LU102257B1

LU102257B1 - System for automatically grinding vehicle-roof weld

Info

Publication number: LU102257B1
Application number: LU102257A
Authority: LU
Inventors: Xuanjun Pan; Xudong Tang; Yang Bai; Ailong Jin
Original assignee: Tonggao Advanced Manufacturing Tech Co Ltd
Priority date: 2019-12-20
Filing date: 2020-03-03
Publication date: 2021-10-25
Also published as: WO2021120398A1; KR102478681B1; CN110842688A; KR20210080281A; LU102257A1

Abstract

The present invention discloses a system for automatically grinding a vehicle-roof weld, including an industrial robot, a grinding unit, and a grinding piece consumption monitoring unit, where the grinding unit is installed on the industrial robot, and the grinding piece consumption monitoring unit is electrically connected to the industrial robot; the industrial robot drives the grinding unit to grind a weld; after grinding the weld is completed, the grinding piece monitoring unit detects grinding consumption of the grinding piece on the grinding unit, and makes a comparison with initial data of the grinding piece; and when the consumption of the grinding piece exceeds a marked threshold, the industrial robot automatically replaces the grinding piece. In the present invention, constant and stable pressure and torque can be output by using an optimally designed floating module, thereby better ensuring grinding quality. A grinding piece detection apparatus device may detect consumption of a grinding wheel online, and can automatically replace the grinding piece. A dust removal apparatus may collect and clean up grinding dust. In this case, cleanliness of the weld is ensured, and the dust may be further prevented from spilling into the air to affect a human body.

Description

SYSTEM FOR AUTOMATICALLY GRINDING VEHICLE-ROOF WELD HU102257

FIELD OF TECHNOLOGY

[0001] The present invention relates to vehicle-roof grinding devices, and in particular, toa system for automatically grinding a car-roof weld.

BACKGROUND

[0002] After a roof of a body-in-white vehicle is welded by using lasers, a small amount of spatter is generated during welding, which causes roughness of a weld and slight unevenness of the weld generated after welding, thereby affecting processing of a next process, and resulting in an unaesthetic formed weld. Therefore, grinding the weld generated after welding is necessary. At present, grinding force, a grinding speed, and other process parameters of an existing grinding device and a grinding system are difficult to control.

Therefore, it is difficult to ensure grinding quality. In addition, during grinding, real-time compensation at a grinding position cannot be realized, and relatively high requirements are posed on commissioning of a robot and fixture positioning. In addition, a dust removal cover in the existing grinding system cannot realize an adaptive adjustment of the Z axis according to consumption of a grinding piece. In this case, not only use frequency of the grinding piece is affected, costs are increased, production efficiency is reduced, but also it is difficult to control dust dispersion, thereby causing harm to human bodies.

SUMMARY

[0003] In Objective of the present invention: To resolve a problem existing in the prior art, the objective of the present invention is to provide a system for automatically grinding a vehicle-roof weld that is capable of detecting a status of a grinding piece in real time and automatically replacing the grinding piece.

[0004] Technical solution: A system for automatically grinding a vehicle-roof weld is provided, including an industrial robot, a grinding unit, and a grinding piece consumption monitoring unit, where the grinding unit is installed on the industrial robot, and the grinding piece consumption monitoring unit is electrically connected to the industrial robot; the industrial robot drives the grinding unit to grind a weld; after grinding the weld is completed, HU102257 the grinding piece monitoring unit detects grinding consumption of the grinding piece on the grinding unit, and makes a comparison with initial data of the grinding piece; and when the consumption of the grinding piece exceeds a marked threshold, the industrial robot automatically replaces the grinding piece.

[0005] Further, the grinding piece consumption monitoring unit includes a photoelectric sensor, where the photoelectric sensor is electrically connected to the industrial robot; each time the grinding unit completes a process, the industrial robot moves the grinding piece to the photoelectric sensor, and detects a position of the grinding piece; the photoelectric sensor sends the detected data to the industrial robot; the industrial robot compares the detected data with an initial position of the grinding piece; and when a position difference of the grinding piece exceeds a marked threshold, the industrial robot automatically replaces the grinding piece.

[0006] Further, the grinding unit includes a grinding module, a constant-force floating module, and a dust removal module, where

[0007] the grinding module includes a servo motor, a conversion mechanism, an automatic clamping head, and a grinding piece, where the conversion mechanism is connected to the servo motor and the automatic clamping head, the automatic clamping head automatically clamps the grinding piece, and the servo motor controls the grinding piece to rotate; and the constant-force floating module includes a device housing, and a pressure sensor, a cylinder I, a cylinder II, and a vertically disposed linear sliding rail are installed within the device housing; a sliding block is disposed on the linear sliding rail, a connecting plate is installed on the sliding block, the cylinder I is connected to the connecting plate, and the connecting plate is fixedly connected to the grinding module by using a connecting component, the connecting plate is pushed by the cylinder I to slide along the linear guide rail up and down, to drive the grinding module to move up and down, thereby generating relative movement with the constant-force floating module; the cylinder II is connected to the grinding module, air supply to the cylinder II is controlled by a proportional valve, and pressure that is output is controlled to be a constant value through closed-loop adjustment in the proportional valve; the pressure sensor is installed on a side of the cylinder II, and is configured to detect grinding pressure. The dust removal module includes a dust removal fan 10108857 cover and a dust removal device, a cover housing support of the dust removal fan cover is disposed above the entire grinding piece, air inlets for dust removal are disposed on two sides of a cover housing, the air inlets for dust removal are connected to the dust removal device, a brush is installed at each of bottom portions on two sides of the cover housing, and dust formed through grinding by the grinding piece is discharged through the air inlets for dust removal.

[0008] Further, the dust removal module includes an air duct switching module, the air duct switching module is provided with an air duct corresponding to the air inlet for dust removal, the air inlet for dust removal is connected to the air duct of the air duct switching module through a tube, and the other end of the air duct switching module is connected to the dust removal device.

[0009] Further, the dust removal module further includes a cover housing adjustment module configured to adjust up and down positions of the dust removal fan cover.

Specifically, the cover housing adjustment module includes a fixing component, a sliding component, and a cover housing connecting component, the fixing component is installed on the grinding unit, a guide rail is disposed on the fixing component, the sliding component is movably connected to the fixing component, and is capable of moving along the guide rail up and down, the dust removal fan cover is installed on the fixing component by using the cover housing connecting component, a motor module is installed on the sliding component, and the motor module is electrically connected to the industrial robot; the industrial robot adjusts the up and down positions of the dust removal fan cover by using a drive motor module. Preferably, a proximity switch is installed on an outer side of the motor module, and is configured to detect a stroke of a motor.

[0010] Further, the servo motor is electrically connected to the industrial robot; after detecting data of the grinding piece, the grinding piece consumption monitoring unit feeds a detected value back to the industrial robot; the industrial robot adjusts a rotational speed of the servo motor in real time, to maintain a constant speed of a grinding line.

[0011] Further, the constant-force floating module is provided with a position sensor, and the position sensor is electrically connected to the industrial robot, and is configured to monitor whether up and down displacements of the grinding unit fall within a safe stroke 10108857 range.

[0012] Further, a scale is disposed on a side of the device housing, and a pointer corresponding to the scale is disposed on a side of the connecting plate.

[0013] Compared with the prior art, the present invention has the following significant advantages: An optimally designed constant-force floating apparatus may implement displacement compensation during grinding, which not only can output constant and stable pressure and torque and better ensure grinding quality, but also can alleviate impact caused by fluctuation of a weld trajectory and consumption of the grinding piece, and in addition can alleviate an increased loss of the grinding wheel caused by excessive grinding force. A grinding piece detection apparatus is added to detect consumption of the grinding wheel online, and can implement automatic replacement of the grinding piece. A perfect follow-up dust removal apparatus can collect and remove dust generated during grinding, so as to prevent the dust from spilling into the air or remaining on the weld, which not only ensures the cleanliness and beautiful appearance of the weld, but also avoids impact of inhaled dust on a human body.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Fig. 1 shows a structure of a system for automatically grinding a vehicle-roof weld according to the present invention;

[0015] Fig. 2 is a schematic structural diagram of a grinding device;

[0016] Fig. 3 is a schematic structural diagram of a constant-force floating module; and

[0017] Fig. 4 is a schematic structural diagram of a grinding module.

DESCRIPTION OF THE EMBODIMENTS

[0018] The technical solutions of the present invention are described below in detail with reference to accompanying drawings and specific embodiments.

[0019] As shown in Fig. 1, a system for automatically grinding a vehicle-roof weld is provided, including an industrial robot 1, a grinding unit 2, and a grinding piece consumption monitoring unit 3. The grinding unit 2 includes an "inverted L"-shaped quiet arm 201. An upper end of the quiet arm 201 is connected to the industrial robot 1 by using a robot flange 10108857

101. The grinding piece consumption monitoring unit 3 is placed on the ground on a side of the industrial robot 1 and is electrically connected to the industrial robot 1. The industrial robot drives the grinding unit 2 to grind a weld. After grinding the weld is completed, the 5 grinding piece monitoring unit 3 detects grinding consumption of the grinding piece on the grinding unit 2, and makes a comparison with initial data of the grinding piece. When the consumption of the grinding piece exceeds a marked threshold, the industrial robot 1 automatically replaces the grinding piece.

[0020] The grinding piece consumption monitoring unit 3 includes a main body bracket 301. A photoelectric sensor 302 is installed on the top of the main body bracket 301, and is preferably a fork-type photoelectric sensor. The photoelectric sensor 302 is electrically connected to the industrial robot. Each time the grinding robot completes a process, the grinding wheel is moved to an intermediate gap of the fork-type photoelectric sensor to detect the grinding consumption. A detected position is compared with an initial position. When a position difference exceeds a marked threshold, the industrial robot automatically replaces the grinding piece.

[0021] The constant-force floating module 6 is installed on an inner side of the quiet arm 201. The constant-force floating module 6 mainly has two functions: 1. implementing gravity compensation on a grinding module and balancing gravity; 2. applying constant grinding pressure.

[0022] As shown in Fig. 2 and Fig. 3, the constant-force floating module 6 includes a device housing 608, the device housing 608 is fixed on the quiet arm 201, a surface of the device housing is an opening, and a linear sliding rail 601, a pressure sensor 602, a cylinder I 603, and a cylinder II 604 are disposed in the housing. The cylinder I 603 is configured to balance the gravity of the grinding unit, and the cylinder II 604 is configured to provide constant grinding pressure. Specifically, two linear sliding rails 601 are laid symmetrically and vertically, a sliding block is disposed on the linear sliding rail 601, and a connecting plate 605 is fixed on the sliding block of the linear sliding rail 601. On the one hand, the connecting plate 605, serving as a cover plate, is disposed on a side of the opening of the housing. On the other hand, a lower end of the connecting plate 605 is fixedly connected to the grinding module 4 by using a connecting component 606. The cylinder I 603 is connected 10108857 to the connecting plate 605, and the connecting plate 605 1s pushed by the cylinder I 603 to slide along the linear guide rail 601, so as to drive the grinding module 4 to move up and down, thereby generating relative movement with the device housing 608, and precisely controlling a straight trajectory of the grinding module 4 in a Z direction. The cylinder II 604 installed on a cylinder connecting seat is connected to the grinding module 4. Air supply to the cylinder II 604 is controlled by a proportional valve, and pressure that is output is controlled to be a constant value through closed-loop adjustment in the proportional valve. The pressure sensor 602 is disposed on a side of the cylinder II 604, and is configured to detect grinding pressure.

[0023] Further, a position sensor 607 configured to detect that up and down displacements of the grinding module fall within a safe stroke range is further disposed on the constant-force floating module 6. The position sensor includes at least an upper limit position sensor and a lower limit position sensor. The upper limit position sensor is configured to detect an upper limit position of the grinding module, and the lower limit position sensor is configured to detect a lower limit position of the grinding module. When the grinding module exceeds upper and lower displacement limits, that is, when the upper limit position sensor and the lower limit position sensor detect a signal, an alarm signal is activated and the device stops running. In addition, a safe position sensor may be disposed between the upper limit position sensor and the lower limit position sensor, to indicate that the grinding module is located within a normal stroke range. Specifically, the sensor can be of a contact type or a non-contact type. Contact type: A stroke switch is installed within the device housing, and a stopper of a limiting position is installed at a fixed point that moves relative to the stroke switch, or an opposite installation position is used. When a mechanical contact of the stroke switch meets the stopper, a control circuit is cut off (or changed) and operation is stopped. Non-contact type: A common dry reed switch, a sensor of a photoelectric type, a sensor of an induction type, or the like may be used.

[0024] Still further, a scale is engraved on a side of the device housing 608, and a pointer corresponding to the scale is disposed on a side of the connecting plate 605. A range ability of the scale is between plus 10 mm and minus 10 mm. The scale is configured to intuitively reflect up and down strokes of the grinding module. HU102257

[0025] The grinding module 4 includes a servo motor 401, a conversion mechanism 402, an automatic clamping head 403, and a grinding piece 404. The conversion mechanism 402 is connected to the servo motor 401 and the automatic clamping head 403. The automatic clamping head 403 automatically clamps the grinding piece 404. The servo motor 401 controls the grinding piece 404 to rotate. The servo motor 401 is electrically connected to the industrial robot. After detecting data of the grinding piece, the grinding piece consumption monitoring unit feeds a detected value to the industrial robot. The industrial robot adjusts a rotational speed of the servo motor in real time, to maintain a constant speed of a grinding line.

[0026] The dust removal module 5 includes a dust removal fan cover 501, an air duct switching module 502, and a dust removal device. À cover housing support of the dust removal fan cover 501 is disposed above the entire grinding piece 404, air inlets 504 for dust removal are disposed on two sides of a cover housing, a brush 505 is installed at each of bottom portions on two sides of the cover housing, the air duct switching module 502 has two air ducts, the air inlets 504 for dust removal are connected to the corresponding air ducts of the air duct switching module 502 through a tube (a connection relationship indicated by curves in Fig. 2), and the air duct switching module 502 is connected to the dust removal device by using a connecting piece 503. Dust formed through grinding by the grinding piece is discharged through the air inlets 504 for dust removal. In addition, after the grinding wheel is worn, to ensure normal operation of the system, a height of the dust removal fan cover needs to be adaptively adjusted. Therefore, the dust removal module 5 preferably further includes a cover housing adjustment module for automatically adjusting upper and lower positions of the dust removal fan cover. Specifically, the cover housing adjustment module includes a fixing component 506, a sliding component 507, and a cover housing connecting component 508, the fixing component is installed on the quiet arm 201, a guide rail is disposed on the fixing component, the sliding component is movably connected to the fixing component, and is capable of moving along the guide rail up and down, the dust removal fan cover 1s installed on the fixing component by using the cover housing connecting component, a motor module is installed on the sliding component, and the motor module is electrically connected to the industrial robot. The industrial robot adjusts the up and down positions of HU102257 the dust removal fan cover by using the drive motor module. Preferably, a proximity switch is installed on an outer side of the motor, to detect a stroke of the motor.

[0027] To further facilitate the robot automatically replacing the grinding piece, the system is also provided with a grinding piece placing rack 7, so that a plurality of grinding pieces can be installed.

[0028] Working principle:

[0029] Before a grinding state is entered, a position of a grinding piece that has not been used for grinding needs to be first marked, and certain air pressure is injected into the cylinder II. At this time, the pointer on the connecting plate is aligned with a zero-scale position on a side surface of a housing of a floating module, which is a marked state. In this state, the robot guides a grinding head to move to a position of the fork-type photoelectric sensor. Before the grinding piece comes into contact with the photoelectric sensor, a signal output by a touch device is always 0. When a grinding wheel touches the sensor, the signal that is output is 1. In this case, a six-axis coordinate position of the robot is recorded, namely (x,y, z, A, B, C). The industrial robot drives the grinding head to realize an automatic weld grinding process on a roof of a body-in-white vehicle. Each time weld grinding is completed, the operations are repeated, to obtain (x', y', z', A', B', C') in a current state. Among values recorded each time, a difference exists only among values Z. Based on a formula in a robot program, a difference vertical Az = z — z' is obtained each time, and this difference is separately transmitted to a motor that controls the dust removal fan cover and a motor that controls the grinding piece. The motor that controls the dust removal fan cover enables, based on the difference, the dust removal fan cover to move upwards by a displacement of the same difference value. The motor that controls the grinding piece changes a speed of the grinding piece based on a displacement difference, so that a line speed of the grinding piece is kept constant, so that the grinding state 1s controlled.

[0030] In summary, the grinding piece consumption detection station detects the position of the grinding wheel (the grinding piece), and a control center of the industrial robot feeds back a difference between the position of the grinding piece and a position of a grinding piece that was unused during detection for the first time (a difference between a value detected when grinding is performed once and a value when grinding is not performed), to 10108857 reflect usage of the grinding wheel after each grinding. When the detected value difference 1s greater than the marked value, the grinding wheel is replaced. During grinding of the present invention, constant torque and constant pressure are used, which can efficiently remove dust.

A rotational speed of the servo motor and the position and height of the dust removal fan cover may be further automatically adjusted according to the consumption of the grinding wheel after use, to increase use frequency of the grinding wheel. Through cooperation of the components, two-way automatic grinding of the weld on the roof and automatic replacement of the grinding piece can be realized.

Claims

CLAIMS LU102257

1. A system for automatically grinding a vehicle-roof weld, comprising an industrial robot, a grinding unit, and a grinding piece consumption monitoring unit, wherein the grinding unit is installed on the industrial robot, and the grinding piece consumption monitoring unit is electrically connected to the industrial robot; the industrial robot drives the grinding unit to grind a weld; after grinding the weld is completed, the grinding piece monitoring unit detects grinding consumption of the grinding piece on the grinding unit, and makes a comparison with initial data of the grinding piece; and when the consumption of the grinding piece exceeds a marked threshold, the industrial robot automatically replaces the grinding piece.

2. The system for automatically grinding the vehicle-roof weld according to claim 1, wherein the grinding piece consumption monitoring unit comprises a photoelectric sensor, wherein the photoelectric sensor is electrically connected to the industrial robot; each time the grinding unit completes a process, the industrial robot moves the grinding piece to the photoelectric sensor, and detects a position of the grinding piece; the photoelectric sensor sends the detected data to the industrial robot; the industrial robot compares the detected data with an initial position of the grinding piece; and when a position difference of the grinding piece exceeds a marked threshold, the industrial robot automatically replaces the grinding piece.

3. The system for automatically grinding the vehicle-roof weld according to claim 1 or 2, wherein the grinding unit comprises a grinding module, a constant-force floating module, and a dust removal module, wherein the grinding module comprises a servo motor, a conversion mechanism, an automatic clamping head, and a grinding piece, wherein the conversion mechanism is connected to the servo motor and the automatic clamping head, the automatic clamping head automatically clamps the grinding piece, and the servo motor controls the grinding piece to rotate; and the constant-force floating module comprises a device housing, and a pressure sensor, a cylinder I, a cylinder II, and a vertically disposed linear sliding rail are installed within the device housing; a sliding block is disposed on the linear sliding rail, a connecting plate is installed on the sliding block, the cylinder I is connected to the connecting plate, and the connecting plate is fixedly connected to the grinding module by using a connecting HU102257 component; the connecting plate is pushed by the cylinder I to slide along the linear guide rail up and down, to drive the grinding module to move up and down, thereby generating relative movement with the constant-force floating module; the cylinder II is connected to the grinding module, air supply to the cylinder II is controlled by a proportional valve, and pressure that is output is controlled to be a constant value through closed-loop adjustment in the proportional valve; the pressure sensor is installed on a side of the cylinder II, and is configured to detect grinding pressure; and the dust removal module comprises a dust removal fan cover and a dust removal device, a cover housing support of the dust removal fan cover is disposed above the entire grinding piece, air inlets for dust removal are disposed on two sides of a cover housing, the air inlets for dust removal are connected to the dust removal device, a brush is installed at each of bottom portions on two sides of the cover housing, and dust formed through grinding by the grinding piece is discharged through the air inlets for dust removal.

4. The system for automatically grinding the vehicle-roof weld according to claim 3, wherein the dust removal module comprises an air duct switching module, the air duct switching module is provided with an air duct corresponding to the air inlet for dust removal, the air inlet for dust removal is connected to the air duct of the air duct switching module through a tube, and the other end of the air duct switching module is connected to the dust removal device.

5. The system for automatically grinding the vehicle-roof weld according to claim 3, wherein the dust removal module further comprises a cover housing adjustment module configured to adjust up and down positions of the dust removal fan cover.

6. The system for automatically grinding the vehicle-roof weld according to claim 5, wherein the cover housing adjustment module comprises a fixing component, a sliding component, and a cover housing connecting component, the fixing component is installed on the grinding unit, a guide rail is disposed on the fixing component, the sliding component is movably connected to the fixing component, and is capable of moving along the guide rail up and down, the dust removal fan cover is installed on the fixing component by using the cover housing connecting component, a motor module is installed on the sliding component, and the motor module is electrically connected to the industrial robot; the industrial robot adjusts HU102257 the up and down positions of the dust removal fan cover by using a drive motor module.

7. The system for automatically grinding the vehicle-roof weld according to claim 6, wherein a proximity switch is installed on an outer side of the motor module, and is configured to detect a stroke of a motor.

8. The system for automatically grinding the vehicle-roof weld according to claim 3, wherein the servo motor is electrically connected to the industrial robot; after detecting data of the grinding piece, the grinding piece consumption monitoring unit feeds a detected value back to the industrial robot; the industrial robot adjusts a rotational speed of the servo motor in real time, to maintain a constant speed of a grinding line.

9. The system for automatically grinding the vehicle-roof weld according to claim 1, wherein the constant-force floating module is provided with a position sensor that is configured to detect a relative displacement of a connecting plate to the device housing, and the position sensor is electrically connected to the industrial robot.

10. The system for automatically grinding the vehicle-roof weld according to claim 1, wherein a scale is disposed on a side of the device housing, and a pointer corresponding to the scale is disposed on a side of a connecting plate.