An eight-degree-of-freedom linear structured light variable pitch screw measuring device

Abstract

The present invention discloses an eight-degree-of-freedom linear structured light variable pitch screw measuring device, which is used for rapid, complete, and accurate non-contact three-dimensional coordinate measurement of variable pitch screws, belonging to the fields of precision testing technology and complex surface measurement. The present invention designs an adjustable automatic clamping module, which can be used for the installation of various types of variable pitch screws from small to large. Moreover, the linear structured light sensor has eight degrees of freedom, and can perform optimal angle adjustment for the normal direction of the target helix to avoid the phenomenon of light re-reflection and obtain more complete left and right surface contour data of the variable pitch screw. It can solve the problems of low efficiency, inaccurate measurement, insufficient degrees of freedom for sensor angle adjustment, and large weight in the existing measuring devices, which makes it inconvenient for the precise measurement and installation of screws, and greatly increases the practicability of the device.

Description

Technical Field

[0001] The present invention relates to an eight-degree-of-freedom variable pitch screw measuring device based on a line structured light sensor, belonging to the fields of precision testing technology and complex surface measurement. Background Art

[0002] Screws are key complex surface components applied in key national equipment such as injection molding machine drives and deep-sea ore lifting pipe connections. Due to geometric errors in the screw processing link, an overturning moment will be generated, resulting in uneven forces on the screw thread pair during high-speed operation, affecting the transmission stability, accuracy, and service life of the entire mechanical system. Therefore, there is an urgent need to develop a high-precision measurement device for quickly obtaining the geometric errors of variable pitch screws.

[0003] Currently, the measurement devices mainly include three types: (1) Traditional contact measurement devices. Patent CN202222626032.5 obtains the contour data of a single cross-section of the measured target by moving a contact sensor with only two degrees of freedom. The measurement principle is simple, but there are disadvantages such as incomplete contour data and easy wear of the sensor. (2) Point structured light non-contact measurement devices. Patent CN200910057360.4 uses a non-contact traditional point structured light instead of a traditional contact sensor, with three degrees of freedom. While the sensor is driven in the lateral movement degree of freedom, the measured target has a rotational degree of freedom, further improving the measurement speed. However, the device does not consider the optical measurement angle of the sensor and does not have the degree of freedom for optimal angle adjustment. There are situations where the point structured light is scattered and re-reflected, resulting in inaccurate measurements. (3) Line structured light non-contact measurement devices. Patent CN201910926364.5 clamps and restricts the degrees of freedom of the measured target, using the form of line structured light instead of point structure, but the sensor also only has two degrees of freedom and can only obtain the contour parameters of a single cross-section of the measured object, with the problem of incomplete measurement data. In summary, the existing variable pitch screw measurement devices still have problems such as low measurement efficiency, inaccurate measurement, and insufficient degrees of freedom for sensor angle adjustment. It is worth noting that none of the above consider the problem of inconvenient installation for precise measurement of heavy screws.

[0004] To overcome the above problems, the present invention discloses an eight-degree-of-freedom line structured light variable pitch screw measuring device, which comprehensively considers the problems of measurement efficiency, integrity, accuracy, and large-size clamping. An innovative rotary module is adopted to adaptively clamp variable pitch screws of different sizes and different pitch types. There is an eight-degree-of-freedom adjustment module that enables two line structured light sensors to obtain the contour information of the entire helical surface at the optimal angle, greatly increasing the practicality of the device. Summary of the Invention

[0005] The present invention provides an eight-degree-of-freedom linear structured light variable pitch screw measuring device, which designs a double-line structured light probe to synchronously obtain the left and right surface profiles, so as to improve the measurement efficiency and data integrity, and designs an automatic clamping module to avoid the operation safety hazards caused by the large weight of the measurement target.

[0006] Aiming at the problems of the existing variable pitch screw measuring devices, the device of the present invention makes a principled innovation. The basic idea is as follows: ① In order to avoid the inaccurate structured light measurement caused by multiple reflections due to angle problems, a multi-degree-of-freedom structure is designed to adjust the measurement posture to achieve the optimal measurement angles of two groups of linear structured light sensors. ② For the installation of large-size and large-weight variable pitch screws, a double sprocket module combined with a 90-degree guide is designed, and then combined with a gripper unit to automatically lift, turn and clamp the measured target, so as to improve the safety and stability of the clamping process.

[0007] To achieve the above purposes and principles, the technical solution of the present invention is as follows:

[0008] An eight-degree-of-freedom linear structured light variable pitch screw measuring device is composed of eight parts: a sprocket module 1, a clamping and reversing module 2, a screw clamping module 3, a turntable module 4, an angle adjustment module 5, a displacement adjustment module 6, an operation panel 7, and a frame 8;

[0009] The clamping and reversing module 2 and two sets of sprocket modules 1 are installed on the left side of the frame 8. The sprocket module 1 drives the clamping and reversing module 2 to work. The clamping and reversing module 2 serves as the installation platform for the measured workpiece, mainly completing processes such as reversing and installing the variable pitch screw. The screw clamping module 3 is installed at the right end of the clamping and reversing module 2. The screw clamping module 3 can realize the automatic clamping and release of the variable pitch screw. The turntable module 4 and the displacement adjustment module 6 are installed on the right side of the frame 8. The main work of the turntable module 4 is to complete the clamping and positioning of the variable pitch screw, and at the same time drive the variable pitch screw to rotate at a constant speed during measurement. The main work of the displacement adjustment module 6 is to drive the angle adjustment module 5 installed at the end of the X-axis to perform horizontal movement in the X-axis direction and vertical movement in the Z-axis direction, so that the linear structured light sensor can select an optimal position for measurement. The angle adjustment module 5 has multiple degrees of freedom to enable the linear structured light sensor to achieve the optimal angle adjustment for measurement, so as to obtain effective profile data of more profile surfaces of the variable pitch screw. The operation panel 7 is installed on the right edge of the frame 8 and can realize the control of the entire device;

[0010] The sprocket module 1 includes a sprocket motor 1.1, a sprocket mechanism 1.2, a reversing transmission rod 1.3, a sprocket slider 1.4, and a double-column guide rail 1.5;

[0011] The double-column guide rail 1.5 is fixed on the frame 8. The sprocket motor 1.1 is installed at the rear side of the double-column guide rail 1.5, and the sprocket mechanism 1.2 is installed at the front side of the double-column guide rail 1.5. The rear end of the reversing transmission rod 1.3 is fixed to a link in the sprocket mechanism 1.2 and is assembled inside the sprocket slider 1.4. The sprocket slider 1.4 is installed on the double-column guide rail 1.5. The sprocket mechanism 1.2 is driven by the sprocket motor 1.1 to drive the sprocket slider 1.4 to move on the double-column guide rail 1.5, thereby driving the workpiece to be measured to complete the up-and-down lifting process;

[0012] The clamping and reversing module 2 includes a steering column 2.1, a guide slider 2.2, a steering guide rail 2.3, and a cam groove 2.4;

[0013] The guide slider 2.2 and the steering guide rail 2.3 are fixed to the left side of the frame 8. The steering column 2.1 is installed on the steering guide rail 2.3. The front end of the reversing transmission rod 1.3 is connected to the steering column 2.1 to enable the steering column 2.1 to move up and down together with the reversing transmission rod 1.3 to complete the up-and-down lifting process. The cam groove 2.4 is on the cylindrical surface of the steering column 2.1. There is a circular protrusion at the front end of the guide slider 2.2 that is connected to the cam groove 2.4 to enable the steering column 2.1 to rotate 90° while moving up and down to complete the clamping and reversing processes;

[0014] The screw clamping module 3 includes a clamping steering motor 3.1, a worm and gear mechanism 3.2, a clamping module rotating shaft 3.3, a steering base 3.4, a gripper unit guide rail 3.5, a gripper motor 3.6, a gripper 3.7, a clamping slider 3.8, and a gripper unit 3.9;

[0015] The worm and gear mechanism 3.2 is installed at the end of the steering column 2.1. The clamping steering motor 3.1 is installed on the worm and gear mechanism 3.2 and provides driving force. The left end of the clamping module rotating shaft 3.3 is coaxially fixed to the worm gear in the worm and gear mechanism 3.2. The right end of the clamping module rotating shaft 3.3 is fixed to the bottom of the steering base 3.4 by bolts. Due to the self-locking characteristic of the worm and gear, the safety and stability of the clamping and reversing process can be fully guaranteed. The gripper unit guide rail 3.5 is installed on the steering base 3.4. Two gripper units 3.9 are respectively assembled at the upper and lower ends of the gripper unit guide rail 3.5. The distance between the two gripper units 3.9 can be changed to adapt to the measurement requirements of workpieces to be measured with different lengths and complete the variable pitch screw clamping process;

[0016] The gripper unit 3.9 includes a gripper motor 3.6, a gripper 3.7, and a clamping slider 3.8. Among them, the clamping slider 3.8 is assembled on the gripper unit guide rail 3.5. The gripper motor 3.6 is installed on the outside of the clamping slider 3.8. Two grippers 3.7 are provided on the clamping slider 3.8. The distance between the two grippers 3.7 is changed by rotating the gripper motor 3.6 to adapt to the measurement requirements of workpieces to be measured with different diameters;

[0017] The displacement adjustment module 6 includes a cross beam 6.1, an X-axis module 6.2, and a Z-axis module 6.3;

[0018] The Z-axis module 6.3 is fixed on the frame 8, the X-axis module 6.2 is installed on the Z-axis module 6.3 and can move in the Z-axis direction, and the cross beam 6.1 is installed on the X-axis module 6.2 and can move in the X-axis direction. Therefore, two additional degrees of freedom of movement F1 and F2 can be added to the line structured light sensor;

[0019] The angle adjustment module 5 includes a D-shaped frame 5.1, a probe motor 5.2, a bidirectional lead screw 5.3, a probe unit 5.4, a probe slider 5.5, a probe 5.6, an inclination adjustment servo 5.7, a probe support 5.8, a linear grating 5.9, a D-shaped frame steering motor 5.10, a worm and worm gear mechanism II 5.11, and a D-shaped frame rotating shaft 5.12;

[0020] The worm and worm gear mechanism II 5.11 is installed on the cross beam 6.1 by bolts, the D-shaped frame steering motor 5.10 is installed on the worm and worm gear mechanism II 5.11, the right end of the D-shaped frame rotating shaft 5.12 is connected to the worm and worm gear mechanism II 5.11 by bolts, the left end of the D-shaped frame rotating shaft 5.12 is connected to the D-shaped frame 5.1 by bolts, and the D-shaped frame steering motor 5.10 drives the worm and worm gear mechanism II 5.11, which can drive the D-shaped frame 5.1 to rotate, so that the line structured light sensor has another degree of freedom of rotation F3 relative to the workpiece to be measured;

[0021] The probe motor 5.2 and the bidirectional lead screw 5.3 are both installed on the D-shaped frame 5.1. The bidirectional lead screw 5.3 has two threads with different helix directions, that is, one left-handed thread and the other right-handed thread. The probe units 5.4 are respectively installed on the two left and right-handed threads of the bidirectional lead screw 5.3, and the linear grating 5.9 is installed on the side of the D-shaped frame 5.1 to accurately feedback the displacement data of the two probe units 5.4 in real time to achieve a full closed-loop for measuring position and attitude adjustment and improve the measurement accuracy. The middle of the D-shaped frame 5.1 is hollowed out to reduce weight and ensure stability. The probe motor 5.2 drives the bidirectional lead screw 5.3 to rotate, driving the synchronous relative movement of the two probe units 5.4, so that the line structured light sensor has two degrees of freedom of movement F4 and F5 relative to the workpiece to be measured;

[0022] The probe unit 5.4 consists of a probe slider 5.5, a probe 5.6, an inclination adjustment servo 5.7, and a probe bracket 5.8. The probe slider 5.5 is installed on the bidirectional lead screw 5.3. The bottom of the probe bracket 5.8 is connected to the probe slider 5.5 by bolts. The top of the probe bracket 5.8 is connected to the inclination adjustment servo 5.7 by bolts. The probe 5.6 is installed on the inclination adjustment servo 5.7 by bolts, which can adjust the measurement angle and attitude of the structured light sensor in the normal direction of the helix of the variable pitch screw, avoid the phenomenon of light re - reflection, obtain the contour information of the entire helical surface, improve the measurement efficiency and integrity. The two probes 5.6 are both installed on the inclination adjustment servo 5.7, which can endow the line structured light sensor with two rotational degrees of freedom F6 and F7 relative to the workpiece to be measured;

[0023] The turntable module 4 includes a chuck motor 4.1, a circular grating 4.2, a three - jaw chuck 4.3, a variable pitch screw 4.4, an upper center 4.5, and a workbench 4.6;

[0024] The workbench 4.6 is fixed on the frame 8, and the chuck motor 4.1 is installed at the bottom by bolts. The three - jaw chuck 4.3 is installed on the workbench 4.6. By rotating the chuck motor 4.1, the three - jaw chuck 4.3 can clamp, release, and rotate the variable pitch screw 4.4. Therefore, the line structured light sensor has an additional rotational degree of freedom F8 relative to the workpiece to be measured. The upper center 4.5 and the three - jaw chuck 4.3 are coaxially installed on the workbench 4.6, and the circular grating 4.2 is coaxially installed outside the three - jaw chuck 4.3, which can accurately feedback the angular displacement data of the variable pitch screw 4.4 in real - time to achieve a full closed - loop for measurement angle and attitude adjustment, improving the measurement accuracy;

[0025] In summary: Under the combined action of the sprocket module 1, the clamping and commutation module 2, and the screw clamping module 3, the processes of clamping, lifting, and clamping commutation of the variable pitch screw can be realized. At the same time, under the combined action of the turntable module 4, the angle adjustment module 5, and the displacement adjustment module 6, the line structured light sensor has two translational degrees of freedom F1 and F2 in the X - axis and Z - axis directions on the cross - beam 6.1, a rotational degree of freedom F3 in the axis direction of the D - shaped frame rotating shaft 5.12, two translational degrees of freedom F4 and F5 in the axis direction of the bidirectional lead screw 5.3, two rotational degrees of freedom F6 and F7 on the inclination adjustment servo 5.7, and a rotational degree of freedom F8 in the axis direction of the variable pitch screw 4.4. Through the above eight degrees of freedom, the line structured light sensor can obtain the contour information of the helical surface of the variable pitch screw in the optimal angle and position attitude;

[0026] The measurement steps of the whole device are as follows:

[0027] The first step: Restore the whole device to the initial position.

[0028] Step 2: Control the screw clamping module 3 to clamp the upper and lower ends of the variable pitch screw 4.4. Clamp the commutation module 2 and perform a 90° turning and lifting process to install the variable pitch screw 4.4 onto the turntable module 4.

[0029] Step 3: Control the displacement adjustment module 6 to adjust the position of the line structured light sensor and select an optimal measurement position.

[0030] Step 4: Adjust the distance between the two line structured light sensors so as to obtain the spiral surface contour information on both the left and right sides of the variable pitch screw 4.4.

[0031] Step 5: Adjust the measurement attitude angles of the two line structured light sensors so that they can emit laser along the normal of the spiral line of the variable pitch screw 4.4.

[0032] Step 6: While the variable pitch screw 4.4 rotates at a constant speed, ensure that the two line structured light sensors always adjust their positions and angles according to the changes in the pitch and the normal of the spiral line of the variable pitch screw 4.4. After the data acquisition is completed, turn off the entire device.

[0033] Step 7: After the measurement is completed, print and output the three-dimensional coordinates.

[0034] The beneficial effects of the present invention are as follows:

[0035] 1. In the present invention, an adjustable automatic clamping module is designed, which can be used for the installation of various types of variable pitch screws from small to large. It solves the problem of inconvenient installation caused by large size and heavy weight, and the device has strong applicability and higher safety.

[0036] 2. The line structured light sensor in the present invention has eight degrees of freedom, and can perform optimal angle adjustment in the direction of the normal of the spiral line of the variable pitch screw, avoiding the phenomenon of light multiple reflection and making the measurement more accurate.

[0037] 3. The double line structured light sensor in the present invention can obtain a more complete left and right surface of the variable pitch screw than the traditional point-line measurement, and the measurement efficiency is higher. Description of the Drawings

[0038] Figure 1 General layout of an eight-degree-of-freedom line structured light variable pitch screw measuring device;

[0039] Figure 2 Structural diagram of the sprocket transmission part;

[0040] Figure 3 Structural diagram of the variable pitch screw installation part;

[0041] Figure 4 Structural diagram of the variable pitch screw clamping part;

[0042] Figure 5Structural diagram of the measuring part of the variable pitch screw

[0043] Figure 6 Structural diagram of the probe part

[0044] Figure 7 Working flow chart of an eight-degree-of-freedom linear structured light variable pitch screw measuring device

[0045] The labels in the figure are as follows: 1 - sprocket module, 2 - clamping and reversing module, 3 - screw clamping module, 4 - turntable module, 5 - angle adjustment module, 6 - displacement adjustment module, 7 - operation panel, 8 - frame, 1.1 - sprocket motor, 1.2 - sprocket mechanism, 1.3 - reversing transmission rod, 1.4 - sprocket slider, 1.5 - double-column guide rail, 2.1 - steering column, 2.2 - guide slider, 2.3 - steering guide rail, 2.4 - cam groove, 3.1 - clamping steering motor, 3.2 - worm and worm gear mechanism 1, 3.3 - clamping module rotating shaft, 3.4 - steering base, 3.5 - gripper unit guide rail, 3.6 - gripper motor, 3.7 - gripper, 3.8 - clamping slider, 3.9 - gripper unit, 4.1 - chuck motor, 4.2 - circular grating, 4.3 - three-jaw chuck, 4.4 - variable pitch screw, 4.5 - upper center, 4.6 - workbench, 5.1 - D-shaped frame, 5.2 - probe motor, 5.3 - bidirectional lead screw, 5.4 - probe unit, 5.5 - probe slider, 5.6 - probe, 5.7 - tilt adjustment servo, 5.8 - probe support, 5.9 - linear grating, 5.10 - D-shaped frame steering motor, 5.11 - worm and worm gear mechanism 2, 5.12 - D-shaped frame rotating shaft, 6.1 - cross beam, 6.2 - X-axis module, 6.3 - Z-axis module. Specific implementation mode

[0046] The following combines the accompanying drawings and specific embodiments to further illustrate this aspect.

[0047] Example 1: Measure a variable pitch screw made of 45 steel, with a diameter of 45 mm and a length of 500 mm.

[0048] As Figure 1As shown in the figure, an eight-degree-of-freedom linear structured light variable pitch screw measuring device consists of eight parts: a sprocket module 1, a clamping and commutation module 2, a screw clamping module 3, a turntable module 4, an angle adjustment module 5, a displacement adjustment module 6, an operation panel 7, and a frame 8. The clamping and commutation module 2 and two sets of sprocket modules 1 are installed on the left side of the frame 8. The sprocket module 1 drives the clamping and commutation module 2 to work. The clamping and commutation module 2 serves as the installation platform for the workpiece to be measured, mainly completing the commutation and installation processes of the variable pitch screw. The screw clamping module 3 is installed at the right end of the clamping and commutation module 2. The screw clamping module 3 can realize the automatic clamping and release of the variable pitch screw. The turntable module 4 and the displacement adjustment module 6 are installed on the right side of the frame 8. The main function of the turntable module 4 is to complete the clamping and positioning of the variable pitch screw, and at the same time drive the variable pitch screw to rotate uniformly during measurement. The main function of the displacement adjustment module 6 is to drive the angle adjustment module 5 installed at the end of the X-axis to move horizontally in the X-axis direction and vertically in the Z-axis direction, so that the linear structured light sensor can select an optimal position for measurement. The angle adjustment module 5 has multiple degrees of freedom to enable the linear structured light sensor to achieve the optimal angle adjustment for measurement, thereby obtaining more effective contour data of the variable pitch screw's contour surface. The operation panel 7 is installed on the right edge of the frame 8 and can realize the control of the entire device;

[0049] As Figure 2 shown in the figure, the sprocket module 1 includes a sprocket motor 1.1, a sprocket mechanism 1.2, a commutation drive rod 1.3, a sprocket slider 1.4, and a double-column guide rail 1.5. The double-column guide rail 1.5 is fixed on the frame 8. The sprocket motor 1.1 is installed at the rear of the double-column guide rail 1.5. The sprocket mechanism 1.2 is installed at the front of the double-column guide rail 1.5. The rear end of the commutation drive rod 1.3 is fixed to a link in the sprocket mechanism 1.2 and is assembled inside the sprocket slider 1.4. The sprocket slider 1.4 is installed on the double-column guide rail 1.5. The sprocket mechanism 1.2 is driven by the sprocket motor 1.1 to drive the sprocket slider 1.4 to move on the double-column guide rail 1.5, thereby driving the workpiece to be measured to complete the up-and-down lifting process.

[0050] As Figure 2 、 Figure 3 shown in the figure, the clamping and commutation module 2 includes a steering column 2.1, a guide slider 2.2, a steering guide rail 2.3, and a cam groove 2.4. The guide slider 2.2 and the steering guide rail 2.3 are fixed on the left side of the frame 8. The steering column 2.1 is installed on the steering guide rail 2.3. The front end of the commutation drive rod 1.3 is connected to the steering column 2.1 to enable the steering column 2.1 to move up and down together with the commutation drive rod 1.3 to complete the up-and-down lifting process. The cam groove 2.4 is on the cylindrical surface of the steering column 2.1. The front end of the guide slider 2.2 has a circular protrusion connected to the cam groove 2.4 to enable the steering column 2.1 to rotate 90° while moving up and down to complete the clamping and commutation processes.

[0051] As shown Figure 4 in the figure, the screw clamping module 3 includes a clamping steering motor 3.1, a worm and worm gear mechanism 3.2, a clamping module rotating shaft 3.3, a steering base 3.4, a gripper unit guide rail 3.5, a gripper motor 3.6, a gripper 3.7, a clamping slider 3.8, and a gripper unit 3.9. The worm and worm gear mechanism 3.2 is installed at the end of the steering column 2.1. The clamping steering motor 3.1 is installed on the worm and worm gear mechanism 3.2 and provides driving force. The left end of the clamping module rotating shaft 3.3 is coaxially fixed with the worm gear in the worm and worm gear mechanism 3.2. The right end of the clamping module rotating shaft 3.3 is fixed to the bottom of the steering base 3.4 by bolts. Due to the self-locking characteristic of the worm and worm gear, the safety and stability of the clamping commutation process can be fully ensured. The gripper unit guide rail 3.5 is installed on the steering base 3.4. Two gripper units 3.9 are respectively assembled at the upper and lower ends of the gripper unit guide rail 3.5. The distance between the two gripper units 3.9 can be changed to adapt to the measurement requirements of workpieces to be measured with different lengths and complete the variable pitch screw clamping process. The gripper unit 3.9 includes a gripper motor 3.6, a gripper 3.7, and a clamping slider 3.8. Among them, the clamping slider 3.8 is assembled on the gripper unit guide rail 3.5. The gripper motor 3.6 is installed on the outside of the clamping slider 3.8. Two grippers 3.7 are provided on the clamping slider 3.8. The distance between the two grippers 3.7 is changed by rotating the gripper motor 3.6 to adapt to the measurement requirements of workpieces to be measured with different diameters.

[0052] As shown Figure 5 in the figure, the displacement adjustment module 6 includes a cross beam 6.1, an X-axis module 6.2, and a Z-axis module 6.3. The Z-axis module 6.3 is fixed on the frame 8. The X-axis module 6.2 is installed on the Z-axis module 6.3 and can move in the Z-axis direction. The cross beam 6.1 is installed on the X-axis module 6.2 and can move in the X-axis direction. Therefore, two additional degrees of freedom F1 and F2 can be added to the line structured light sensor.

[0053] As shown Figure 5 in the figure, the turntable module 4 includes a chuck motor 4.1, a circular grating 4.2, a three-jaw chuck 4.3, a variable pitch screw 4.4, an upper center 4.5, and a workbench 4.6. The workbench 4.6 is fixed on the frame 8. The chuck motor 4.1 is installed at the bottom by bolts. The three-jaw chuck 4.3 is installed on the workbench 4.6. The clamping, releasing, and rotation of the variable pitch screw 4.4 by the three-jaw chuck 4.3 are realized by rotating the chuck motor 4.1. Therefore, a rotational degree of freedom F8 is added to the line structured light sensor relative to the workpiece to be measured. The upper center 4.5 is coaxially installed on the workbench 4.6 with the three-jaw chuck 4.3. The circular grating 4.2 is coaxially installed outside the three-jaw chuck 4.3 to accurately feedback the angular displacement data of the variable pitch screw 4.4 in real time to realize the full closed-loop of the measurement angle attitude adjustment and improve the measurement accuracy.

[0054] As shown Figure 6 in the figure, the angle adjustment module 5 includes a D-shaped frame 5.1, a probe motor 5.2, a bidirectional lead screw 5.3, a probe unit 5.4, a probe slider 5.5, a probe 5.6, an inclination adjustment servo 5.7, a probe support 5.8, a linear grating 5.9, a D-shaped frame steering motor 5.10, a worm and worm gear mechanism II 5.11, and a D-shaped frame rotating shaft 5.12. The worm and worm gear mechanism II 5.11 is installed on the cross beam 6.1 through bolts. The D-shaped frame steering motor 5.10 is installed on the worm and worm gear mechanism II 5.11. The right end of the D-shaped frame rotating shaft 5.12 is connected to the worm and worm gear mechanism II 5.11 through bolts, and the left end of the D-shaped frame rotating shaft 5.12 is connected to the D-shaped frame 5.1 through bolts. The D-shaped frame steering motor 5.10 drives the worm and worm gear mechanism II 5.11, which can drive the D-shaped frame 5.1 to rotate, so that the line structured light sensor has another rotational degree of freedom F3 relative to the workpiece to be measured. The probe motor 5.2 and the bidirectional lead screw 5.3 are both installed on the D-shaped frame 5.1. The bidirectional lead screw 5.3 has two threads with different helix directions, that is, one left-handed thread and the other right-handed thread. The probe units 5.4 are respectively installed on the two left- and right-handed threads of the bidirectional lead screw 5.3. The linear grating 5.9 is installed on the side of the D-shaped frame 5.1 to accurately feedback the displacement data of the two probe units 5.4 in real time to achieve a full closed-loop for measuring position and attitude adjustment and improve the measurement accuracy. The middle of the D-shaped frame 5.1 is hollowed out to reduce weight and ensure stability. The probe motor 5.2 drives the bidirectional lead screw 5.3 to rotate, driving the synchronous relative movement of the two probe units 5.4, so that the line structured light sensor has two translational degrees of freedom F4 and F5 relative to the workpiece to be measured. The probe unit 5.4 consists of a probe slider 5.5, a probe 5.6, an inclination adjustment servo 5.7, and a probe support 5.8. The probe slider 5.5 is installed on the bidirectional lead screw 5.3. The bottom of the probe support 5.8 is connected to the probe slider 5.5 through bolts. The top of the probe support 5.8 is connected to the inclination adjustment servo 5.7 through bolts. The probe 5.6 is installed on the inclination adjustment servo 5.7 through bolts, which can realize the adjustment of the measurement angle and attitude of the structured light sensor in the normal direction of the helix of the variable pitch screw, avoid the phenomenon of light double reflection, obtain the contour information of the entire helical surface, improve the measurement efficiency and integrity. The two probes 5.6 are both installed on the inclination adjustment servo 5.7, which can make the line structured light sensor have two rotational degrees of freedom F6 and F7 relative to the workpiece to be measured.

[0055] The complete measurement process of this device is as shown Figure 7 in the figure

[0056] Step 1: Start the measurement and reset.

[0057] Restore the circular grating 4.2, the D-shaped frame 5.1, the two probe units 5.4, the linear grating 5.9, the X-axis module 6.2, and the Z-axis module 6.3 to their initial positions.

[0058] Step 2: Clamp, lift and install the workpiece to be measured.

[0059] Clamp the upper and lower ends of the variable pitch screw 4.4 with a diameter of 45 mm and a length of 500 mm through the screw clamping module 3. Start the sprocket motor 1.1 in the sprocket module 1, lift the clamping and reversing module 2. At the same time, the clamping and reversing module 2 completes a 90° turning action, installs the variable pitch screw 4.4 on the three-jaw chuck 4.3, adjusts the position of the upper center 4.5. The screw clamping module 3 releases the upper and lower ends of the variable pitch screw 4.4. Start the sprocket motor 1.1 again to make the clamping and reversing module 2 return to the initial position. Then start the chuck motor 4.1 to realize the clamping of the variable pitch screw 4.4 by the three-jaw chuck 4.3, so as to complete the positioning and clamping of the variable pitch screw 4.4.

[0060] Step 3: Select the best measurement position of the line structured light sensor.

[0061] Start the X-axis module 6.2, adjust the position of the angle adjustment module 5 in the X-axis direction, so that the distance between the line structured light sensor and the line structured light sensor is within the range of 40 mm to 80 mm from the surface to be measured of the variable pitch screw 4.4. Start the Z-axis module 6.3, adjust the position of the angle adjustment module 5 in the Z-axis direction, so that the height of the line structured light sensor is flush with the upper end of the surface to be measured of the variable pitch screw 4.4.

[0062] Step 4: Based on the full closed-loop control of the linear grating 5.9, adjust the distance between the two line structured light sensors according to the pitch of the surface to be measured.

[0063] Control the probe motor 5.2 to rotate to drive the two probe units 5.4 to move linearly towards each other, and synchronously adjust the helical surface of the variable pitch screw, so that the two line structured light sensors can obtain the contour information of the helical surfaces on the left and right sides.

[0064] Step 5: Adjust the attitude angles of the two line structured light sensors according to the surface to be measured.

[0065] Control the tilt adjustment servo 5.7 to adjust the attitude angle of the probe 5.6, so that the line structured light sensor emits laser along the normal of the helix of the variable pitch screw 4.4 to avoid the phenomenon of light re-reflection.

[0066] Step 6: Based on the full closed-loop control of the circular grating 4.2, obtain the contour information of the helical surface of the variable pitch screw 4.4.

[0067] Start the chuck motor 4.1 to drive the three-jaw chuck 4.3, thereby driving the variable pitch screw 4.4 to rotate at a constant speed. Operate the X-axis module 6.2 and the Z-axis module 6.3 to ensure that the distance between the wire knot optical sensor and the surface to be measured of the variable pitch screw 4.4 is always maintained within the range of 40 mm to 80 mm. Operate the probe motor 5.2 to control the distance between the two probe units 5.4 to always change following the change of the lead of the variable pitch screw 4.4. Operate the inclination adjustment servo 5.7 to finely adjust the attitude angles of the two wire knot optical sensors so that they always emit laser along the normal direction of the helix of the variable pitch screw 4.4. At the same time, the circular grating 4.2 emits a signal to trigger the two probe units 5.4 to perform sampling every time the variable pitch screw 4.4 rotates a certain angle. After the data acquisition is completed, turn off the chuck motor 4.1 to stop the rotation of the variable pitch screw 4.4.

[0068] Step 7: End the measurement, print, and output the three-dimensional coordinates.

Claims

1. An eight-degree-of-freedom linear structured light variable pitch screw measuring device, characterized in that: It is composed of eight parts: a sprocket wheel module 1, a clamping and reversing module 2, a screw clamping module 3, a turntable module 4, an angle adjustment module 5, a displacement adjustment module 6, an operation panel 7, and a frame 8. On the left side of the frame 8, two sets of clamping and reversing modules 2 and sprocket wheel modules 1 are installed. At the right end of the clamping and reversing module 2, a screw clamping module 3 is installed. The turntable module 4 and the displacement adjustment module 6 are installed on the right side of the frame 8. The X-axis end of the displacement adjustment module 6 is fixed to the angle adjustment module 5 by bolts. The operation panel 7 is installed on the right edge of the frame 8. The screw clamping module 3 includes a clamping steering motor 3.1, a worm and gear mechanism 3.2, a clamping module rotating shaft 3.3, a steering base 3.4, a gripper unit guide rail 3.5, a gripper motor 3.6, a gripper 3.7, a clamping slider 3.8, and a gripper unit 3.

9. The worm and gear mechanism 3.2 is installed at the end of the steering column 2.

1. The clamping steering motor 3.1 is installed on the worm and gear mechanism 3.

2. The left end of the clamping module rotating shaft 3.3 is coaxially fixed with the worm of the worm and gear mechanism 3.

2. The right end of the clamping module rotating shaft 3.3 is fixed to the bottom of the steering base 3.4 by bolts. The gripper unit guide rail 3.5 is installed on the steering base 3.

4. Two gripper units 3.9 are respectively assembled at the upper and lower ends of the gripper unit guide rail 3.

5. The gripper unit 3.9 includes a gripper motor 3.6, a gripper 3.7, and a clamping slider 3.

8. Among them, the clamping slider 3.8 is assembled on the gripper unit guide rail 3.

5. The gripper motor 3.6 is installed on the outside of the clamping slider 3.

8. Two grippers 3.7 are provided on the clamping slider 3.

8. The angle adjustment module 5 includes a D-shaped frame 5.1, a probe motor 5.2, a bidirectional lead screw 5.3, a probe unit 5.4, a probe slider 5.5, a probe 5.6, an inclination adjustment servo 5.7, a probe support 5.8, a linear grating 5.9, a D-shaped frame steering motor 5.10, a worm and gear mechanism 5.11, and a D-shaped frame rotating shaft 5.

12. The worm and gear mechanism 5.11 is installed on the cross beam 6.1 by bolts. The D-shaped frame steering motor 5.10 is installed on the worm and gear mechanism 5.

11. The right end of the D-shaped frame rotating shaft 5.12 is connected to the worm and gear mechanism 5.11 by bolts. The left end of the D-shaped frame rotating shaft 5.12 is connected to the D-shaped frame 5.1 by bolts. The probe motor 5.2 and the bidirectional lead screw 5.3 are both installed on the D-shaped frame 5.

1. Among them, the bidirectional lead screw 5.3 has two threads with different helix directions, that is, one left-handed thread and the other right-handed thread. The probe units 5.4 are respectively installed on the two left- and right-handed threads of the bidirectional lead screw 5.

3. The linear grating 5.9 is installed on the side of the D-shaped frame 5.

1. The probe unit 5.4 is composed of a probe slider 5.5, a probe 5.6, an inclination adjustment servo 5.7, and a probe support 5.

8. Among them, the probe slider 5.5 is installed on the bidirectional lead screw 5.

3. The bottom of the probe support 5.8 is connected to the probe slider 5.5 by bolts. The top of the probe support 5.8 is connected to the inclination adjustment servo 5.7 by bolts. The probe 5.6 is installed on the inclination adjustment servo 5.7 by bolts.

2. The eight-degree-of-freedom linear structured light variable pitch screw measuring device according to claim 1, characterized in that: The sprocket wheel module 1 includes a sprocket wheel motor 1.1, a sprocket wheel mechanism 1.2, a reversing transmission rod 1.3, a sprocket wheel slider 1.4, and a double-column guide rail 1.

5. The double-column guide rail 1.5 is fixed on the frame 8. The sprocket wheel motor 1.1 is installed at the rear side of the double-column guide rail 1.

5. The sprocket wheel mechanism 1.2 is installed at the front side of the double-column guide rail 1.

5. The rear end of the reversing transmission rod 1.3 is fixed to a link in the sprocket wheel mechanism 1.2 and is assembled inside the sprocket wheel slider 1.

4. The sprocket wheel slider 1.4 is installed on the double-column guide rail 1.

5.

3. The eight-degree-of-freedom linear structured light variable pitch screw measuring device according to claim 1, characterized in that: The clamping and reversing module 2 includes a steering column 2.1, a guide slider 2.2, a steering guide rail 2.3, and a cam groove 2.

4. The guide slider 2.2 and the steering guide rail 2.3 are fixed on the left side of the frame 8. The steering column 2.1 is installed on the steering guide rail 2.

3. The front end of the reversing transmission rod 1.3 is connected to the steering column 2.

1. The cam groove 2.4 is on the cylindrical surface of the steering column 2.

1. There is a circular protrusion at the front end of the guide slider 2.2, which is connected to the cam groove 2.

4.

4. The eight-degree-of-freedom linear structured light variable pitch screw measuring device according to claim 1, characterized in that: The displacement adjustment module 6 includes a cross beam 6.1, an X-axis module 6.2, and a Z-axis module 6.

3. The Z-axis module 6.3 is fixed on the frame 8. The X-axis module 6.2 is installed on the Z-axis module 6.

3. The cross beam 6.1 is installed on the X-axis module 6.

2.

5. The eight-degree-of-freedom linear structured light variable pitch screw measuring device according to claim 1, characterized in that: The turntable module 4 includes a chuck motor 4.1, a circular grating 4.2, a three-jaw chuck 4.3, a variable pitch screw 4.4, an upper center 4.5, and a workbench 4.

6. The workbench 4.6 is fixed on the frame 8. The chuck motor 4.1 is installed at the bottom through bolts. The three-jaw chuck 4.3 is installed on the workbench 4.

6. The upper center 4.5 and the three-jaw chuck 4.3 are coaxially installed on the workbench 4.

6. The circular grating 4.2 is coaxially installed outside the three-jaw chuck 4.3.

Images