Bolt hole identification tool and identification method

Abstract

The invention provides a bolt hole recognition tool and recognition method, and relates to the field of aperture recognition, the bolt hole recognition tool comprises a laser target module capable of irradiating a circular aperture and a cross, a control module, at least three distance measuring sensors and a mechanical arm used for adjusting the orientation of the laser target module and the distance measuring sensors; the distance measuring sensors are located on the same working plane, the orientation of each distance measuring sensor is consistent with the orientation of the laser marker handle module, and the orientation is perpendicular to the working plane; the laser target module and the distance measuring sensor are both arranged at the movable end of the mechanical arm. The movable end of the mechanical arm can rotate around at least two mutually perpendicular directions as axes in a three-dimensional space; the control module is electrically connected with the laser target module, the distance measuring sensor and the mechanical arm. The posture of the mechanical arm is adjusted according to distance measuring information of the distance measuring sensor and faces the plane where the threaded hole is located, and it is guaranteed that the threaded hole detection result is accurate; and then a laser target module is matched to identify the aperture of the threaded hole.

Description

Technical Field

[0001] The invention relates to the technical field of bolt hole diameter measurement, and in particular to a bolt hole identification tool. Background Art

[0002] The existing threaded hole aperture detection is mainly through more complex image recognition, such as the content shown in the patent with application publication number CN105698694A and application publication number CN112102272A; or it is relatively simple to use straight rods of different sizes for direct attempts, such as the content shown in the patent with authorization announcement number CN203364723U. For the former, although it can achieve higher accuracy and a wider detection range, its equipment composition is complex and the volume is large, resulting in poor portability; and for the latter, there are many problems such as inconvenience in use and carrying, and a small detection size range. Therefore, it is proposed to use a cross target aperture combined with a distance to obtain the threaded hole size, wherein when the target aperture coincides with the edge of the threaded hole, the aperture of the threaded hole is proportional to the distance between the two. There is a prerequisite in the method of measuring the aperture of the target, that is, the target needs to be oriented directly to the threaded hole or the plane where the threaded hole is located, and when the operator operates it personally, it is extremely difficult to control the target transmitter to face the threaded hole. Therefore, an auxiliary device is needed to help adjust the angle between the target launcher and the threaded hole. Summary of the invention

[0003] The purpose of the present invention is to solve the deficiencies of the prior art and provide a bolt hole identification tool and an identification method.

[0004] In a first aspect, the present invention provides a bolt hole identification tool, comprising: a laser target module capable of irradiating a circular aperture and a cross, a control module, at least three ranging sensors, and a mechanical arm for adjusting the orientation of the laser target module and the ranging sensor; wherein the ranging sensors are located in the same working plane, the orientation of each ranging sensor is consistent with the orientation of the laser target module, and the orientation is perpendicular to the working plane; the laser target module and the ranging sensor are both arranged at the movable end of the mechanical arm; the movable end of the mechanical arm can rotate around at least two mutually perpendicular directions as an axis in three-dimensional space; and the control module is electrically connected to the laser target module, the ranging sensor, and the mechanical arm, respectively.

[0005] Furthermore, the robotic arm includes: a first rotating device rotating around the spatial Y axis, a second rotating device rotating around the spatial Z axis and a supporting base, wherein the first rotating device is movably arranged on the supporting base; the second rotating device is movably arranged on the first rotating device, and the second rotating device is also connected to the ranging sensor and the laser target module; the supporting base is used to connect to an external connection surface.

[0006] Furthermore, the three ranging sensors are distributed in an isosceles right triangle; and in the initial state, one of the two right sides of the isosceles right triangle coincides with or is parallel to the axis of rotation of the first rotating device, and the other right side coincides with or is parallel to the axis of rotation of the second rotating device.

[0007] Furthermore, the three ranging sensors located in the same working plane are distributed around the laser target module in an isosceles right triangle; the ranging sensors adopt ultrasonic ranging sensors.

[0008] Furthermore, a housing is fixedly arranged at the movable end of the robotic arm; the control module is fixedly arranged inside the housing; the end face of the control module far from the robotic arm serves as the working plane, and three ranging sensors and a laser target module are fixedly arranged on the working plane of the control module; the battery pack is detachably connected to the outside of the housing through a buckle structure, and the battery pack is also electrically connected to the control module.

[0009] Furthermore, the control module includes: a power supply circuit, a power supply control module, a signal processing circuit, a controller, and a communication module; wherein, the power supply circuit includes a laser head power supply that converts the battery pack power supply into a 5V voltage, an ultrasonic sensor power supply that converts the battery pack power supply into a 12V voltage, and a system power supply that converts the battery pack power supply into a 3.3V voltage. The system power supply is connected to the controller to provide a stable working voltage; the signal processing circuit is arranged between the ranging sensor and the controller to transmit the information collected by the ranging sensor to the controller. The ultrasonic sensor power supply is connected to the ranging sensor through the power supply control module to provide 12V voltage for the ranging sensor. The laser head power supply is connected to the laser target module through the power supply control module to provide 5V voltage for the laser target module. The power supply control module is connected to the controller through a control IO, and the controller is connected to the communication module.

[0010] Furthermore, the robotic arm includes: a servo controller, and the servo controller is electrically connected to the servo motors in the first rotating device and the second rotating device respectively; the servo controller is also communicatively connected to the control module.

[0011] In a second aspect, the present invention provides a method for identifying bolt holes, based on the above bolt hole identification tool, including the following steps:

[0012] Step 1: Start the three ranging sensors located on the working plane, so that the three ranging sensors are oppositely arranged with respect to the plane where the threaded hole to be detected is located, and in the initial state, one of the two right sides of the isosceles right triangle coincides with or is parallel to the axis of rotation of the first rotating device, and the other right side coincides with or is parallel to the axis of rotation of the second rotating device;

[0013] Step 2: Obtain the distance information L1, L2, and L3 from the three ranging sensors respectively, which are the distances from the plane where the threaded hole is located. Among them, the ranging sensors corresponding to the distance information L1 and L2 are on the same right-angled side, and the ranging sensors corresponding to the distance information L2 and L3 are on the same right-angled side;

[0014] Step 3: The controller calculates the rotation angles θ and σ of the robotic arm in two directions according to the distance information collected by the ranging sensors;

[0015] Step 4: The controller activates the laser target module, makes the laser target module face the threaded hole directly, aligns the circle of the laser target module with the bolt hole, and calculates the size information of the threaded hole according to the ranging information.

[0016] Further, the rotation angle θ in Step 3 is: The rotation angle σ is: LA is the spacing between the ranging sensors corresponding to L1 and L2 on the working plane, and LB is the spacing between the ranging sensors corresponding to L2 and L3 on the working plane.

[0017] Further, initialize the state vector x k =[θ σ] T , process noise Q, observation noise R, and covariance matrix P;

[0018] Obtain the three distances L1, L2, and L3 measured by the ranging sensors;

[0019] Use the state prediction model to predict the state vector:

[0020] x k∣k-1 =Fx k-1∣k-1 +w k ;

[0021] Among them, F is the state transition matrix, F adopts the identity matrix, w k is the process noise, w k obeys the Gaussian distribution: Q is the process noise:

[0022]

[0023] Among them, q θ , q σ is the variance of the rotation angle random walk noise;

[0024] Perform covariance prediction according to the following formula:

[0025] P k∣k-1 =P k-1∣k-1 +Q;

[0026] Build the observation model:

[0027] The relationship between the distance measurement values and angles of the three ranging sensors is as follows:

[0028]

[0029] By using L1 - L2 and L3 - L2 to eliminate d, we get:

[0030]

[0031] The ranging sensors are arranged in an isosceles right - triangle. Given LA = LB, the matrix is invertible, and the rotation angles θ and σ can be directly solved.

[0032] Then the observation model is:

[0033]

[0034] where the non - linear function h(x k ) is:

[0035]

[0036] v k is the noise covariance matrix of the ranging sensors;

[0037] Linearize the observation model and calculate the Jacobian matrix H k :

[0038]

[0039] Calculate the Kalman gain using the Jacobian matrix:

[0040]

[0041] Update the state vector based on the Kalman gain:

[0042] x k∣k = x k∣k-1 + K k (z k - h(x k∣k-1 ));

[0043] Update the covariance based on the Kalman gain:

[0044] P k∣k = (I - K k H k )P k∣k-1 ;

[0045] Iterate the above process until the elements of the updated state vector are less than the set threshold;

[0046] Use the filtered state vector to control the manipulator for attitude adjustment.

[0047] The beneficial effects of the present invention are as follows:

[0048] By providing at least three ranging sensors located on the same working plane, the pose of the tool is adjusted to keep it facing the plane where the threaded hole is located, ensuring the accuracy of the threaded hole detection result.

[0049] By arranging the ranging sensors in an isosceles right triangle distribution, it is convenient to perform Kalman filtering subsequently, and the rotation angle is adjusted more accurately according to the distance values detected by the ranging sensors.

[0050] By providing a communication module, remote communication and remote control are realized, expanding the application scope of this embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The drawings herein are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0053] Figure 1 Schematic diagram of the overall structure of the bolt hole identification tool provided by the embodiment of the present invention Figure 1 ;

[0054] Figure 2 Schematic diagram of the overall structure of the bolt hole identification tool provided by the embodiment of the present invention Figure 2 ;

[0055] Figure 3 Exploded view of the overall structure of the bolt hole identification tool provided by the embodiment of the present invention;

[0056] Figure 4 Schematic diagram of the battery pack provided by the embodiment of the present invention;

[0057] Figure 5 Relationship diagram of the control module provided by the embodiment of the present invention;

[0058] Figure 6 Schematic diagram of the controller provided by the embodiment of the present invention;

[0059] Figure 7 Schematic diagram of the laser head power supply provided by the embodiment of the present invention;

[0060] Figure 8 Schematic diagram of the system power supply provided by the embodiment of the present invention;

[0061] Figure 9 Schematic diagram of the signal processing circuit provided by the embodiment of the present invention;

[0062] Figure 10 Schematic diagram of the working plane where the distance sensor is located and the plane where the bolt to be measured is located provided by the embodiment of the present invention;

[0063] Figure 11 Schematic diagram of calculating the rotation angle and measuring the distance in an identification method provided by the embodiment of the present invention;

[0064] Figure 12 Schematic diagram of calculating the rotation angle and measuring the distance in another identification method provided by the embodiment of the present invention.

[0065] Explanation of the attached drawing reference numerals: 1. Laser target module, 2. Control module, 3. Distance measuring sensor, 4. Housing, 41. Slide groove, 42. Slide bar, 43. Card slot, 5. Battery pack, 51. Notch, 52. Elastic buckle. Detailed implementation manners

[0066] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0067] It should be noted that in this article, the term "comprising", "including" or any other variation thereof is intended to cover a non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0068] Embodiment 1

[0069] As Figures 1 to 4 shown, the present invention provides a bolt hole identification tool, including: a laser target module 1, a control module 2, at least three distance measuring sensors 3, and a robotic arm for adjusting the orientations of the laser target module 1 and the distance measuring sensors 3.

[0070] The laser target module 1 can irradiate a circular aperture and a cross, and the center of the cross coincides with the center of the aperture. When detecting the aperture of the threaded hole, it is necessary to control the edge of the aperture irradiated by the laser target module 1 to coincide as much as possible with the edge of the threaded hole.

[0071] At least three of the ranging sensors 3 are located on the same working plane, and the orientations of the respective ranging sensors 3 are the same as the orientation of the laser target module 1 and are perpendicular to the working plane; specifically, the laser target module 1 and the ranging sensors 3 are both provided at the movable end of the robotic arm. In three-dimensional space, the movable end of the robotic arm can rotate around at least two mutually perpendicular directions as axes.

[0072] The control module 2 is electrically connected to the laser target module 1, the ranging sensors 3, and the robotic arm respectively. The control module 2 is used to process the distance information between the ranging sensors 3 and the bolt to be measured, and adjust the rotation angle of the robotic arm and change the posture of the robotic arm according to the distance from the bolt to be measured. In some other embodiments, a larger number of ranging sensors 3 are arranged in the working plane to adjust the pose more precisely.

[0073] The robotic arm includes a first rotating device that rotates around the Y axis of space, a second rotating device that rotates around the Z axis of space, and a support base. The first rotating device is movably provided on the support base; the second rotating device is movably provided on the first rotating device; the support base is used to connect to an external connection surface to improve the overall portability. It should be noted that the rotation axes of the first rotating device and the second rotating device are close to the working plane, so that the working plane will not have a large spatial displacement when the robotic arm rotates. The robotic arm also includes a servo controller, and the servo controller is electrically connected to the servo motors in the first rotating device and the second rotating device respectively; the servo controller is also communicatively connected to the control module 2. The control module 2 controls the rotation angle of the robotic arm by controlling the servo motors through the servo controller.

[0074] As Figure 2 shown, the three ranging sensors 3 are distributed in an isosceles right triangle; and when in the initial state, one of the two right sides of the isosceles right triangle coincides with or is parallel to the axis of rotation of the first rotating device, and the other right side of the isosceles right triangle coincides with or is parallel to the axis of rotation of the second rotating device. The three ranging sensors 3 located on the same working plane are distributed in a triangle around the laser target module 1; the end of the laser target module 1 and the ranging sensors 3 are on the same plane, so that the ranging sensors 3 can be used to adjust the angle and can also be used to calculate the aperture of the threaded hole; in this example, the ranging sensors 3 use ultrasonic ranging sensors.

[0075] A bolt hole recognition tool further includes a housing 4 and a battery pack 5; wherein the housing 4 is fixedly arranged at the movable end of the robotic arm; the control module 2 is fixedly arranged inside the housing 4; the end face of the control module 2 far from the robotic arm serves as the working plane, and three distance measuring sensors 3 and a laser target module 1 are fixedly arranged on the working plane of the control module 2; the battery pack 5 is detachably connected to the outside of the housing 4 through a snap structure, and the battery pack 5 is also electrically connected to the control module 2. As Figure 3 and Figure 4 shown, a rectangular chute 41 is arranged at the part of the housing 4 for connecting the battery pack 5, raised slide bars 42 are arranged on both sides of the chute 41, notch openings 51 corresponding to the slide bars 42 are arranged on both sides of the battery pack 5, a sunken clamping groove 43 is also arranged in the chute 41 of the housing 4, and an elastic snap 52 corresponding to the clamping groove 43 is arranged on the battery pack 5. When the slide bars 42 are inserted into the notch openings 51 on both sides of the battery pack 5, the elastic snap 52 on the battery pack 5 is snapped into the clamping groove 43 to achieve snap connection. For convenient disassembly, the pressing part of the elastic snap 52 is arranged on the bottom of the battery pack 5, on the inclined plane near its edge, and a gap is formed between the inclined plane and the housing 4 to facilitate pressing down the elastic snap 52 to separate it from the clamping groove 43. A T-shaped rod-like structure for connecting with the robotic arm is also arranged at the end of the housing 4.

[0076] As Figure 5 shown, the control module 2 includes: a power supply circuit, a power supply control module, a signal processing circuit, a controller, and a communication module; wherein, the power supply circuit includes a laser head power supply that converts the power supply of the battery pack 5 into a 5V voltage, an ultrasonic sensor power supply that converts the power supply of the battery pack 5 into a 12V voltage, and a system power supply that converts the power supply of the battery pack 5 into a 3.3V voltage. The system power supply is connected to the controller to provide a stable working voltage; the signal processing circuit is arranged between the distance measuring sensor 3 and the controller to transmit the information collected by the distance measuring sensor 3 to the controller; the ultrasonic sensor power supply is connected to the ultrasonic distance measuring sensor serving as the distance measuring sensor through the power supply control module to provide a 12V voltage for the distance measuring sensor 3. The laser head power supply is connected to the laser target module through the power supply control module to provide a 5V voltage for the laser target module. The power supply control module is connected to the controller through a control IO. The controller of the control module 2 is connected to the communication module, and the communication module is used to implement WIFI communication and communication with a remote platform to achieve remote control and comparison; in this example, through the communication module, part of the more cumbersome information processing process can be transmitted to a remote platform with more powerful computing power for processing, which can effectively simplify the overall circuit structure of the device and reduce the volume of the device; in addition, remote processing can also be achieved, and the aperture of the threaded hole can be recognized remotely, and based on this, operations such as remote screw installation can be completed.

[0077] In this example, the voltage directly output by the battery pack 5 is 12V. The capacity of the battery pack 5 is related to the ideal working duration of the bolt hole identification tool. Set the ideal working duration of the bolt hole identification tool as T, the total power of the bolt hole identification tool except the robotic arm part as P, and the working load rate is calculated according to 50%. The battery capacity C is approximately: C = 0.5 * 1.2P / V * T; as shown in the following table, the table includes the power consumption table of each component of the bolt hole identification tool:

[0078]

[0079] As Figure 6 shown, Figure 6 An example of the controller is given. The controller is provided with two pins, 5V_EN and 12V_EN, which respectively control the power-on of the laser target module 1 and the ranging sensor 3. The controller is provided with five pins, SEN_N1, SEN_N2, SEN_N3, SEN_N4, and SEN_N5, which support communication with the ranging sensor 3. The controller is provided with serial communication pins connected to the communication module.

[0080] As Figure 7 shown, Figure 7 A circuit schematic diagram of the laser head power supply is given. The TLV76750DGNR step-down voltage regulator chip is used to convert the 12V battery pack voltage into the 5V power supply voltage of the laser target module.

[0081] As Figure 8 shown, Figure 8 A circuit schematic diagram of the system power supply is given. The LM317DCYR step-down voltage regulator chip is used to convert the 12V battery pack voltage into the 3.3V working voltage of the controller.

[0082] As Figure 9 shown, Figure 9 A signal processing circuit arranged between the ranging sensor 3 and the controller is given, including coupling resistors coupled between the SEN_N1, SEN_N2, SEN_N3, SEN_N4, and SEN_N5 pins of the controller and the signal transmission ends LEN_N1, LEN_N2, LEN_N3, LEN_N4, and LEN_N5 of each ranging sensor 3, and an RC parallel circuit grounded.

[0083] Embodiment 2

[0084] A bolt hole identification method, based on the bolt hole identification tool described above, the method includes the following steps:

[0085] Step 1: Start the three ranging sensors 3 located on the working plane, so that the three ranging sensors 3 are oppositely arranged with respect to the plane where the threaded hole to be detected is located. As Figure 10As shown, when in the initial state, one of the two right-angled sides of the isosceles right triangle coincides with or is parallel to the axis of rotation of the first rotating device, and the other right-angled side coincides with or is parallel to the axis of rotation of the second rotating device;

[0086] Step 2: Obtain the distance information L1, L2, and L3 from the plane where the threaded hole is located, which are respectively collected by the three ranging sensors 3. Among them, the ranging sensors corresponding to the distance information L1 and L2 are on the same right-angled side, and the ranging sensors corresponding to the distance information L2 and L3 are on the same right-angled side;

[0087] Step 3: As Figure 11 and Figure 12 shown, the controller calculates the rotation angles θ and σ of the robotic arm in two directions according to the distance information collected by the ranging sensors 3; the controller adjusts the posture of the robotic arm according to the rotation angles. The rotation angle θ is: The rotation angle σ is: LA is the spacing between the ranging sensors corresponding to L1 and L2 on the working plane, and LB is the spacing between the ranging sensors corresponding to L2 and L3 on the working plane.

[0088] In the specific implementation process, the controller uses the extended Kalman filter to optimize the rotation angles. The process includes:

[0089] Initialize the state vector x k = [θ σ] T , the process noise Q, the observation noise R, and the covariance matrix P;

[0090] Obtain the three distances L1, L2, and L3 measured by the ranging sensors;

[0091] Use the state prediction model to predict the state vector:

[0092] x k∣k-1 = Fx k-1∣k-1 + w k ;

[0093] Among them, F is the state transition matrix, F adopts the identity matrix, w k is the process noise, w k obeys the Gaussian distribution: Q is the process noise:

[0094]

[0095] Among them, q θ , q σ is the variance of the rotation angle random walk noise;

[0096] Perform covariance prediction according to the following formula:

[0097] Pk∣k-1 = P k-1∣k-1 + Q;

[0098] Modeling Observation Model:

[0099] The relationship between the distance measurement values and angles of three ranging sensors is:

[0100]

[0101] By using L1 - L2 and L3 - L2 to eliminate d, we get:

[0102]

[0103] The ranging sensors are arranged in an isosceles right triangle. Since LA = LB, the matrix is invertible, and the rotation angles θ and σ can be directly calculated;

[0104] Then the observation model is:

[0105]

[0106] where the non - linear function h(x k ) is:

[0107]

[0108] v k is the noise covariance matrix of the ranging sensors;

[0109] Linearize the observation model and calculate the Jacobian matrix H k :

[0110]

[0111] Calculate the Kalman gain using the Jacobian matrix:

[0112]

[0113] Update the state vector based on the Kalman gain:

[0114] x k∣k = x k∣k-1 + K k (z k - h(x k∣k-1 ));

[0115] Update the covariance based on the Kalman gain:

[0116] P k∣k = (I - K k H k )P k∣k-1 ;

[0117] Iterate the above process until the elements of the updated state vector are less than the set threshold;

[0118] Use the filtered state vector to control the manipulator to adjust its posture.

[0119] Step 4: The controller activates the laser target module 1 to make the laser target module 1 face the threaded hole directly, obtains the size information of the threaded hole, and ends the step. Among them, the size information of the threaded hole is positively correlated with the distance between the laser target module 1 and the threaded hole at this time, and the distance between the laser target module 1 and the threaded hole can be obtained by the distance measuring sensor 3.

[0120] During the implementation process, by setting at least three distance measuring sensors 3 located on the same working plane, the pose of the tool is adjusted to keep it facing the plane where the threaded hole is located, ensuring that the detection result of the threaded hole is relatively accurate; by setting the distance measuring sensors 3 to be distributed in an isosceles right triangle, it is convenient to obtain the rotation angle according to the distance values detected by the distance measuring sensors 3; by setting the communication module, remote communication and remote control are realized, expanding the application scope of this embodiment.

[0121] In the embodiments provided by the present invention, it should be understood that the disclosed structures and methods can be implemented in other ways. For example, the structural embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point, the displayed or discussed mutual coupling or direct coupling or communication connection can be through some interfaces, and the indirect coupling or communication connection of the structure or unit can be in electrical, mechanical or other forms.

[0122] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0123] In addition, the functional units in each embodiment of the present invention can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0124] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A bolt hole identification tool, characterized in that: include: A laser target module (1) capable of irradiating a circular aperture and a cross, a control module (2), at least three distance measuring sensors (3), and a mechanical arm for adjusting the orientation of the laser target module (1) and the distance measuring sensors (3); wherein the distance measuring sensors (3) are located on the same working plane, the orientation of each distance measuring sensor (3) is consistent with the orientation of the laser target module (1), and the orientation is perpendicular to the working plane; the laser target module (1) and the distance measuring sensor (3) are both arranged at the movable end of the mechanical arm; the movable end of the mechanical arm can rotate around at least two mutually perpendicular directions as axes in a three-dimensional space; and the control module (2) is electrically connected to the laser target module (1), the distance measuring sensor (3), and the mechanical arm, respectively.

2. A bolt hole identification tool according to claim 1, characterized in that: The mechanical arm comprises: a first rotating device rotating around a spatial Y axis, a second rotating device rotating around a spatial Z axis, and a supporting base, wherein the first rotating device is movably arranged on the supporting base; the second rotating device is movably arranged on the first rotating device, and the second rotating device is also connected to the distance measuring sensor (3) and the laser target module (1); and the supporting base is used to be connected to an external connection surface.

3. A bolt hole identification tool according to claim 2, characterized in that: The three distance measuring sensors (3) are distributed in an isosceles right triangle; and in an initial state, one of the two right-angled sides of the isosceles right triangle coincides with or is parallel to the axis of rotation of the first rotating device, and the other right-angled side coincides with or is parallel to the axis of rotation of the second rotating device.

4. A bolt hole identification tool according to claim 3, characterized in that: The three distance measuring sensors (3) located on the same working plane are distributed around the laser target module (1) in the form of an isosceles right triangle; the distance measuring sensors (3) are ultrasonic distance measuring sensors.

5. A bolt hole identification tool according to claim 1, characterized in that: A housing (4) is fixedly arranged at the movable end of the robot arm; a control module (2) is fixedly arranged inside the housing (4); an end surface of the control module (2) at an end away from the robot arm serves as a working plane, and three distance measuring sensors (3) and a laser target module (1) are fixedly arranged on the working plane of the control module (2); the battery pack (5) is detachably connected to the outside of the housing (4) via a snap-fit ​​structure, and the battery pack (5) is also electrically connected to the control module (2).

6. A bolt hole identification tool according to claim 5, characterized in that: The control module (2) comprises: a power supply circuit, a power supply control module, a signal processing circuit, a controller and a communication module; wherein the power supply circuit comprises a laser head power supply for converting the power supplied by the battery pack (5) into a 5V voltage, an ultrasonic sensor power supply for converting the power supplied by the battery pack (5) into a 12V voltage, and a system power supply for converting the power supplied by the battery pack (5) into a 3.3V voltage, the system power supply being connected to the controller and being used to provide a stable working voltage; the signal processing circuit is arranged between the distance measuring sensor (3) and the controller and is used to transmit information collected by the distance measuring sensor (3) to the controller; the ultrasonic sensor power supply is connected to the distance measuring sensor via the power supply control module and provides a 12V voltage for the distance measuring sensor (3); the laser head power supply is connected to the laser target module (2) via the power supply control module and provides a 5V voltage for the laser target module (1); the power supply control module is connected to the controller via a control IO, and the controller is connected to the communication module.

7. A bolt hole identification tool according to claim 2, characterized in that: The mechanical arm comprises: a servo controller, which is electrically connected to the servo motors in the first rotating device and the second rotating device respectively; the servo controller is also communicatively connected to the control module (2).

8. A bolt hole identification method, characterized in that: The bolt hole identification tool according to any one of claims 1 to 7 comprises the following steps: Step 1: Start the three distance measuring sensors located on the working plane, so that the three distance measuring sensors are arranged relative to the plane where the threaded hole to be detected is located, and in the initial state, one of the two right-angled sides of the isosceles right triangle coincides with or is parallel to the axis of rotation of the first rotating device, and the other right-angled side coincides with or is parallel to the axis of rotation of the second rotating device; Step 2: Obtain distance information L1, L2 and L3 from the plane where the threaded hole is located, respectively collected by three distance measuring sensors, wherein the distance measuring sensors corresponding to the distance information L1 and L2 are on the same right angle side, and the distance measuring sensors corresponding to the distance information L2 and L3 are on the same right angle side; Step 3: The controller calculates the rotation angles θ and σ of the robot arm in two directions according to the distance information collected by the ranging sensor; Step 4: The controller starts the laser target module, so that the laser target module is facing the threaded hole, the circle of the laser target module is aligned with the bolt hole, and the threaded hole size information is calculated based on the distance measurement information.

9. A bolt hole identification method according to claim 8, characterized in that: In step 3, the rotation angle θ calculated by the controller according to the distance information collected by the ranging sensor is: The rotation angle σ is: LA is the distance between the distance measuring sensors corresponding to L1 and L2 on the working plane, and LB is the distance between the distance measuring sensors corresponding to L2 and L3 on the working plane.

10. A bolt hole identification method according to claim 8, characterized in that: In step 3, the controller uses extended Kalman filtering to optimize the rotation angle, and the process includes: Initialize the state vector x k =[θσ] T , process noise Q, observation noise R and covariance matrix P; Get three distances L1, L2, L3 measured by the ranging sensor; Use the state prediction model to predict the state vector: x k∣k-1 =Fx k-1∣k-1 +w k ; Among them, F is the state transfer matrix, F uses the unit matrix, w k is the process noise, w k Obey Gaussian distribution: Q is the process noise: Among them, q θ ,q σ is the variance of the random walk noise of the rotation angle; Covariance prediction is performed according to the following formula: P k∣k-1 =P k-1∣k-1 +Q; Modeling Observation Model: The relationship between the distance measurement values ​​and angles of the three ranging sensors is: Eliminate d through L1-L2, L3-L2, and get: The distance measuring sensors are arranged in an isosceles right triangle, LA=LB, then the matrix is ​​reversible, and the rotation angles θ and σ can be directly solved; The observation model is: The nonlinear function h(x k )for: v k is the noise covariance matrix of the ranging sensor; Linearize the observation model and calculate the Jacobian matrix H k : The Kalman gain is calculated using the Jacobian matrix: Update the state vector based on the Kalman gain: x k∣k =x k∣k-1 +K k (z k -h(x k∣k-1 )); Covariance update based on Kalman gain: P k∣k =(I-K k H k )P k∣k-1 ; The above process is iterated until the updated state vector element is less than the set threshold; the filtered state vector controls the robotic arm to adjust its posture.

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