cannot move in the axial direction, or it is detached from the cylinder There is a risk. On the other hand, like the present invention, separately from the wheel portion, by providing a clamping member that sandwiches the cylinder, the rotational speed of the left and right wheel portions is different, or one wheel portion has a problem, Alternatively, even if there is a difference in the rotation of the left and right wheel portions due to the irregularities on the surface of the cylinder, the mobile robot can be reliably moved along the axial direction. For this reason, if a camera, a sensor, or the like is mounted on this mobile robot, even a target surface that cannot be directly inspected by an operator can be inspected by the mobile robot.

  As described above, there are various methods for configuring the main body portion so that the contact angle of the magnet with the surface of the cylindrical body can be adjusted. For example, the main body portion can be configured as follows. That is, the main body portion includes a pair of support members to which the wheel portions are respectively attached, and the both support members are configured to be adjustable in angle. Thereby, the angle of two wheel parts can be changed by adjusting the angle of both support members. For example, when the angle formed by the two support members is 0 degree, the two wheel portions are parallel to each other, but the end portions (magnets) of the wheel portions face each other by changing the angles of the two support members. Can be. Thereby, a cylinder can also be pinched | interposed with a wheel part.

  The sandwiching portion can have various configurations. For example, the sandwiching portion can be configured to extend from the main body portion in the axial direction of the cylindrical body and include an extension portion to which the sandwiching member is attached.

  Further, when the main body portion is constituted by a pair of support members, the clamping portion can be constituted as follows. That is, the sandwiching portion includes a pair of extension members extending from the main body portion in the axial direction of the cylindrical body, the sandwiching members are attached to the extension members, and the extension members are connected to the support members. Attach to each. By doing so, when the angles of the two supporting members are changed, the angles of the both holding members can also be changed. Thereby, according to the diameter of a cylinder, the angle of both clamping members can be changed and a cylinder can be clamped.

  In each of the above mobile robots, at least one auxiliary wheel capable of contacting the surface of the cylindrical body can be provided in the holding portion. Thereby, a clamping part can be moved smoothly along a cylinder.

  Each of the mobile robots may further include a communication unit that wirelessly receives a signal for driving the wheel unit from the outside. In this way, the mobile robot can be remotely operated from a remote position, and for example, inspection of a bridge or the like can be easily performed. In addition to this, it is also possible to configure not to perform remote operation but to automatically move along a predetermined route.

  In each of the mobile robots described above, the distance between the axis of the wheel portion and the center of gravity of the mobile robot, and the distance along the axial direction of the cylindrical body can be within 10 mm. Thereby, the pitching during traveling of the mobile robot can be reduced.

  In each of the mobile robots, the distance between the axis of the wheel unit and the center of gravity of the mobile robot, and the distance along the axial direction of the cylindrical body is the distance between the axis of the wheel unit and the extension member. It can be within 10% of the length to the tip.

  With the mobile robot according to the present invention, it is possible to reliably move the cylinder.

It is a top view of the mobile robot which concerns on one Embodiment of this invention. It is a front view of FIG. It is a side view of FIG. It is a front view for demonstrating the angle change of the mobile robot of FIG. It is a circuit diagram which shows an example of a structure of the motor driver used for the mobile robot of FIG. It is a figure which shows schematic structure of the mysterious gear mechanism used for the mobile robot of FIG. It is a model figure which examines the magnetic force of a magnet. It is a graph which shows the relationship between the magnetic force of the magnet in the model of FIG. 7, and the distance with steel materials. It is a model figure which examines the magnetic force of the inclined magnet. It is a graph which shows the relationship between the magnetic force of the magnet in the model of FIG. 9, and the distance with steel materials. It is a model figure of the mobile robot which moves a cylindrical body. It is a model figure of the mobile robot which moves on a flat steel plate. It is a side view of the model of the mobile robot which examined pitching. It is a top view part of FIG. It is a graph which shows the time change of pitch angle (theta).

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, an embodiment of a mobile robot according to the present invention will be described with reference to the drawings. 1 is a plan view of the mobile robot, FIG. 2 is a front view of FIG. 1, and FIG. 3 is a side view of FIG. The mobile robot according to the present embodiment is for inspecting a building made of steel (metal) such as a bridge, and in particular, inspecting while moving on a cylindrical body whose surface is made of metal. Is to do.

  As shown in FIG. 1, the mobile robot includes a main body 1, a pair of wheel parts 21 and 22 attached to both sides of the main body 1, and a pair of wheel drives that respectively drive the wheel parts 21 and 22. Parts 31 and 32. The main body 1 is attached with a clamping portion 8 for sandwiching the cylindrical body. Hereinafter, each member will be described in detail. In FIG. 2 and FIG. 3, for convenience of explanation, some members are omitted.

<1. Main unit>
As shown in FIGS. 1 to 3, the main body 1 includes a pair of plate-like support members 11 and 12, and these support members 11 and 12 are connected to each other via a hinge 13 so that the angle can be adjusted. Has been. The wheel members 21 and 22 are attached to the support members 11 and 12, respectively. Here, since each support member 11 and 12, each wheel part 21 and 22, and each wheel drive part 31 and 32 are the substantially same structures, below, about the member of the same structure for convenience of explanation, FIG. The member disposed on the right side is referred to as the first member and the member disposed on the left side is referred to as the second member. For example, the support member disposed on the right side in FIG. 2 is referred to as a first support member 11, and the support member disposed on the left side is referred to as a second support member 12. Hereinafter, the direction in which the mobile robot moves on the cylindrical body may be referred to as the front-rear direction or the axial direction, and the direction perpendicular thereto, that is, the direction in which the support members 11 and 12 are arranged is referred to as the width direction or the left-right direction.

  First, the connection between the first support member 11 and the second support member 12 will be described. Each support member 11, 12 is formed in a rectangular plate shape, is arranged so that one side faces each other, and is connected by a hinge 13. And the angle of both the supporting members 11 and 12 can be adjusted with the angle adjustment mechanism 4 mentioned later.

  Further, a main controller 5 for driving the wheel portions 21 and 22 and the angle adjusting mechanism 4 is attached to the lower surface of the first support member 11, and the main controller 5 is driven to a driving DC motor described later. A signal is transmitted. In addition, an operation signal is transmitted to the main controller 5 from a receiver 6 similarly attached to the first support member 11. A radio signal for operation is transmitted to the receiver 6 from a transmitter (not shown) outside the robot. On the other hand, the battery box 7 is provided in the 2nd supporting member 12, and this becomes a power supply of each DC motor and another electronic device.

  Next, the angle adjustment mechanism 4 will be described with reference to FIG. FIG. 4 is a front view for explaining the angle change of the mobile robot. As shown in the figure, a third motor 41 for angle adjustment is provided on the upper surface of the second support member 12, and the first link member 42 is fixed to the rotation shaft of the third motor 41. The first link member 42 has one end fixed to the rotation shaft of the third motor 41 and the other end extending so as to face the first support member 11 side. The second link member 43 is swingably connected to the other end. The second link member 43 has one end connected to the first link member 42 and the other end connected to the upper surface of the first support member 11 so as to be swingable.

  With this configuration, when the third motor 41 is driven and the first link member 42 swings away from the second support member 12, for example, as shown in FIG. The angle formed by the member 42 and the second link member 43 is reduced. Thereby, the 2nd link member 43 rocks the 2nd support member 12 with respect to the 1st support member 11, and the angle which both the support members 11 and 12 make becomes small. Thus, by driving the third motor and swinging the first link member, the angles of the support members can be adjusted, whereby the angles of the wheel portions 21 and 22 are also changed. For example, as shown in FIG. 4A, when both support members 11 and 12 are arranged in parallel, the tip portions of the wheel portions 21 and 22 are parallel, but in FIG. As shown, when the angles of the support members 11 and 12 are changed, the angles of the front end portions of the wheel portions 21 and 22 are also changed to follow the curved surface.

<2. Wheel part and wheel drive part>
Next, the structure of the wheel parts 21 and 22 and the wheel drive parts 31 and 32 that drive them will be described. Since the configurations of the wheel units 21 and 22 and the wheel drive units 31 and 32 are substantially the same, the first wheel unit 21 and the first wheel drive unit 31 attached to the first support member 11 will be described below.

  As shown in FIGS. 1 to 3, a first motor driver 311, a first DC motor 312, and a first gear box 313 constituting the first wheel drive unit 31 are attached to the lower surface of the first support member 11. Yes. The first motor driver 311 is electrically connected to the main controller 5, the battery box 7, and the first DC motor 312, receives the drive signal transmitted from the main controller 5, and is supplied from the battery box 7. The first DC motor 312 is driven by the current.

  The configuration of the first motor driver 311 is not particularly limited, and various types can be cited. For example, as shown in FIG. 5, a variable speed type using four FETs and two NPN transistors. An H-bridge circuit can be employed.

  A drive shaft (not shown) of the first DC motor 312 is connected to the first gear box 313. The first gear box 313 includes an output shaft 314. The output shaft 314 protrudes to the side of the first support member 11, and the first wheel portion 21 is connected to the first gear box 313. With this configuration, the rotation of the drive shaft of the first DC motor 312 is decelerated and output from the output shaft 314. The first gear box 313 can have various configurations. In addition to a normal gear, a planetary gear mechanism or a mysterious gear mechanism can be used, or these can be appropriately combined.

Here, as an example, a gear box in which a mysterious gear as shown in FIG. 6 is combined with a normal gear can be used. As shown in the figure, the mysterious gear mechanism is a modification of the planetary gear mechanism including the sun gear G1, the planetary gear G2, the planetary carrier G3, the fixed gear G4, and the outer gear G5. In the planetary gear G2 of the planetary gear mechanism, The number of teeth meshing with the fixed gear G4 is equal to the number of teeth meshing with the outer gear G5. The reduction gear ratio of this mysterious gear is obtained by the following equation. Z _S is the number of teeth of the sun gear G1, Z _F is the number of teeth of the fixed gear G4, and Z _O is the number of teeth of the outer gear G5.

For example, if the number of teeth Z _S of the sun gear G1 is 8, the number of teeth Z _F of the fixed gear G4 is 50, and the number of teeth Z _O of the outer gear G5 is 48, the reduction ratio R _gear is calculated to be −174, and in the reverse rotation direction. It decelerates significantly and rotates. The motor torque is increased by (174 × transmission efficiency η) times by this reduction mechanism. The transmission efficiency η can be obtained by the following equation, assuming that the transmission efficiency between individual gears is uniformly ηg in the Kudryavtsev equation.

  For example, when ηg = 90%, η = 42.3% is calculated, and when ηg = 85%, η = 21.6%.

  In order to further improve the reduction ratio, the first gear box 313 has a small gear attached to the output shaft of the mysterious gear, the large gear meshed with the small gear, and the output shaft 314 attached to the large gear. Can do. As an example, if the number of teeth of the small gear is 16 and the number of teeth of the large gear is 72, the reduction ratio is 4.5. As a result, the reduction ratio of the first gear box 313 is 774 (= 172 * 4.5).

  Next, the first wheel portion 21 will be described with reference to FIG. As shown in FIG. 3, the first wheel portion 21 includes a cylindrical base portion 211 connected to the output shaft 314, and eight rod-like members 212 protruding radially from the base portion 211. That is, the bar-shaped member 212 is provided every 45 degrees from the outer peripheral surface of the base 211, and a magnet 213 is attached to the tip of each bar-shaped member 212. However, the number of the rod-shaped members 212 can be changed as appropriate, and can be, for example, 8 to 10 (the angle between adjacent rod-shaped members 212 is 45 to 36 °). If this is less than eight, as will be described later, depending on the rotational position of the wheel portions 21, 22, the magnets 213, 223 may not be attracted to the cylindrical body in either of the two wheel portions 21, 22. This is because, if there are more than ten, for example, when there is a step on the surface of the cylindrical body, the gap between the rod-shaped members 212 becomes too narrow, and the step may not enter the gap.

  The magnet 213 is formed in a cylindrical shape having an internal space, and a screw (not shown) inserted into the internal space is screwed to the tip of the rod-shaped member 212. Thereby, the magnet 213 can rotate around the axis of the rod-shaped member 212. The magnet 213 used here is a permanent magnet. Although the kind is not specifically limited, For example, a neodymium magnet can be used. A rubber adhesive can be applied to the surface of the magnet 213 as necessary. This is for suppressing slippage between the magnet 213 and the cylindrical body. As the adsorption strength of the magnet 213 to the cylindrical body (metal surface), for example, it is preferable that the weight of an object that can be supported by one magnet 213 is larger. For example, as the performance required for the magnet 213 used here, the weight that can be supported by one magnet 213 is preferably 1 or more times the weight of the mobile robot, more preferably 2 or more times, It is particularly preferably 3 times or more. However, this is intended for use under severe conditions where the mobile robot moves in a state of hanging from the cylindrical body. When moving the upper surface of the cylindrical body extending in the horizontal direction, It may be smaller than the weight.

  Moreover, since the 1st wheel part 21 rotates, the magnet 213 repeats adsorption | suction and detachment | leave to a cylindrical body with rotation of the wheel part 21. FIG. Therefore, if the magnet 213 is attracted too strongly, there is a problem that it cannot be detached.

  For example, as shown in FIG. 7, when a magnet composed of a neodymium magnet having a diameter of 8 mm, a thickness of 5 mm, and a surface magnetic flux density of 0.45 T is considered, if this magnet is adsorbed to a steel material, it will be pulled away unless a force of 15 N or more is applied. I can't. Therefore, when a distance L is provided between the magnet and the steel material, the magnetic force decreases according to the distance L as shown in FIG. FIG. 8 is a plot of the results obtained using the magnet air gap magnetic flux density / adsorption force calculation tool of Neomag Co., Ltd. When the distance to the magnet is 0.4 mm, the magnetic force is obtained as 14.7N. Here, since the analysis becomes theoretically difficult when the distance between the magnet and the steel material is extremely short, the area of 0.0 mm <L <0.4 mm is assumed to be 14.7 N, which is the same as 0.4 mm. To do. And if the wheel part rotates a little (angle (alpha)) from the state which the magnet and steel materials are contacting in the surface, the distance between a magnet and iron materials changes with places like FIG. For example, when L = c, the magnetic force Fm can be obtained by integration as in the following equation. The numerical calculation result in the case of c = 0.4 mm is shown in FIG.

  Here, r is the radius of the magnet. When α = 22.5 °, Fm is about 1.2N. Therefore, it is reduced to 8% compared to when α = 0, and the force for pulling the magnet 213 away from the cylindrical body is small. Therefore, if the torque which acts on the base part 211 of the wheel part 21 is adjusted, and the entire lower surface of the magnet 213 is in contact with the cylindrical body 100, a force for separating the magnet from the cylindrical body 100 can be applied. Since the magnet 213 is inclined from the cylindrical body by the rotation of the portion 21, the magnetic force is reduced.

<3. Nipping part>
Next, the clamping part 8 is demonstrated. As shown in FIGS. 1 to 3, the clamping unit 8 includes extension members 81 and 82 attached to the support members 11 and 12, and clamping members 831 and 832 attached to the extension members 81 and 82, respectively. It is equipped with. That is, the first extension member 81 and the first clamping member 831 are attached to the first support member 11, and the second extension member 82 and the second clamping member 832 are attached to the second support member 12.

  The first extending member 81 includes a rod-shaped first horizontal portion 811 extending rearward from the first support member 11 and a rod-shaped portion extending vertically (upward in FIGS. 2 and 3) from the rear end portion of the first horizontal portion 811. And an L-shape having a first vertical portion 812. A first auxiliary wheel 841 is rotatably attached to the tip of the first vertical portion 812. At this time, the length of the first vertical portion 812 is such that the vertical distance from the upper surface of the first support member 11 of the first auxiliary wheel 841 is substantially the same position as the magnet 213 of the first wheel portion 21 described above. Is set. Further, the above-described first clamping member 831 is attached to the tip of the first vertical portion 812. The first clamping member 831 is a rod-shaped member formed in an arc shape, and extends upward from the tip of the first vertical portion 812.

  The second extending member 82 and the second holding member 832 are configured in the same manner, but the second holding member 832 is formed in a target shape with the first holding member 831. That is, the first and second clamping members 831 and 832 are both formed in an arc shape that is convex outward in the width direction, and the cylindrical body is sandwiched from below by these clamping members 831 and 832. It is like that. At this time, it is preferable that the holding members 831 and 832 are formed of a deformable (elastically or plastically deformable) material along the outer peripheral surface of the cylindrical body.

<4. Movement of mobile robot>
As shown in FIG. 11, the mobile robot configured as described above moves on the surface of a cylindrical body 100 made of a steel material such as a bridge. Therefore, although illustration is omitted, if a camera or various sensors (for example, a temperature sensor, an eddy current type flaw detection probe, an ultrasonic sensor, a radar exploration system, etc.) are attached to the main body 1, the surface of the building can be inspected. it can.

  At that time, the worker first installs the mobile robot on the surface of the cylindrical body 100. At this time, the angle adjustment mechanism 4 is driven to adjust the angles of the support members 11 and 12 so that the tip surfaces of the magnets 213 of the respective wheel portions 21 are in contact with the cylindrical body 100 substantially in parallel. Thereby, one of the magnets 213 and 223 is firmly attracted to the cylindrical body 100 in each of the two wheel portions 21 and 22, and the mobile robot is fixed to the cylindrical body 100. At the same time, the cylindrical body 100 is sandwiched between the both clamping members 831 and 832. Since the distance between both the clamping members 831 and 832 is narrowed by the angle of the support members 11 and 12, the cylindrical body 100 can be firmly clamped. Further, as long as each of the clamping members 831 and 832 can be deformed, it may be appropriately deformed along the surface of the cylindrical body 100.

  Thus, when the mobile robot is mounted on the cylindrical body 100, an operation signal is transmitted from the outside to the mobile robot receiver 6 by a wireless transmitter. At this time, the operator does not perform installation on the cylindrical body 100 but can also attach the cylindrical body 100 by operating the mobile robot.

  Then, when the receiver 6 receives a signal, this signal is transmitted to the main controller 5. The main controller 5 processes this signal and sends it to the first and second motor drivers 311 and 321, respectively. These motor drivers 311 and 321 receive a forward or reverse command signal (hereinafter referred to as an FWD signal or a BWD signal) and a PWM signal for controlling a voltage applied to the motor. For example, when the receiver 6 receives the forward signal, the main controller 5 transmits an FWD signal and a PWM signal having a high duty ratio to the motor drivers 311 and 321. As a result, the first and second DC motors 312 and 322 rotate in the positive direction at the same rotational speed.

  At this time, each wheel part 21, 22 rotates, and at least one magnet 213, 223 is attracted to the cylindrical body 100 by each wheel part 21, 22, so that the mobile robot can move while being attracted to the cylindrical body 100. . Therefore, the mobile robot can be moved while being suspended from the cylindrical body 100.

  In addition to moving on the cylindrical body 100, it is also possible to move on a flat steel plate (metal surface). In this case, as shown in FIG. 12, the magnet of the wheel unit 21 is placed on the steel plate H with the lower surface of the support member 11 facing downward and the sandwiching member 831 extending from the steel plate H in the opposite direction. Adsorb. Thereby, the mobile robot can move on the steel plate while dragging the holding part 8. At this time, if the PWM signal having a different duty ratio is transmitted between the first DC motor on the right side and the second DC motor on the left side so that a difference occurs between the rotation speeds of the left and right wheels, the mobile robot turns to the right or left side. To do.

<5. Features>
As described above, according to the present embodiment, each wheel portion 21, 22 is composed of a plurality of rod-like members 212, 222 attached radially and magnets 213, 223 attached to the tip portions thereof. . Thereby, the mobile robot can be attracted to the cylindrical body 100 made of metal by the magnets 213 and 223. Since any of the magnets 213 and 223 is always attracted to the cylindrical body 100 as the wheel portions 21 and 22 rotate, it is prevented from falling off the cylindrical body 100 even if the mobile robot moves. Can do. Further, since the rod-shaped members 212 and 222 are arranged radially, for example, even when a step is provided on the surface of the cylindrical body 100, the step enters between the adjacent rod-shaped members 212 and 222. Can be overcome.

  Further, by changing the angles of the support members 11 and 12, the contact angles of the magnets 213 and 223 of the wheel portions 21 and 22 can be adjusted with respect to the surface of the cylindrical body 100. Therefore, the contact angle of the magnets 213 and 223 can be optimally adjusted in accordance with the diameter of the cylindrical body 100, so that the mobile robot can be prevented from falling off the cylindrical body 100. Particularly, it is advantageous when the diameter of the cylindrical body 100 is small, and the magnets 213 and 223 can be firmly adsorbed even if the outer diameter of the cylindrical body 100 is smaller than the width of the mobile robot. At this time, if the contact angle of the magnets 213 and 223 with respect to the surface of the cylindrical body 100 is vertical, the magnets 213 and 223 are firmly adsorbed to the cylindrical body 100, so that the falling off from the cylindrical body 100 is surely prevented. be able to. For example, when the outer diameter of the cylindrical body 100 is equal to or greater than half the width of the mobile robot, the mobile robot can be reliably adsorbed to the cylindrical body.

  Furthermore, since the clamping unit 8 having a pair of clamping members 831 and 832 that sandwich the cylindrical body 100 from the outside in the radial direction is provided, the main body unit 1 can be prevented from being displaced from the cylindrical body 100. 1 can be reliably moved along the axial direction of the cylindrical body 100. For example, the rotational speeds of the left and right wheel parts 21 and 22 are different, a problem occurs in one of the wheel parts 21 and 22, or the left and right wheel parts 21 and 22 rotate due to unevenness on the surface of the cylindrical body 100. Even if a difference occurs, the pair of clamping members 831 and 832 can prevent the traveling direction of the mobile robot from being bent, so that the mobile robot can be reliably moved along the axial direction.

  In the above-described embodiment, the mobile robot is attached to the lower surface of the cylindrical body 100 extending in the horizontal direction. However, the mobile robot can be attached to the upper surface and side surfaces of the cylindrical body 100. Further, even when the cylindrical body 100 extends vertically or obliquely, the mobile robot can naturally move without dropping off.

  By the way, the present inventor has a phenomenon called so-called pitching in which the extension members 81 and 82 vibrate around the axis of the wheel portions 21 and 22 of the main body 1 while the mobile robot is traveling. Found that there is. If such pitching frequently occurs during traveling of the mobile robot, the mobile robot may fall off the traveling surface, particularly the cylindrical body 100. Therefore, a method for reducing pitching was examined as follows.

  As shown in FIG. 13, when pitching occurs, the extension members 81 and 82 vibrate at a pitch angle θ about the shaft centers of the wheel portions 21 and 22. Here, as shown in FIG. 14, the inventor passes a distance Lg in the front-rear direction between the axis S of the wheel portions 21 and 22 and the gravity center position G of the mobile robot in the plan view (through the center in the width direction). It was found that the pitching varies depending on the distance on the straight line N). Therefore, a flat ceiling surface 100 is provided for six types of mobile robots in which the distance Lg is changed to −5 mm, 0 mm, 5 mm, 10 mm, 12.5 mm, and 15.0 mm (minus is the left side of FIG. 14 from the axis S). And the change of the pitch angle θ (°) for 5 seconds was determined. However, the weight of each mobile robot is 380 g, the total length Lx of the mobile robot is 180 mm, the diameters of the wheel portions 21 and 22 are 110 mm, and the horizontal portions 811 and 821 of the extension members 81 and 82 from the axis S of the wheel portions 21 and 22. The length Lk to the tip was set to 125 mm. The results are as shown in FIG.

  As shown in FIG. 15, it can be seen that as the absolute value of the distance Lg increases, pitching occurs and the pitch angle θ increases. This is because the extension members 81 and 82 are easily separated from the ceiling surface 100 when the center of gravity G of the mobile robot is behind the axis S of the wheel portions 21 and 22. Therefore, it is preferable that the center of gravity G of the mobile robot is as close as possible to the axis S of the wheel portions 21 and 22, and the absolute value of the distance Lg is 10 mm or less. Alternatively, the distance Lg may be within 10% of the length Lk from the axial center S of the wheel portions 21 and 22 to the distal ends of the horizontal portions 811 and 821 of the extension members 81 and 82.

  In particular, when the center of gravity G is in front of the axis S (on the side opposite to the extension members 81 and 82), the extension members 81 and 82 can easily come into contact with the ceiling surface 100, so that pitching can be reduced. However, it is difficult to dispose the center of gravity G in front of the axis S because of the structure of the mobile robot. In this respect, the distance Lg is preferably in the range of −5 mm to 10 mm, and more preferably −5 mm to 0 mm.

  As described above, in order to reduce pitching during traveling, it is preferable to reduce the distance Lg, and in particular, to arrange the center of gravity G in front of the axis S. For this purpose, for example, FIG. In the example, the main controller 5, the receiver 6, the battery box 7, the motor drivers 311, 321, etc. Is preferably arranged on the opposite side.

<6. Modification>
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning.

<6.1>
In the above-described embodiment, the pair of wheel portions 21 and 22 are provided in the main body portion 1, but two or more pairs of wheel portions can be provided.

<6.2>
In the above embodiment, the two support members 11 and 12 are provided. However, for example, three or more support members may be connected to change the angle.

<6.3>
In the said embodiment, in order to change the angle of the wheel parts 21 and 22, the angle of the support members 11 and 12 is changed, However, The method is not specifically limited, The method other than the said embodiment may be used. Moreover, you may enable it to change the angle of the wheel parts 21 and 22 with respect to the supporting members 11 and 12 instead of changing the angle of both the supporting members 11 and 12, for example. Or the attachment angle of the rod-shaped members 212 and 222 and the magnets 213 and 223 may be changed.

<6.4>
In addition, the auxiliary wheels 841 and 842 are not necessarily required, and may be configured not to be provided. However, if the auxiliary wheels 841 and 842 are provided, the cylinder body 100 can be moved smoothly.

<6.5>
In the above embodiment, the clamping members 831 and 832 are configured to be displaced in conjunction with the support members 11 and 12, but the distance between the clamping members 831 and 832 is independent of the support members 11 and 12. You may make it changeable. Moreover, the structure of the clamping part 8 and the clamping members 831 and 832 is not specifically limited, What is necessary is just to be comprised so that a cylindrical body may be clamped. Therefore, for example, one extension portion having the same configuration as the extension members 81 and 82 can be provided, and the clamping members 831 and 832 can be provided here. Alternatively, the clamping members 831 and 832 can be provided directly on the main body 1 without providing the extension members 81 and 82.

<6.6>
In the above-described embodiment, the motors 312 and 322 are provided as the drive units for the wheel units 21 and 22, respectively, and the wheel units 21 and 22 are configured to be driven independently. It is not limited to. For example, all the wheel portions can be driven by one motor. In this case, it is necessary to provide a coupling mechanism and a steering mechanism that can drive a plurality of wheel portions with one motor. The number of motor drivers can be changed as appropriate according to the number of motors.

<6.7>
In the above embodiment, the mobile robot is operated wirelessly, but the main controller may be set so that the mobile robot follows the designated route so as to automatically operate without using the wireless.

<6.8>
The positions of the battery box 7, the main controller 5, the receiver 6, the motor drivers 311 and 321, the motors 312 and 322, the gear boxes 313 and 323, and the like shown in the above embodiment can be changed as appropriate. It suffices if they are arranged at such positions. Further, the form of the main body 1 is not limited to that described above, and may be any form as long as it can support the above-described members such as the battery box 7 and the motors 312 and 322, and may be other than those described above. Moreover, you may divide | segment into plurality.

<6.9>
The mobile robot of the above embodiment has been described as an inspection robot such as a bridge, but is not limited to this, and can be applied to all robots that move on a metal target surface such as steel. Therefore, the present invention can be applied not only to inspection but also to a transfer robot, a narrow area unknown space mapping robot, and the like.

<6.10>
In the said embodiment, although the test object surface was the cylindrical body 100, if the cross section is a cylindrical body, the mobile robot which concerns on this invention is applicable.

DESCRIPTION OF SYMBOLS 1: Main-body part 11: 1st support member 12: 2nd support member 21: 1st wheel part 22: 2nd wheel part 8: Clamping part 81: 1st extension member 82: 2nd extension member 831: 1st clamping member 832: Second clamping member

Claims (8)

A mobile robot that moves along the axial direction on a cylindrical body whose surface is made of metal,
The main body,
At least a pair of wheel portions disposed on both sides of the body portion and driven to rotate;
A sandwiching part attached to the main body part and having a pair of sandwiching members sandwiching the cylindrical body from the outside in the radial direction;
With
Each wheel part is
The base,
A plurality of rod-shaped members projecting radially from the base, and a magnet attached to the tip of each rod-shaped member;
With
A mobile robot configured to be capable of adjusting a contact angle of the magnet with respect to a surface of the cylindrical body. The body portion includes a pair of support members to which the wheel portions are respectively attached.
The mobile robot according to claim 1, wherein the both support members are configured to be adjustable in angle.   3. The mobile robot according to claim 1, wherein the holding portion includes an extension portion to which the holding member is attached while extending in the axial direction of the cylindrical body from the main body portion. The clamping part includes a pair of extending members extending from the main body part in the axial direction of the cylindrical body,
Each of the extending members is attached with the holding member,
The mobile robot according to claim 2, wherein each extension member is attached to each support member.   The mobile robot according to any one of claims 1 to 4, wherein the clamping unit includes at least one auxiliary wheel capable of contacting the surface of the cylindrical body.   The mobile robot according to claim 1, further comprising a communication unit that wirelessly receives a signal for driving the wheel unit from the outside.   The mobile robot according to any one of claims 1 to 6, wherein a distance between an axis of the wheel unit and a center of gravity of the mobile robot and a distance along an axial direction of the cylindrical body is within 10 mm. .   The distance between the axis of the wheel part and the center of gravity of the mobile robot, and the distance along the axial direction of the cylinder is 10 of the length from the axis of the wheel part to the tip of the extension member. The mobile robot according to claim 4, which is within%.