Fastening device and fastening method

Abstract

A fastening device assembles an assembly component to an assembled component by fastening a fastening member. The fastening device includes a camera that captures an image of an area including at least a first fastening hole of the assembly component in a state where the assembly component is placed on an upper portion of the assembled component having a second fastening hole, and a controller that calculates a first position of the first fastening hole and a second position of the second fastening hole based on the captured image. The controller controls a robot to move the fastening member and insert the fastening member into the first fastening hole based on the first position, and moves the assembly component in a state where the fastening member is inserted into the first fastening hole in the direction of the second position, and controls the robot to fasten the fastening member in accordance with detection that the fastening member is inserted into the second fastening hole.

Description

Technical Field

[0001] This invention relates to fastening devices and fastening methods. Background Technology

[0002] In the manufacturing of products such as battery packs for electric vehicles, process automation is required. One example of a process requiring automation is the bolt tightening process, which involves inserting fastening units such as bolts or screws into fastening holes on a workpiece for tightening.

[0003] As an example of automation of the fastening process, there is Japanese Patent Application Publication No. 2012-20345. In Japanese Patent Application Publication No. 2012-20345, a process for searching the position of a fastening hole over a wide range is disclosed by calculating coordinates in such a way that the movement trajectory of the fastening component becomes a spiral track. Summary of the Invention

[0004] Japanese Patent Application Publication No. 2012-20345 discloses a fastening device that searches for a fastening hole in a spiral motion, expanding outwards from a certain point, when the screw has not entered the fastening hole. However, this spiral search method results in a time-consuming search for the fastening hole.

[0005] One of the objectives of this invention is to provide a fastening device and fastening method that reduces the time spent on bolt fastening.

[0006] The first aspect of the present invention provides a fastening device for assembling an assembly component to an assembly component by fastening a fastening member. The fastening device includes an imaging device and a control device. The imaging device captures an image of an area including at least the first fastening hole, with the assembly component having a first fastening hole placed on top of the assembly component having a second fastening hole. The control device calculates a first position of the first fastening hole and a second position of the second fastening hole based on the captured image. The control device controls a robot to move the fastening member and insert it into the first fastening hole based on the first position, and moves the assembly component with the fastening member inserted into the first fastening hole toward the second position. Based on the detection that the fastening member is inserted into the second fastening hole, the control device controls the robot to fasten the fastening member.

[0007] The second solution, based on the fastening device of the first solution, may also involve the control device calculating the second position of the second fastening hole based on the image of the second fastening hole in the captured image, provided that the captured image contains at least a portion of the image of the second fastening hole.

[0008] The third option can also be based on the fastening device of the first or second option described above, wherein the fastening device has a storage device that stores distance information representing the distance from the outline of the assembled component to the second fastening hole, and the control device calculates the second position based on the position of the outline of the assembled component in the captured image and the distance information when the captured image does not contain at least a portion of the image of the second fastening hole.

[0009] The fourth option can also be based on the fastening device of any of the first to third options mentioned above, wherein the fastening device further includes a force sensor that measures the force applied to the fastening member, and when the assembly component moves toward the second position while the fastening member is inserted into the first fastening hole, the control device stops the movement if the sensor value of the force sensor exceeds a first threshold.

[0010] The fifth option can also be based on the fastening device of any of the first to fourth options above, wherein the fastening device includes at least one of a force sensor that measures the force applied to the fastening member and a displacement sensor that measures the amount of movement of the fastening member, and the control device detects that the fastening member is inserted into the second fastening hole when the sensor value or the change in the sensor value exceeds a second threshold.

[0011] The sixth solution can also be based on the fastening device of any of the first to fifth solutions mentioned above. If the control device moves the assembly component to the second position after the fastening member is inserted into the first fastening hole and does not detect that the fastening member is inserted into the second fastening hole, the robot is controlled so that the assembly component, while the fastening member is inserted into the first fastening hole, performs reciprocating motion while changing its direction of movement.

[0012] The seventh solution can also be based on the fastening device of any of the first to sixth solutions described above, wherein when the calculated distance between the first position and the second position is less than a predetermined value, the control device moves the fastening member based on the first position and inserts it into the first fastening hole, and the assembly component moves towards the second position without inserting the fastening member into the first fastening hole, thereby fastening the fastening member.

[0013] The eighth embodiment can also be based on the fastening device of any of the first to seventh embodiments described above, wherein the assembly component has a plurality of first fastening holes, a portion of the plurality of first fastening holes are fastened after the other first fastening holes, and the control device moves the assembly component in the direction of the second position while the fastening member of the other first fastening holes is in a state of being loosened.

[0014] The fastening method of the ninth aspect of the present invention includes: taking a picture of an area including at least the first fastening hole while an assembly having a first fastening hole is placed on top of an assembly having a second fastening hole; calculating a first position of the first fastening hole and a second position of the second fastening hole based on the captured image; controlling a robot to move a fastening member and insert it into the first fastening hole based on the first position, and moving the assembly having the fastening member inserted into the first fastening hole toward the second position; and controlling the robot to fasten the fastening member based on detecting that the fastening member has been inserted into the second fastening hole.

[0015] According to schemes one through nine, the time spent on bolt tightening can be shortened. Attached Figure Description

[0016] Figure 1 This is an overall view of the fastening device in this embodiment.

[0017] Figure 2 This is a hardware structure diagram of the fastening device in this embodiment.

[0018] Figure 3 This is a flowchart illustrating the processing flow of the fastening device in this embodiment.

[0019] Figure 4A It is a diagram that schematically shows the positional relationship between the upper and lower holes.

[0020] Figure 4B It is a diagram that schematically shows the positional relationship between the upper and lower holes.

[0021] Figure 5 This is a diagram illustrating one example of corrective treatment.

[0022] Figure 6 This is a flowchart illustrating the corrective treatment process.

[0023] Figure 7 This diagram illustrates the detection and processing of the insertion state.

[0024] Figure 8A This is a diagram illustrating one example of corrective treatment.

[0025] Figure 8B This is a diagram illustrating one example of corrective treatment.

[0026] Figure 8C This is a diagram illustrating one example of corrective treatment.

[0027] Figure 8D This is a diagram illustrating one example of corrective treatment. Detailed Implementation

[0028] The following is based on Figures 1 to 8D An embodiment of the present invention will be described.

[0029] (Structure of the fastening device)

[0030] use Figure 1 and Figure 2 The structure of the fastening device in the embodiment will be described. Figure 1 This is an overall view of the fastening device 10 in this embodiment. Figure 2 This diagram illustrates the hardware structure of the fastening device in this embodiment. The fastening device 10 in this embodiment includes, for example, a robotic arm 15, a control device 11, a nut wrench control unit 13, and a control panel 14. The robotic arm 15 includes, for example, a camera 51, a nut wrench 52, a sleeve 53, a force sensor 54, and a displacement sensor 55.

[0031] exist Figure 1 The workpiece mounting section 60 shown displays a base member 20 (the part to be assembled). A robot arm 15 is mounted on a platform. As an example, in this embodiment, the fastening device 10 assembles a busbar 30 (the assembly part) on the base member 20. Figure 1 , Figure 2 (Not shown in the image).

[0032] It should be noted that, in this embodiment, the X-axis and Y-axis directions are two mutually orthogonal straight lines on a plane that are parallel to the insertion direction of the fastening unit. The Z-axis direction is parallel to the insertion direction of the screw (fastening unit).

[0033] The robotic arm 15 is, for example, a 6-axis multi-joint robotic arm. The robotic arm 15 is configured as a multi-joint arm having multiple links and joints connecting these links to form rotatable joints. Each joint is equipped with an actuator (not shown) for driving each joint. The actuator may be, for example, a motor, a hydraulic drive, or a pneumatic drive unit.

[0034] The imaging device 51 includes, for example, an imaging element such as a charge-coupled device (CCD) and a lens section as an optical system. The imaging device 51 captures images of the component placed on the workpiece mounting section 60 and generates image data.

[0035] The nut wrench 52 is a hand tool or similar device mounted on the front end of the robotic arm 15. The nut wrench 52 has a sleeve 53 that can rotate around a central axis via a drive unit. The sleeve 53 is mounted on the front end of the nut wrench 52. The sleeve 53 may have, for example, a magnetic attraction function (or vacuum attraction function) generated by a magnet, which is used to hold the bolt 40.

[0036] The nut wrench 52 rotates the sleeve 53 around the axis according to the control signal from the control device 11. Additionally, the nut wrench 52 stops the rotation of the sleeve 53 according to the control signal from the nut wrench control unit 13. This causes the recess of the sleeve 53 to engage with the head of the bolt 40.

[0037] Force sensor 54 and displacement sensor 55 are mounted on the front end of robot arm 15. Force sensor 54 is, for example, a tactile sensor capable of detecting 6-axis components (force components in the three-axis directions of X, Y and Z axes, and torque components in the three-axis directions of X, Y and Z axes).

[0038] When the sleeve 53 of the nut wrench 52 contacts the bolt 40, the force sensor 54 detects the change in the contact state of the sleeve 53 relative to the bolt 40. Specifically, the force sensor 54 sequentially detects the three-axis component of the contact force (reaction force) and the three-axis component of the contact torque experienced by the sleeve 53 on the bolt 40. The force sensor 54 sequentially outputs the detection results of the six-axis components to the control device 11.

[0039] The force sensor 54 can also be a torque sensor that detects the torque of the motor. In this case, multiple torque sensors detect the torque of the motor and output the detection results to the control device 11.

[0040] The detection unit of the control device 11 infers the change in the contact force between the sleeve 53 and the bolt 40 based on the detection results of multiple torque sensors.

[0041] Displacement sensor 55 measures the distance from the sensor to the object. Based on the measured position information, displacement sensor 55 measures the amount of movement (displacement) of the object when it moves from one position to another. In this embodiment, displacement sensor 55 measures, for example, the amount of movement of bolt 40 in the Z-axis direction.

[0042] The control device 11 is constructed using a processor such as an IPU (Intelligence Processing Unit) and memory. The memory is, for example, a semiconductor memory, which includes ROM (Read Only Memory) for storing various control programs and RAM (Random Access Memory) for providing temporary operating areas. The control device 11 reads the programs stored in the memory to control the operation of each device.

[0043] The control device 11 causes the robotic arm 15 to move by supplying control signals to it. Specifically, the control device 11 drives the actuator of the robotic arm 15, causing the actuator shaft to rotate. The control device 11 detects the contact state and displacement time changes between the sleeve 53 and the bolt 40 based on the sensor detection results, as waveform data. The control device 11 processes the captured image data generated by the imaging device 51.

[0044] The nut wrench control unit 13 controls the rotation of the nut wrench 52. For example, when the nut wrench control unit 13 detects an increase in torque accompanying the rotation of the socket 53, it sends a tightening completion signal to the control device 11. The control panel 14 includes, for example, a power amplifier, a power supply, and a PLC (Programmable Logic Controller).

[0045] Figure 3 This is a flowchart illustrating the processing flow of the fastening device 10 in this embodiment. Figure 3 The example illustrates the process of assembling the busbar 30 to the base member 20 by tightening the bolts 40. Both the base member 20 and the busbar 30 have tightening holes. The tightening device 10 inserts the bolts 40 into the tightening holes of the base member 20 and the busbar 30, thus tightening them.

[0046] Hereinafter, the fastening hole 21 (second fastening hole) of the base member 20 will be referred to as the lower hole, and the fastening hole 31 (first fastening hole) of the busbar 30 will be referred to as the upper hole. It should be noted that in this embodiment, the busbar 30 is exemplified as an assembly component, and the base member 20 is exemplified as an assembled component, but this is not a limitation. It can also be applied to assembling other components together. The busbar 30 is an example of an assembly component in this embodiment. The assembly component in this embodiment can also be a bracket, other common fastening components, etc. A bracket is a support member or mounting metal member used to connect components together. Furthermore, in this embodiment, the bolt 40 is exemplified as a fastening component (fastening unit), but this is not a limitation. The fastening component can also be a screw or other component.

[0047] The base member 20 is transported and positioned on the workpiece mounting section 60. The robot arm 15, positioned on the base member 20 on the workpiece mounting section 60, places the busbar 30, which is the component to be assembled, on it (step S11). The control device 11 controls the robot arm 15 to hold the busbar 30 and to position the busbar 30 at a pre-indicated target coordinate.

[0048] With the busbar 30 mounted on the base member 20, the imaging device 51 captures an image from above of the area including at least the upper hole 31 of the busbar 30 (step S12). The imaging device 51 thereby generates image data of the area including at least the upper hole 31.

[0049] The control device 11 detects the image of the upper hole 31 from the generated captured image data and calculates the center position of the upper hole 31 in the captured image data (step S13). The control device 11 detects the outline of the upper hole 31 from the captured image data. The memory stores, for example, information about the distance (distance along the X-axis, distance along the Y-axis) from the outline of the upper hole 31 in the busbar 30 to the center coordinates.

[0050] The control device 11 calculates the center position of the upper hole 31 in the captured image data based on the position information of the detected contour of the upper hole 31 and the distance information read from the memory. The control device 11 converts the calculated center position of the upper hole 31 into spatial coordinates and calculates the center coordinates of the upper hole 31.

[0051] The control device 11 determines whether at least a portion of the image of the lower hole 21 of the base member is included in the captured image data (step S14). In cases where the offset between the busbar 30 and the base member 20 is small and the distance between the upper hole 31 and the lower hole 21 is small, for example, a portion or all of the lower hole 21 can be seen from the inside of the upper hole 31. In this case, at least a portion of the image of the lower hole 21 is included in the captured image data.

[0052] During the handling of the base component 20, its position may shift due to various factors. Alternatively, the position of the base component 20 or the busbar 30 may shift during the placement of the busbar 30. In such cases, the distance between the upper hole 31 and the lower hole 21 may increase. When the positional shift between the busbar 30 and the base component 20 is large, and the distance between the upper hole 31 and the lower hole 21 is also large, for example, the lower hole 21 may be hidden by the busbar 30 or located on the periphery (outer side) of the busbar 30.

[0053] When the lower hole 21 is covered by the busbar 30, no image of the lower hole 21 is detected from the captured image data. On the other hand, when the lower hole 21 is located around the busbar 30, at least a portion of the lower hole 21 is detected from the captured image data outside the busbar 30.

[0054] Figure 4A , 4B It is a diagram that schematically shows the positional relationship between the upper hole 31 and the lower hole 21. Figure 4A This indicates a state where a portion of the lower hole 21 can be viewed from the inside of the upper hole 31. In this state, when the upper hole 31 is photographed from above, at least a portion of the image of the lower hole 21 is included in the captured image data.

[0055] on the other hand, Figure 4B This indicates a state where the lower hole 21 is covered by the busbar 30 due to the offset of the busbar 30's mounting position. In this state, when the upper hole 31 is photographed from above, the image of the lower hole 21 is not included in the captured image data.

[0056] Thus, depending on the positional relationship between the upper hole 31 and the lower hole 21, whether or not the image data includes the lower hole 21 will differ. Return to Figure 3 The flowchart shows that the control device 11 calculates the center coordinates of the lower hole 21 based on the generated captured image data.

[0057] If an image of the lower hole is detected from the captured image data (step S14), the control device 11 calculates the center coordinates of the lower hole 21 based on the image of the lower hole 21 in the captured image data (step S15). For example, the control device 11 detects part or all of the outline of the lower hole 21 from the captured image data. The control device 11 calculates the center position of the lower hole 21 based on the positional relationship between the outline of the upper hole 31 and the outline of the lower hole 21 in the captured image data. For example, the control device 11 obtains the distance between the upper hole 31 and the lower hole 21, and calculates the center position of the lower hole 21 based on the center position of the upper hole 31 and the obtained distance. The control device 11 converts the calculated center position of the lower hole 21 into spatial coordinates and calculates the center coordinates of the lower hole 21.

[0058] On the other hand, if no image of the lower hole is detected from the captured image data (No in step S14), the control device 11 calculates the center coordinates of the lower hole 21, for example, based on the contour of the base member 20 detected from the captured image data. In this embodiment, the contour refers, for example, to the shape or form of the outer side of the base member 20. The outer contour is also referred to as a character line.

[0059] The control device 11 detects the contour of the base member 20 from the captured image data (step S16). The control device 11 may detect the contour using techniques such as pattern matching. The control device 11 may also detect the contour based on other analytical processing of the captured image data.

[0060] For example, the memory stores information about the distance (distance along the X-axis and distance along the Y-axis) from the contour of the base member 20 to the center coordinates of the lower hole 21. Based on the detected contour position information and the distance information read from the memory, the control device 11 calculates the center position of the lower hole 21 in the captured image data. The control device 11 converts the calculated center position of the lower hole 21 into spatial coordinates and calculates the center coordinates of the lower hole 21 (step S17).

[0061] It should be noted that the control device 11 can also calculate the center coordinates of the lower hole 21 based on the position offset of the base member 20. In this case, the memory stores, for example, information about the position of the contour and the position of the lower hole 21 when the base member 20 is properly configured. The control device 11 obtains the position offset of the base member 20 by comparing the position of the contour detected based on the captured image data with the stored position. Based on the obtained position offset and the position information of the lower hole 21 when properly configured, the control device 11 calculates the center position of the lower hole 21 in the captured image data. Thus, the control device 11 is able to calculate the center coordinates of the lower hole 21 in space.

[0062] When the lower hole 21 is located around the busbar 30, assuming the image of the lower hole is detected from the captured image data, the center coordinates of the lower hole 21 are calculated according to step S15. However, when the lower hole 21 is located around the busbar 30, the control device 11 can also calculate the center coordinates of the lower hole 21 according to steps S16 and S17. That is, the control device 11 can also obtain the center coordinates of the lower hole 21 by detecting the outline of the base member 20, just as when the lower hole 21 is hidden by the busbar 30.

[0063] The control device 11 controls the robotic arm 15 to grasp the bolt 40 and move it to the center coordinates of the upper hole 31 calculated in step S13 (step S18). By controlling the robotic arm 15, the control device 11 moves the grasped bolt 40 to the calculated center coordinates of the upper hole 31, thereby inserting the bolt 40 into the upper hole 31. In this way, by detecting the position of the upper hole 31 based on captured image data, the bolt 40 can be inserted into the upper hole 31 with high precision and high speed.

[0064] The control device 11 performs a correction process (step S19). While the control device 11 controls the robot arm 15 to insert the bolt 40 into the upper hole 31 of the busbar 30, it moves the busbar 30. When the upper hole 31 aligns with the lower hole 21 through this movement, the bolt 40 falls into the lower hole 21 of the base member 20, and the bolt 40 is inserted into both the upper hole 31 and the lower hole 21. Figure 6 The flowchart illustrates the details of the corrective treatment.

[0065] As a result of the correction process, when the bolt 40 is detected to be inserted into the lower hole 21, the control device 11 controls the robot arm 15 to tighten the bolt 40 (step S20). The control device 11 instructs the nut wrench control unit 13 to rotate the sleeve 53, thereby tightening the bolt 40.

[0066] Figure 5 This is a schematic diagram illustrating an example of a correction process. Bolt 40a is shown inserted into the upper hole 31 of the busbar 30, and the upper hole 31 is not aligned with the lower hole 21.

[0067] Through a correction process, the busbar 30 and bolt 40a are moved together, so that the upper hole 31 aligns with the lower hole 21. As a result of this movement, bolt 40b remains inserted into the upper hole 31 of the busbar 30 and falls into the lower hole 21 of the base member 20. It can be seen that by bolt 40b falling into the lower hole 21, the bolt 40 is in a state where it can be tightened.

[0068] Figure 6 This is a flowchart illustrating the correction process. The control device 11 determines whether the distance between the center coordinates of the upper hole 31 and the center coordinates of the lower hole 21 is within a predetermined threshold (step S31). If the distance is within the threshold (yes in step S31), it indicates that the positions of the upper hole 31 and the lower hole 21 are almost identical, and it is determined that alignment of the upper hole 31 and the lower hole 21 is unnecessary. In this case, the control device 11 omits the processes S32 to S37. Therefore, unnecessary processes are omitted, improving efficiency.

[0069] The threshold specified in step S31 is, for example, 0.5 mm. However, it is not limited to this example. For example, the specified threshold can also be set according to the diameter of the bolt 40, the size of the component, the material, etc.

[0070] On the other hand, if the distance between the center coordinates of the upper hole 31 and the center coordinates of the lower hole 21 exceeds a predetermined threshold (No in step S31), it indicates that the positions of the upper hole 31 and the lower hole 21 have shifted. Therefore, the control device 11 controls the robot arm 15 to begin moving the busbar 30 with the bolt 40 inserted into the upper hole 31 (step S32). Specifically, the control device 11 moves the busbar 30 towards the... Figure 3 The center coordinates of the lower hole 21 calculated in step S15 or S17 are used to move the hole in a straight line.

[0071] The robotic arm 15 in this embodiment is equipped with a bolt clamping mechanism. By clamping the part that holds the busbar 30, the busbar 30 can be held in a rigid state during movement. This prevents phenomena such as twisting or falling off of the bolt 40. In addition, by having a bolt clamping mechanism, not only can relatively light components such as the busbar 30 be moved, but also heavy components can be moved.

[0072] The control device 11 initiates the movement of the busbar 30 and acquires the sensor value measured by the force sensor 54. The control device 11 determines whether the acquired sensor value exceeds a threshold (step S33). When the busbar 30 moves together with the bolt 40, a large load may sometimes be applied to the bolt 40 due to reasons such as being jammed by other components. Due to the applied load, scratches or deformation of the components may occur on the bolt 40 or the base component 20 corresponding to the weight of the components.

[0073] Therefore, when movement begins, the control device 11 measures the magnitude of the force applied to the bolt 40 using the force sensor 54. If the force applied to the bolt 40 exceeds a predetermined threshold (as stated in step S33), the control device 11 determines that an abnormal state has occurred. Then, the control device 11 issues a warning (step S34) and terminates the correction process. In this way, by determining the load applied to the bolt 40 at the start of movement of the busbar 30, the occurrence of abnormal states can be suppressed in advance.

[0074] On the other hand, if the sensor value is less than the threshold (No in step S33), the control device 11 continues to move the busbar 30. While moving the busbar 30, the control device 11 detects the insertion status of the bolt 40 into the lower hole 21 (step S35). That is, the control device 11 detects whether the bolt 40 has fallen into the lower hole 21.

[0075] Figure 7 This diagram illustrates the detection and processing of the insertion state. In this embodiment, the control device 11 detects whether the bolt 40 has been inserted into the lower hole 21 based on the sensor values ​​of the force sensor 54 and the displacement sensor 55.

[0076] Force sensor 54 measurement Figure 7The force (reaction force value) is in the direction indicated by arrow Y1. When the bolt 40 is not in the lower hole 21 during movement, the bolt 40 is grounded with the base member 20, thereby maintaining the reaction force from the base member 20 in the Z-axis direction within a fixed range. On the other hand, when the bolt 40 falls into the lower hole 21, the reaction force value decreases. The control device 11 obtains the reaction force value in the Z-axis direction from the force sensor 54, and detects a change in the force applied to the bolt 40 in the Z-axis direction if the reaction force value exceeds a predetermined threshold. Alternatively, the control device 11 detects a change in the force applied to the bolt 40 in the Z-axis direction if the change in the reaction force value exceeds a predetermined threshold. Thus, the control device 11 detects the bolt 40 falling into the lower hole 21, that is, the bolt 40 being inserted into the lower hole 21.

[0077] Displacement sensor 55, for example, measures Figure 7 The displacement in the Z-axis direction is indicated by arrow Y2. When the bolt 40 is not in the lower hole 21 during movement, the position of the bolt 40 in the Z-axis direction changes little. On the other hand, when the bolt 40 falls into the lower hole 21, the displacement temporarily increases along with a significant change in position. If the displacement exceeds a predetermined threshold, the control device 11 detects a rapid change in the position of the bolt 40. Alternatively, the control device 11 detects a rapid change in the position of the bolt 40 if the degree of change in displacement exceeds a predetermined threshold. Therefore, the control device 11 detects the bolt 40 falling into the lower hole 21, that is, the bolt 40 being inserted into the lower hole 21.

[0078] In this way, by detecting the insertion state using sensor values ​​from the force sensor 54, displacement sensor 55, etc., it is possible to detect with high precision whether the bolt 40 is properly inserted. This avoids situations where tightening is performed when the bolt 40 is improperly or insufficiently inserted, potentially causing damage or breakage to the component. In this embodiment, when the busbar 30 moves together with the bolt 40, tilting or twisting of the bolt 40 may sometimes occur during movement. To address this, detection processing based on the sensor values ​​of the force sensor 54 and detection processing based on the sensor values ​​of the displacement sensor 55 are combined. Therefore, even when the busbar 30 moves together with the bolt 40, the insertion state of the bolt 40 can be detected with high precision.

[0079] It should be noted that in this embodiment, the control device 11 is shown to perform detection processing based on sensor values ​​measured by the force sensor 54 and the displacement sensor 55. However, it is not limited to this example. The control device 11 may also perform detection processing based on sensor values ​​measured by either the force sensor 54 or the displacement sensor 55. Alternatively, the detection device may determine the insertion of the bolt 40 based on the torque value when the bolt 40 is tightened.

[0080] If the bolt 40 is detected to be inserted into the lower hole 21 (yes in step S36), the control device 11 ends the correction process. On the other hand, if the bolt 40 is not detected to be inserted into the lower hole 21 even if a linear movement is made in the direction of the calculated center coordinate of the lower hole 21 (no in step S36), the control device 11 performs alignment by other methods (step S37).

[0081] The control device 11 searches for the position of the lower hole 21 in the surrounding area while aligning the upper hole 31 with the lower hole 21, thereby performing a correction process.

[0082] Even after correction based on the position of the lower hole 21 calculated from the captured image data, if the bolt 40 still does not fall in, consider the following situations: The base member 20 and the busbar 30 move in tandem, causing a positional shift; or the base member 20 itself is tilted. In these cases, the position coordinates of the lower hole 21 calculated from the captured image data may be inappropriate. Alternatively, due to manufacturing errors, the position of the lower hole 21 in the base member 20 may initially be offset. In such cases, the control device 11 switches to another method to search for the position of the lower hole 21.

[0083] For example, the control device 11 controls the robotic arm 15, causing the busbar 30 to reciprocate while changing its direction of movement, with the bolt 40 inserted. Specifically, the control device 11 controls the robotic arm 15 to reciprocate the busbar 30 while changing its direction of movement around the current position of the bolt 40. That is, the control device 11 searches for the position of the lower hole 21 from all directions. By performing such a search, the position of the lower hole 21 can be detected even when it is unclear.

[0084] Thus, in this embodiment, if the control device 11 does not detect the insertion state even when the position of the lower hole 21 is calculated based on the captured image data, it performs alignment using other methods. By combining multiple different lower holes 21, the success rate of the correction process can be improved.

[0085] If the control device 11 detects that the bolt 40 has been inserted into the lower hole 21 according to the procedure of step S37 (as in step S36), the control device 11 ends the correction process. On the other hand, if the bolt 40 is not detected to be inserted into the lower hole 21 even if other search methods are used, the control device 11 issues a warning and ends the correction process.

[0086] Figures 8A-8D This is a diagram illustrating one example of corrective treatment. Figure 8A An example is shown where a portion of the lower hole 21 is not visible from the inside of the upper hole 31 and the lower hole 21 is covered by the busbar 30.

[0087] according to Figure 8A Since the lower hole 21 of the base member 20 is covered by the busbar 30, the image of the lower hole 21 is not detected in the captured image data. Because the image of the upper hole 31 is included in the captured image data, the control device 11 calculates the center coordinates of the upper hole 31 based on the captured image data. Additionally, the control device 11 detects the contour of the base member 20 from the captured image data and calculates the center coordinates of the lower hole 21 based on the distance information between the contour and the lower hole 21.

[0088] The control device 11 controls the robotic arm 15, causing the bolt 40 to move towards the calculated center coordinates of the upper hole 31. Thus, as... Figure 8B As shown, a bolt 40 is inserted into the upper hole 31 of the busbar 30. The control device 11 causes the busbar 30, with the bolt 40 inserted into the upper hole 31, to move linearly in the direction (Y3) of the calculated center coordinate of the lower hole 21.

[0089] The result is, as Figure 8C In this way, bolt 40 moves to the position of lower hole 21 on the XY plane. The positions of upper hole 31 and lower hole 21 on the XY plane overlap, thus... Figure 8D Then the bolt 40 falls into the lower hole 21. Thus, the bolt 40 is inserted into both the upper hole 31 and the lower hole 21. In this state, the bolt 40 is tightened, thereby assembling the busbar 30 to the base member 20.

[0090] As described above, the fastening device 10 of this embodiment includes an imaging device 51 and a control device 11. The imaging device captures images of an assembly component (e.g., a busbar) having a first fastening hole (upper hole) placed on top of an assembly component (e.g., a base member) having a second fastening hole (lower hole), capturing images of at least the area containing the first fastening hole. The control device calculates a first position of the first fastening hole and a second position of the second fastening hole based on the captured image. The control device controls a robot to move a fastening member and insert it into the first fastening hole based on the first position, and moves the assembly component with the fastening member inserted into the first fastening hole towards the second position. The control device controls the robot to fasten the fastening member based on the detection that a fastening member (e.g., a bolt) has been inserted into the second fastening hole. As described above, the busbar is an example of an assembly component in this embodiment, and the base member is an example of an assembly component in this embodiment. Similarly, the bolt is an example of a fastening member in this embodiment.

[0091] In this way, with the busbar 30 mounted on the base member 20, the fastening device 10 captures images of at least the area including the upper hole 31. This allows the positional relationship between the upper hole 31 and the lower hole 21 to be detected based on the image data obtained from a single capture. By calculating the positional relationship in the image data, the positional information of the upper hole 31 and the lower hole 21 can be calculated with high precision. Therefore, based on the calculated positional information of the upper hole 31 and the lower hole 21, the bolt 40 can be inserted into the upper hole 31 of the busbar 30, and the busbar 30 can be moved linearly towards the lower hole 21 while the bolt 40 is inserted into the upper hole 31. This eliminates the need for searching the area surrounding the lower hole 21. Thus, the alignment of the upper hole 31 and the lower hole 21 can be achieved with high precision and high speed with fewer steps. Therefore, the fastening process can be automated, and the time spent on the fastening process can be reduced.

[0092] Furthermore, in this embodiment, when the captured image includes at least a portion of the image of the second fastening hole, the control device calculates the second position of the second fastening hole based on the image of the second fastening hole in the captured image. Thus, by capturing an image of at least the area including the upper hole 31 while the busbar 30 is mounted on the base member 20, and by capturing an image of at least a portion of the captured image data including images of the upper hole 31 and the lower hole 21, the positions of the upper hole 31 and the lower hole 21 can be detected. Therefore, the positions of the upper hole 31 and the lower hole 21 can be calculated with a single capture.

[0093] Furthermore, the fastening device in this embodiment includes a storage unit (storage device) that stores distance information representing the distance from the outline of the assembled component to the second fastening hole. When the captured image does not include at least a portion of the second fastening hole, the control device calculates the second position based on the position and distance information of the outline of the assembled component in the captured image. Therefore, even when the lower hole 21 is hidden by the busbar 30, the position of the lower hole 21 can be calculated based on the captured image data. Thus, even if the positions of the upper hole 31 and the lower hole 21 are offset, the position of the lower hole 21 can be calculated in addition to the position of the upper hole 31 with a single capture.

[0094] Furthermore, the fastening device in this embodiment also includes a force sensor that measures the force applied to the fastening member. When the assembly component, with the fastening member inserted into the first fastening hole, moves towards the second position, the control device stops the movement if the force sensor reading exceeds a first threshold. Therefore, when the busbar 30 is moved with the bolt 40 inserted into the upper hole 31, abnormal conditions can be detected in advance. This facilitates automation of the fastening process and suppresses deformation and damage to the bolt 40.

[0095] Furthermore, the fastening device in this embodiment includes at least one of a force sensor that measures the force applied to the fastening member and a displacement sensor that measures the amount of movement of the fastening member. The control device detects that the fastening member has been inserted into the second fastening hole when the sensor value or the change in the sensor value exceeds a second threshold. This allows for high-precision detection of whether the bolt 40 is inserted into the lower hole 21. Therefore, it is possible to avoid damage or breakage to the member caused by performing fastening procedures when the bolt 40 is improperly or insufficiently inserted. Thus, it facilitates the automation of fastening procedures and enables high-precision fastening.

[0096] Furthermore, in this embodiment, if the control device moves the assembly component from the state where the fastening member is inserted into the first fastening hole to the direction of the second position without detecting that the fastening member has been inserted into the second fastening hole, it controls the robot to perform a reciprocating motion while changing the direction of movement of the assembly component from the state where the fastening member is inserted into the first fastening hole. In this way, even if the bolt 40 cannot be inserted when moving to the position of the lower hole 21 calculated based on the captured image data, other search methods can be switched. Thus, by combining multiple different search methods for the lower hole 21, the success rate of the correction process can be improved.

[0097] Furthermore, in this embodiment, when the calculated distance between the first and second positions is less than a predetermined value, the control device performs the following processing: Based on the first position, the control device moves the fastening member and inserts it into the first fastening hole; and without inserting the fastening member into the first fastening hole, the assembled component moves towards the second position to fasten the fastening member. Thus, when alignment of the upper hole 31 and the lower hole 21 is not required, unnecessary steps can be omitted, improving processing efficiency.

[0098] (Modified Example)

[0099] In the above embodiment, the case of fastening the busbar 30 with a single fastening hole using bolts 40 is illustrated, but it can also be applied when fastening multiple fastening holes. For example, the busbar 30 has multiple fastening holes. For example, after fastening a portion of the fastening holes with bolts 40, the busbar 30 is fixed to the base member 20. Because it is fixed, it is sometimes impossible to move the busbar 30 when performing correction processing on the other fastening holes.

[0100] Therefore, when the busbar 30 has multiple fastening holes, the control device 11 can also control the fastening holes of the objects to be fastened to a temporary fastening state (floating state). A temporary fastening state, for example, indicates a state where the tightness has been loosened. The control device 11 can also strengthen the tightness of the bolts 40 in each fastening hole after temporary fastening has been completed for multiple fastening holes. Thus, even when the assembly component has multiple fastening holes, the automation of the fastening process can be promoted.

[0101] It should be noted that in the above embodiment, an example is given of performing additional search processing (step S37) when it is impossible to align the upper hole 31 with the lower hole 21 based on the position of the lower hole 21 calculated from the captured image data. For cases where the busbar 30 has multiple fastening holes, the processing can also be performed as follows. For example, the control device 11 can issue a warning and terminate the fastening process if the insertion state is not detected during the correction process of the second or subsequent fastening hole among the multiple fastening holes (No in S36). This allows for early detection of abnormalities in the correction process, improving processing efficiency.

[0102] In addition to the case where the busbar 30 has multiple fastening holes, sometimes multiple components (assembly components) are assembled on a single base component 20 (assembled component). In such cases, sometimes a portion of the multiple components is fixed to the base component 20 so that it cannot move during the straightening process of the other components. In such cases, the control device 11 can also control the fastening holes of each of the multiple components to a temporary fastening state. After the temporary fastening of the fastening holes of each of the multiple components is completed, the control device 11 can also strengthen the fastening degree of the fastening holes of each component.

[0103] It should be noted that the control device 11 can also determine the tightening sequence for multiple fastening holes. The control device 11 performs the tightening process according to the predetermined tightening sequence. At this time, the control device 11 tightens the other fastening holes in a temporary tightening state until the last fastening hole is tightened using the bolt 40. After the last fastening hole is tightened, the control device 11 controls the other fastening holes from the temporary tightening state to the truly tightened state.

[0104] Thus, the assembly component in the modified example has multiple first fastening holes. A portion of these first fastening holes are fastened after the others. In this case, the control device moves the assembly component, with the fastening members in the other first fastening holes loosened, towards a second position. Therefore, even when the busbar 30 has multiple fastening holes, the busbar 30 can be moved individually for each of the multiple upper holes 31. Thus, even when the busbar 30 has multiple fastening holes, automated fastening processes can be facilitated.

[0105] The present invention has been described above using embodiments, but the present invention is not limited to such embodiments and can be modified and replaced in various ways without departing from the spirit of the present invention.

Claims

1. A fastening device that assembles an assembly component to an assembly component by fastening a fastening member, wherein, The fastening device includes: A camera device that, with the assembled component having a first fastening hole placed on top of the assembled component having a second fastening hole, captures images of an area including at least the first fastening hole. as well as The control device calculates the first position of the first fastening hole and the second position of the second fastening hole based on the captured image. The control device controls the robot, moves the fastening member to the first fastening hole based on the first position, and moves the assembly component to the second position while the fastening member is inserted into the first fastening hole. Based on the detection that the fastening member is inserted into the second fastening hole, the control device controls the robot to fasten the fastening member.

2. The fastening device according to claim 1, wherein, When the captured image contains at least a portion of the second fastening hole, the control device calculates the second position of the second fastening hole based on the image of the second fastening hole in the captured image.

3. The fastening device according to claim 1 or 2, wherein, The fastening device includes a storage device that stores distance information, representing the distance from the outline of the assembled component to the second fastening hole. When the captured image does not contain at least a portion of the image of the second fastening hole, the control device calculates the second position based on the position of the outline of the assembled component in the captured image and the distance information.

4. The fastening device according to claim 1 or 2, wherein, The fastening device also includes a force sensor that measures the force applied to the fastening member. When the assembly component moves toward the second position while the fastening member is inserted into the first fastening hole, the control device stops the movement if the sensor value of the force sensor exceeds a first threshold.

5. The fastening device according to claim 1 or 2, wherein, The fastening device includes at least one of a force sensor that measures the force applied to the fastening member and a displacement sensor that measures the amount of movement of the fastening member. When the sensor value or the change in the sensor value exceeds a second threshold, the control device detects that the fastening member has been inserted into the second fastening hole.

6. The fastening device according to claim 1 or 2, wherein, If the control device moves the assembly component toward the second position after the fastening member is inserted into the first fastening hole, and does not detect that the fastening member is inserted into the second fastening hole, the control device controls the robot to make the assembly component, while changing its direction of movement, reciprocate while the fastening member is inserted into the first fastening hole.

7. The fastening device according to claim 1 or 2, wherein, When the calculated distance between the first position and the second position is less than a predetermined value, the control device moves the fastening member based on the first position and inserts it into the first fastening hole. Furthermore, without inserting the fastening member into the first fastening hole, the assembly moves towards the second position to fasten the fastening member.

8. The fastening device according to claim 1 or 2, wherein, The assembly component has a plurality of the first fastening holes. A portion of the first fastening holes are fastened after the other first fastening holes. The control device moves the assembled component toward the second position when the fastening members of the other first fastening holes are loosened.

9. A fastening method for assembling assembly components to assembly parts by fastening fastening members. The fastening method includes: With the assembled component having a first fastening hole placed on top of the assembled component having a second fastening hole, a photograph is taken of the area including at least the first fastening hole. Based on the captured images, calculate the first position of the first fastening hole and the second position of the second fastening hole; The robot is controlled to move the fastening member and insert it into the first fastening hole based on the first position, and the assembled component, with the fastening member inserted into the first fastening hole, is moved toward the second position. as well as Based on the detection that the fastening member has been inserted into the second fastening hole, the robot is controlled to fasten the fastening member.

Images