Contact type automatic hole making normal alignment device and rapid calibration and method searching method

Abstract

The invention belongs to the technical field of automatic hole making, and discloses a contact type automatic hole making normal alignment device and a rapid calibration and method searching method. The device comprises a calibration surface, a calibration detachable stop block, a pressure foot support, a pressure foot, a limiting pin, a depth adjusting threaded pin, an extension spring, a linear displacement sensor, a sliding spherical groove, a limiting stop block, a calibration detachable stop block fixing screw and a replaceable nose. According to the method, the problem that the normal direction of the compressed curved surface cannot be obtained by an existing normal direction measuring method in the automatic hole making process is solved, and hole making on the surface of a product with large curvature change is met.

Description

Technical Field

[0001] This invention belongs to the field of automated hole-making technology, specifically relating to a contact-type automatic hole-making normal alignment device and a rapid calibration and normal-finding method, used for rapid calibration and normal alignment during the automatic hole-making process on workpiece surfaces of various sizes and curvatures. Background Technology

[0002] Automated hole drilling is a crucial step in the production cycle of an aircraft. Currently, aircraft assembly work has very high requirements for hole drilling quality. During the assembly process of an aircraft, there are more than a million mounting holes for connecting fasteners of different specifications and functions. Hole drilling is time-consuming, and the accuracy of normal measurement directly affects the processing quality of automated hole drilling.

[0003] The basic principle of current hole-making normal measurement is to measure the positions of 3 to 4 points near the hole location, and then calculate the actual normal of the hole location by fitting the measured points to a plane or curved surface. Current normal alignment devices and methods generally have the following drawbacks: (1) The automatic hole-making process generally requires pressing the product surface. After pressing, the product surface deforms, and the normal of the hole position will also change. The existing normal measurement method measures the normal of the processing area when it is not pressed, and cannot obtain the normal of the curved surface after pressing. (2) The measurement accuracy of existing measurement methods is greatly affected by factors such as the curvature of the product surface and the distance between sensor measurement points. For product surfaces with different curvatures, it is necessary to design corresponding measurement point distances to improve measurement accuracy. Usually, a set of normal alignment devices cannot be applied to the normal alignment of holes made on product surfaces with large curvature changes.

[0004] (3) Existing normal alignment devices require calibration of the sensors used to determine the position and orientation of the sensors. The calibration method is complex and time-consuming. (4) For products of different shapes, there are specific requirements for the size of the pressure foot nose of the normal alignment device. However, the existing pressure foot of the normal alignment device is not easily replaceable and the replacement is not convenient. Summary of the Invention

[0005] This invention addresses the problem that existing normal measurement methods cannot obtain the normal vector of the surface after compression during automated hole making. It provides a contact-type automated hole making normal alignment device and a rapid calibration method, which can realize rapid sensor calibration and rapid nose replacement. During automated hole making, it measures the normal vector of the hole position under compression, which meets the requirements of hole making on product surfaces with large curvature changes, and effectively solves the problems mentioned in the background technology.

[0006] The technical solution of this invention is implemented as follows: In a first aspect, the present invention provides a contact-type automatic hole-making normal alignment device, comprising: The pressure foot support has a calibration surface and a mounting surface on one side. A sliding spherical groove is provided in the mounting surface, and four first through holes and four second through holes are evenly distributed on the outer edge of the sliding spherical groove. The pressure foot has replaceable noses and sliding balls on both sides, which are installed in the sliding ball groove; The calibration assembly includes four detachable calibration stops, four limit pins, and four tension springs. The four detachable calibration stops are evenly distributed on the outer edge of the sliding spherical groove. The limit pins and tension springs are disposed in the second through hole. The two ends of the tension springs are respectively connected to the limit pins and the pressure feet. The method-finding component includes four linear displacement sensors, which are fixedly installed in the first through hole, with their acquisition ends in contact with the surface of the pressure foot.

[0007] As a further technical solution of the present invention: the calibration surface and the mounting surface are in the same plane; during operation, the bottom surface of the pressure foot support is in a horizontal state.

[0008] As a further technical solution of the present invention: the calibrated detachable stop block is connected to the mounting surface by calibrated detachable stop block fixing screws.

[0009] As a further technical solution of the present invention: the thickness of the sliding ball is slightly greater than the depth of the sliding ball groove, so that there is a certain distance between the surface of the pressure foot and the mounting surface.

[0010] As a further technical solution of the present invention: the tail end of the linear displacement sensor is limited by a limiting block.

[0011] As a further technical solution of the present invention: a depth adjustment threaded pin is sleeved on the limiting pin, and a threaded section is provided in the second through hole, and the limiting pin moves in the second through hole through the depth adjustment threaded pin.

[0012] As a further technical solution of the present invention: a threaded hole is provided on the pressure foot, and the replaceable nose is threadedly connected in the threaded hole; The replaceable nose tip features a stepped structure design.

[0013] As a further technical solution of the present invention: the center of the sliding spherical groove is located at the center point of the pressure foot pressing surface.

[0014] Secondly, the present invention provides a rapid calibration method using the above-mentioned contact-type automatic hole-making normal alignment device, which includes the following steps: Step 1: Install the calibrated removable stop block on the pressure foot support and secure it with the calibrated removable stop block fixing screws; Step 2: Connect the pressure foot to the tension spring and place it into the sliding ball groove. The pressure foot should be in close contact with the calibrated removable stop block. This can be considered as the pressure surface of the pressure foot being parallel to the calibration surface. Step 3: Record the values ​​of the four linear displacement sensors in this state as if the hole direction is perpendicular to the product surface, and then remove the calibration detachable block to complete the calibration work.

[0015] Thirdly, the present invention provides a rapid method for finding the normal orientation using the above-mentioned contact-type automatic hole-making normal alignment device, which includes the following steps: Step 1: Establish an xoy coordinate system, with the xy plane coinciding with the calibration plane and the oz axis coinciding with the principal axis direction. The heads of the four linear displacement sensors are located at points A, B, C, and D, respectively, and their projection points on the xy plane are points A', B', C', and D'. At this point, the lengths of the four linear displacement sensors are... l 1 、l 2 、l 3 、l 4. The normal vectors of planes ABD and BCD are respectively n ABD and n BCD ; Step 2: Four linear displacement sensors are evenly distributed. Assuming the distance between any two adjacent linear displacement sensors is 2d, the coordinates of points A, B, C, and D are calculated as follows: ; Step 3: Calculate vectors AB, AD, CB, and CD, and obtain: ; Step 4: Calculate the normal vectors of planes ABD and BCD. n ABD and n BCD Therefore, we can conclude that: n ABD = AB × AD n BCD = CB × CD ; Step 5: Calculate the fitted unit normal vector n Therefore, we can conclude that: ; Step 6: Solve for the normal deflection angle; the unit normal vector of the z-axis is... OZ =

[001] T The angle θ between the fitted unit normal vector and the z-axis unit normal vector is the deviation angle of the normal vector after the pressure foot presses against the product surface. The calculation yields: .

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention can measure the normal direction of the hole to be made in the product surface under a pressed state; (2) This invention is applicable to the normal measurement and alignment of products with large variations in the curvature of the hole-making surface; (3) The present invention simplifies the sensor calibration method, reducing the complexity and time consumption of sensor calibration; (4) This invention is applicable to scenarios where there are multiple requirements for the size of the presser foot nose. It is highly replaceable and easy to replace.

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is an exploded view of the contact-type automatic hole-making and normal alignment device of the present invention. Figure 2 This is a schematic diagram illustrating the normal measurement principle of the present invention; Figure 3 This is a schematic diagram of the assembly of the contact-type automatic hole-making normal alignment device of the present invention; Figure 4 This is a cross-sectional schematic diagram of the contact-type automatic hole-making normal alignment device of the present invention.

[0019] Among them, 1-calibration surface; 2-calibration removable stop block; 3-pressure foot support; 4-pressure foot; 5-limit pin; 6-depth adjustment threaded pin; 7-tension spring; 8-linear displacement sensor; 9-sliding ball groove; 10-limit stop block; 11-calibration removable stop block fixing screw; 12-replaceable nose tip. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be described in more detail below with reference to the accompanying drawings.

[0021] In the accompanying drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present invention.

[0022] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] The following is in conjunction with the appendix Figure 1-4 The embodiments of the present invention will be described in detail below.

[0024] Example 1 This invention provides a contact-type automatic hole-making normal alignment device, comprising: The pressure foot support 3 has a calibration surface 1 and a mounting surface on one side. A sliding spherical groove 9 is provided in the mounting surface. Four first through holes and four second through holes are evenly distributed on the outer edge of the sliding spherical groove 9. The pressure foot 4 has a replaceable nose 12 and a sliding ball on each side, which are installed in the sliding ball groove 9. The pressure foot rolls sensitively in the sliding ball groove 9 through the sliding ball, thereby causing the pressure foot to deflect and driving the linear displacement sensor 8 in the deflection direction to work. The linear displacement sensor 8 is used to measure the sliding angle of the pressure foot.

[0025] The calibration assembly includes four detachable calibration stops 2, four limit pins 5 and four tension springs 7. The four detachable calibration stops 2 are evenly distributed on the outer edge of the sliding spherical groove 9. The limit pins 5 and tension springs 7 are disposed in the second through hole. The two ends of the tension springs 7 are respectively connected to the limit pins 5 and the pressure feet 4. The method-finding component includes four linear displacement sensors 8, which are fixedly installed in the first through hole, and their acquisition ends are in contact with the surface of the pressure foot 4.

[0026] Furthermore, the calibration surface 1 and the mounting surface are in the same plane; during operation, the bottom surface of the pressure foot support 3 is in a horizontal state. The calibration surface 1 is used to calibrate a plane perpendicular to the normal.

[0027] Furthermore, the detachable calibration stop 2 is connected to the mounting surface via detachable calibration stop fixing screws 11. The detachable calibration stop is used to calibrate the linear displacement sensor.

[0028] Furthermore, the thickness of the sliding ball is slightly greater than the depth of the sliding ball groove 9, so that there is a certain distance between the surface of the pressure foot 4 and the mounting surface.

[0029] Furthermore, the tail end of the linear displacement sensor 8 is limited by a limiting block 10.

[0030] Furthermore, the limiting pin 5 is fitted with a depth adjustment threaded pin 6, and a threaded section is provided in the second through hole. The limiting pin 5 moves in the second through hole through the depth adjustment threaded pin 6.

[0031] Furthermore, a threaded hole is provided on the pressure foot 4, and the replaceable nose 12 is threaded into the threaded hole; the pressure foot 4 is used to press the product surface.

[0032] The replaceable nose tip 12 adopts a stepped structure design.

[0033] Furthermore, the center of the sliding spherical groove 9 is located at the center point of the pressing surface of the pressure foot 4.

[0034] This invention provides a rapid calibration method using the above-mentioned contact-type automatic hole-making normal alignment device, which includes the following steps: Step 1: Install the calibrated removable stop block 2 on the pressure foot support 3 and fix it with the calibrated removable stop block fixing screw 11; Step 2: Connect the pressure foot 4 to the tension spring 7 and place it into the sliding ball groove 9. The pressure foot 4 is in close contact with the calibrated removable stop block 2, which can be regarded as the pressing surface of the pressure foot 4 being parallel to the calibration surface 1. Step 3: Record the values ​​of the four linear displacement sensors 8 in this state as if the hole direction is perpendicular to the product surface, and then remove the calibrating detachable block 2 to complete the calibration work.

[0035] This invention provides a rapid method for finding the normal orientation using the aforementioned contact-type automatic hole-making normal alignment device, comprising the following steps: Step 1: Establish the xoy coordinate system, with the xy plane coinciding with calibration surface 1 and the oz axis coinciding with the principal axis direction. The heads of the four linear displacement sensors 8 are located at points A, B, C, and D, respectively, and their projection points on the xy plane are points A', B', C', and D'. At this time, the lengths of the four linear displacement sensors 8 are respectively... l 1 、l 2 、l 3 、l 4. The normal vectors of planes ABD and BCD are respectively n ABD and n BCD ; Step 2: Four linear displacement sensors 8 are evenly distributed. Assuming the distance between any two adjacent linear displacement sensors 8 is 2d, the coordinates of points A, B, C, and D are calculated as follows: ; Step 3: Calculate vectors AB, AD, CB, and CD, and obtain: ; Step 4: Calculate the normal vectors of planes ABD and BCD. n ABD and n BCD Therefore, we can conclude that: n ABD = AB × AD nBCD = CB × CD ; Step 5: Calculate the fitted unit normal vector n Therefore, we can conclude that: ; Step 6: Solve for the normal deflection angle; the unit normal vector of the z-axis is... OZ =

[001] T The angle θ between the fitted unit normal vector and the z-axis unit normal vector is the deviation angle of the normal vector after pressure foot 4 presses the product surface. The calculation yields: .

[0036] In a preferred embodiment of the present invention, the diameter of the pressure foot 4 is set to 60mm, the maximum swing angle is 6°, the distance between two adjacent linear displacement sensors 8 in step 2 is 2d=40mm, and the vectors AB, AD, CB, and CD are: .

[0037] Example 2 like Figures 1 to 4 As shown, the present invention provides a contact-type automatic hole-making normal alignment device and a rapid calibration and method for finding the normal.

[0038] The contact-type automatic hole-making normal alignment device includes: calibration surface 1, detachable calibration stop 2, pressure foot support 3, pressure foot 4, limit pin 5, depth adjustment threaded pin 6, tension spring 7, linear displacement sensor 8, sliding spherical groove 9, limit stop 10, detachable calibration stop fixing screw 11, and replaceable nose tip 12. Calibration surface 1 is used to calibrate a plane perpendicular to the normal. Furthermore, the calibrated removable stop block 2 is used to calibrate the linear displacement sensor 8. When the calibrated removable stop block 2 is fixed on the pressure foot support 3, the pressure foot 4 is placed into the sliding ball groove 9 and pressed against the calibrated removable stop block 2, so that the readings of the four linear displacement sensors 8 are adjusted to be consistent, and the calibration work is completed. Furthermore, the sliding spherical groove 9 is the placement position of the pressure foot 4, providing support and sliding direction, and the center of the sliding spherical groove is located at the center point of the pressure surface of the pressure foot 4; Furthermore, the pressure foot support 3 provides support, and the calibration surface 1 and the sliding spherical groove 9 are both part of the pressure foot support 3; Furthermore, pressure foot 4 is used to press the product surface, and replaceable nose 12 is installed on pressure foot 4; Furthermore, the limiting pin 5 is used to hold and limit the position of the tension spring 7; Furthermore, the depth adjustment threaded pin 6 is installed on the pressure foot support 3, and the limit pin 5 is inserted therein. The position of the limit pin can be adjusted by rotating the depth adjustment threaded pin 6. Furthermore, the linear displacement sensor 8 is used to measure the sliding angle of the pressure foot; Furthermore, the limit stop 10 is used to limit the position of the linear displacement sensor 8; Furthermore, the calibrated removable stop block fixing screw 11 is used to fix the calibrated removable stop block 2.

[0039] In addition, this invention also designs a rapid calibration and method for finding the normal orientation of the contact-type automatic hole-making device. The rapid calibration method for the contact-type automatic hole-making normal alignment device includes the following steps: Step 1: Install the calibrated removable stop block 2 on the pressure foot support 3 and fix it with the calibrated removable stop block fixing screw 11.

[0040] Step 2: Connect the pressure foot 4 to the tension spring 7 and place it into the sliding ball groove 9. The pressure foot 4 is in close contact with the calibrated removable stop block 2, which can be regarded as the pressing surface of the pressure foot 4 being parallel to the calibration surface 1.

[0041] Step 3: Record the values ​​of the four linear displacement sensors 8 in this state as if the hole-making direction is perpendicular to the product surface, and then remove the calibration detachable block 2 to complete the calibration work.

[0042] The method for finding the normal alignment of a contact-type automatic hole-making device includes the following steps: Step 1, establish as follows Figure 2 The xoy coordinate system is shown, with the xy plane coinciding with calibration plane 1 and the oz axis coinciding with the principal axis direction. The heads of the four linear displacement sensors 8 are located at points A, B, C, and D, respectively, and their projection points on the xy plane are points A', B', C', and D'. At this time, the lengths of the four linear displacement sensors 8 are... l 1 、l 2 、l 3 、l 4. The normal vectors of planes ABD and BCD are respectively n ABD and n BCD .

[0043] Step 2: The four linear displacement sensors 8 are evenly distributed. Assuming the distance between any two adjacent linear displacement sensors 8 is 2d, the coordinates of points A, B, C, and D are calculated as follows:

[0044] Step 3, Calculation AB, AD, CB, CD Vectors, yielding:

[0045] Step 4: Calculate the normal vectors of planes ABD and BCD. n ABD and n BCD Therefore, we can conclude that: n ABD = AB × AD n BCD = CB × CD Step 5: Calculate the fitted unit normal vector. n Therefore, we can conclude that:

[0046] Step 6, solve for the normal deflection angle. The unit normal vector of the z-axis is... OZ =

[001] T The angle θ between the fitted unit normal vector and the z-axis unit normal vector is the deviation angle of the normal vector after the presser foot presses against the product surface. The calculation yields:

[0047] In a preferred embodiment of the present invention, the diameter of the pressure foot 4 is set to 60mm, the maximum swing angle is 6°, and the distance between two adjacent linear displacement sensors 8 in step 2 is 2d=40mm. AB, AD, CB, CD The vector is: .

[0048] This invention presses the product surface and, by measuring the normal deflection angle, obtains the direction and angle of the normal deflection, which can then be used as a basis for automatic hole-making normal adjustment.

[0049] Thus, the objective of this invention has been achieved.

[0050] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A contact automatic hole-making normal alignment device, characterized by, It comprises: The pressure foot support has a calibrated surface and a mounting surface on one side, and a sliding spherical groove is arranged in the mounting surface, four first through holes and four second through holes are uniformly distributed on the outer edge of the sliding spherical groove; The pressure foot has replaceable nose and sliding ball on both sides, and is installed in the sliding spherical groove; The calibration assembly comprises four calibration detachable blocks, four limit pins and four extension springs, the four calibration detachable blocks are uniformly distributed on the outer edge of the sliding spherical groove, the limit pins and the extension springs are arranged in the second through holes, and the extension springs are connected with the limit pins and the pressure foot at both ends, respectively; The law finding assembly comprises four linear displacement sensors, the linear displacement sensors are fixedly installed in the first through holes, and the collection ends of the linear displacement sensors are in contact with the surface of the pressure foot.

2. The contact method normal alignment device of claim 1, wherein, The calibrated surface and the mounting surface are in the same plane; during operation, the bottom surface of the pressure foot support is in a horizontal state.

3. The contact method normal alignment device of claim 1, wherein, The calibration detachable block is connected to the mounting surface by a calibration detachable block fixing screw.

4. The contact method normal alignment device of claim 1, wherein, The thickness of the sliding ball is slightly larger than the depth of the sliding spherical groove, so that the surface of the pressure foot has a certain distance from the mounting surface.

5. The contact method normal alignment device of claim 1, wherein, The tail end of the linear displacement sensor is limited by a limit block.

6. The contact method normal alignment device of claim 1, wherein, The limit pin is sleeved with a depth adjusting threaded pin, and a threaded section is arranged in the second through hole, and the limit pin moves in the second through hole through the depth adjusting threaded pin.

7. The contact method normal alignment device of claim 1, wherein, A threaded hole is arranged on the pressure foot, and the replaceable nose is threadedly connected in the threaded hole; The replaceable nose adopts a stepped structure design.

8. The contact method normal alignment device of claim 4, wherein, The center of the sliding spherical groove is located at the center point of the pressure foot pressing surface.

9. A fast calibration method using the contact-type automatic hole-making method alignment device according to any one of claims 1-8, characterized in that, It comprises the following steps: Step 1: install the calibration detachable block on the pressure foot support, and fix it by using the calibration detachable block fixing screw; Step 2: connect the pressure foot with the extension spring and put it into the sliding spherical groove, the pressure foot is in close contact with the calibration detachable block, which can be regarded as that the pressing surface of the pressure foot is parallel to the calibrated surface; Step 3: record the value of the four linear displacement sensors in this state as the direction perpendicular to the product surface, and then remove the calibration detachable block to complete the calibration work.

10. A method for quickly finding the normal direction of a workpiece using the contact-type automatic hole-making normal direction finding device according to any one of claims 1 to 8, characterized by, It comprises the following steps: Step 1: Establish the xoy coordinate system, the xy plane coincides with the calibration surface, the oz axis coincides with the main shaft direction, wherein the head positions of the four linear displacement sensors are located at A, B, C, D points, and the projection points on the xy plane are A', B', C', D' points; At this time, the lengths of the four linear displacement sensors are l 1 、l 2 、l 3 、l 4, the normal vectors of the planes ABD and BCD are n ABD and n BCD ; Step 2: the four linear displacement sensors are uniformly distributed, and the distance between adjacent two linear displacement sensors is 2d, then the coordinates of points A, B, C and D are calculated as: ； Step 3: calculate the AB, AD, CB and CD vectors, and get: ； Step 4: Calculate the normal vectors of the planes ABD and BCD n ABD and n BCD resulting in: n ABD = AB × AD n BCD = CB × CD ； Step 5: Calculate the fitted unit normal vector n which gives: ； Step 6: normal angle solution; The z-axis unit normal vector is OZ = [001] T The angle θ between the fitted unit normal vector and the z-axis unit normal vector is the deviation angle of the normal direction after the pressure foot presses the product surface. The calculation result is: 。

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