WO2014087999A1

WO2014087999A1 - Mobile robot

Info

Publication number: WO2014087999A1
Application number: PCT/JP2013/082472
Authority: WO
Inventors: 洋吾高田; 忠雄川合; 洋司川上
Original assignee: 公立大学法人大阪市立大学
Priority date: 2012-12-04
Filing date: 2013-12-03
Publication date: 2014-06-12
Also published as: JP5846516B2; JPWO2014087999A1

Abstract

Provided is a mobile robot capable of reliably moving along an object surface produced from metal regardless of the shape of the object surface. A mobile robot moves over an object surface produced from metal, and is provided with: two or more casing parts which are disposed with a space therebetween; at least one output shaft which is rotatably supported by each of the casing parts; a wheel part which is disposed on each of both sides of each of the casing parts and rotationally driven by each of the output shafts; at least one driving part which rotationally drives the output shaft; and a coupling part which couples the casing parts adjacent to each other and at least part of which is elastically deformable. Each of the wheel parts is provided with a base coupled to the output shaft, a plurality of rod-shaped members radially projecting from the base, and magnets attached to the leading ends of the respective rod-shaped members.

Description

Mobile robot

The present invention relates to a mobile robot.

Conventionally, general inspection work for bridges has been carried out with a work scaffold 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 worker is heavy. In order to solve this, for example, Non-Patent Document 1 proposes a bridge inspection robot. This robot is configured to inspect the bridge with an on-board camera while running while sandwiching the flange below the main girder of the bridge from both sides.

Non-Patent Document 2 discloses a robot equipped with an endless track and a permanent magnet. The robot is attracted to the bridge plate by the permanent magnet, and moves along the bridge plate by the endless track. It is configured. And the bridge is inspected with the installed camera.

However, since the robot described in Non-Patent Document 1 travels with a flange in between, it cannot be used on a bridge without a flange. Further, although the robot described in Non-Patent Document 2 uses an endless track, it can move only on a horizontal plane because it is attracted to the bridge steel plate by a permanent magnet arranged on the bottom surface. Therefore, the bridge steel plate provided with a step cannot be used, and it is difficult to use it for an actual bridge inspection like the robot described in Non-Patent Document 1.

As described above, the currently proposed inspection robot has a problem in practical use and cannot be used depending on the shape of the bridge. In addition to the inspection of bridges, such a problem is a problem that can occur in general robots that move on a target surface made of metal.

Therefore, the present invention has been made to solve such a problem, and a mobile robot capable of reliably moving along the target surface regardless of the shape of the target surface made of metal. The purpose is to provide.

The mobile robot according to the present invention is arranged on two sides of each casing, two or more casing sections arranged at intervals, an output shaft rotatably supported by each casing section, A wheel portion that is rotationally driven by each output shaft, at least one drive portion that rotationally drives the output shaft, a connection portion that connects the adjacent housing portions to each other, and at least a part of which is elastically deformable, The wheel portion includes a base portion connected to the rotating shaft, a plurality of rod-like members projecting radially from the base portion, and a magnet attached to the tip of each rod-like member.

According to this configuration, each wheel portion is composed of a plurality of rod-like members attached radially and a magnet attached to the tip portion thereof. 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. Furthermore, since the rod-shaped members are arranged radially, for example, even when a step is provided on the target surface, the step enters between adjacent rod-shaped members, so that the step can be overcome. Therefore, even if the target surface is not flat but has a complicated uneven shape, the target surface can be moved while being attracted by the magnet, and can be reliably moved on the target surface. 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.

In addition, since the adjacent housing portions are connected by a connecting portion that can be elastically deformed, each housing portion is not restricted by the operation of the adjacent housing, and the motion operation timing of the adjacent housing portion is not limited. The connecting portion can absorb the shift, and smooth operation is possible. For example, the wheel portion rotates while any of the magnets is attracted to the target surface. Therefore, when the mobile robot moves forward, each housing portion moves forward while repeating forward movement and stoppage in small increments. At this time, the mobile robot moves forward as a whole if both of the adjacent front and rear casings are moving forward. For example, when the front casing is stopped, the rear casing moves forward. Even if you try, the mobile robot cannot move forward.

On the other hand, in the present invention, since the adjacent housing parts are connected by the elastically deformable connecting part, when the front housing part stops and the rear housing part moves forward, the rear side While the advancing force of the casing portion is stored by the elastic deformation of the connecting portion, only the casing portion can be advanced a little. The forward force stored in this way is released when the front case moves forward and presses the front case so that it can move forward quickly. Therefore, in the mobile robot of the present invention, the connecting portion can absorb the deviation of the operation between the adjacent housing portions, and can smoothly move.

In the mobile robot, the magnet can be rotatably attached around the axis of the rod-shaped member at the tip of the rod-shaped member.

With this configuration, for example, when the mobile robot turns, the rod-shaped member can rotate in the turning direction even when the magnet is attracted to the target surface. Therefore, the turning operation can be performed smoothly.

The connecting portion can have various configurations, for example, a pair of rod-shaped connecting members formed in a rod shape and a spring member that connects the pair of connecting members. Thereby, the difference in operation between the adjacent casings as described above can be reliably absorbed, and smooth movement is possible. In addition, for example, the connecting portion can be configured by a rod-shaped member formed of an elastic material that is deformable in the axial direction.

In the above mobile robot, the driving unit can be provided for each wheel unit, and the one driving unit can be configured to rotate and drive one wheel unit independently.

According to this configuration, since each wheel part is driven to rotate independently, a high driving force can be obtained as a whole mobile robot, and the rotation of the left and right wheel parts can be changed. Operation can be performed easily.

The mobile robot further includes a communication unit that transmits and receives signals to and from the drive unit, and the communication unit has a function of receiving a signal for driving the drive unit from outside by radio. Can be configured.

In this way, the mobile robot can be remotely operated from a remote position, and for example, inspection of bridges and 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 the above mobile robot, a steering mechanism for steering the wheel portion can be provided in at least one housing portion. The case portion can be turned by changing the rotation speeds of the left and right wheel portions, but the turning radius can be further reduced by steering the wheel portions by the steering mechanism.

The mobile robot according to the present invention can reliably move along the target surface regardless of the shape of the target surface made of metal.

It is the top view (a) of the mobile robot which concerns on one Embodiment of this invention, and the enlarged view (b) of a wheel part. It is a block diagram which shows the electrical structure 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. 5, 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. 7, and the distance with steel materials. It is a model diagram of a mobile robot climbing a vertical plane. It is a perspective view of a mobile robot provided with a steering mechanism. It is a perspective view of a mobile robot provided with a steering mechanism. It is a perspective view of a mobile robot provided with a steering mechanism. It is a perspective view of a mobile robot provided with a steering mechanism. It is a photograph which shows the mobile robot which concerns on an Example.

The mobile robot according to the present embodiment is for inspecting a building made of steel (metal) such as a bridge. Although the details will be described later, the mobile robot is attracted to the steel material by the magnet provided on the wheel portion, and the bridge is inspected by moving while maintaining this state. First, the outline will be described. As shown in FIG. 1, the mobile robot is configured by connecting a front housing part 1 and a rear housing part 2 by a connecting part 3. Each of the

casing parts

1 and 2 is provided with two wheel parts 41 to 44 arranged on the left and right, respectively, and is configured to move by rotation of a total of four wheel parts 41 to 44. These wheel portions 41 to 44 are driven by four independent DC motors 51 to 54, respectively, and drive signals to the motors 51 to 54 are sent from a main controller 6 attached to the rear casing 2. Sent. In addition, an operation signal is transmitted to the main controller 6 from a receiver 7 provided in the rear casing 2. A radio signal for operation is transmitted to the receiver 7 from a transmitter (not shown) outside the robot. In addition, a battery box 8 is provided in the front casing 1 and serves as a power source for the DC motors 51 to 54. Hereinafter, this mobile robot will be described in more detail. In the following, for convenience of explanation, the direction in which both housing parts are arranged may be referred to as the front-rear direction, and the direction perpendicular thereto may be referred to as the width direction or the left-right direction.

<1. Electrical configuration of mobile robot>
First, the electrical configuration of this mobile robot will be described with reference to FIG. FIG. 2 is a block diagram showing an electrical configuration of the mobile robot. Motor drivers 511 to 541 are electrically connected to the DC motors 51 to 54 that drive the wheel portions 41 to 44. The configurations of the motor drivers 511 to 541 are not particularly limited, and various types can be mentioned. For example, as shown in FIG. 3, the variable speed type using four FETs and two NPN transistors. An H-bridge circuit can be employed. Further, a battery box 8 is provided in the front casing 1, and current is supplied from the battery box 8 to the DC motors 51 to 54 via motor drivers 511 to 541. The motor drivers 511 to 541 are electrically connected to the main controller 6 (for example, a microcomputer), and drive signals for driving the DC motors 51 to 54 are transmitted from the main controller 6. As described above, the receiver 7 is connected to the main controller 6, and the receiver 7 that receives a radio signal from the outside transmits an operation signal to the main controller 6. Note that transmission of control signals between devices can be performed not only in one direction but also in two-way communication.

<2. Mechanical configuration of mobile robot>
Next, the mechanical configuration of this mobile robot will be described. In the following description, description of a cable that performs transmission and reception of specific signals is omitted, but description thereof is omitted because it is only necessary to be connected as shown in FIG. First, the front casing 1 will be described. The front casing 1 includes a plate-like base 11 extending in the width direction, and the above-described battery box 8 is attached to the center of the base 11. The

DC motors

51 and 52 and the

gear boxes

61 and 62 described above are disposed on both sides of the battery box 8, respectively. Hereinafter, for convenience of explanation, the DC motor 51 and the gear box 61 arranged on the right side of the battery box 8 are referred to as a first motor and a first gear box, and the left side of the battery box 8 is the second motor 52. This is referred to as a second gear box 62. The motor drivers attached to the

motors

51 and 52 are referred to as first and second motor drivers 511 and 512, respectively.

The first motor 51 is disposed on the right side of the base 11, and a drive shaft (not shown) of the first motor 51 protrudes toward the right end of the base 11. A first motor driver 511 is connected in the vicinity of the first motor 51, and the battery box 8 is electrically connected to the first motor 51 through the first motor driver 511. The drive shaft of the first motor 51 is connected to the first gear box 61. The first gear box 61 is disposed at the right end of the base 11 and includes an output shaft 611. Then, the rotation of the drive shaft of the first motor 51 is decelerated and output from the output shaft 611. The first gear box 61 can have various configurations. In addition to a normal gear, a planetary gear mechanism or a wonder 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. 4 is combined with a normal gear can be used. As shown in the figure, the mysterious gear mechanism is a modified planetary gear mechanism including a sun gear, a planetary gear, a planetary carrier, a fixed gear, and an outer gear. The number is equal to the number of teeth meshing with the outer gear. 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, Z _F is the number of teeth of the fixed gear, and Z _O is the number of teeth of the outer gear.

For example, the number of teeth Z _{S of the} sun gear is 8, the number of teeth Z _F of the fixed gear is 50, the number of teeth of the outer gear Z _O
When 48 is 48, the reduction ratio R _gear is calculated to be −174, and the _gear rotates at a reduced speed in the reverse rotation direction. 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%, it is calculated as η = 42.3%, and when ηg = 85%, it is calculated as η = 21.6%.

In order to further improve the reduction ratio, the first gear box 61 is attached with a small gear on the output shaft of the mysterious gear, meshed with the small gear, and attached with an output shaft 611 on the large gear, It protruded from the right end of the base 11. 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 61 is 774 (= 172 * 4.5). Further, a wheel portion 41 described later is attached to the tip of the output shaft 611.

On the other hand, the second motor 52 and the second gear box 62 are configured in the same manner, and current is supplied to the second motor 52 from the battery box 8 via the second motor driver 521 attached thereto. The second motor 52 and the second gear box 62 are arranged on the left side of the base 11, the output shaft 621 of the second gear box 62 protrudes from the left end of the base 11, and the wheel part 42 is attached to the tip thereof. Yes.

Next, the wheel portions 41 to 44 will be described. Since all four wheel portions have the same configuration, the wheel portion 41 attached to the first output shaft 611 will be described. The wheel portion 41 includes a cylindrical base portion 411 connected to the output shaft 611, and eight rod-like members 412 that protrude radially from the base portion 411. That is, the bar-shaped member 412 is provided every 45 degrees from the outer peripheral surface of the base 411, and a magnet 413 is attached to the tip of each bar-shaped member 412. However, the number of rod-like members 412 can be changed as appropriate, and can be 8 to 10 (the angle between adjacent rod-like members 412 is 45 to 36 °), for example. This is because if there are fewer than 8, the magnet 413 may not be attracted to the inspection target surface in any of the four wheel portions 41 to 44 depending on the rotational position of the wheel portion 41, as will be described later. If the number is greater than 10, the gap between the rod-like members 412 becomes too narrow, and there is a possibility that a step does not enter the gap.

As shown in FIG. 1B, the magnet 413 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-like member 412. Yes. Thereby, the magnet 413 can rotate around the axis of the rod-shaped member 412. The magnet 413 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 413 as necessary. This is for suppressing slippage between the magnet 413 and the steel material. As the adsorption strength of the magnet 413 to the steel material (metal surface), for example, it is preferable that the weight of an object that can be supported by one magnet 413 is larger. For example, as the performance required for the magnet 413 used here, the weight that can be supported by one magnet 413 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 while hanging on the target surface. When moving on a horizontal flat surface, the weight of the mobile robot Can be small.

Further, since the wheel portion 41 rotates, the magnet 413 repeats the adsorption and detachment to the surface to be inspected as the wheel portion 41 rotates. Accordingly, if the magnet 413 is attracted too strongly, there is a problem that it cannot be detached.

For example, as shown in FIG. 5, 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 studied, if this magnet is adsorbed to a steel material, the magnet should be separated 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. 6 is a plot of the results obtained using a 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 when a wheel part rotates a little (angle (alpha)) from the state which a magnet and steel materials contact 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. FIG. 8 shows the result of numerical calculation when c = 0.4 mm.

Where 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 separating the magnet 413 from the steel material is small. Therefore, if the torque which acts on the base part 411 of the wheel part 41 is adjusted and the whole lower surface of the magnet 413 is in contact with the steel material, and the force which separates this from the steel material can be applied, then the rotation of the wheel part 41 is performed. As a result, the magnet 413 is inclined from the steel material, so that the magnetic force decreases.

Regarding this point, the case where the magnet 413 is further separated from the steel material is as follows. For example, as shown in FIG. 9, consider a case in which a mobile robot moves up a vertical plane. In this example, the force acting on the mobile robot includes a robot weight Fg, a magnet attracting force Fm, and a reaction force Fr from the wheel portion 41 of the front housing unit 1. Since the wheel portion 43 of the rear housing portion 2 tries to rotate around the point A, it is necessary to cause the motor to generate a torque that overcomes the load torque T _L of the following equation.

For example, if the weight Fg of the robot is 450 g and the length of each rod-like member 412 is 62 mm, Lh = 57 mm (= 62 cos (22.5)) in the state of FIG. Since Fg is a force that supports a quarter of 450 g, it is about 1.1 N, and Fm can be found to be about 1.2 N when α = 22.5 ° is read in FIG. When the wheel parts of both housing parts are synchronized, Fr = 0. At that time, using the above equation, the load torque T _L is calculated as 0.120 Nm. Therefore, the torque transmitted from each motor to the output shaft may be calculated so as to overcome such load torque. In addition, when the wheel parts of both the

housing parts

1 and 2 are not synchronized, the maximum Fr is the weight of the rear housing part 2, and therefore, the output (torque) of each motor is taken into consideration. Can also be set. Thus, the mobile robot can move while adsorbed to the steel material.

The above examination was a case where the vehicle travels on a vertical steel material, but when the mobile robot travels on a horizontal plane, it is necessary to generate a torque that overcomes the load torque T _L of the following equation in the motor. .

On the other hand, when the vehicle travels while hanging below the horizontal plane, it is necessary to cause the motor to generate a torque that overcomes the load torque T _L of the following expression.

In either case, the load torque T _L is smaller than when traveling on a vertical surface. Therefore, if the torque transmitted from each motor to the output shaft is calculated so as to overcome the load torque in consideration of traveling on a vertical surface, the traveling performance of horizontal plane movement does not cause a problem.

The front housing unit 1 has been described above, but the rear housing unit 2 has substantially the same configuration. That is, the base, the DC motor, the motor driver, the gear box, and the wheel portion have the same configuration. However, the battery case 8 is not provided in the rear casing 2, and current is supplied from the battery box 8 of the front casing 1 to the

motors

53 and 54 of the rear casing 2 by an electric cable (not shown). Is supplied. In addition, as shown in FIG. 1, a main controller 6 is provided at a position corresponding to the position where the battery box 8 is provided in the front casing 1 (the center of the rear casing), A receiver 7 is provided in the vicinity of the left motor driver 541.

Further, the front housing part 1 and the rear housing part 2 are connected by a connecting part 3. The connecting portion 3 includes a pair of connecting members 31 formed in a rod shape, and a spring member 32 sandwiched between the connecting members 31. The spring member 32 can be contracted and expanded in the axial direction of the connecting member 31 and can be bent in the width direction. Both connecting members 31 are formed of a rigid metal or the like, and are connected to the vicinity of the centers of the

bases

11 and 21 of both

housing parts

1 and 2, respectively.

<3. Movement of mobile robot>
The mobile robot configured as described above moves on the surface of a building made of steel such as a bridge. Although illustration is omitted, if a camera or various sensors (for example, a temperature sensor, an eddy current flaw detection probe, an ultrasonic sensor, a radar exploration system, etc.) are attached to any one of the

casings

1 and 2, the surface of the building is Can be inspected.

At that time, the worker first installs the mobile robot on the inspection target surface. Since the inspection target surface is made of a metal such as steel, one of the magnets 413 is attracted to the inspection target surface in each of the four wheel portions 41 to 44, and the mobile robot is fixed to the inspection target surface. . Then, the operation signal is transmitted from the outside to the receiver 7 of the mobile robot by a wireless transmitter. At this time, the operator can move to the inspection target surface by operating the mobile robot instead of performing installation on the inspection target surface.

Thus, when the receiver 7 receives a signal, this signal is transmitted to the main controller 6. The main controller 6 processes this signal and sends it to the motor drivers 511 to 514 attached to the motors 51 to 54, respectively. Each of the motor drivers 511 to 514 receives 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 7 receives the forward signal, the main controller 6 transmits an FWD signal and a PWM signal with a high duty ratio to the motor drivers 511 to 514. As a result, the DC motors 51 to 54 rotate in the positive direction at the same rotational speed. On the other hand, when making a turn, PWM signals having different duty ratios are transmitted between the

right DC motors

51 and 53 and the

left DC motors

52 and 54 so that the rotational speeds of the left and right wheels are different. . As a result, the mobile robot turns to the right or left.

At this time, the respective wheel portions 41 to 44 rotate, and at least one magnet is attracted to the inspection target surface by the respective wheel portions 41 to 44, so that the mobile robot can move while being attracted to the inspection target surface. Therefore, it is possible to move the mobile robot suspended from the lower surface of the bridge, and to move the vertical surface of the bridge up and down.

<4. Features>
As described above, according to the present embodiment, each of the wheel portions 41 to 44 is composed of the plurality of rod-like members 412 attached radially and the magnet 413 attached to the tip portion thereof. Thereby, a mobile robot can be attracted | sucked to the object surface comprised with metals, such as a bridge, with a magnet. Since any one of the magnets 413 is always attracted to the target surface as the wheel portions 41 to 44 rotate, it can be prevented that the mobile robot moves away from the target surface even if it moves. Furthermore, since the rod-like members 412 are arranged radially, for example, even when a step is provided on the target surface, the step enters between the adjacent rod-like members 412, so that the step can be overcome. . Therefore, even if the target surface is not flat but has a complicated uneven shape, the target surface can be moved while being attracted by the magnet, and the target surface can be moved reliably.

Moreover, since the

adjacent housing parts

1 and 2 are connected by a connecting part that can be elastically deformed, the

respective housing parts

1 and 2 are adjacent to each other without being restricted by the operation of the adjacent housings. Since the connecting part 3 absorbs the shift of the motion operation timing of the part, a smooth operation is possible. For example, since the wheel portions 41 to 44 rotate with any of the magnets attracted to the target surface, when the mobile robot moves forward, both the

casing portions

1 and 2 move forward while repeating forward movement and stoppage in small increments. To do. At this time, if both the housing parts are advanced in both directions, the mobile robot advances as a whole. For example, when the front housing part 1 is stopped, the rear housing part 2 is advanced. Even if you try, the mobile robot cannot move forward.

On the other hand, in this embodiment, since both the

housing parts

1 and 2 are connected by the connecting part 3 described above, when the front housing part 1 stops and the rear housing part 2 moves forward, While the advancing force of the rear housing part 2 is stored in the spring member 32 in the form of deformation due to the elastic deformation of the spring member 32 in the connecting part 3, only the rear housing part 2 can advance a little. The forward force stored in this way is released when the front housing part 1 moves forward, and the spring member 32 presses the front housing part 1, so that the front housing part 1 moves forward quickly. Can do. Therefore, in this mobile robot, the connecting part 3 can absorb the deviation of the operation between the

adjacent casing parts

1 and 2 and can smoothly move.

<5. Modification>
<5.1>
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. For example, in the above-described embodiment, the number of housing units is two, but may be more. For example, three or more casings may be arranged in a straight line, and adjacent casings may be connected by the connecting portion as described above.

<5.2>
Further, in the above embodiment, the motors 51 to 54 as the drive units are provided for the wheel units 41 to 44, respectively, so that the wheel units 41 to 44 are 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. Or you may comprise so that a motor may be provided for each housing | casing part and both wheel parts may be driven with one motor. The number of motor drivers can be changed as appropriate according to the number of motors.

<5.3>
The mobile robot may be provided with a steering mechanism for steering the wheel portion. For example, as shown in FIG. 10, the front housing part 1 is composed of a pair of left and right first and

second casings

81, 82, a connecting part that connects the

casings

81, 82, and a turning mechanism. Each

casing

81, 82 is formed in a block shape and has the same configuration, but a second casing 82 on the left side of FIG. 10 includes a second motor (DC motor) 52 for driving the second wheel portion 42, a second one. A second gear box 62 and a first motor driver 521 are accommodated, and the second wheel portion 42 is connected to an output shaft 512 protruding from the second gear box 62. Further, the first casing 81 is similarly configured and drives the first wheel portion 41.

The connecting portion is composed of an upper connecting portion 83 material and a lower connecting member 84 for connecting the upper surfaces and lower surfaces of the

casings

81 and 82 to each other. These connecting

members

83 and 84 are formed in a plate shape, and both end portions thereof are swingably connected to the first casing 81 and the second casing 82, respectively. A support member 85 is fixed in the vertical gap between the

connection members

83 and 84, and the connection member 31 described above is fixed to the support member 85. A servo motor 87 is attached near the center of the upper connecting member 83, and the servo motor 87 is electrically connected to the main controller 62.

A steering tie rod 86 is provided in front of the connecting portion, and both ends of the steering tie rod 86 are swingably connected to the

casings

81 and 82. The steering tie rod 86 and the servo motor 87 described above are connected by a link mechanism 9. The link mechanism 9 includes first and

second link members

91 and 92 that are swingably connected. The first link member 91 having a short length is fixed to the rotation shaft of the servomotor 87, and the second A link member 92 is swingably connected to the end of the steering tie rod 86 on the first casing 81 side. In order to make the turn smooth, the turning mechanism is based on the Ackermann principle.

With the above configuration, when turning to the right, the first link member 91 is rotated to the right by the servo motor 87 based on a command from the main controller 62 as shown in FIG. As a result, the second link member 92 pushes the steering tie rod 87 to the right, and both

casings

81 and 82 tilt to the right. As a result, the first and

second wheel portions

41 and 42 tilt to the right, and the mobile robot turns to the right. At this time, it is also possible to control the number of revolutions so that a difference occurs in the number of revolutions of the

wheel portions

41 and 42.

On the other hand, when turning to the left, the first link member 91 is rotated to the left by the servo motor 87 as shown in FIG. As a result, the second link member 92 pulls the steering tie rod 86 to the left, and both the

casings

81 and 82 tilt to the left. As a result, the first and

second wheel portions

41 and 42 tilt to the left, and the mobile robot turns to the left. As described above, when the steering mechanism is provided, the turning radius can be reduced as compared with the above-described embodiment, and thus turning is possible even in a narrow region.

In the above example, a steering mechanism is provided in the front casing 1, but a steering mechanism may be provided in the rear casing 2. Further, when the steering mechanisms are provided in both the

housing parts

1 and 2, as shown in FIG. 13, the turning radius can be further reduced. Further, the configuration of the steering mechanism is not limited to that described above, and may be a gear mechanism as well as a link mechanism as long as the wheel portion can be tilted, and is not particularly limited. In the case where a plurality of housing parts are provided, a steering mechanism can be provided in at least one housing part.

<5.4>
It is also possible to attach a rotary encoder (rotation detection unit) to each wheel 41 to 44 and calculate the rotation speed of each wheel unit 41 to 44 by the main controller 62 based on a signal transmitted from each rotary encoder. Thereby, when a difference arises in load in each wheel part, it can control to make each wheel part into the same number of rotations.
<5.5>
The connecting portion 3 is not particularly limited as long as it is a member that can be elastically deformed at least in the front-rear direction in addition to the connecting member 31 and the spring member 32 as described above.

<5.6>
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.

<5.7>
The positions of the battery box 8, the main controller 6, the receiver 7, the motor drivers 511 to 541, the motors 51 to 54, the gear boxes 61 to 64, and the like shown in the above embodiment can be changed as appropriate. What is necessary is just to be arrange | positioned at the body part. Further, the forms of the

housing parts

1 and 2 are not limited to those described above, and may be any form that can support the above-described members such as the battery box 8 and the motors 51 to 54, and other than the above-described

bases

11 and 21. An aspect may be sufficient. Moreover, you may divide | segment into plurality.

<5.8>
In the above-described embodiment, it has been shown that cameras and various sensors are mounted on the

casing units

1 and 2, but various devices can be mounted on the robot. For example, an iron ion detector for detecting corrosion, an ultrasonic sensor for detecting internal cracks, an electromagnetic ultrasonic sensor (EMAT) for detecting internal cracks, a GPS, a mirror, a high-intensity LED light, a laser range sensor, and the like can be mounted.

Of these, the mirror can be used for light reflection. For example, if a mirror is mounted on a mobile robot, it is possible to use a reflection of light to show an area that is hidden behind a steel frame such as a steel slab. If this mirror is photographed with a telephoto camera or the like, visual inspection is possible.

Also, the high-intensity LED light is used to make the image clearer when shooting with the camera, thereby enabling shooting with the camera in a place where the sun does not shine.

The laser range sensor can be used to create a 3D map of the bridge. For example, since bridges that are likely to collapse are old, it is suspicious whether CAD drawings as well as paper drawings are stored. If there is no actual paper, it is necessary to directly survey the existing bridge. However, since it is extremely difficult to perform surveying artificially, it is desirable to mount a laser range sensor on the mobile robot of the present invention.

<5.9>
Although the mobile robot of the above embodiment has been described as a robot for inspection of a bridge or the like, it 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.

Hereinafter, examples of the present invention and comparative examples for comparison will be described. However, the present invention is not limited to the following examples.

(Example)
As an example, the mobile robot shown in the above embodiment as shown in FIG. 10 was produced. Details of each part are as follows.

(1) Control system / Main controller (PIC18F2320 manufactured by Microchip Technology)
・ Receiver (RG 411B manufactured by JR PROPO)
・ Transmitter (JG PROPO XG7)
・ Motor driver (variable speed H-bridge circuit consisting of the following parts)
-FET (2 SP8M4) 2 -NPN transistor (C1815)
・ Battery box (4 AAA batteries)
(2) Drive system / DC motor (input voltage: 3-6V, output: about 10W)
・ Gearbox (reduction ratio is 774 by the combination of the following mechanisms)
-Mysterious gear mechanism (reduction ratio 174)
-Small gear with 16 teeth and large gear with 72 teeth
(3) Number of wheel parts / bar-shaped members 8 pieces, length 62mm (aluminum alloy)
・ Magnet (neodymium magnet) Surface magnetic flux density 0.45T, diameter 8mm, thickness 5mm
(4) Connecting part / each connecting member: SUS material with an outer diameter of 2 mm and a length of 7 mm / spring member: SP joint made by Rainbow Products (material: stainless steel, wire diameter: 1 mm, effective number of turns: 19, coil average diameter: 9mm)
(5) Overall weight 550g
(6) Total length, total width 190mm between each chassis part Overall length of robot 300mm, total width 160mm

A voltage of 6.0 V was applied to each DC motor to the mobile robot according to the example configured as described above. As a result, the vehicle ran at 167 mm / s on the horizontal plane. Further, the vehicle ran at 71 mm / s without slipping on the vertical surface. On the vertical plane, an additional load was loaded, and the vehicle traveled even when the load was 500 g.

(Comparative example)
The comparative example changed only the structure of the connection part in the said Example. That is, only a connecting member having the same total length without using a spring member is used, so that there is no deformation at the connecting portion.

When traveling on a horizontal plane under the same conditions as in the example, it traveled at 141 mm / s, and the speed was lower than in the example. On the other hand, when traveling on a vertical surface, it slipped without a load, but increased only slightly so that it was difficult to measure the speed. When the load was 300 g, the vehicle did not travel at all.

Therefore, smooth operation on the horizontal and vertical surfaces was confirmed by providing the elastically deformable connecting portion as in the example.

DESCRIPTION OF SYMBOLS 1 Front side housing | casing part 2 Rear side housing | casing part 3 Connection part 31 Connection member 32 Spring member 41-44 Wheel part 411 Base part 412 Rod-like member 413 Magnet 51-54 DC motor (drive part)
511 to 514 Motor driver (drive unit)

Claims

A mobile robot that moves on a target surface made of metal,
Two or more housing parts arranged at intervals, and
At least one output shaft rotatably supported by each housing part;
Wheel portions that are arranged on both sides of each housing and are rotationally driven by each output shaft;
At least one drive unit for rotationally driving the output shaft;
The adjacent casing parts are connected to each other, and at least a part thereof is elastically deformable, and includes a connection part,
Each wheel part is
A base coupled to the output shaft;
A plurality of rod-shaped members projecting radially from the base, and a magnet attached to the tip of each rod-shaped member;
Mobile robot equipped with.
2. The mobile robot according to claim 1, wherein the magnet is attached to the tip of the rod-shaped member so as to be rotatable around the axis of the rod-shaped member.
The mobile robot according to claim 1 or 2, wherein the connecting portion includes a pair of connecting members formed in a rod shape and a spring member that connects the pair of connecting members.
The drive unit is provided for each of the wheel units, and one of the wheel units is configured to be independently driven to rotate by the one drive unit. The mobile robot described in 1.
A communication unit that transmits and receives signals to and from the drive unit;
The mobile robot according to claim 1, wherein the communication unit has a function of wirelessly receiving a signal for driving the driving unit from the outside.
The mobile robot according to any one of claims 1 to 5, wherein at least one of the housing units includes a steering mechanism that steers the wheel unit.