Robotic Hole-Making End Effector and Hole-Making Method for Curved Parts

Abstract

This invention relates to a robotic end effector for drilling curved parts and its drilling method, belonging to the field of robotic automated drilling and riveting. It includes: a frame unit, a feed unit, a spindle unit, a conformal controllable pressure foot unit, a normal alignment unit, and a measuring unit. The frame unit connects to the robot flange and provides mounting positions for other functional modules; the spindle unit is mounted on the movable module of the feed unit; the feed unit is mounted on the frame unit; the conformal controllable pressure foot unit is mounted at the foremost end of the actuator; the normal alignment unit is integrated into the conformal pressure foot unit; and the measuring unit is mounted on one side of the frame unit. This invention can adaptively conformally press the workpiece according to different curved surface structures, ensuring the stability of the robotic drilling system while significantly reducing workpiece deformation under pressure and improving drilling accuracy. The device has high integration, comprehensive functions, and is compatible with both curved and flat parts, significantly improving the processing efficiency and quality of components.

Description

Technical Field

[0001] This invention relates to the field of robotic automated drilling and riveting technology, and in particular to a robotic end effector for drilling curved parts and a drilling method thereof. Background Technology

[0002] With the increasing precision requirements for drilling in components in fields such as aerospace, energy, and marine engineering, traditional manual drilling is no longer sufficient due to its low efficiency and poor accuracy. The rise of digital systems and industrial robots has led to the rapid development of high-degree-of-freedom automated drilling technology using industrial robots equipped with end effectors in the aerospace industry. However, while industrial robots offer high flexibility, their insufficient rigidity can cause chatter and other problems, ultimately affecting drilling accuracy. Therefore, improving the processing stability of robotic drilling systems and ensuring processing quality is a pressing issue that needs to be addressed.

[0003] The "Compact Hole-Making End Effector with Shared Guide Rail for Electric Spindle and Pressure Foot" invented by Li Tian et al. (patent application number CN201711268101.7) integrates the pressure foot module at the front end of the end effector by sharing a set of guide rails between the electric spindle of the hole-making module and the pressure foot of the pressure foot module, thereby improving the machining stability of the hole-making system. The "An Industrial Robot End Effector Based on Drilling, Riveting, and Milling Integration" invented by Dai Jialong et al. (patent application number CN202210914930.2) uses a servo motor to drive the pressure foot and spindle, achieving precise driving of the pressure foot module, and integrates a normal alignment function on the pressure foot module. The ONCE automatic hole-making system mentioned by Kevin Sitton et al. in their article "ONe-sided Cell End effector Robotic Drilling System" is one of the earliest proposed methods to use a pressure foot device to assist the robot in hole making to ensure machining quality. The above patents all aim to improve the stability of robotic drilling systems by integrating a pressure foot structure at the front end of the end effector. This approach is suitable for processing flat workpieces or workpieces with small curvature. However, for workpieces with large or variable curvature, the pressure foot module cannot achieve effective clamping, and the reduced contact area leads to large local deformation of the workpiece, ultimately affecting processing quality. How to effectively clamp workpieces with large or variable curvature, improve the processing stability and versatility of robotic drilling systems, and thus ensure the required drilling accuracy remains a challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a robotic end effector device for drilling curved parts, which enables automated drilling of curved workpieces, can achieve conformal clamping, thereby reducing workpiece deformation and improving drilling accuracy.

[0005] The technical solution of the present invention:

[0006] A robotic end effector for drilling curved parts includes: a frame unit 1, a feed unit 2, a spindle unit 3, a conformal controllable pressure foot unit 4, a normal alignment unit 5, and a measurement unit 6. The frame unit 1 connects the various functional modules and provides the connection position between the end effector and the robot flange. The feed unit 2 is mounted on the frame unit 1 and carries the spindle unit 3 to meet different feed requirements during hole making. The spindle unit 3 is mounted on the movable module of the feed unit 2 to meet the requirements of different speeds during processing. The conformal controllable pressure foot unit 4 is mounted between the front end of the end effector and the frame unit 1 to achieve conformal clamping of components with different curvatures, which can ensure the stability of clamping and reduce the deformation of the workpiece. The normal alignment unit 5 is integrated around the conformal pressure foot unit 4 to automatically find the axis direction of the hole to be processed before hole making, ensuring the perpendicularity of the processed hole. The measuring unit 6 is mounted on one side of the frame unit 1 to realize the position loop feedback of the feed unit 2, and at the same time detect the position of the pressure foot in real time and feed it back to the feed unit 2 to ensure the accuracy of blind hole processing or countersinking.

[0007] Furthermore, the frame unit 1 includes a flange connector 101 and a slide base 102, with the flange connector 101 fixed to the upper surface of the slide base 102.

[0008] Furthermore, the feed unit 2 is arranged below the frame unit 1 and includes a servo motor 201, a reducer 202, a lead screw and nut pair support - fixed side 203, an elastic coupling 204, a lead screw and nut pair 205, a lead screw and nut pair support - support side 206, a linear guide rail 207, a slider 208, a photoelectric switch 209, a first connecting plate 210, and a hard limit stop 211. The servo motor 201 is coaxially connected to the reducer 202, and their axes are in the same vertical plane as the central axis of the frame unit 1. One end of the reducer 202 is connected to the servo motor 201, and the other end is connected to one end of the lead screw and nut pair 205 via a flexible coupling 204 and fixed to the lead screw and nut pair support-fixed side 203. The other end of the lead screw and nut pair 205 is fixed to the frame unit 1 via the lead screw and nut pair support-support side 206. Both the lead screw and nut pair support-fixed side 203 and the lead screw and nut pair support-support side 206 are fixed on the central axis of the frame unit 1. The two linear guide rails 207 Fixed to frame unit 1, parallel to and symmetrically arranged on both sides of lead screw and nut pair 205, slider 208 is arranged on two linear guide rails 207; photoelectric switch 209 is fixed to frame unit 1 through first connecting plate 210, photoelectric switch 209 is arranged on the same straight line parallel to lead screw and nut pair 205, located between lead screw and nut pair 205 and one of the linear guide rails 207, used for positioning the origin 2 of feed unit and first-level hard limit; hard limit stop block 211 is fixed to frame unit 1, distributed at both ends of lead screw and nut pair 205, used for second-level hard limit of feed unit 2.

[0009] Preferably, the lead screw nut auxiliary support-fixed side 203, lead screw nut auxiliary support-support side 206, linear guide rail 207, first connecting plate 210, and hard limit block 211 are all fixed on the lower surface of the slide base 102 of the frame unit 1, and the two linear guide rails 207 are fixed on the shoulder of the slide base 102.

[0010] Furthermore, the spindle unit 3 is arranged below the feed unit 2 and includes a second connecting plate 301, a clamping seat 302, an electric spindle 303, a tool holder 304, and a cutting tool 305. The second connecting plate 301 is positioned and fixed to the slider 208 of the feed unit 2 by a positioning surface; the clamping seat 302 is positioned to the second connecting plate 301 by one side and two pins, and is fixed to the lower surface of the second connecting plate 301 to ensure that the axis of the clamping seat 302 and the axis of the lead screw nut pair 205 are in the same vertical plane; the side of the electric spindle 303 is closely positioned and fixed to one end face of the clamping seat 302; the tool holder 304 is fixed to the end of the electric spindle 303 and is coaxial with the electric spindle 303, and is tightened by a built-in hydraulic cylinder in the electric spindle 303; the cutting tool 305 is installed on the tool holder 304 by cold pressing.

[0011] Furthermore, the conformal controllable pressure foot unit 4 is arranged at the foremost end of the robot's hole-making end effector device, fixed to the frame unit 1, and located in front of the spindle unit 3. It includes a drive and feedback module 401, a base module 402, a conformal module 403, and a locking module 404. The drive and feedback module 401 is installed at the foremost end of the actuator and connected to the frame unit 1, completing the pressure foot's clamping action and clamping force feedback function. The base module 402 is used to stably connect the pressure foot to the robot's end effector and provides installation positions for the conformal module 403 and the locking module 404. The conformal module 403 uses an array of cylindrical pins 40301 to automatically adapt to the surface shape of workpieces with different curvatures and conform to the shape. The locking module 404 is used to lock the conformed cylindrical pin array 40301 to ensure the stability of the conformation.

[0012] Furthermore, the drive and feedback module 401 is arranged on the front side of the spindle unit 3, and includes a clamping cylinder 40101, a third connecting plate 40102, a first fixed seat 40103, a pressure sensor 40104, and a drive connector 40105. The clamping cylinder 40101 is fixed to the frame unit 1 through the third connecting plate 40102, ensuring that the axis of the clamping cylinder 40101 coincides with the central axis of the frame unit 1; one end of the pressure sensor 40104 is coaxially connected to the piston rod of the clamping cylinder 40101 through the first fixed seat 40103; the other end is fixed to the drive connector 40105; the lower surface of the drive connector 40105 is connected to the base module 402 in the conformal controllable pressure foot unit 4, which plays the role of transmitting the cylinder thrust.

[0013] Furthermore, the base module 402 includes a base 40201, a pressure foot body 40202, a drive unit rear cover plate 40203, a pin fixing block 40204, and a pin base 40205; the base 40201 is fixed to the front end of the robot end effector during use; the pressure foot body 40202 is fixedly connected to the base 40201; the drive unit rear cover plate 40203 is fixed to the pressure foot body 40202 for locking. The drive unit 40401 in module 404 provides an installation position; the pin base 40205 is fixed to the pressure foot body 40202; the pin fixing block 40204 is fixedly connected to the pin base 40205, and the pin fixing block 40204 and the pin base 40205 are used to provide springback and assembly space for the cylindrical pin 40301 in the conformal module 403, and can press the pin fixing plate 40304 and the pin connecting plate 40303.

[0014] Furthermore, the conformal module 403 includes a cylindrical pin 40301, a return spring 40302, and a baffle. The cylindrical pin 40301 is divided into three segments, A, B, and C, from its tail end to its head end. The shaft diameter Rc of segment C is the largest, the shaft diameter Rb of segment B is the smallest, and the shaft diameter Ra of segment A is between that of segments C and B. The baffle is fixed to the base module 402 and has an array of through holes, which are clearance-fitted with the cylindrical pin 40301. The return spring 40302 and the baffle are slidably sleeved on the cylindrical pin 40301 in sequence. In section B of section 1, the two end faces of the baffle contact the end face of section A of cylindrical pin 40301 and one end of return spring 40302, respectively. The other end of return spring 40302 contacts the end face of section C of cylindrical pin 40301. The cylindrical pins 40301 on the same baffle together form a cylindrical pin array. The cylindrical pin array 40301 is tangent to the inner wall of the assembly space reserved on the base module 402 at section C. The assembly space reserved on the base module 402 provides guidance for the extension and retraction of the cylindrical pins 40301.

[0015] Preferably, the baffle includes a pin connecting plate 40303 and a pin fixing plate 40304. The pin connecting plate 40303 has an array of circular through holes, and the pin fixing plate 40304 has gourd-shaped irregular holes. The diameter of the larger circular hole in the irregular hole is equal to the diameter of the circular through holes on the pin connecting plate 40303, and is larger than the shaft diameter Ra of segment A of the cylindrical pin 40301 and smaller than the shaft diameter Rc of segment C of the cylindrical pin 40301. The diameter of the small round hole in the shaped hole is larger than the shaft diameter Rb of the cylindrical pin 40301B section and smaller than the shaft diameter Ra of the cylindrical pin 40301A section; the pin connecting plate 40303 and the pin fixing plate 40304 have the same plate size. After they are completely overlapped, they together show the minimum diameter of the through hole and the clearance fit with the cylindrical pin 40301B section. After the pin connecting plate 40303 and the pin fixing plate 40304 are overlapped and fixed to each other, they can position the cylindrical pin 40301.

[0016] More preferably, the pin connecting plate 40303 and the pin fixing plate 40304 are completely overlapped and connected by screws, and the two are placed together in the reserved space of the pin base 40205 and the pin fixing block 40204 to achieve clamping and fixing.

[0017] Furthermore, the locking module 404 includes a drive unit 40401, a lever 40402, a lever pin 40403, and a pressure block 40405. The drive unit 40401 is fixed on the base module 402, and the pressure block 40405 is disposed in the base module 402, capable of contacting one side of the cylindrical pin array 40301, and having a certain clamping space. One end of the lever 40402 is connected to the drive unit 40401, and the other end is rotatably connected to the base module 402 through the lever pin 40403. One end of the lever 40402 is driven by the drive unit 40401, and the other end can rotate around the lever pin 40403 relative to the base module 402, thereby pressing the pressure block 40405.

[0018] Preferably, the locking module 404 further includes a locking block 40404 and a drive unit connecting plate 40406. The lever pin 40403 passes through the lever 40402 and the locking block 40404 respectively, and is in clearance fit with the lever 40402 and the locking block 40404 to provide a fulcrum for the rotation of the lever 40402. The locking block 40404 is fixedly connected to the base module 402. The drive unit 40401 is fixed on the drive unit connecting plate 40406, and then the assembly of the drive unit 40401 and the drive unit connecting plate 40406 is positioned on the base module 402 by three-sided positioning.

[0019] More preferably, the locking block 40404 is fixedly connected to the pin fixing block 40204; the driving unit 40401 and the driving unit connecting plate 40406 are fixed together on the driving unit rear cover plate 40203 and locked by screws.

[0020] Furthermore, the alignment module 5 is used to align the perpendicularity of the tool axis to the workpiece surface before drilling. The alignment module 5 includes a second fixed base 501 and a laser generator 502; the second fixed base 501 is fixed on the base module 502; the laser generator 502 is positioned on the second fixed block 501 through three-sided positioning.

[0021] Preferably, the second fixing seat 501 is positioned on the pin fixing block 40204 from three sides and fixed by screws.

[0022] Furthermore, the measuring unit 6 includes a spindle grating probe 601, a spindle grating probe holder 602, a pressure foot grating probe 603, a pressure foot grating probe holder 604, and a grating ruler 605. The spindle grating probe 601 is fixed to the second connecting plate 301 via the spindle grating probe holder 602 and is used to detect the position information of the feed unit 2; the pressure foot grating probe 603 is fixed to the base module 402 in the conformal controllable pressure foot unit 4 via the grating probe holder 604 and is used to feed back the real-time position of the conformal controllable pressure foot unit 4 and feed it back to the feed unit 2 to ensure the accuracy of their relative positions; the grating ruler 605 is horizontally set on one side of the frame unit 1.

[0023] The method for drilling holes using the above-mentioned robot end effector device suitable for curved parts comprises the following steps:

[0024] S1: Turn on the gas supply, power on the system, and initialize all devices;

[0025] S2: Confirm the working status and water output of the water chiller and hydraulic station;

[0026] S3: Control the spindle unit 3 via the host computer to start the air seal and check the tool status;

[0027] S4: Start the robot positioning control program and reach the first hole-making position;

[0028] S5: The normal alignment module 5 is activated, and the robot automatically finds the normal and adjusts the tool axis to coincide with the normal of the hole-making area;

[0029] S6: The conformal controllable pressure foot unit 4 works. The upper computer controls the amount of air input to achieve the pressure foot to be pushed out with a small force, ensuring effective contact between the conformal controllable pressure foot and the curved part, and realizing adaptive conformation. After the conformation is completed, the upper computer executes the locking and shaping program to complete the workpiece surface shape locking and shaping under this working condition. Finally, the upper computer sets the clamping force to clamp the workpiece.

[0030] S7: Hole-making program starts, electric spindle 303 rotates, set feed speed and rotation speed, and begin hole making;

[0031] S8: Hole making is complete. Spindle unit 3 retracts the tool and returns to the initial position. Electric spindle 303 stops rotating.

[0032] S9: The host computer controls the conformal controllable pressure foot unit 4 to retract quickly as a whole, and then restores the contacts to their initial state, thus completing the machining of one hole.

[0033] By repeating steps S4-S9, the task of continuously machining holes can be completed.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1. This invention addresses the needs of the processing object by using a conformal controllable pressure foot to achieve conformal clamping of different curved parts, thereby reducing the deformation of the workpiece while ensuring stable clamping.

[0036] 2. The feed is fed through a double closed-loop feedback through the measurement unit, and the position of the pressure foot is detected in real time and fed back to the feed unit to ensure the accuracy of blind hole machining or countersinking.

[0037] 3. The feed unit, spindle unit, conformal pressure foot unit, and alignment unit are highly integrated, and the overall structure of the end effector is optimized to achieve hardware and software integration and visualization. The overall structure is compact, which improves the accessibility and versatility of the end effector, expands its working range, and ultimately achieves efficient and high-precision hole machining of curved parts. Attached Figure Description

[0038] Figure 1 This is an isometric view of the robot end effector device for drilling curved parts according to the present invention;

[0039] Figure 2 This is a schematic diagram of the feeding unit mechanism of the present invention;

[0040] Figure 3 This is an isometric drawing of the main spindle unit mechanism of the present invention;

[0041] Figure 4 This is a right view of the spindle unit mechanism of the present invention;

[0042] Figure 5 This is a schematic diagram of the conformal pressure foot unit mechanism of the present invention;

[0043] Figure 6 This is a schematic diagram of the conformal pressure foot unit drive and feedback module mechanism of the present invention;

[0044] Figure 7 This is a partial planar view of the conformal pressure foot unit of the present invention;

[0045] Figure 8 This is a partial planar view of the conformal module of the conformal pressure foot unit of the present invention;

[0046] Figure 9 This is a schematic diagram of the installation of the drive module in the locking module of the conformal pressure foot unit of the present invention;

[0047] Figure 10 This is a schematic diagram of the measuring unit mechanism of the present invention;

[0048] Figure 11 This is a specific embodiment of the present invention;

[0049] In the diagram: 1-Frame unit; 2-Feed unit; 3-Spindle unit; 4-Conformable controllable pressure foot unit; 5-Normal alignment unit; 6-Measurement unit 6; 101-Flange connector; 102-Slide base; 201-Servo motor; 202-Reducer; 203-Screw and nut pair support - fixed side; 204-Flexible coupling; 205-Screw and nut pair; 206-Screw and nut pair support - support side; 20 7-Linear guide; 208-Slider; 209-Photoelectric switch; 210-First connecting plate; 211-Hard limit stop; 301-Second connecting plate; 302-Clamping seat; 303-Electric spindle; 304-Tool holder; 305-Tool; 401-Drive and feedback module; 402-Base module; 403-Conformal module; 404-Locking module; 40101-Clamping cylinder; 40102-Third connecting plate Plate; 40103-First fixed seat; 40104-Pressure sensor; 40105-Drive connector; 40201-Base; 40202-Pressure foot body; 40203-Drive module rear cover; 40204-Pin fixing block; 40205-Pin base; 40301-Cylindrical pin; 40302-Reset spring; 40303-Cylindrical pin connecting plate; 40304-Cylindrical pin fixing plate Fixed plate; 40401-Drive module; 40402-Lever; 40403-Lever pin; 40404-Locking block; 40405-Pressure block; 40406-Drive module connecting plate; 501-Second fixed seat; 502-Laser generator; 601-Main spindle grating probe; 602-Main spindle grating probe fixing seat; 603-Pressure foot grating probe; 604-Pressure foot grating probe fixing seat; 605-Grammar ruler. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Reference Figure 1The present invention discloses a robot end effector device for drilling curved parts, including a frame unit 1, a feed unit 2, a spindle unit 3, a conformal controllable pressure foot unit 4, a normal alignment unit 5, and a measurement unit 6. The frame unit 1 connects the various functional modules and provides the connection position between the end effector and the robot flange. The feed unit 2 is mounted on the frame unit 1 and carries the spindle unit 3 to meet different feed requirements during hole making. The spindle unit 3 is mounted on the movable module of the feed unit 2 to meet the requirements of different speeds during processing. The conformal controllable pressure foot unit 4 is mounted between the front end of the end effector and the frame unit 1 to achieve conformal clamping of components with different curvatures, which can ensure the stability of clamping and reduce the deformation of the workpiece. The normal alignment unit 5 is integrated around the conformal pressure foot unit 4 to automatically find the axis direction of the hole to be processed before hole making, ensuring the perpendicularity of the processed hole. The measuring unit 6 is mounted on one side of the frame unit 1 to realize the position loop feedback of the feed unit 2, and at the same time detect the position of the pressure foot in real time and feed it back to the feed unit 2 to ensure the accuracy of blind hole processing or countersinking.

[0052] Reference Figure 1 and Figure 2 The frame unit 1 includes a flange connector 101 and a slide base 102, with the flange connector 101 fixed to the upper surface of the slide base 102.

[0053] The feed unit 2 is arranged below the slide base 102 and includes a servo motor 201, a reducer 202, a lead screw and nut pair support - fixed side 203, an elastic coupling 204, a lead screw and nut pair 205, a lead screw and nut pair support - support side 206, a linear guide rail 207, a slider 208, a photoelectric switch 209, a first connecting plate 210, and a hard limit stop 211. The servo motor 201 is coaxially connected to the reducer 202, and their axes are in the same vertical plane as the central axis of the slide base 102. One end of the reducer 202 is connected to the servo motor 201, and the other end is connected to one end of the lead screw and nut pair 205 via a flexible coupling 204 and fixed to the lead screw and nut pair support-fixed side 203. The other end of the lead screw and nut pair 205 is fixed to the slide base 102 via the lead screw and nut pair support-support side 206. Both the lead screw and nut pair support-fixed side 203 and the lead screw and nut pair support-support side 206 are fixed on the central axis of the slide base 102. The two linear guide rails 207 are fixed. The slider 208 is fixed on the shoulder of the slide base 102, parallel to the lead screw and nut pair 205 and symmetrically arranged on both sides of the lead screw and nut pair 205. The slider 208 is arranged on two linear guide rails 207. The photoelectric switch 209 is fixed to the slide base 102 through the first connecting plate 210. The photoelectric switch 209 is arranged on the same straight line parallel to the lead screw and nut pair 205, located between the lead screw and nut pair 205 and one of the linear guide rails 207, and is used for the origin positioning and first-level hard limit of the feed unit 2. The hard limit block 211 is fixed on the slide base 102 and distributed at both ends of the lead screw and nut pair 205, and is used for the second-level hard limit of the feed unit 2.

[0054] Reference Figure 3 and Figure 4 The spindle unit 3 is arranged below the feed unit 2 and includes a second connecting plate 301, a clamping seat 302, an electric spindle 303, a tool holder 304, and a cutting tool 305. The second connecting plate 301 is positioned and fixed to the slider 208 of the feed unit 2 by a positioning surface; the clamping seat 302 is positioned to the second connecting plate 301 by one side and two pins, and is fixed to the lower surface of the second connecting plate 301 to ensure that the axis of the clamping seat 302 and the axis of the lead screw nut pair 205 are in the same vertical plane; the side of the electric spindle 303 is closely positioned and fixed to one end face of the clamping seat 302; the tool holder 304 is fixed to the end of the electric spindle 303 and is coaxial with the electric spindle 303, and is tightened by a built-in hydraulic cylinder in the electric spindle 303; the cutting tool 305 is installed on the tool holder 304 by cold pressing.

[0055] Reference Figure 5The conformal controllable pressure foot unit 4 is arranged at the foremost end of the robot's hole-making end effector device, fixed to the frame unit 1, and located outside the spindle unit 3. It includes a drive and feedback module 401, a base module 402, a conformal module 403, and a locking module 404. The drive and feedback module 401 is installed at the foremost end of the actuator and connected to the frame unit 1, completing the pressure foot's clamping action and clamping force feedback function. The base module 402 is used to stably connect the pressure foot to the robot's end effector and provides installation positions for the conformal module 403 and the locking module 404. The conformal module 403 uses an array of cylindrical pins 40301 to automatically adapt to the surface shape of workpieces with different curvatures and conform to the shape. The locking module 404 is used to lock the conformed cylindrical pin array 40301 to ensure the stability of the conformation.

[0056] Reference Figure 5 and Figure 6 The drive and feedback module 401 is arranged on the front side of the spindle unit 3, and includes a clamping cylinder 40101, a third connecting plate 40102, a first fixed seat 40103, a pressure sensor 40104, and a drive connector 40105. The clamping cylinder 40101 is fixed to the frame unit 1 through the third connecting plate 40102, ensuring that the axis of the clamping cylinder 40101 coincides with the central axis of the frame unit 1; one end of the pressure sensor 40104 is coaxially connected to the piston rod of the clamping cylinder 40101 through the first fixed seat 40103; the other end is fixed to the drive connector 40105; the lower surface of the drive connector 40105 is connected to the base module 402 in the conformal controllable pressure foot unit 4, which plays the role of transmitting the cylinder thrust.

[0057] Reference Figure 7 The base module 402 includes a base 40201, a pressure foot body 40202, a drive unit rear cover plate 40203, a pin fixing block 40204, and a pin base 40205. The base 40201 is fixed to the front end of the robot's end effector during use. The pressure foot body 40202 is fixedly connected to the base 40201. The drive unit rear cover plate 40203 is fixed to the pressure foot body 40202, providing an installation position for the drive unit 40401 in the locking module 404. The pin base 40205 is fixed to the pressure foot body 40202. The pin fixing block 40204 is fixedly connected to the pin base 40205. The pin fixing block 40204 and the pin base 40205 provide springback and assembly space for the cylindrical pin 40301 in the conformal module 403, and can press against the pin fixing plate 40304 and the pin connecting plate 40303.

[0058] Reference Figure 8The conformal module 403 includes a cylindrical pin 40301, a return spring 40302, a pin connecting plate 40303, and a pin fixing plate 40304. The cylindrical pin 40301 is divided into three segments, A, B, and C, from the tail end to the head end. The shaft diameter Rc of segment C is the largest, the shaft diameter Rb of segment B is the smallest, and the shaft diameter Ra of segment A is between that of segment C and segment B. The pin connecting plate 40303 has an array of circular through holes, and the pin fixing plate 40304 has gourd-shaped irregular holes. The diameter of the larger circular hole of the irregular hole is equal to the diameter of the circular through hole on the pin connecting plate 40303, and is larger than the shaft diameter Ra of the cylindrical pin 40301A segment but smaller than the shaft diameter Rc of the cylindrical pin 40301C segment. The diameter of the smaller circular hole of the irregular hole is larger than the shaft diameter Rb of the cylindrical pin 40301B segment but smaller than the shaft diameter Ra of the cylindrical pin 40301A segment. The pin connecting plate 40303 and the pin fixing plate 40304 have the same plate size. When they are completely overlapped, the minimum diameter of the through hole is clearance-fitted with the cylindrical pin 40301B segment. After the pin connecting plate 40303 and the pin fixing plate 40304 are overlapped and fixed to each other with screws, the cylindrical pin 40301 can be positioned. The pin connecting plate 40303 and the pin fixing plate 40304 are placed together in the reserved space of the pin base 40205 and the pin fixing block 40204 to achieve clamping and fixing. The return spring 40302, the pin connecting plate 40303, and the pin fixing plate 40304 are sequentially slidably sleeved on section B of the cylindrical pin 40301. The outer end face of the pin fixing plate 40304 contacts the end face of section A of the cylindrical pin 40301, the inner end face of the pin connecting plate 40303 contacts one end of the return spring 40302, and the other end of the return spring 40302 contacts the end face of section C of the cylindrical pin 40301. The cylindrical pins 40301 on the same pin connecting plate 40303 together form a cylindrical pin array. The cylindrical pin array 40301 is tangent to the inner wall of the assembly space reserved on the pin fixing block 40204 of the base module 1 at section C. The assembly space reserved on the pin fixing block 40204 provides guidance for the extension and retraction of the cylindrical pins 40301.

[0059] Reference Figure 7 and Figure 9The locking module 404 includes a drive unit 40401, a lever 40402, a lever pin 40403, a locking block 40404, a pressure block 40405, and a drive unit connecting plate 40406. The pressure block 40405 is disposed in the pin fixing block 40204 of the base module 402, and can contact one side of the cylindrical pin array 40301, and has a certain clamping space. One end of the lever 40402 is connected to the drive unit 40401, and the other end is rotatably connected to the pin fixing block 40204 via the lever pin 40403. One end of the lever 40402 is driven by the drive unit 40401, and the other end can rotate relative to the pin fixing block 40204 around the lever pin 40403, thereby pressing the pressure block 40405. The locking module 404 also includes a locking block 40404 and a drive unit connecting plate 40406. The lever pin 40403 passes through the lever 40404. 02 is in clearance fit with locking block 40404 and lever 40402, providing a fulcrum for the rotation of lever 40402; locking block 40404 is fixedly connected to pin fixing block 40204 of base module 402; driving unit 40401 is fixed on driving unit connecting plate 40406, and then driving unit 40401 and driving unit connecting plate 40406 are fixed together on driving unit rear cover plate 40203 by three-sided positioning, and locked by screws.

[0060] Reference Figure 7 The normal alignment unit 5 includes a second fixed base 501 and a laser generator 502. The second fixed base 501 is positioned on the pin fixing block 40204 on three sides and is fixed by a threaded connection; the laser generator 502 is positioned on the second fixed base 501 on three sides and is fixed by a threaded connection.

[0061] Reference Figure 10 The measuring unit 6 includes a spindle grating probe 601, a spindle grating probe holder 602, a pressure foot grating probe 603, a pressure foot grating probe holder 604, and a grating ruler 605. The spindle grating probe 601 is fixed to the second connecting plate 301 via the spindle grating probe holder 602 and is used to detect the position information of the feed unit 2. The pressure foot grating probe 603 is fixed to the base module 402 in the conformal controllable pressure foot unit 4 via the grating probe holder 604 and is used to provide feedback on the real-time position of the conformal controllable pressure foot unit 4 and to the feed unit 2, ensuring the accuracy of their relative positions. The grating ruler 605 is horizontally set on one side of the frame unit 1.

[0062] Reference Figure 11 The robotic hole-making system's hole-making workflow for curved surfaces is as follows:

[0063] S1: Turn on the gas supply, power on the system, and initialize all devices;

[0064] S2: Confirm the working status and water output of the water chiller and hydraulic station;

[0065] S3: Control the spindle unit 3 via the host computer to start the air seal and check the tool status;

[0066] S4: Start the robot positioning control program and reach the first hole-making position;

[0067] S5: The normal alignment module 5 is activated, and the robot automatically finds the normal and adjusts the tool axis to coincide with the normal of the hole-making area;

[0068] S6: The conformal controllable pressure foot unit 4 works. The upper computer controls the amount of air input to achieve the pressure foot to be pushed out with a small force, ensuring effective contact between the conformal controllable pressure foot and the curved part, and realizing adaptive conformation. After the conformation is completed, the upper computer executes the locking and shaping program to complete the workpiece surface shape locking and shaping under this working condition. Finally, the upper computer sets the clamping force to clamp the workpiece.

[0069] S7: Hole-making program starts, electric spindle 303 rotates, set feed speed and rotation speed, and begin hole making;

[0070] S8: Hole making is complete. Spindle unit 3 retracts the tool and returns to the initial position. Electric spindle 303 stops rotating.

[0071] S9: The host computer controls the conformal controllable pressure foot unit 4 to retract quickly as a whole, and then restores the contacts to their initial state, thus completing the machining of one hole.

[0072] By repeating steps S4-S9, the task of continuously machining holes can be completed.

[0073] As a preferred embodiment:

[0074] The drive and feedback module 401 described above also includes an air pipe, a speed control valve, a solenoid valve, an electro-proportional valve, a triplet, an air source, and an amplifier. The air pipe connects the various components of the air circuit and transmits air pressure. The air source is connected to the laboratory air supply pipeline to provide thrust to the pressure foot. One end of the triplet is connected to the air source, and the other end is connected to the electro-proportional valve, which filters impurities, oil mist, and dries the gas. The other end of the electro-proportional valve is connected to the solenoid valve, which is also connected to the control system. By receiving current signals from the control system, it can output different clamping forces. The air inlet of the solenoid valve is connected to the electro-proportional valve, and the air outlet is connected to the rod-side and rodless end of the cylinder 40101 through two speed control valves, respectively. The solenoid valve is used to extend and retract the pressure foot, and the speed control valve adjusts the opening degree. The extension speed of cylinder 40101 is controlled to make the pressing process more stable. As a pneumatically driven end effector, cylinder 40101 completes the thrust output of the pressure foot. Cylinder 40101 is fixed to the robot automatic hole-making end effector frame unit through the third connecting plate 40102, ensuring that the axis of the pressing cylinder 40101 coincides with the central axis of the frame unit. One end of the pressure sensor 40104 is coaxially connected to the piston rod of cylinder 40101; the other end is fixed to the drive connector 40105. The lower surface of the drive connector 40105 is connected to the base module 402, which plays the role of transmitting the cylinder thrust. One end of the amplifier is connected to the pressure sensor 40104, which receives and amplifies the pressure signal, and the other end is connected to the control system, which ultimately transmits the pressing force to the control system. The control system is also connected to the drive unit 40401 of the locking module 404, and controls the degree of locking of the cylindrical pin array 40301 in the conformal module 403 by the drive unit 40401.

[0075] The specific steps for S6 are as follows:

[0076] S6.1: Turn on the air source, set the thrust through the control system, and control the opening of the electric proportional valve to control the output thrust of cylinder 40101 and push out the conformal module 403.

[0077] S6.2: The cylindrical pin array 40301 in the conformal module 403 contacts the workpiece to be processed. According to the curvature characteristics of the workpiece surface, the cylindrical pin array 40301 achieves adaptive conformal at different points.

[0078] S6.3: The control system controls all the drive units 40401 in the locking module 404 to act simultaneously, pushing the lever 40402 to lock the conformal cylindrical pin 40301, thus completing the shape locking.

[0079] S6.4: The clamping force is set by the control system, and the opening of the electric proportional valve is set to control the output thrust of the cylinder 40101. The clamping force is measured in real time by the pressure sensor 40104 and fed back to the control system. The PID control executed by the control system accurately applies clamping force to the workpiece.

[0080] S6.5: The workpiece is deformed under pressure, and its curvature changes. Some contacts in the 40301 array of cylindrical pins detach from the workpiece surface.

[0081] S6.6: Determine whether the requirement that all contacts are in contact with the workpiece surface is met;

[0082] S6.7: If not satisfied, the control system controls each drive unit of the locking module 3 to operate simultaneously, pushing the lever 40402 to achieve a small degree of unlocking of the cylindrical pin 40401;

[0083] S6.8: The contact point that has detached from the workpiece surface automatically rebounds under the action of the return spring 40302 and re-adheres to the workpiece surface;

[0084] S6.9: Repeat step S6.3 to complete the second locking;

[0085] S6.10: Repeat S6.6 to S6.9 until the requirements are met; the robot's automatic hole-making end effector begins hole making.

Claims

1. A robotic end effector for drilling holes in curved parts, characterized in that, include: The system comprises a frame unit (1), a feed unit (2), a spindle unit (3), a conformal controllable pressure foot unit (4), a normal alignment unit (5), and a measurement unit (6). The frame unit (1) connects the various functional modules and provides the connection position between the end effector and the robot flange. The feed unit (2) is mounted on the frame unit (1) and carries the spindle unit (3) during hole making to meet different feed requirements. The spindle unit (3) is mounted on the movable module of the feed unit (2) to meet different speed requirements during processing. The conformal controllable pressure foot unit... (4) Installed between the front end of the end effector and the frame unit (1), it is used to realize the conformal clamping of components with different curvatures, which can ensure the stability of the clamping and reduce the deformation of the workpiece; The normal alignment unit (5) is integrated around the conformal controllable pressure foot unit (4), which is used to automatically find the axis direction of the hole to be processed before drilling, and ensure the perpendicularity of the processed hole; The measuring unit (6) is installed on one side of the frame unit (1), which is used to realize the position loop feedback of the feed unit (2), and at the same time detect the position of the pressure foot in real time and feed it back to the feed unit (2), ensuring the accuracy of blind hole processing or countersinking; The conformal controllable pressure foot unit (4) is arranged at the front end of the robot hole-making end effector device, fixed to the frame unit (1), and located in front of the spindle unit (3); it includes a drive and feedback module (401), a base module (402), a conformal module (403), and a locking module (404); the drive and feedback module (401) is installed at the front end of the actuator and connected to the frame unit (1) to complete the pressing action of the pressure foot and the pressing force feedback function; the base module (402) is used to stably connect the pressure foot to the robot end effector and to provide an installation position for the conformal module (403) and the locking module (404); the conformal module (403) uses a cylindrical pin (40301) array to automatically adapt to the surface shape of workpieces with different curvatures and conform to the shape; the locking module (404) is used to lock the cylindrical pin (40301) array after conformation to ensure the stability of conformation; The conformal module (403) includes a cylindrical pin (40301), a return spring (40302), and a baffle. The cylindrical pin (40301) is divided into three segments, A, B, and C, from its tail end to its head end. The shaft diameter Rc of segment C is the largest, the shaft diameter Rb of segment B is the smallest, and the shaft diameter Ra of segment A is between that of segment C and segment B. The baffle is fixed to the base module (402) and has an array of through holes, which are clearance-fitted with the cylindrical pin (40301). The return spring (40302) and the baffle are slidably sleeved on segment B of the cylindrical pin (40301). The two ends of the baffle are in contact with the A-segment end face of the cylindrical pin (40301) and one end of the return spring (40302), respectively. The other end of the return spring (40302) is in contact with the C-segment end face of the cylindrical pin (40301). The cylindrical pins (40301) on the same baffle together form a cylindrical pin (40301) array. The cylindrical pin (40301) array is tangent to the inner wall of the assembly space reserved on the base module (402) at segment C. The assembly space reserved on the base module (402) provides guidance for the extension and retraction of the cylindrical pins (40301). The locking module (404) includes a drive unit (40401), a lever (40402), a lever pin (40403), and a pressure block (40405). The drive unit (40401) is fixed on the base module (402), and the pressure block (40405) is disposed in the base module (402) and can contact one side of the cylindrical pin array (40301) and has a certain clamping space. One end of the lever (40402) is connected to the drive unit (40401), and the other end is rotatably connected to the base module (402) through the lever pin (40403). One end of the lever (40402) is driven by the drive unit (40401), and the other end can rotate around the lever pin (40403) relative to the base module (402) to clamp the pressure block (40405).

2. The robot end effector for drilling curved parts according to claim 1, characterized in that, The frame unit (1) includes a flange connector (101) and a slide base (102), with the flange connector (101) fixed to the upper surface of the slide base (102).

3. The robot end effector for drilling curved parts according to claim 1, characterized in that, The feed unit (2) is arranged below the frame unit (1) and includes a servo motor (201), a reducer (202), a screw and nut pair support-fixed side (203), a flexible coupling (204), a screw and nut pair (205), a screw and nut pair support-support side (206), a linear guide rail (207), a slider (208), a photoelectric switch (209), a first connecting plate (210), and a hard limit stop (211); the servo motor (201) is coaxially connected to the reducer (202), and its axis is in the same vertical plane as the central axis of the frame unit (1); one end of the reducer (202) is connected to the servo motor (201), and the other end is connected to one end of the lead screw and nut pair (205) through the flexible coupling (204), and fixed on the lead screw and nut pair support-fixed side (203); the other end of the lead screw and nut pair (205) is fixed through the lead screw and nut pair support-support side (206). On the frame unit (1); the screw nut pair support-fixed side (203) and the screw nut pair support-support side (206) are both fixed on the central axis of the frame unit (1); the two linear guide rails (207) are fixed on the frame unit (1), parallel to the screw nut pair (205) and symmetrically arranged on both sides of the screw nut pair (205), and the slider (208) is arranged on the two linear guide rails (207); the photoelectric switch (209) is connected through the first A connecting plate (210) is fixed on the frame unit (1), and a photoelectric switch (209) is arranged on the same straight line parallel to the lead screw nut pair (205), located between the lead screw nut pair (205) and one of the linear guide rails (207), for the origin positioning and first-level hard limit of the feed unit (2); the hard limit block (211) is fixed on the frame unit (1) and distributed at both ends of the lead screw nut pair (205), for the second-level hard limit of the feed unit (2).

4. The robot end effector for drilling curved parts according to claim 1, characterized in that, The spindle unit (3) is arranged below the feed unit (2) and includes a second connecting plate (301), a clamping seat (302), an electric spindle (303), a tool holder (304), and a cutting tool (305). The second connecting plate (301) is positioned and fixed to the slider (208) of the feed unit (2) by a positioning surface. The clamping seat (302) is positioned and fixed to the second connecting plate (301) by one side and two pins. On the lower surface, ensure that the axis of the clamping seat (302) and the axis of the lead screw nut pair (205) are in the same vertical plane; the side of the electric spindle (303) is closely positioned and fixed to one end face of the clamping seat (302); the tool holder (304) is fixed to the end of the electric spindle (303) and is coaxial with the electric spindle (303), and is tightened by the built-in oil cylinder of the electric spindle (303); the tool (305) is installed on the tool holder (304) by cold pressing.

5. The robot end effector for drilling curved parts according to claim 1, characterized in that, The normal alignment unit (5) is used to align the perpendicularity of the tool axis to the workpiece surface before drilling; the normal alignment unit (5) includes a second fixed seat (501) and a laser generator (502); the second fixed seat (501) is fixed on the base module (402); the laser generator (502) is positioned on the second fixed seat (501) by three sides.

6. The robotic end effector for drilling curved parts according to claim 1, characterized in that, The measuring unit (6) includes a spindle grating probe (601), a spindle grating probe holder (602), a pressure foot grating probe (603), a pressure foot grating probe holder (604), and a grating ruler (605). The spindle grating probe (601) is fixed to the second connecting plate (301) through the spindle grating probe holder (602) and is used to detect the position information of the feed unit (2). The pressure foot grating probe (603) is fixed to the base module (402) in the conformal controllable pressure foot unit (4) through the pressure foot grating probe holder (604) and is used to feed back the real-time position of the conformal controllable pressure foot unit (4) and feed it back to the feed unit (2) to ensure the accuracy of their relative positions. The grating ruler (605) is horizontally set on one side of the frame unit (1).

7. The robotic end effector for drilling curved parts according to claim 4, characterized in that, The drive and feedback module (401) is arranged on the front side of the spindle unit (3) and includes a clamping cylinder (40101), a third connecting plate (40102), a first fixed seat (40103), a pressure sensor (40104), and a drive connector (40105). The clamping cylinder (40101) is fixed on the frame unit (1) through the third connecting plate (40102), and the axis of the clamping cylinder (40101) is coincident with the central axis of the frame unit (1). One end of the pressure sensor (40104) is coaxially connected to the piston rod of the clamping cylinder (40101) through the first fixed seat (40103); the other end is fixed on the drive connector (40105). The lower surface of the drive connector (40105) is connected to the base module (402) in the conformal controllable pressure foot unit (4) to transmit the cylinder thrust. The base module (402) includes a base (40201), a pressure foot body (40202), a drive unit rear cover plate (40203), a pin fixing block (40204), and a pin base (40205); the base (40201) is fixed to the front end of the robot end effector during use; the pressure foot body (40202) is fixedly connected to the base (40201); the drive unit rear cover plate (40203) is fixed on the pressure foot body (40202) and serves as a locking module (40205). The drive unit (40401) in 04) provides an installation position; the pin base (40205) is fixed on the pressure foot body (40202); the pin fixing block (40204) is fixedly connected to the pin base (40205), and the pin fixing block (40204) and the pin base (40205) are used to provide springback and assembly space for the cylindrical pin (40301) in the conformal module (403), and can press the pin fixing plate (40304) and the pin connecting plate (40303).

8. The robotic end effector for drilling curved parts according to claim 7, characterized in that, The baffle includes a pin connecting plate (40303) and a pin fixing plate (40304). The pin connecting plate (40303) has an array of circular through holes, and the pin fixing plate (40304) has gourd-shaped irregular holes. The diameter of the larger circular hole in the irregular hole is equal to the diameter of the circular through holes on the pin connecting plate (40303), and is larger than the shaft diameter Ra of segment A of the cylindrical pin (40301) but smaller than the shaft diameter Rc of segment C of the cylindrical pin (40301). The diameter of the small round hole is larger than the shaft diameter Rb of section B of the cylindrical pin (40301) and smaller than the shaft diameter Ra of section A of the cylindrical pin (40301); the pin connecting plate (40303) and the pin fixing plate (40304) have the same plate size. After they are completely overlapped, they together show the minimum diameter of the through hole and the clearance fit with section B of the cylindrical pin (40301). After the pin connecting plate (40303) and the pin fixing plate (40304) are overlapped and fixed to each other, they can position the cylindrical pin (40301). The locking module (404) further includes a locking block (40404) and a drive unit connecting plate (40406). The lever pin (40403) passes through the lever (40402) and the locking block (40404) respectively, and is in clearance fit with the lever (40402) and the locking block (40404) to provide a fulcrum for the rotation of the lever (40402). The locking block (40404) is fixedly connected to the base module (402). The drive unit (40401) is fixed on the drive unit connecting plate (40406), and then the assembly of the drive unit (40401) and the drive unit connecting plate (40406) is positioned on the base module (402) by three-sided positioning.

9. A hole-making method using any one of claims 1-8 for a robot end effector suitable for curved surfaces, characterized in that, The steps are as follows: S1: Turn on the gas supply, power on the system, and initialize all devices; S2: Confirm the working status and water output of the water chiller and hydraulic station; S3: Control the spindle unit (3) via the host computer to start the air seal and check the tool status; S4: Start the robot positioning control program and reach the first hole-making position; S5: The normal alignment unit (5) is started, and the robot automatically finds the normal and adjusts the tool axis to coincide with the normal of the hole-making area; S6: The conformal controllable pressure foot unit (4) works. The upper computer controls the size of the air source input to realize the pressure foot is pushed out with a small force, ensuring the effective contact between the conformal controllable pressure foot and the curved part, realizing adaptive conformation. After the conformation is completed, the upper computer executes the locking and shaping program to complete the workpiece surface shape locking and shaping under this working condition. Finally, the upper computer sets the clamping force to clamp the workpiece. S7: The hole-making program is started, the electric spindle (303) rotates, the feed speed and rotation speed are set, and hole-making begins; S8: Hole making is completed, the spindle unit (3) retracts the tool and returns to the initial position, and the electric spindle (303) stops rotating; S9: The host computer controls the conformal controllable pressure foot unit (4) to retract quickly as a whole, and then restores the contacts to the initial state, thus completing the processing of one hole; By repeating steps S4-S9, the task of continuously machining holes can be completed.

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