Autonomous driving device, autonomous driving method, and metal plate manufacturing method

Abstract

To enable predetermined work to be performed on an object at a proper position without moving a carriage when a positional deviation occurs with respect to a target position of the carriage when a working unit mounted on the carriage performs the predetermined work on the object.SOLUTION: An autonomous traveling apparatus includes: a carriage 1 for driving drive wheels 3 and traveling on a metal plate (object) S; a positioning system 10 (position detecting means) for detecting a position of the carriage 1 on the metal plate S; a grinding unit (working unit) 2 mounted on the carriage 1 and for performing predetermined work on the metal plate S; and an on-board computer 5 and a controller (control unit) 6 for correcting a position of the grinding unit 2 relative to the carriage 1 in accordance with an amount of deviation between the position of the carriage 1 detected by the positioning system 10 and a target position when performing the work.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an autonomous mobile device that travels on an object and performs a predetermined task on the object, an autonomous mobile method, and a method for manufacturing a metal plate using an autonomous mobile device. [Background technology]

[0002] An example of an autonomous mobile device that travels over an object to perform work on the object is the self-propelled inspection device for metal plates described in Patent Document 1. In this self-propelled inspection device for metal plates, a cart travels autonomously over the metal plate based on position information from an indoor positioning system, and a flaw detection head mounted on the cart inspects the metal plate for defects present on the surface or inside the metal plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-134494 Summary of the Invention [Problem to be solved by the invention]

[0004] In the self-propelled inspection device for metal plates described in Patent Document 1, if a discrepancy occurs between the position of the cart based on position information from an indoor positioning system and the target position, the cart is moved to correct the positional discrepancy. However, depending on the cart's traveling structure, particularly the steering structure, moving the cart to correct the positional discrepancy can take time and be inefficient. Furthermore, moving the cart to correct the positional discrepancy can sometimes cause a new positional discrepancy, resulting in the need to retry the movement multiple times to accurately align the cart. In other words, depending on the cart's traveling structure and the type of positional discrepancy, there is a need for an autonomous traveling device and method that can perform a specified task on an object at the appropriate position without moving the cart.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide an autonomous driving device and method for performing a specified task on an object at an appropriate position without moving the cart when a positional deviation occurs between the cart and its target position, as well as a method for manufacturing metal plates. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, an autonomous driving device according to one aspect of the present invention comprises a trolley that drives drive wheels to travel on an object, a position detection means that detects the position of the trolley on the object, a working unit that is mounted on the trolley and performs a predetermined task on the object, and a control unit that, when performing the task, corrects the position of the working unit relative to the trolley in accordance with the amount of deviation between the position of the trolley detected by the position detection means and a target position.

[0007] Furthermore, an autonomous driving method according to one aspect of the present invention comprises driving a cart over an object based on position information from a position detection means, detecting the amount of deviation between the target position of the cart and its actual position when a predetermined task is performed on the object by a working unit mounted on the cart, and correcting the position of the working unit relative to the cart based on the amount of deviation. Furthermore, a method for manufacturing a metal plate according to one aspect of the present invention is characterized in that it includes a grinding step in which the autonomous driving device is caused to run on a metal plate as the target object and the surface of the metal plate is ground by the working unit. [Effects of the Invention]

[0008] According to the present invention, for example, when grinding a specified position on the surface of a metal plate, the position of the working part relative to the cart can be corrected according to the amount of deviation between the position of the cart and the target position, thereby enabling the specified work to be performed at the appropriate position on the object without moving the cart. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a schematic diagram illustrating a grinding step in a method for manufacturing a metal plate, which is one embodiment of an autonomous driving device and method thereof of the present invention. FIG. [Figure 2] FIG. 2 is a side view showing a schematic configuration of the carriage of FIG. [Figure 3] FIG. 2 is a block diagram of control in the grinding process of FIG. 1. [Figure 4] 2 is an explanatory diagram of the movement of the carriage in the grinding process of FIG. 1. [Figure 5] 2 is an explanatory diagram of the movement of the carriage in the grinding process of FIG. 1. [Figure 6] 3 is a flowchart of a calculation process for correcting a positional deviation executed by the on-board computer of FIG. 2. [Figure 7] FIG. 7 is an explanatory diagram of the operation of the calculation process in FIG. 6. [Figure 8] FIG. 7 is an explanatory diagram of the operation of the calculation process in FIG. 6. [Figure 9] 10A and 10B are diagrams illustrating the amount of positional deviation from a target position with respect to vertical movement. [Figure 10] 10A and 10B are diagrams illustrating the amount of positional deviation from a target position with respect to lateral movement. [Figure 11] 7 is a diagram illustrating the correlation between the amount of deviation of the carriage position during lateral movement and the amount of deviation of the grinding position, which is determined by the calculation process of FIG. 6. [Figure 12] 1. FIG. 4 is a front view showing another schematic configuration of the carriage of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of an autonomous driving device, an autonomous driving method, and a method for manufacturing a metal plate according to the present invention will be described in detail below with reference to the drawings. The embodiment described below exemplifies a device and a method for embodying the technical concept of the present invention, and the technical concept of the present invention does not limit the materials, shapes, structures, arrangements, etc. of the components to the following embodiment. Furthermore, the drawings are schematic. Therefore, it should be noted that the relationship between thickness and planar dimensions, ratios, etc., differ from the actual ones, and the drawings also include portions where the relationship and ratio of dimensions differ from each other.

[0011] FIG. 1 is a schematic diagram of a grinding process in a metal plate manufacturing method according to one embodiment of an autonomous mobile device and method thereof. This grinding process involves grinding the surface of a metal plate S, specifically a steel plate, placed parallel to an indoor floor. In this embodiment, a cart 1 travels over the top surface (surface) of the target metal plate S, and a grinding unit 2, which is a working unit attached to the cart 1, grinds the surface of the metal plate S little by little at each destination of the cart 1, until the entire surface is ground. As the cart 1 moves, its position is detected by a positioning system 10, which is a position detection means. Based on the position information of the cart 1 detected by the positioning system 10, the cart 1 is moved to a target position on the metal plate S, and after grinding a predetermined area of ​​the surface of the metal plate S at that position, it moves to the next target position and repeats the grinding operation.

[0012] The positioning system 10 measures its own position (indoor position) in an indoor space based on the principle of triangulation. Specifically, the positioning system 10 is configured with multiple navigation transmitters 11 arranged indoors, particularly around the metal plate S, a navigation receiver 8 mounted on the carriage 1, and an on-board computer 5 (see FIG. 2). The on-board computer 5 is installed with position calculation software for calculating the position of the navigation receiver 8 as the position of the carriage 1, a target position for moving the carriage 1 to the grinding position, and setting software for setting route information. The setting software can pre-set the grinding ranges and order for each grinding operation for each metal plate S to be ground, the movement route from the previous grinding range to the next grinding range, the grinding area within each grinding range, and the movement route of the carriage 1. Therefore, the trolley 1 is moved sequentially to the target position set by this setting software, and the control amount for each actuator to be described later for that movement is output from the on-board computer 5 to a controller 6 (see Figure 2) that controls the movement of the trolley 1.

[0013] The positioning system 10 may be, for example, an indoor global positioning system (IGPS). IGPS is an indoor positioning system that applies the global positioning system (GPS). IGPS is described in detail in U.S. Patent No. 6,501,543. When IGPS is applied to the positioning system 10, each navigation transmitter 11 emits a rotating fan beam. The rotating fan beam may be a laser fan beam or another optical radiation means. The navigation receiver 8 receives the rotating fan beam emitted from the navigation transmitter 11. The rotating fan beam is offset by a predetermined angle, allowing the three-dimensional coordinate values ​​of the navigation receiver 8, i.e., its position and height in the horizontal plane, to be measured. The received information by the navigation receiver 8 is transmitted to the onboard computer 5, which calculates the position of the navigation receiver 8 according to the principle of triangulation. The on-board computer 5 can then obtain position information for the traveling bogie 1 equipped with the navigation receiver 8 by repeatedly performing calculations on the signals received from the multiple navigation transmitters 11. A monitor computer 15 is installed indoors to monitor the position of the bogie 1, the grinding state of the metal plate S, etc.

[0014] FIG. 2 is a side view showing a schematic configuration of the bogie 1 of FIG. 1. As shown in FIG. 1, the bogie 1 has wheels 3 and 4 arranged at the four corners of, for example, a box-shaped frame, and each wheel 3 and 4 rotates around a rotation axis extending in a direction perpendicular to the plane of FIG. 2. In this embodiment, the wheel 3 on the left side of FIG. 2 is a drive wheel, and the wheel 4 on the right side is a steered wheel. The drive wheel 3 is rotated by the driving force of the travel actuator 12 via a drive mechanism 25. Therefore, when the steered wheels 4 are not steered, the bogie 1 travels in the left-right direction in FIG. 2. Here, the left side of FIG. 2 is defined as the front, and the right side is defined as the rear. In other words, the bogie 1 travels in the front-rear direction by driving the drive wheels 3. Meanwhile, the steered wheels 4 are steered by the driving force of the steering (turning) actuator 13 via a steering mechanism 26. For example, a general Ackermann steering (turning) mechanism is used for the steering mechanism 26. Note that the drive wheels 3 in this embodiment are not steered.

[0015] A grinding unit 2 is mounted on the front of the carriage 1, i.e., on the drive wheel 3 side, as a working unit for grinding the surface of the metal plate S. A grinding wheel 7 with a cylindrical outer periphery is disposed at the lowest end of the grinding unit 2 as a grinding tool. In this embodiment, the grinding wheel 7 is rotated about a rotation axis extending in the front-to-rear direction to grind the surface of the metal plate S. A coated abrasive may also be used as the grinding tool instead of the grinding wheel 7. The grinding wheel 7 is attached to a grinding device 16 and is rotated by the driving force of a grinding motor 17. An elevator 14 is attached above the grinding device 16 to raise and lower the grinding device 16 together with the grinding wheel 7. The elevator 14 is attached to a slide device 9, and the slide device 9 moves the elevator 14 together with the grinding device 16 in a direction perpendicular to the plane of the paper in FIG. 2 along a slide base 18 (see FIG. 1) extending in a direction perpendicular to the plane of the paper in FIG. 2. Therefore, in this grinding section 2, the lifting device 14 can lower the grinding device 16 to bring the grinding wheel 7 into contact with the surface of the metal plate S or move it away from the surface of the metal plate S. Furthermore, by rotating the grinding wheel 7 while it is in contact with the surface of the metal plate S, the surface of the metal plate S can be ground in the contact area of ​​the grinding wheel 7. Furthermore, by sliding the grinding device 16 with the sliding device 9 while rotating the grinding wheel 7 on the surface of the metal plate S, the grinding area can be moved (expanded) in the direction perpendicular to the plane of the paper in FIG.

[0016] A control box (control panel) 19 is mounted at the rear of the bogie 1, i.e., on the steered wheel 4 side, and the above-mentioned navigation receiver 8 is mounted above this control box 19. Inside the control box 19, there is disposed an on-board computer 5 and a controller 6 for controlling the drive state of each actuator of the bogie 1. This controller 6 is constructed as a computer system with an arithmetic processing function, and for example, a programmable logic controller or the like is applied. Note that the controller 6 does not need to be separate from the on-board computer 5; for example, it is possible for a single computer to function as both the on-board computer 5 and the controller 6.

[0017] FIG. 3 is a block diagram of the control for this grinding process. As described above, the navigation receiver 8 receives rotating fan beams from multiple navigation transmitters 11. The information received by the navigation receiver 8 is transmitted to the onboard computer 5, which calculates the position of the navigation receiver 8 as the position of the bogie 1. The onboard computer 5 outputs to the controller 6 control amounts for each actuator for moving the bogie 1 to a target position according to the set grinding ranges, their order, and the movement path from the previous grinding range to the next grinding range. The controller 6 outputs drive signals according to the control amounts for the actuators for moving the bogie 1, namely, the traveling actuator 12 and the steering (turning) actuator 13. During movement of the bogie 1, the position of the moving bogie 1 is detected, and feedback control is performed on the traveling actuator 12 and the steering (turning) actuator 13 so that the bogie 1 moves along the set movement path. Furthermore, when the carriage 1 arrives at the grinding range, the on-board computer 5 outputs the control amounts of the actuators of the lifting device 14, the grinding device 16, and the sliding device 9 to the controller 6. The controller 6 outputs drive signals according to the control amounts of the actuators of the lifting device 14, the grinding device 16, and the sliding device 9. Information and the state of signal exchange between the on-board computer 5 and the controller 6 are wirelessly transmitted to the monitor computer 15 and monitored.

[0018] Next, the grinding range and its movement in this embodiment will be described. In this embodiment, the bogie 1 has drive wheels 3 at the front and steerable wheels 4 at the rear. The drive wheels 3 are not steered, and the bogie 1 moves (travels) only in the fore-and-aft direction when the steerable wheels 4 are not steered. Therefore, when the steerable wheels 4 are not steered, the orientation of the steerable wheels 4 coincides with the fore-and-aft direction of the drive wheels 3. If the state in which the orientation of the steerable wheels 4 coincides with the fore-and-aft direction is defined as the neutral state, then as long as the steerable wheels 4 are maintained in the neutral state, the bogie 1 moves "straight" only in the fore-and-aft direction. For example, when the hatched area in Figure 4a is set as the grinding range, the grinding wheel 7 (grinding unit 2) is set at the frontmost position of the grinding range and at one end of the sliding direction of the slide device 9, i.e., the lateral direction. In this state, the grinding wheel 7 is brought into contact with the surface of the metal plate S to perform grinding. From there, while maintaining the grinding state, if the grinding wheel 7 is moved toward the other end in the horizontal direction by the sliding device 9, the area corresponding to the contact width of the grinding wheel 7 will be ground along the path of its movement. In other words, the area that can be ground in one grinding operation while the carriage 1 is stopped is the grinding area. When the grinding wheel 7 reaches the other end in the horizontal direction, the carriage 1 is moved backward by the contact width of the grinding wheel 7, and grinding is then performed while moving the grinding wheel 7 from the other end in the horizontal direction toward one end, for example. This is repeated sequentially to grind a predetermined grinding range. When the carriage 1 is moved "straight" forward and backward, it is only necessary to control the drive amount of the travel actuator 12, so the movement (stopping) control is highly accurate.

[0019] On the other hand, the amount of lateral sliding of the grinding wheel 7 by the sliding device 9 is limited, so the lateral length of the grinding area (= grinding range) per grinding is also limited. Therefore, once grinding of the grinding range is completed, the carriage 1 is moved backward (retracted) a predetermined distance as shown by the arrow in FIG. 4a. Next, the carriage 1 moves to the next grinding range adjacent to the previous grinding range in the lateral direction. To do this, the steering wheels 4 are steered (turned) from the position where the carriage 1 has retreated, and the carriage 1 moves forward (advance) while moving laterally as shown in FIG. 4b. As a result, for example, when the carriage 1 moves to the most forward position of the metal plate S, the next grinding range adjacent to the previous grinding range in the lateral direction can be ground. Therefore, when grinding the surface of a large metal plate S, for example, as shown in FIG. 5, after grinding the lowest grinding range, the carriage 1 is retreated and then moved laterally to the grinding range in the vertical center, where grinding is performed. After grinding the vertically central grinding range, the carriage 1 is again moved backward and then moved laterally to the uppermost grinding range for grinding. After grinding of these grinding ranges is completed, the grinding ranges further back are ground in the same manner, and this process is repeated sequentially to grind the entire surface of the metal sheet S. Note that, as will be described later, the accuracy of the lateral movement (stopping) of the carriage 1 is not high. Also, in this embodiment, at least during the grinding operation, the carriage 1 does not simply move laterally, but moves laterally to head for the next grinding range. Also, if the carriage 1 is laterally displaced from the target position when it arrives at the initial position (initial stopping position) of the grinding range, in order to correct the positional displacement by steering (turning), it must first move backward and then move forward while steering (turning). Therefore, hereinafter, the lateral movement of the carriage 1 is also referred to as turning.

[0020] In this embodiment, grinding is performed by rotating the grinding wheel 7, whose outer periphery is cylindrical, around a rotation axis extending in the front-to-rear direction. Therefore, a lateral reaction force acts on the carriage 1 during grinding. In this embodiment, the non-steerable drive wheels 3 are located on the side of the grinding section 2 where the grinding reaction force is generated, thereby preventing the carriage 1 from moving due to the grinding reaction force. If the steerable wheels 4 were located on the side of the grinding section 2 where the lateral reaction force is generated, the reaction force could cause the steerable wheels 4 to turn. Furthermore, if the steerable wheels 4 were turned during grinding, the carriage 1 could move in the direction in which the steerable wheels 4 were turned. Other wheel configurations and drive methods for the carriage 1 include a three-wheel system and a four-wheel independent steering drive system. For example, a three-wheel system consisting of two independently drivable drive wheels arranged side by side in the lateral direction and an omni-directional wheel (driven wheel) called an omniwheel located in the center of the carriage's width can fine-tune the direction of the carriage 1 by adjusting the difference in rotational speed between the two drive wheels. However, while omnidirectional wheels make it easy for the bogie 1 to move, especially in the lateral direction, they can move in any direction, so the position of the bogie 1 is easily displaced by grinding reaction forces. Also, the omnidirectional movement method known as the four-wheel independent steering drive method is a method in which the drive shafts and steering shafts of the four wheels are controlled individually, so advanced position and movement control is possible, where the bogie 1 can be moved to any location and rotated on the spot to adjust the angle. However, on the other hand, the large number of control axes has the disadvantage of making the mechanism complicated and the device expensive.

[0021] In this embodiment, of the four wheels 3, 4 of the bogie 1, the two front wheels are drive wheels 3 and the two rear wheels are steerable wheels 4. Therefore, a longitudinal positional deviation of the bogie 1 can be easily corrected by simply controlling the travel actuator 12 while maintaining the steerable wheels 4 in a neutral position. In contrast, a lateral positional deviation requires time to correct because it requires the bogie 1 to turn, i.e., to move forward and backward and to move laterally by steering. Furthermore, even if the bogie 1 is turned, the correction is not always possible. In other words, the correction accuracy is low, and the turning operation may be repeated, which may require a very long time. This is thought to depend on the coefficient of friction between the wheels 3, 4 of the bogie 1 and the surface of the metal plate S. That is, the surface of the metal plate S is the road surface on which the bogie 1 travels. However, the coefficient of friction between the wheels 3, 4, which corresponds to the road surface condition, differs for each metal plate S. Therefore, even if the steering state of the steerable wheels 4 is the same, the amount of lateral movement differs. On the other hand, it is not realistic to parameter-tune the amount and timing of steering of the steered wheels 4 for each surface texture of the metal sheet S. As described above, in this embodiment, misalignment of the carriage 1 in the longitudinal direction is corrected by moving the carriage 1 in the longitudinal direction, and misalignment of the carriage 1 in the lateral direction is corrected by moving the grinding unit 2 laterally relative to the carriage 1. The lateral movement of the grinding unit 2 is performed using a sliding device 9. For example, if the range of movement of the grinding wheel 7 by the sliding device 9 in the lateral direction is 600 mm, 50 mm at both ends is used as a correction allowance for the grinding wheel 7 (grinding unit 2) in response to the lateral misalignment of the carriage 1. The contact width of the grinding wheel 7, i.e., the width of the grinding area, is, for example, 60 mm.

[0022] 6 is a flowchart showing the calculation process for correcting positional deviation that is performed when the carriage 1 arrives at the next grinding range (more precisely, the first stop position in the grinding range). This calculation process is executed in the on-board computer 5. Note that, hereinafter, the fore-and-aft direction is also referred to as the longitudinal direction, and the position of the carriage 1 in the longitudinal direction is referred to as the longitudinal position. Similarly, the position of the carriage 1 in the lateral direction is referred to as the lateral position. In this calculation process, first, in step S1, the received information of the positioning system 10 (navigation receiver 8) is read.

[0023] Next, the process proceeds to step S2, where the position information (vertical position, horizontal position) of the dolly 1 is calculated from the information received by the positioning system 10 read in step S1. Next, the process proceeds to step S3, where target position information (vertical position, horizontal position) for the current grinding range (first stop position) set in the setting software is read. Next, proceed to step S4, where the vertical position deviation amount and horizontal position deviation amount are calculated from the difference between the target position information (vertical position, horizontal position) read in step S3 and the position information (vertical position, horizontal position) of the trolley 1 calculated in step S2.

[0024] Next, the process proceeds to step S5, where the correction control amount of the traveling actuator 12 for correcting the amount of vertical position deviation is calculated. Next, the process proceeds to step S6, where the correction control amount of the slide device 9 for correcting the amount of lateral positional deviation is calculated. Next, the process proceeds to step S7, where the correction control amounts of the traveling actuator 12 and the slide device 9 are output to the controller 6, and then the process returns.

[0025] According to this calculation process, for example, if the carriage 1 is displaced vertically (forward and backward) from the target position shown by the two-dot chain line in FIG. 7, the travel actuator 12 is operated to move the carriage 1 forward and backward, correcting the displacement of the carriage 1 including the grinding unit 2. On the other hand, if the carriage 1 is displaced horizontally from the target position shown by the two-dot chain line in FIG. 8, the operating range of the slide device 9, i.e., the range of movement of the grinding wheel 7 by the slide device 9, is moved horizontally within the range of the displacement correction allowance, thereby moving the grinding unit 2 (grinding wheel 7) horizontally relative to the carriage 1, and moving the grinding unit 2 to the target position to correct the displacement. In other words, the on-board computer 5 and the controller 6 constitute the control unit of this autonomous driving device. Note that in this embodiment, the amount of horizontal displacement of the slide device 9 from the target position did not exceed the displacement correction allowance of ±50 mm, so the vertical and horizontal displacements could be corrected using only the calculation process of FIG. 6. If the amount of lateral positional deviation from the target position exceeds the positional deviation compensation amount of the slide device 9, a step is provided to compare the amount of lateral positional deviation with the positional deviation compensation amount of ±50 mm. If the amount of lateral positional deviation is equal to or less than the positional deviation compensation amount, the slide device 9 is operated to correct the lateral positional deviation, and if it exceeds the compensation amount, a turning operation of the carriage 1 may be performed (retry) to reduce the amount of lateral positional deviation.

[0026] The movement (stopping) position accuracy of the bogie 1 in this embodiment will be described below. Fig. 9 shows the stopping position of the bogie 1 during its vertical movement and the amount of vertical positional deviation that occurred in the bogie 1. The horizontal axis shows the target value of the stopping position for the backward movement of the bogie 1, and the vertical axis shows the amount of vertical positional deviation between the actual stopping position of the bogie 1 and the target position, with the backward direction being negative. In this example, the average value and standard deviation of the vertical positional deviation of the stopping position for backward distances of 20, 40, and 60 (mm) were calculated, and the error bars indicate a range of ±3σ. The average value of the vertical positional deviation was 0.5 mm in the backward direction, and the standard deviation was 0.7 mm.

[0027] Figure 10 shows the stopping position of bogie 1 during lateral movement and the amount of lateral position deviation that occurred in bogie 1. The horizontal axis shows the target value for the stopping position when bogie 1 turns left or right, and the vertical axis shows the actual stopping position of bogie 1 and the amount of lateral position deviation from the target position, with the right turning direction being positive. In this example, the average value and standard deviation of the amount of lateral position deviation of the stopping position for the amount of turning left or right (= lateral movement position target value) set in 150 mm increments are calculated, and the error bars indicate a range of ±3σ. As mentioned above, the system was equipped with a function that retries the turning operation of bogie 1 to reduce the amount of lateral position deviation if the amount of lateral position deviation exceeds the correction amount of ±50 mm, but no retries occurred in a total of N = 148 lateral movement tests. [Example]

[0028] As described above, in the above embodiment, logic was developed to enable grinding of the desired grinding range by adjusting the operating range of the sliding device 9, i.e., the range of movement of the grinding wheel 7 by the sliding device 9, in response to lateral positional deviation of the carriage 1. Therefore, a demonstration experiment was conducted to verify whether the set grinding range could be ground with high precision on an actual metal plate S regardless of the magnitude of lateral positional deviation. As an example of the metal plate S, the surface of a thick steel plate with a tensile strength of 400 MPa and a plate thickness of 12 mm was ground using the grinding device mounted on the autonomous mobile device of the above embodiment. Figure 11 shows the grinding lateral position deviation versus the lateral position deviation for N=53 runs. In the comparative example shown in Figure 10 (without correcting the position of the grinding unit 2), for example, the lateral position deviation reached approximately 20 mm in some cases relative to the target position of 150 mm for right turn. In contrast, in the example in which the lateral position of the grinding unit 2 relative to the carriage 1 was corrected, the actual grinding lateral position deviation was within ±2 mm in all cases, including when the lateral position deviation was approximately 20 mm, as shown in Table 1 below. Table 1 shows the results of pass / fail evaluations of the examples and comparative examples, assuming that the error in visual position adjustment when an operator grinds using a hand grinder is approximately ±5 mm, and using ±5 mm as the threshold value for the amount of lateral grinding position deviation. As a result, even if the carriage 1 is misaligned in the lateral direction, in the embodiment, the desired grinding range can be accurately ground without repeatedly turning the carriage 1. This makes it possible to thoroughly and quickly prepare the specified area on the surface of the steel sheet with high precision, and to provide a high-quality steel sheet from which surface defects and thickness defects have been removed.

[0029] [Table 1]

[0030] Thus, according to the grinding process of the manufacturing method of the metal plate S of this embodiment, when grinding a predetermined position on the surface of the metal plate S, the position of the grinding unit 2 relative to the carriage 1 is corrected according to the amount of lateral positional deviation between the position of the carriage 1 and the target position. This makes it possible to perform the predetermined grinding operation on the metal plate S at an appropriate position without moving the carriage 1. Furthermore, when the bogie 1 travels in the longitudinal direction without being steered, the longitudinal position of the bogie 1 is corrected for the amount of vertical position deviation that occurs in the longitudinal direction, and the position of the grinding unit 2 relative to the bogie 1 is corrected for the amount of lateral position deviation that occurs in the lateral direction perpendicular to the longitudinal direction. This eliminates the need for a mechanism to move the grinding unit 2 in both the longitudinal and lateral directions, and makes it possible to perform grinding work at the appropriate position in both the longitudinal and lateral directions.

[0031] Furthermore, if the carriage 1 has drive wheels 3 and individual steerable wheels 4, and has a running structure that allows it to move laterally by steering (turning) the steerable wheels 4 and driving the drive wheels 3, the amount of lateral positional deviation can be corrected without repeating lateral turning operations, which results in a reduction in the grinding operation time. The bogie 1 also has two drive wheels 3 arranged side by side at the front and two steered wheels 4 arranged side by side at the rear, and the grinding unit 2 that performs grinding work that generates a lateral reaction force is arranged at the front, i.e., on the drive wheel 3 side, to form a positional deviation prevention mechanism. This makes it possible to effectively prevent positional deviation of the bogie 1 due to the grinding reaction force with a simple configuration.

[0032] The above describes the autonomous driving device, the autonomous driving method, and the manufacturing method of the metal plate S according to the embodiments. However, the present invention is not limited to the configurations described in the above embodiments, and various modifications are possible within the scope of the present invention. For example, in the above embodiments, the non-steerable drive wheels 3 are arranged on the grinding unit 2 side, which is the working unit, to provide a displacement prevention structure that prevents displacement of the bogie 1 due to the grinding reaction force. Alternatively, as shown in FIG. 12, the displacement prevention structure may include an electromagnet 20 arranged on the bottom of the bogie 1 and an elevator 21 that raises and lowers the electromagnet 20. In this displacement prevention structure, the electromagnet 20 is lowered onto the metal plate S during grinding, and is excited to magnetically attach to the metal plate S, thereby preventing displacement of the bogie 1. Other structures are also applicable.

[0033] In the above embodiment, the position of the carriage 1 is corrected for a positional deviation in the front-rear direction of the carriage 1, and the position of the grinding unit 2 relative to the carriage 1 is corrected for a positional deviation in the lateral direction. However, a configuration may be adopted in which the position of the grinding unit 2 relative to the carriage 1 is corrected for positional deviations in both the front-rear direction and the lateral direction. Furthermore, the object on which the carriage 1 travels is not limited to the metal plate S, and the work to be performed can be applied to various works other than grinding of the metal plate S. [Explanation of symbols]

[0034] 1 cart 2 Grinding section (working section) 3 drive wheels 4 steering wheels 5. On-board computer (position detection means, control unit) 6 Controller (control unit) 7. Whetstone 8 Navigation receiver (position detection means) 9 Slide device 10 Positioning system (position detection means) 11 Navigation transmitter (position detection means) 20 Electromagnet (position shift prevention structure) S Metal plate

Claims

1. a carriage that drives a drive wheel to travel on the object; a position detection means for detecting a position of the carriage on the object; a working unit that is mounted on the carriage and performs a predetermined work on the object; a control unit that corrects the position of the working unit relative to the carriage in accordance with the amount of deviation between the position of the carriage detected by the position detection means and a target position when the work is performed, The bogie has the drive wheels and separate steerable wheels, and has a running structure that allows it to run in a forward / backward direction by driving the drive wheels, and to move laterally perpendicular to the forward / backward direction by steering the steerable wheels and driving the drive wheels.

2. The autonomous driving device according to claim 1 , wherein the control unit corrects the position of the carriage in the forward / backward direction in response to the amount of deviation occurring in the forward / backward direction, and corrects the position of the working unit relative to the carriage in response to the amount of deviation occurring in the lateral direction.

3. The autonomous mobile device according to claim 2 , wherein the working unit performs a task on the object in which a reaction force acts on the cart.

4. The autonomous driving device according to claim 3 , wherein the working unit performs a grinding operation to grind a surface of the object.

5. The autonomous driving device according to claim 3 , wherein the carriage has a positional deviation prevention structure that prevents positional deviation due to the reaction force.

6. The autonomous driving device described in claim 5, wherein the bogie has two drive wheels arranged side by side in the horizontal direction on one side of the fore-and-aft direction and two steered wheels arranged side by side on the other side of the fore-and-aft direction, and the position shift prevention structure is configured by arranging the working unit that performs work that generates a reaction force in the horizontal direction on one side of the fore-and-aft direction.

7. The bogie has drive wheels and steering wheels, and has a running structure that allows it to travel in a forward-backward direction by driving the drive wheels, and to move in a lateral direction perpendicular to the forward-backward direction by steering the steering wheels and driving the drive wheels, An autonomous driving method in which a cart is driven over an object based on position information from a position detection means, and when a predetermined task is performed on the object by a working unit mounted on the cart, the amount of deviation between a target position and an actual position of the cart is detected, and the position of the working unit relative to the cart is corrected based on the amount of deviation.

8. A method for manufacturing a metal plate, comprising a grinding step of running the autonomous mobile device according to claim 1 on a metal plate as the target object and grinding a surface of the metal plate with the working unit.

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