WO2019165708A1

WO2019165708A1 - Compliant polishing system

Info

Publication number: WO2019165708A1
Application number: PCT/CN2018/087279
Authority: WO
Inventors: 黄丹; 李凯格; 周雪峰; 肖朝文; 程韬波; 蔡奕松; 曾富城
Original assignee: 广东省智能制造研究所
Priority date: 2018-03-02
Filing date: 2018-05-17
Publication date: 2019-09-06
Also published as: CN108161680B; CN108161680A

Abstract

Disclosed is a compliant polishing system, comprising a rack (1), a polishing head (2), a central lead screw (3) and several rolling lead screws (4), wherein the polishing head (2) is rotatably connected to the outer end of the central lead screw (3) and axially positioned on the central lead screw (3), and the central lead screw (3) is connected to the rack (1) in such a way that the central lead screw rotates around its own axis; each rolling lead screw (4) rotates around its own axis and is axially positioned on the rack (1); the rolling lead screws (4) are distributed in the circumferential direction of the central lead screw (3) and are respectively in threaded connection with the central lead screw (3); and the polishing system further comprises a drive mechanism for driving all the rolling lead screws (4) to rotate simultaneously.

Description

a smooth polishing system

Technical field

The invention belongs to the technical field of automatic polishing equipment and relates to a compliant polishing system.

Background technique

Robotic automatic polishing has the advantages of high efficiency, controllable precision and cost saving compared to manual grinding. Robotic automatic polishing is widely used in the manufacture of bathroom parts, plumbing fittings, optical positioning equipment, various blades and molds. In robotic automated polishing, in order to solve the problem of grinding of complex curved parts, reduce surface roughness and improve surface accuracy, the use of compliant polishing tools is a very novel approach. At present, commonly used polishing force control devices include pneumatic power control, electromagnetic force control, and passive spring force control. The current main way to increase efficiency is to increase the size of the polishing disc or to increase the feed rate of the robot.

A disadvantage of the prior art automatic polishing system is that the response speed is not fast enough and the transmission accuracy is not accurate enough.

Summary of the invention

The present invention provides a compliant polishing system in view of the above problems existing in the prior art, and the technical problem to be solved by the present invention is how to improve the transmission accuracy of the polishing system.

The object of the invention can be achieved by the following technical solutions:

A compliant polishing system comprising a frame, a polishing head, a center screw and a plurality of rolling screws, the polishing head being rotatably coupled to the outer end of the central screw and axially positioned on the central screw, characterized The central screw is rotatably coupled to the frame about a shaft, and each of the rolling screws is rotated about the shaft and axially positioned on the frame, and the rolling screws are along the circumference of the central screw. Distributed and separately coupled to the central lead screw, the polishing system further includes a drive mechanism that drives all of the rolling screws to rotate simultaneously.

The working principle is that all the rolling screws of the compliant polishing system are rotated around the shaft and axially positioned on the frame, and the driving mechanism drives all the rolling screws to rotate, and all the rolling screws do not move axially, so The rolling screw simultaneously drives the central screw to rotate and moves the central screw axially, and the central screw drives the polishing head to move axially, and the rolling contact of each structure is contacted by the threaded thread of each rolling screw. Smaller, the transmission accuracy is higher, the stiffness is higher, the torque that can be transmitted is larger, and the movement is more stable.

In a flexible polishing system as described above, the drive mechanism includes a motor, a driving gear and a driven gear, the motor is fixed to the frame, and an output shaft of the motor is fixed to the driving gear, The driving gear meshes with the driven gear, and one end of each rolling screw is fixed to the driven gear. The motor drives the driving gear to rotate, and the driven gear rotates with the driving gear and drives all the rolling screws to rotate at the same time. These rolling screws simultaneously drive the central screw to rotate and move the central screw axially.

In a compliant polishing system as described above, each of the rolling screws is evenly distributed along the circumferential direction of the driven gear. The driven screw rod evenly distributed along the circumferential direction of the driven gear can drive the center screw rod to rotate and move more smoothly, further improving the transmission precision, and the transmitted torque distribution is more uniform.

In a compliant polishing system as described above, the polishing system further includes a screw sleeve fixed to the frame, the center screw and all the rolling screws being located on the wire Inside the rod sleeve.

In a compliant polishing system, a front inner tooth sleeve and a rear inner tooth sleeve are respectively connected to the two ends of the screw sleeve, and the front inner tooth sleeve and the rear inner tooth sleeve respectively A front retaining ring and a rear retaining ring are fixed, and the two ends of each rolling screw are respectively fixed on the front retaining ring and the rear retaining ring, and each rolling screw is evenly distributed along the circumferential direction of the front retaining ring. The rear retaining ring is fixed to the driven gear. In this configuration, the front internal tooth sleeve, the front retaining ring, the rear internal tooth sleeve, the rear retaining ring, the screw sleeve, the center screw, and the plurality of rolling screws constitute the screw assembly.

In a compliant polishing system, the outer end of the center screw is connected with a mounting plate, the polishing head is fixed at a middle portion of the mounting plate, and a lower end portion of the mounting plate is fixed with a connecting rod. The connecting rod is slidably connected to the frame, and the connecting rod is sleeved and fixed with a limit nut. During the process of the polishing head moving axially with the central screw rod, the connecting rod plays a guiding role, so that the movement of the polishing head is more stable, and the limiting nut plays a limiting role on the stroke of the mounting plate.

In a soft polishing system as described above, the outer end portion of the center screw is sleeved and fixed with a self-aligning ball bearing, and the self-aligning ball bearing is fixed to an upper end portion of the mounting plate. The self-aligning ball bearing is set so that the mounting plate only moves axially with the center screw without rotating with the center screw, so the polishing head on the mounting plate only moves horizontally.

In a compliant polishing system as described above, a three-dimensional force sensor is disposed between the polishing head and the mounting plate. A three-dimensional sensor is used to detect the normal force experienced by the polishing head.

In a soft polishing system as described above, the frame comprises a bottom plate, and the front support portion and the rear support plate are respectively fixed at two ends of the bottom plate, and an intermediate support plate is fixed at a middle portion of the bottom plate, the screw sleeve The intermediate support plate is passed through and the two ends of the screw sleeve are respectively fixed to the front support plate and the rear support plate.

In a soft polishing system as described above, the center screw rods are two, and the outer end portions of the center screw rods are all provided with a polishing head, and each of the center screw rods is distributed with a plurality of rolling screw rods in the axial direction, and each rolling The lead rods are all rotated about the shaft and axially positioned on the frame, and each of the rolling screws is respectively threadedly connected with the corresponding center screw. In this embodiment, the polishing system is a double polishing head structure, and the double polishing head can polish and polish two workpieces at the same time to improve work efficiency.

The advantages of the present invention over the prior art are as follows:

1. Each rolling screw of the polishing system is in thread contact with the central screw. The contact gap of this structure is smaller, the transmission precision is higher, the rigidity is higher, the torque that can be transmitted is larger, and the movement is more stable.

2. The torque transmission efficiency of the polishing system is high. Due to the improvement of the transmission rigidity, the device runs more smoothly, the response speed is fast, the device generates less heat, and the service life is longer.

3. The polishing system can adopt double polishing head structure, and the double polishing head can polish and polish two workpieces at the same time to improve work efficiency.

DRAWINGS

Figure 1 is a schematic view showing the structure of the polishing system.

Figure 2 is an exploded view of the polishing system.

Figure 3 is an exploded view of the lead screw assembly.

Figure 4 is a schematic illustration of a single polishing head polishing track and a dual polishing head polishing track.

Figure 5 is a schematic view of the line spacing when a double polishing head is used.

Figure 6 is a schematic view showing the movement relationship of the screw assembly.

In the figure, 1, frame; 1a, bottom plate; 1b, front support plate; 1c, rear support plate; 1d, intermediate support plate; 2, polishing head; 3, center screw; 4. rolling screw; ; 6, the driving gear; 7, driven gear; 8, screw sleeve; 9, front internal tooth sleeve; 10, rear internal tooth sleeve; 11, front retaining ring; 12, rear retaining ring; 13, installation Board; 14, connecting rod; 15, limit nut; 16, self-aligning ball bearing; 17, three-dimensional force sensor.

Detailed ways

The technical solutions of the present invention are further described below with reference to the accompanying drawings, but the present invention is not limited to the embodiments.

Embodiment 1

As shown in FIG. 1-3, the compliant polishing system includes a frame 1, a polishing head 2, a center screw 3, and a plurality of rolling screws 4. The polishing head 2 is rotatably coupled to the outer end of the center screw 3 and axially positioned. On the central screw 3, the central screw 3 is rotatably connected to the frame 1 about the self-axis, and each of the rolling screws 4 is rotated around the shaft and axially positioned on the frame 1, and each rolling screw 4 is along the center wire. The rods are circumferentially distributed and threadedly coupled to the central screw 3, respectively, and the polishing system further includes a drive mechanism that drives all of the rolling screws 4 to rotate simultaneously.

As shown in FIG. 2, in the embodiment, the driving mechanism includes a motor 5, a driving gear 6 and a driven gear 7. The motor 5 is fixed on the frame 1, and the output shaft of the motor 5 is fixedly connected with the driving gear 6, and the driving gear 6 is engaged with the driven gear 7, and one end of each of the rolling screws 4 is fixed to the driven gear 7. The motor 5 drives the driving gear 6 to rotate, and the driven gear 7 rotates with the driving gear 6 and drives all the rolling screws 4 to rotate simultaneously. These rolling screws 4 simultaneously drive the central screw 3 to rotate and axially move the central screw 3.

Preferably, each of the rolling screws 4 is evenly distributed along the circumferential direction of the driven gear 7. The driven screw rod evenly distributed along the circumferential direction of the driven gear 7 can drive the center screw 3 to rotate and move more smoothly, further improving the transmission precision, and the transmitted torque distribution is more uniform.

As shown in Figures 2, 3 and 6, preferably, the polishing system further comprises a screw sleeve 8 fixed to the frame 1, the central screw 3 and all the rolling screws 4 are located in the screw sleeve Inside the barrel 8.

As shown in FIG. 3, in the present embodiment, the front inner tooth sleeve 9 and the rear inner tooth sleeve 10, the front inner tooth sleeve 9 and the rear inner tooth sleeve 10 are respectively connected to the two ends of the screw sleeve 8 respectively. The front retaining ring 11 and the rear retaining ring 12 are respectively fixed inside, and the two end portions of each rolling screw 4 are respectively fixed on the front retaining ring 11 and the rear retaining ring 12, and each rolling screw 4 is along the front retaining ring 11 The circumferential direction is evenly distributed, and the rear retaining ring 12 is fixed to the driven gear 7. In this configuration, the front internal tooth sleeve 9, the front retaining ring 11, the rear internal tooth sleeve 10, the rear retaining ring 12, the screw sleeve 8, the center screw 3, and the plurality of rolling screws 4 constitute a screw assembly.

As shown in FIG. 2, the outer end of the center screw 3 is connected with a mounting plate 13, the polishing head 2 is fixed at the middle of the mounting plate 13, and the lower end of the mounting plate 13 is fixed with a connecting rod 14, and the connecting rod 14 is slidably connected to the machine. On the frame 1, the connecting rod 14 is sleeved and fixed to the limit nut 15. During the axial movement of the polishing head 2 with the central screw rod 3, the connecting rod 14 plays a guiding role, so that the movement of the polishing head 2 is more stable, and the limiting nut 15 plays a limiting role on the stroke of the mounting plate 13.

As shown in FIG. 2, preferably, the outer end portion of the center screw 3 is sleeved and fixed with a self-aligning ball bearing 16, and the self-aligning ball bearing 16 is fixed to the upper end portion of the mounting plate 13. The self-aligning ball bearing 16 is disposed such that the mounting plate 13 moves only axially with the center screw 3 without rotating with the center screw 3, so that the polishing head 2 on the mounting plate 13 only moves horizontally.

As shown in FIG. 2, a three-dimensional force sensor 17 is disposed between the polishing head 2 and the mounting plate 13. A three-dimensional sensor is used to detect the normal force experienced by the polishing head 2.

As shown in FIG. 2, in the embodiment, the frame 1 includes a bottom plate 1a. The two ends of the bottom plate 1a are respectively fixed with a front support plate 1b and a rear support plate 1c. The middle portion of the bottom plate 1a is fixed with an intermediate support plate 1d. The sleeve 8 passes through the intermediate support plate 1d and both ends of the screw sleeve 8 are fixed to the front support plate 1b and the rear support plate 1c, respectively.

As shown in FIG. 1 , preferably, the center screw rods 3 are two, and the outer end portions of the center screw rods 3 are respectively provided with a polishing head 2 , and each of the center screw rods 3 is distributed with a plurality of rolling screw rods 4 in the circumferential direction, and each rolling is performed. The lead rods 4 are all rotated about the self-axis and axially positioned on the frame 1, and each of the rolling screws 4 is screwed to the corresponding center screw 3. In this embodiment, the polishing system is a double polishing head 2 structure, and the double polishing head 2 can polish and polish two workpieces at the same time to improve work efficiency.

As shown in Figure 4, the effect of the double-head polishing head 2 on the polishing line spacing: in order to achieve the required grinding depth, the polishing process is usually repeated, and the left figure of Figure 4 shows the conventional single-head polishing mode, the right of Figure 4 The picture shows the double polishing head 2 method (containing a set of polishing discs), and the feeding direction of the double polishing head 2 is the direction of the polishing track shown in the figure, and the efficiency is obviously twice that of the left drawing.

Figure 5 is a schematic view showing the line spacing when the double-head polishing head 2 is used. The feeding direction of the double-head polishing head 2 is perpendicular to the feeding direction of the double polishing head 2 in the right drawing of Fig. 4, in order to ensure a uniform material removal depth. Plan the line spacing as shown in Figure 5, with an average line spacing of

It is obviously larger than L1 of Fig. 4, so the polishing efficiency is improved.

The relationship between the motor rotation angle and the moving distance of the polishing head 2, and the transmission ratio between the driving gear 6 and the driven gear 7 is i, then

R2 is the pitch diameter of the driven gear 7 and R1 is the pitch diameter of the driving gear 6 and the number of turns of the rolling screw 4 as it moves along the center screw 3

D is the diameter of the screw sleeve 8, and d is the diameter of the rolling screw 4, thereby driving the center screw 3 to move n times, and the pitch of the rolling screw 4 and the center screw 3 is P, and the rotation angle of the motor is θ, the angular velocity of the rolling screw 4 moving along the center screw 3 is ω, and the distance moved by the polishing head 2 is x, then the following equation holds:

Description of system control principle: Considering the difference in contact state of different processing positions, each polishing head 2 of the double polishing head 2 device is controlled by an independent driver and does not affect each other. At a certain processing time, the angle between the polishing head 2 and the direction of gravity is measured by a gravity sensor (not shown), and the normal force detected by the end force sensor is converted into the normal force of the workpiece contact surface, and fed back to the controller and expectation. The force is poor, adaptive PID or fuzzy PID control is applied to the force deviation, the motor rotation angle is calculated and moved at a reasonable speed until the force deviation is less than the set threshold. This cycle completes the required constant force or variable force control.

Embodiment 2

The structure and principle of the embodiment are basically the same as those of the first embodiment. The difference is that the driving mechanism includes the motor 5, the roller, the timing belt and the rotating disk. The roller is sleeved and fixed on the output shaft of the motor 5, and the timing belt is connected. On the roller and the rotating disc, one end portion of each of the rolling screws 4 is respectively fixed to the rotating disc, and each of the rolling screws 4 is evenly distributed along the circumferential direction of the rotating disc.

The specific embodiments described herein are merely illustrative of the spirit of the invention. A person skilled in the art can make various modifications or additions to the specific embodiments described or in a similar manner, without departing from the spirit of the invention or as defined by the appended claims. The scope.

Claims

A compliant polishing system comprising a frame (1), a polishing head (2), a center screw (3) and a plurality of rolling screws (4), the polishing head (2) being rotatably coupled to the central screw ( The outer end of the 3) is axially positioned on the central screw (3), characterized in that the central screw (3) is rotatably connected to the frame (1) around the shaft, and each rolling screw (4) Rotating from the shaft and axially positioning on the frame (1), each rolling screw (4) is distributed along the circumferential direction of the central screw (3) and respectively with the central screw (3) Threaded connection, the polishing system also includes a drive mechanism that drives all of the rolling screws (4) to rotate simultaneously.
A compliant polishing system according to claim 1, wherein the drive mechanism comprises a motor (5), a drive gear (6) and a driven gear (7), said motor (5) being fixed to said frame (1) The output shaft of the motor (5) is fixedly coupled to the driving gear (6), the driving gear (6) is meshed with the driven gear (7), and each rolling screw ( One end of 4) is fixed to the driven gear (7).
A compliant polishing system according to claim 2, characterized in that each of the rolling screws (4) is evenly distributed along the circumferential direction of the driven gear (7).
A compliant polishing system according to claim 2, wherein said polishing system further comprises a screw sleeve (8), said screw sleeve (8) being fixed to said frame (1) The central screw (3) and all of the rolling screws (4) are located within the screw sleeve (8).
A compliant polishing system according to claim 4, wherein both ends of the screw sleeve (8) are respectively connected with a front internal tooth sleeve (9) and a rear internal tooth sleeve (10) The front inner ring sleeve (9) and the rear inner tooth sleeve (10) are respectively fixed with a front retaining ring (11) and a rear retaining ring (12), and two ends of each rolling screw (4) Fixed on the front retaining ring (11) and the rear retaining ring (12), respectively, each rolling screw (4) is evenly distributed along the circumferential direction of the front retaining ring (11), the rear retaining ring (12) ) is fixed to the driven gear (7).
A compliant polishing system according to claim 1, wherein an outer end of said center screw (3) is connected to a mounting plate (13), and said polishing head (2) is fixed to said mounting plate In the middle portion of (13), a lower end portion of the mounting plate (13) is fixed with a connecting rod (14), and the connecting rod (14) is slidably coupled to the frame (1), the connecting rod (14) Upper sleeve and fixed limit nut (15).
A compliant polishing system according to claim 6, wherein the outer end of the center screw (3) is sleeved and fixed with a self-aligning ball bearing (16), and the self-aligning ball bearing (16) ) is fixed to the upper end of the mounting plate (13).
A compliant polishing system according to claim 6, characterized in that a three-dimensional force sensor (17) is arranged between the polishing head (2) and the mounting plate (13).
A compliant polishing system according to claim 5, wherein said frame (1) comprises a bottom plate (1a), and both ends of said bottom plate (1a) are respectively fixed with a front support plate (1b) and a rear support plate (1c), an intermediate support plate (1d) is fixed in a middle portion of the bottom plate (1a), and the screw sleeve (8) passes through the intermediate support plate (1d) and the screw sleeve (8) Both ends are fixed to the front support plate (1b) and the rear support plate (1c), respectively.
A compliant polishing system according to claim 1, wherein the center screw (3) is two, and the outer ends of the center screws (3) are each provided with a polishing head (2), each A plurality of rolling screws (4) are distributed in the circumferential direction of the central screw (3), and each of the rolling screws (4) is rotated around the shaft and axially positioned on the frame (1), and each rolling screw (4) ) respectively connected to the corresponding central screw (3) thread.