CN111644943B

CN111644943B - Automatic grinding robot for weld joints at pipe ends of straight weld steel pipes

Info

Publication number: CN111644943B
Application number: CN202010128822.3A
Authority: CN
Inventors: 原小红; 张瑾宇; 刘晨; 王林军; 马利; 王刚
Original assignee: Baoji Yuzhe Industrial Technology Co ltd
Current assignee: Baoji Yuzhe Industrial Technology Co ltd
Priority date: 2020-02-28
Filing date: 2020-02-28
Publication date: 2022-01-28
Anticipated expiration: 2040-02-28
Also published as: CN111644943A

Abstract

Provides an automatic grinding robot for the weld of the pipe end of a straight weld steel pipe. The Z-direction straight weld grinding platform which is used for grinding by adopting an abrasive belt is arranged at the execution end of the multi-degree-of-freedom manipulator, the abrasive belt is perpendicular to the straight weld and is used for carrying out multi-pass concentric circular motion on the straight weld of the steel pipe according to a planned circular arc track, and meanwhile, the multi-pass fine grinding is carried out on the straight weld of the pipe end, so that on one hand, an efficient grinding mode that the abrasive belt is in line contact with the straight weld is adopted, and the grinding efficiency is improved; the polishing cost is reduced; on the other hand, the accurate adjustment function of the grinding height is realized through the Z-direction straight weld grinding platform, the motion control of the manipulator is simplified, and meanwhile, the automatic identification, high precision, high reliability, high efficiency, high speed and automatic grinding for the straight weld of the steel pipe are realized.

Description

Automatic grinding robot for weld joints at pipe ends of straight weld steel pipes

Technical Field

The invention belongs to the technical field of operation, transportation, grinding and polishing processes, and particularly relates to an automatic grinding robot for a weld joint at a pipe end of a straight weld steel pipe.

Background

The straight welded seam steel pipe is a pipe with axial straight welded seam formed by one-time bending of a steel plate. In order to meet the welding quality of the next steel pipe butt-circumferential welding at the end of the straight welded steel pipe, the straight welded seam with a certain axial depth needs to be polished to meet the durable use requirement of uniform radial stress distribution of the steel pipe to the maximum extent. The API Spec5L standard and GBT 97111-1997 standard are both well defined: the grinding of the steel pipe end can meet the following requirements: the welding line is polished without damaging the base metal; the residual height of the welding line after grinding is less than 0.5 mm.

In the prior art, a robot polishing system with three-dimensional vision and a control method thereof disclosed in publication No. CN109483369A, and a robot polishing system with three-dimensional vision and a control method thereof disclosed in publication No. CN 109483369A: the two technical schemes both adopt a pneumatic polishing technology; although there are certain advantages in flexible output; however, due to the compressibility of the gas, the gas in the pneumatic actuator is easily fluctuated by the change of the external environment temperature, so that the stability of the natural frequency of the pneumatic system is poor, and the final polishing linearity output is not ideal. Moreover, the system performance is not stable due to the serious crawling influence of the low-speed operation of the friction force of the air cylinder of the pneumatic actuating mechanism, so that the reliability of high-precision grinding is restricted. Therefore, the requirements of high precision, high reliability and automatic polishing without damaging the base material cannot be met.

In addition, the robot polishing system with three-dimensional vision disclosed in publication No. CN109483369A and the control method thereof are characterized in that a multi-degree-of-freedom manipulator is adopted to directly carry a grinding wheel for polishing, due to the precision limitation of the motion trajectory planning of the manipulator and the additional rotation angle increment generated by the joint generated by the elastic deformation of each joint trajectory sensor, the displacement generated by the rotation angle increment is amplified by the arm length of each execution unit of the multi-degree-of-freedom manipulator, so that the precision of polishing by directly carrying a grinding head by the multi-degree-of-freedom manipulator is limited, and the technical requirements that can be achieved by manual polishing cannot be completely replaced.

Moreover, the automatic compensation system for flexible polishing disclosed in the publication number CN208117512U realizes the axial automatic compensation function of the execution end of the multi-degree-of-freedom manipulator; but grinding by using a grinding wheel; the grinding wheel and the welding line of the steel pipe are polished in point contact, the grinding efficiency is low, the replacement cost of the grinding wheel is high, and the power utilization rate of a machine tool is not ideal. Therefore, in the prior art, the straight weld grinding aiming at the pipe end of the straight weld steel pipe is lacked, the abrasive belt grinding is adopted, the multi-degree-of-freedom mechanical arm motion control is simplified, meanwhile, the grinding precision is improved, the grinding cost is reduced, the automatic identification and high-precision grinding of the weld of the pipe end of the straight weld steel pipe are realized, and the following improved technical scheme is provided.

Disclosure of Invention

The technical problem solved by the invention is as follows: the automatic grinding robot for the weld joints at the pipe ends of the straight weld steel pipes is provided, a Z-direction straight weld grinding platform for grinding by adopting an abrasive belt is arranged at the execution end of a multi-degree-of-freedom manipulator, and the grinding efficiency is improved by an efficient grinding mode that the abrasive belt is in vertical linear contact with the weld joints of the steel pipes; the polishing cost is reduced; meanwhile, the motion control of the manipulator is simplified, and meanwhile, the polishing precision is improved; the technical problem of lack among the prior art can realize the accurate equipment of polishing of sand belt to steel pipe straight weld can be solved.

The technical scheme adopted by the invention is as follows: the automatic grinding robot for the weld of the pipe end of the straight weld steel pipe is provided with a Z-direction straight weld grinding platform which is fixedly connected with an execution end of a multi-degree-of-freedom manipulator and is ground by adopting an abrasive belt; the Z-direction straight weld grinding platform arranged in the Z-direction straight weld grinding platform consists of a flange mounting rack, an X-direction rack and a triangular grinding mechanism which vertically ascends and descends in the Z direction relative to the X-direction rack; the flange mounting rack is of a spatial three-dimensional hollow right-angled triangle structure; the top end face of one horizontal right-angle side is fixedly connected with the execution tail end of the six-degree-of-freedom manipulator into a whole on the horizontal plane through a horizontal flange plate, and the other vertical right-angle side is fixedly connected with the horizontal left end of the X-direction rack into a whole; a triangular grinding mechanism which vertically ascends and descends in the Z direction relative to the X-direction rack is arranged at the horizontal right end of the X-direction rack; the laser contourgraph is fixedly installed at the bottom of the outer side of the horizontal right end of the triangular polishing mechanism; the flange mounting rack and the X-direction rack are made of aluminum alloy.

Among the above-mentioned technical scheme, for solving triangle grinding machanism relative X to the Z of high accuracy, high reliability, stable support of frame to mechanical movement, further: the triangular grinding mechanism comprises a pair of front and rear vertical installation side plates; the inner side plate bodies of the front and rear vertical installation side plates are respectively vertically and symmetrically provided with a pair of vertical slide rails in parallel, the vertical slide rails are respectively matched with a pair of vertical guide rail slide blocks in a sliding manner, and the outer sides of the pair of vertical guide rail slide blocks are fixedly connected with the back sides of the vertical base plate bodies; the inner side of one of the vertical guide rail sliding block bodies is fixedly connected with a screw rod sliding block, and the screw rod sliding block is screwed and matched with a vertical screw rod; the upper end and the lower end of the vertical screw rod are respectively rotatably supported through a screw rod mounting seat assembly and fixedly mounted on the vertical inner side wall of one of the vertical mounting side plate bodies; the power input end at the top end of the vertical screw rod is coaxially and fixedly connected with a Z-direction vertical speed reducing motor, and the Z-direction vertical speed reducing motor is fixedly installed by taking the top of the inner side wall of a vertical plate body of one vertical installation side plate as a support; the Z-direction vertical speed reducing motor drives the vertical screw rod to rotate so as to realize vertical displacement of the screw rod sliding block, and the screw rod sliding block is fixedly connected with a plate body at one end of the L-shaped adapter plate; the plate body at the other end of the L-shaped adapter plate is fixedly connected with the back side of the vertical substrate; a grinding mechanism is fixedly arranged on the front surface of the vertical substrate plate body; the Z-axis vertical speed reducing motor drives the vertical substrate to drive the grinding mechanism to vertically displace in the Z direction relative to the front and rear vertical installation side plates; in addition, the outer sides of the front and rear vertical installation side plate bodies are fixedly connected with the vertical inner side wall of the X-direction rack horizontal right end plate body into a whole.

Among the above-mentioned technical scheme, in order to solve the tight function that rises of abrasive band on the coping mechanism, the technical problem that the convenient change function of abrasive band realized, further: the triangular grinding mechanism is provided with a driving wheel, an adjusting wheel and a grinding wheel, wherein the driving wheel, the adjusting wheel and the grinding wheel are used for tensioning and wrapping the abrasive belt outside and are distributed in a triangular shape on the outer side of the vertical substrate; wherein the grinding wheel is arranged below the driving wheel and the adjusting wheel; the polishing wheel is driven by a Z-direction three-axis cylinder to realize linear tensioning displacement adjustment of the polishing wheel in the Z-axis direction; the adjusting wheel adjusts the pitch angle of the adjusting wheel in the horizontal axial direction by rotating the hand wheel so as to prevent the abrasive belt from deviating.

In the technical scheme, in order to realize the function of correcting the abrasive belt on the grinding mechanism: the adjusting wheel body supports the wheel body to rotate on the adjusting wheel shaft at a high speed through a plurality of groups of ball bearings I and bearing holes by using check rings; one end of the adjusting wheel shaft is rotatably connected with the adjusting wheel frame through a cylindrical pin; the other end of the adjusting wheel shaft is connected with the output end of the joint bearing; the input end of the joint bearing is connected with a vertical linear displacement executing end of a screw pair of a screw nut consisting of a nut, a bolt and a hand wheel; one end of the adjusting wheel shaft is pushed to rotate around a hinge point of a cylindrical pin at the other end of the adjusting wheel shaft in a pitching manner by rotating a hand wheel through the transmission of a nut bolt, a screw rod and a screw pair so as to prevent an abrasive belt outside the adjusting wheel body from deviating.

Among the above-mentioned technical scheme, for the quick replacement and the installation technical problem of grinding wheel when solving grinding wheel wearing and tearing back influence precision on the coping mechanism, further: the grinding wheel is coaxially and rotatably supported at a high speed by a plurality of groups of ball bearings II, hole check rings and shaft end covers and is arranged in the middle of the grinding wheel shaft body; the two axial ends of the polishing wheel shaft body are respectively clamped and clamped by using wheel shaft grooves which are symmetrically formed in the upper and lower mounting frames up and down by using lower fastening bolts which vertically penetrate through the shaft body, so that the polishing wheel shaft can be detachably, horizontally and fixedly mounted in the wheel shaft grooves of the upper and lower mounting frame bodies; the upper and lower mounting frames are composed of an inverted U-shaped upper mounting frame and a pair of lower mounting frame clamping plate bodies; the horizontal top of the outer side of the upper mounting frame is fixedly connected with the execution tail end of the Z-direction three-axis cylinder; wherein the Z-direction triaxial cylinder is fixedly installed by taking a plate body outside the vertical substrate as a carrier; the outer side of the Z-direction triaxial cylinder body is fixedly supported and provided with a laser contourgraph through a contourgraph mounting seat; the outer circumference of the wheel body of the grinding wheel is also provided with a rubber layer.

Among the above-mentioned technical scheme, for further promoting triangle grinding machanism and carry the bistrique in the lifting precision of Z to mechanical lift, further: and an upper limit proximity switch, a zero point proximity switch and a lower limit proximity switch which are just opposite to the detection of the vertical guide rail slide block are fixedly arranged on the inner side of one of the front and rear vertical mounting side plates.

In the above technical solution, further: the triangular grinding mechanism is provided with a Z-direction vertical speed reducing motor; a motor shield used for hiding the motor installation is arranged on the outer side of the Z-direction vertical speed reducing motor; the triangular grinding mechanism is provided with an external tensioning wrapping abrasive belt, a driving wheel, an adjusting wheel and a grinding wheel which are distributed in a triangular shape; wherein, the upside of the outer sides of the driving wheel and the adjusting wheel at the upper part is provided with a grinding head protective cover which is reversely buckled.

Compared with the prior art: the invention designs an automatic grinding robot for the weld of the pipe end of a straight weld steel pipe, which can fixedly install the platform at the execution end of a manipulator; adopting abrasive belt grinding with higher grinding ratio to replace grinding wheel grinding; the abrasive belt grinding type Z-direction straight weld grinding platform reciprocates along a planned circular arc track in a direction perpendicular to the weld joint, and is subjected to multi-pass grinding in a grinding mode of line contact between the abrasive belt in the width direction and the weld joint, so that the grinding ratio is improved, the motion control of a manipulator is simplified, and the grinding precision of the weld joint is improved; the technical problems of high precision, high reliability, automatic identification and automatic grinding aiming at the straight welding seam with certain axial depth at the end of the straight welding seam steel pipe and without damaging the parent metal are solved; the abrasive belt grinding type Z-direction straight weld grinding platform has a Z-direction lifting adjusting function to correct the deviation, so that the grinding precision is improved, and the motion control is simplified; the abrasive belt of the triangular grinding mechanism in the platform has a tensioning adjusting function and an abrasive belt deviation rectifying function; the abrasive belt is simple and convenient to replace and maintain; the requirements of high precision, high efficiency, high reliability and automatic polishing of straight welding seams at the ends of the steel pipes are completely met.

Compared with the prior art, the invention has the following advantages:

1. according to the scheme, the Z-direction straight weld grinding platform is mounted at the execution end of the manipulator, and the manipulator directly carries a grinding wheel for grinding; on one hand, the technical problems that polishing precision is limited due to limited manipulator track planning precision and manual secondary polishing is still needed are solved, and high-precision polishing is realized; on the other hand, the Z-direction straight weld grinding platform adopts an abrasive belt triangular grinding mechanism 3-3 to replace a grinding wheel for grinding, so that the grinding precision is higher and the grinding ratio is more efficient; meanwhile, the grinding head can be prevented from damaging the base metal to the maximum extent;

2. according to the scheme, the abrasive belt is in line contact with the welding line, and compared with a polishing mode that the abrasive wheel is in point contact with the welding line; the grinding ratio of the abrasive belt grinding instead of the grinding wheel grinding is improved by 4-10 times, the production efficiency is high, the replacement cost is low, and the power utilization rate of a machine tool is high;

3. according to the scheme, the triangular polishing mechanism 3-3 adopts pneumatic vertical tensioning to adjust the height of the polishing wheel; a hand wheel is adopted to adjust an abrasive belt of an adjusting wheel to prevent the abrasive belt from deviating; the structure is compact, and the transmission is stable; the abrasive belt is easy and convenient to replace;

4. according to the scheme, the adjusting wheel is pushed by the hand wheel 331 to rotate around a hinge point of the cylindrical pin 338 at the other end of the adjusting wheel shaft 332 by rotating the hand wheel 331; preventing the abrasive belt 3-303 from deviating; the structure is simple, the adjustment is convenient, and the device is economical and practical;

5. in the scheme, the grinding wheel shaft is clamped, horizontally and fixedly installed by upper and lower mounting frames (3201 and 3203); the grinding wheel is rotatably mounted on a grinding wheel shaft at a high speed through a ball bearing II 3206 of a hole-bearing retainer ring 3207 and a shaft end cover 3208; the polishing wheel is convenient and convenient to disassemble, install and replace; the maintenance in the later period is facilitated; the structure is supported stably and reliably;

6. according to the scheme, the transmission of the Z-direction straight weld grinding platform 3 is precise, stable and reliable; the double-guide supporting structure of the double-slide rail and the slide block act together; the requirements of accurate, stable and reliable polishing displacement adjustment of the Z-direction straight weld grinding platform can be met;

7. according to the scheme, the hollowed-out aluminum alloy flange mounting frame 3-1 and the X-direction rack 3-2 are fixedly connected with the multi-degree-of-freedom manipulator, so that the lightweight, reliable and stable carrying of the manipulator execution end is realized; the motor protective cover and the grinding head protective cover act together; the appearance is beautiful, the protection performance is excellent, and the support is stable and reliable; the universality of the integrated installation of the Z-direction straight weld grinding platform 4 and the execution end of the multi-degree-of-freedom manipulator is ideal; not only can the outer straight welding line be polished; the X-direction frame 3-2 can also enable the triangular polishing mechanism 3-3 to extend into the opening of the steel pipe, so that polishing of a straight welding seam in the steel pipe is met;

8. in the scheme, a Z-direction straight weld grinding platform 3 cooperates with an upper limit proximity switch, a lower limit proximity switch and a zero point proximity switch; reliable guarantee is provided for high-precision finish grinding; the residual height of the welded seam after grinding can be controlled within 0-0.3 mm; is far higher than the requirements of API Spec5L standard and GBT 97111-1997 standard;

9. according to the scheme, the laser contourgraph 2 is fixed at the bottom of the outer side of the triangular polishing mechanism; reliable guarantee is provided for the accuracy and timeliness of data acquisition; the method does not need complex cloud computing, and has the advantages of high precision, high strength, intelligent detection, real-time feedback, high response speed and the like.

Drawings

FIG. 1 is a perspective view of the robotic arm of the present invention in an operative condition;

FIG. 2 is a perspective view of the robot assembly of FIG. 1;

FIG. 3 is a rear elevational view of the triangular grinding mechanism 3-3;

FIG. 4 is a rear perspective view of the triangular sanding mechanism;

FIG. 5 is a front right side perspective view of the triangular sanding mechanism;

FIG. 6 is a front left side perspective view of the triangular sanding mechanism;

FIG. 7 is an adjustment schematic of a hand wheel adjustment mechanism of the adjustment wheel;

FIG. 8 is a front view of a hand wheel adjustment mechanism for an adjustment wheel;

FIG. 9 is a perspective view of a hand wheel adjustment mechanism of the adjustment wheel;

FIG. 10 is a front view of a cylinder tensioning principle of a grinding wheel in the triangular grinding mechanism;

FIG. 11 is a front view of the grinding wheel with the three-axis cylinder portion removed;

FIG. 12 is a cross-sectional view of the mounting structure for the grinding wheel and grinding hub of FIG. 11;

FIG. 13 is a perspective view of the grinding wheel of FIG. 11 with the three-axis cylinder portion removed;

FIG. 14 is a rear view of the triangular sanding mechanism with proximity switches installed;

FIG. 15 is a perspective view of a Z-direction straight weld grinding table;

FIG. 16 is a front view of a Z-direction straight weld grinding table;

FIG. 17 is a diagram of a grinding wheel belt following a planned circular arc trajectory

Grinding the top view of the straight welding line at the 12 point position of the steel pipe in multiple passes;

FIG. 18 is a flow chart of a straight weld grinding process of the present invention;

FIG. 19 is a wiring diagram of a control circuit of the Z-direction vertical deceleration motor of the present invention;

FIG. 20 is a three-dimensional trajectory coordinate diagram of the laser profiler walking along a planned circular arc trajectory in accordance with the present invention;

FIG. 21 is a two-dimensional trajectory coordinate diagram of the laser profiler walking along a planned circular arc trajectory in accordance with the present invention;

FIG. 22 is a three-dimensional trajectory coordinate graph of the laser profiler planning circular arc trajectory walking scanning tracking straight weld;

FIG. 23 is a two-dimensional coordinate diagram of weld reinforcement data fitted by a one-pass circular arc fitting data after a straight weld is scanned and tracked by a laser profiler;

FIG. 24 is a three-dimensional view of a straight weld simulation image of the laser profiler scanning tracking straight weld of FIG. 22;

FIG. 25 is a two-dimensional coordinate graph of weld reinforcement data after a certain pass of straight weld grinding;

fig. 26 is a three-dimensional view of the simulated imaging of fig. 25.

Detailed Description

Specific embodiments of the invention are described below in conjunction with fig. 1-26. It is to be understood that the following description of the embodiments is merely exemplary and not intended to limit the invention in any way.

The following examples are given to facilitate a better understanding of the invention, but do not limit the invention. The experimental procedures in the following examples are conventional unless otherwise specified. The components and materials used in the following examples are commercially available unless otherwise specified. The control circuit in the following embodiments is implemented in a conventional control manner unless otherwise specified.

In the present invention, without going to the contrary, it is understood that: the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings for ease of description and simplicity of description only, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that the terms "mounted," "connected," "disposed," and "provided" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected unless otherwise explicitly stated or limited. For example, they may be directly connected to each other or indirectly connected to each other through other intermediate members. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The automatic grinding robot for the weld of the pipe end of the straight weld steel pipe is provided with a Z-direction straight weld grinding platform 3 which is fixedly connected with an execution end of a multi-degree-of-freedom manipulator 1 and is used for grinding by adopting an abrasive belt, wherein the Z-direction straight weld grinding platform 3 consists of a flange mounting frame 3-1, an X-direction rack 3-2 and a triangular grinding mechanism 3-3 which vertically ascends and descends in the Z direction relative to the X-direction rack 3-2 (as shown in figure 1, figure 2, figure 15 and figure 16). The flange mounting rack 3-1 is in a spatial three-dimensional hollow right-angled triangle structure; the top end face of one horizontal right-angle side is fixedly connected with the execution tail end of the six-degree-of-freedom manipulator 1 into a whole on the horizontal plane through a horizontal flange 3-11, and the other vertical right-angle side is fixedly connected with the horizontal left end of the X-direction rack 3-2 into a whole; the horizontal right end of the X-direction rack 3-2 is provided with a triangular polishing mechanism 3-3 which vertically ascends and descends in the Z direction relative to the X-direction rack 3-2; the laser contourgraph 2 is fixedly installed at the bottom of the outer side of the horizontal right end of the triangular polishing mechanism 3-3; the flange mounting rack 3-1 and the X-direction rack 3-2 are made of aluminum alloy.

Firstly, the horizontal right-end triangular polishing mechanism 3-3 of the X-direction frame 3-2 is arranged to finish the polishing use requirements of the outer straight weld joint and the inner straight weld joint of the steel pipe, and meanwhile, the motion control of the mechanical arm track planning is simplified. Thereby the Z-direction straight weld grinding platform 3 can be directly extended into the inner side of the pipe end orifice of the steel pipe. Secondly, the Z-direction straight weld grinding platform 3 is light and beautiful; the connection and the support with the multi-degree-of-freedom manipulator are reliable and stable; and the universal assembly and installation can be realized with the multi-freedom-degree manipulator.

On the basis of the above embodiment, (as shown in fig. 3 and 4) the triangular grinding mechanism 3-3 includes a pair of front and rear vertical installation side plates 301, wherein a pair of vertical slide rails 302 are respectively vertically and symmetrically installed on the inner side plates of the front and rear vertical installation side plates 301 in parallel, the vertical slide rails 302 are respectively matched with a pair of vertical guide rail sliders 303 in a sliding manner, and the outer sides of the pair of vertical guide rail sliders 303 are fixedly connected with the back sides of the vertical base plates 309; so as to drive the vertical base plate 309 to vertically displace along the vertical slide rail 302 along with the guide rail slide block 303; the inner side of one of the vertical guide rail sliding blocks 303 is fixedly connected with a screw rod sliding block 304, and the screw rod sliding block 304 is screwed and matched with a vertical screw rod 305; the upper end and the lower end of the vertical screw 305 are rotatably supported and fixedly mounted on the vertical inner side wall of one of the vertical mounting side plates 301 through a screw mounting seat assembly 306 respectively; the power input end at the top end of the vertical screw 305 is coaxially and fixedly connected with a Z-direction vertical speed reducing motor 3-302, and the Z-direction vertical speed reducing motor 3-302 is fixedly installed by taking the top of the inner side wall of a vertical plate body of a vertical installation side plate 301 as a support; the Z-direction vertical speed reducing motor 3-302 drives the vertical screw rod 305 to rotate to realize the vertical displacement of the screw rod sliding block 304, and the screw rod sliding block 304 is fixedly connected with a plate body at one end of the L-shaped adapter plate 308; the plate body at the other end of the L-shaped adapter plate 308 is fixedly connected with the back side of the vertical base plate 309, so that the vertical base plate 309 is driven to vertically displace through the L-shaped adapter plate 308 by the vertical displacement of the screw rod sliding block 304; then a pair of vertical guide rail sliding blocks 303 fixedly connected with the back of the plate body of the vertical base plate 309 support the vertical base plate 309 to vertically move along a pair of vertical sliding rails 302 in a double-sliding mode; a grinding mechanism is fixedly arranged on the front surface of the plate body of the vertical substrate 309; the Z-axis vertical speed reducing motors 3-302 drive the vertical base plate 309 to drive the coping mechanism to vertically displace in the Z direction relative to the front and rear vertical mounting side plates 301; in addition, the outer sides of the plate bodies of the front and rear vertical installation side plates 301 are fixedly connected with the vertical inner side walls of the plate bodies at the right end of the X-direction rack 3-2.

When in use: firstly, the front and rear vertical mounting side plates 301 are used for fixedly supporting and mounting the triangular grinding mechanism 3-3 by taking the X-direction frame 3-2 of the Z-direction straight weld grinding platform 3 as a carrier. Secondly, the realization of Z direction height control function in the triangle grinding mechanism 3-3: adopt two slide rail sliders, two slide rail sliders provide the straight line direction on the one hand, and on the other hand plays the effect of bearing. The conversion from rotary motion to linear motion is realized through a screw pair of a screw rod nut; the vertical transmission displacement is stable, reliable, precise and efficient; and reliable guarantee is provided for the Z-direction high-precision linear displacement of the grinding head in the Z-direction straight weld grinding platform 3. The use requirement for realizing the Z-direction polishing height linear displacement adjusting function of the Z-direction straight weld grinding platform 3 can be met accurately, stably and reliably.

On the basis of the above embodiment: (as shown in fig. 5 and 6), the triangular grinding mechanism 3-3 comprises a driving wheel 31, an adjusting wheel 33 and a grinding wheel 32, wherein the driving wheel 31, the adjusting wheel 33 and the grinding wheel 32 are externally tensioned to wrap the abrasive belt 3-303 and are distributed in a triangular shape on the outer side of a vertical base plate 309; wherein the grinding wheel 32 is arranged below the driving wheel 31 and the adjusting wheel 33; the grinding wheel 32 is driven by a Z-direction three-axis cylinder 321 to realize the linear tensioning displacement adjustment of the grinding wheel 32 in the Z-axis direction; the adjusting wheel 33 adjusts the pitch angle of the adjusting wheel 33 in the horizontal axial direction by rotating the hand wheel 331 so as to prevent the abrasive belt 3-303 from deviating. Linearly grinding the axial straight weld of the steel pipe in a linear contact mode of EF abrasive belt width d as shown in figure 17 through the abrasive belts 3-303 which are tensioned in a triangular shape and rotate at high speed in the vertical direction; the grinding and polishing with high grinding ratio, high efficiency and high equipment utilization rate are realized. And the realization of the abrasive belt tensioning function and the abrasive belt deviation rectifying and adjusting function is realized.

When in use: the abrasive belt 3-303 is adopted for grinding instead of grinding by using an abrasive wheel, and compared with grinding by using an abrasive wheel, the grinding ratio of the abrasive belt 3-303 is 4-10 times of that of the abrasive wheel, so that the abrasive belt 3-303 has the advantages of high productivity, low replacement cost and high machine tool power utilization rate. The abrasive belt grinding wheel set of the grinding mechanism consists of a grinding wheel with pneumatic tension adjusting function, a driving wheel driven by a motor to rotate and an adjusting wheel with deviation rectifying adjusting function which are distributed in a triangular manner; the structure is compact, and the transmission is stable; when the abrasive belt is replaced, the abrasive belt is easily disassembled by retracting the piston rod of the three-shaft cylinder; the abrasive belt is easy and convenient to replace.

On the basis of the above embodiment: further: in order to realize the function of correcting and adjusting the abrasive belt, the wheel body of the adjusting wheel 33 supports the wheel body to rotate at a high speed on the adjusting wheel shaft 332 (as shown in fig. 7) through a plurality of groups of ball bearings I337 and bearing holes by using check rings 333; one end of the adjusting wheel shaft 332 is rotatably connected with an adjusting wheel frame 339 through a cylindrical pin 338; the other end of the adjusting wheel shaft 332 is connected with the output end of a joint bearing 336; the input end of the knuckle bearing 336 is connected with the vertical linear displacement executing end of a screw pair of a screw nut consisting of a nut 335, a bolt 334 and a hand wheel 331 (as shown in figure 7); for the adjustment wheel frame 339, it should be noted that: the adjusting wheel frame 339 comprises a first adjusting wheel frame (shown in figures 8 and 9) which is vertically supported by a hand wheel 331, a nut 335 and a bolt 334 and is mounted by a joint bearing 336, and also comprises a second adjusting wheel frame (shown in figures 7 and 9) which is vertically and parallelly fixedly connected with the first adjusting wheel frame into a whole; the top end of the vertical plate body of the second adjusting wheel frame is provided with a groove; the groove side plate is hinged and rotatably connected with the hinged end of the adjusting wheel shaft 332 through a cylindrical pin 338; the other end of the adjustment wheel shaft 332 is fixedly connected with the output end of a knuckle bearing 336 supported and mounted on the first adjustment wheel frame, so that the right end of the adjustment wheel shaft 332 is pushed along with the output end of the knuckle bearing to rotate around the hinge point of the left end adjustment wheel shaft 332 as shown in fig. 7 to realize pitch adjustment of the adjustment wheel shaft 332; further adjusting the pitch angle of the horizontal installation of the adjusting wheel on the adjusting wheel shaft 332; thereby adjusting the position of sanding belt 3-303 towards the inside or the outside in the direction shown in fig. 6; the abrasive belt is prevented from deviating.

When in use: (as shown in fig. 7), the hand wheel 331 is rotated, the lead screw and nut screw pair transmission is carried out through the nut 335 and the bolt 334, the pushing knuckle bearing 336 acts, and then the adjusting wheel shaft 332 is pushed through the output end of the pushing knuckle bearing 336 to rotate around the hinge point of the cylindrical pin 338 at the left end of the adjusting wheel shaft 332 in a pitching mode in the direction shown in fig. 7; so as to prevent the abrasive belts 3-303 outside the wheel body of the adjusting wheel 33 from deviating.

On the basis of the above embodiment, in order to realize the function of tensioning and adjusting the abrasive belt by the grinding wheel 32; meanwhile, the abrasive belt is convenient to replace; and the grinding wheel bearing is convenient to replace. (see fig. 10, 11, 12 and 13), the grinding wheel 32 is coaxially and rotatably supported at high speed on the middle part of the body of the grinding wheel shaft 3202 (see fig. 12) through a plurality of groups of ball bearings ii 3206, a hole retainer 3207 and a shaft end cover 3208; regarding the principle of quick and convenient disassembly and assembly between the ball bearing ii 3206 and the grinding wheel 32 and the grinding wheel shaft 3202, it should be noted that: (as shown in fig. 12), the shaft end cover 3208 is used for axially pressing a bearing outer ring of the ball bearing ii 3206 and coaxially and fixedly connecting the bearing outer ring of the ball bearing ii 3206 and the grinding wheel into a whole, so that the shaft end cover 3208 is conveniently disassembled, and the ball bearing ii 3206 is disassembled; one end of the polishing wheel shaft 3202 is an optical shaft, and the other end is a step shaft; the inner side end face of the boss of the step shaft is used for limiting and axially pressing a bearing inner ring of the right ball bearing II 3206, and the bearing inner ring of the right ball bearing II 3206 and the grinding wheel shaft 3202 are axially pressed and fixedly connected into a whole by using a right shaft end cover 3208 in the direction shown in fig. 12 to form the grinding wheel shaft 3202 and the bearing inner ring of the ball bearing II 3206. Similarly, on one hand, the left shaft end cover 3208 compresses and coaxially fixedly connects the bearing inner ring of the ball bearing II 3206 on the left side of the grinding wheel shaft 3202 and the grinding wheel shaft 3202 into a whole; on the other hand, the left shaft end cover 3208 compresses the bearing outer ring of the ball bearing II 3206 and the wheel body of the grinding wheel 32 axially through another compression ring arranged on the inner side wall of the cover body, and the bearing outer ring and the wheel body are coaxially and fixedly connected into a whole. The functions of quick mounting and dismounting of the whole grinding wheel shaft and the grinding wheel rotating assembly are realized: (see fig. 12) the axial ends of the body of grinding wheel axle 3202 are clamped by upper and lower fastening bolts 3205 vertically penetrating through the body respectively and using wheel axle grooves 3204 (combination 11) formed by upper and lower mounting

frames

3201, 3203 in up-and-down symmetry to clamp the body of the grinding wheel axle 3202 at the two ends of the body of the grinding wheel axle 3202, so that the grinding wheel axle 3202 can be detachably, horizontally and fixedly mounted in the wheel axle grooves 3204 of the upper and lower mounting frames (3201, 3203) (see fig. 12), and the grinding wheel rotating assembly on the grinding wheel axle is integrally dismounted by dismounting the lower fastening bolts 3205. furthermore, in order to realize the tensioning adjustment and loosening adjustment functions of the abrasive belts 3-303 wrapped around the body of the grinding wheel assembly integrally including the upper and lower mounting frames (3201, 3203), the upper and lower mounting frames (3201, 3203) are composed of an inverted U-shaped upper mounting frame 3201 and a pair of lower mounting frame 3203 clamping plates, wherein the horizontal top (see fig. 13) outside the upper mounting frame 3201 is fixedly connected with the end of the Z-performing end (see fig. 13) 10) (ii) a Wherein the Z-direction triaxial cylinder 321 is fixedly mounted by taking a plate body outside the vertical base plate 309 as a carrier; the laser profiler 2 is fixedly supported and installed on the outer side of the cylinder body of the Z-direction triaxial cylinder 321 through a profiler installation seat 201 (shown in FIG. 6); the contourgraph mounting base 201 is fixedly connected with the cylinder body of the Z-direction triaxial cylinder 321 into a whole. The contourgraph mounting base 201 is a block structure provided with fastening screw holes; the outer circumference of the wheel body of the grinding wheel 32 is also provided with a rubber layer; the service life of the grinding wheel is prolonged on one hand through the arrangement of the rubber layer; on the other hand, the frictional resistance of the grinding wheel to the abrasive belt is increased.

When in use: the upper mounting frame 3201 and the lower mounting frame 3203 clamp and horizontally fix and mount the grinding wheel shaft 3202; and a grinding wheel 32 is coaxially and rotatably supported and mounted on the grinding wheel shaft 3202 through a ball bearing II 3206. The installation structure makes the polishing wheel firmly installed; the wheel body supporting structure is stable and reliable; the grinding wheel, the grinding wheel shaft assembly comprising the ball bearing II 3206, the hole retainer ring 3207 and the shaft end cover 3208 can be conveniently and quickly assembled, disassembled and installed; the maintenance is convenient; the structure is stable and reliable; and the maintenance is easy.

On the basis of the above embodiment: an upper limit proximity switch 91, a zero point proximity switch 92 and a lower limit proximity switch 93 which are detected by a vertical guide rail slide block 303 are fixedly arranged on the inner side of one of the front and rear vertical installation side plates 301 (as shown in figure 14). Through the arrangement of the limit and zero proximity switches, the positioning accuracy of the grinding mechanism relative to the front and rear vertical installation side plates 301 of the PLC-controlled triangular grinding mechanism 3-3 in the Z-direction vertical displacement motion is improved, and further the grinding accuracy is improved. The residual height of the welded seam after grinding can be controlled within +0-0.3 mm; is far higher than the requirements of API Spec5L standard and GBT 97111-1997 standard.

On the basis of the above embodiment: (see fig. 15 and 16) the triangular grinding mechanism 3-3 is provided with a Z-direction vertical speed reducing motor 3-302; a motor shield 3-21 for hiding an aluminum alloy skin structure for motor installation is arranged on the outer side of the Z-direction vertical speed reduction motor 3-302; the triangular grinding mechanism 3-3 is provided with an external tensioning wrapping abrasive belt 3-303, a driving wheel 31, an adjusting wheel 33 and a grinding wheel 32 which are distributed in a triangular shape; wherein the grinding wheel 32 is arranged at the bottommost part; the upside of the outer sides of the driving wheel 31 and the adjusting wheel 33 above the grinding wheel 32 is provided with inverted aluminum alloy grinding head shields 3-22; the grinding head protective cover can be fixedly connected with the top of the plate body on the outer side of the vertical base plate 309 into a whole in a welding mode; and the grinding head protective cover is of an inverted arc structure. In addition, the laser contourgraph 2 is fixedly connected with a supporting structure of a grinding wheel 32 at the bottom end of the grinding mechanism into a whole and moves along with the grinding mechanism; and reliable guarantee is provided for the accuracy and timeliness of the near-end scanning data acquisition.

The working principle of the invention is as follows: the robot manipulator integrally comprises a mechanical arm 1 and an abrasive belt grinding type Z-direction straight weld grinding platform 3; the Z-direction straight weld grinding platform 3 is provided with a high-precision laser contourgraph, identifies and tracks the pipe end straight weld through a self-developed visual detection algorithm, and provides data support for the vertical feeding linear displacement of the Z-direction speed reduction motor in the grinding process. And the Z-direction straight weld grinding platform 3 and the PLC establish full closed-loop position control. The tracking of the straight welding line is carried out by the mechanical arm 1 in a circular arc track motion, and multiple tracking scanning of the straight welding line is realized by cooperating with the axial feeding displacement of the mechanical arm if necessary so as to meet the full scanning coverage of the straight welding line with the length of L; after scanning is finished, calculating a grinding pass N according to the grinding length L and the width d of the grinding belt; realizing successive grinding of N times; and when polishing is carried out in each pass, the grinding head guides the Z-direction speed reducing motor to accurately grind the weld reinforcement according to the recorded weld reinforcement, so that accurate grinding operation of the inner weld joint and the outer weld joint of the welded pipe with the straight weld joint is completed.

From the above description it can be found that: according to the invention, the Z-direction straight weld grinding platform is arranged at the execution end of the manipulator, so that the manipulator directly carries a grinding wheel for grinding; on one hand, the technical problems that polishing precision is limited due to limited manipulator track planning precision and manual secondary polishing is still needed are solved, and high-precision polishing is realized; on the other hand, the Z-direction straight weld grinding platform adopts the abrasive belt triangular grinding mechanism 3-3 to replace a grinding wheel for grinding, so that the grinding precision is higher, and the grinding head can be prevented from damaging the base metal to the maximum extent. The abrasive belt is in line contact with the welding line, and compared with a grinding mode that the grinding wheel is in point contact with the welding line, the abrasive belt is in line contact with the welding line; the abrasive belt grinding is adopted to replace the grinding wheel grinding ratio, the productivity is improved by 4-10 times, the replacement cost is low, and the machine tool power utilization rate is high. According to the triangular polishing mechanism 3-3, the height of a polishing wheel is adjusted by pneumatic vertical tensioning; a hand wheel is adopted to adjust an abrasive belt of an adjusting wheel to prevent the abrasive belt from deviating; the structure is compact, and the transmission is stable; the abrasive belt is simple and convenient to replace. According to the invention, the adjusting wheel is pushed by the hand wheel 331 to rotate around the hinge point of the cylindrical pin 338 at the other end of the adjusting wheel shaft 332 by rotating the hand wheel 331; preventing the abrasive belt 3-303 from deviating; simple structure, convenient adjustment, economy and practicality. The grinding wheel shaft is clamped, horizontally and fixedly installed by upper and lower mounting frames (3201 and 3203); the grinding wheel is rotatably mounted on a grinding wheel shaft at a high speed through a ball bearing II 3206 of a hole-bearing retainer ring 3207 and a shaft end cover 3208; the polishing wheel is convenient and convenient to disassemble, install and replace; the maintenance in the later period is facilitated; the structure is supported stably and reliably. The Z-direction straight weld grinding platform 3 is precise, stable and reliable in transmission; the double-guide supporting structure of the double-slide rail and the slide block act together; the requirements of accurate, stable and reliable polishing displacement adjustment of the Z-direction straight weld grinding platform can be met. The hollow aluminum alloy flange mounting frame 3-1 and the X-direction frame 3-2 are fixedly connected with the multi-degree-of-freedom manipulator, so that the lightweight, reliable and stable carrying of the manipulator execution end is realized; the motor protective cover and the grinding head protective cover act together; the appearance is beautiful, the protection performance is excellent, and the support is stable and reliable; the universality of the integrated installation of the Z-direction straight weld grinding platform 4 and the execution end of the multi-degree-of-freedom manipulator is ideal; not only can the outer straight welding line be polished; the triangular polishing mechanism 3-3 can also extend into the opening of the steel pipe in the X-direction frame 3-2, so that the polishing use of a straight welding seam in the steel pipe is met. The Z-direction straight weld grinding platform 3 of the invention cooperates with an upper limit proximity switch and a lower limit proximity switch and a zero point proximity switch to act together; reliable guarantee is provided for high-precision finish grinding; the residual height of the welded seam after grinding can be controlled within 0-0.3 mm; is far higher than the requirements of API Spec5L standard and GBT 97111-1997 standard. According to the scheme, the laser contourgraph 2 is fixed at the bottom of the outer side of the triangular polishing mechanism; reliable guarantee is provided for the accuracy and timeliness of data acquisition; the method does not need complex cloud computing, and has the advantages of high precision, high strength, intelligent detection, real-time feedback, high response speed and the like.

In addition, with respect to the coping method using the automatic coping robot for the pipe end weld of the straight welded steel pipe according to the present invention, (see fig. 1 in combination with fig. 18), the technique described herein is also described in each flowchart. For ease of discussion, certain operations are described in these flowcharts as different constituent steps performed in a particular order. These implementations are exemplary and not limiting. Certain operations may be grouped together and performed in a single operation, and certain operations may be performed in an order different than employed in the examples described in this disclosure.

The method comprises the following steps:

step S001, determining the position of the steel pipe: the automatic grinding robot for the weld at the pipe end of the straight weld steel pipe comprises an upper computer, a PLC, a motion control card, a mechanical arm 1, a non-contact laser contourgraph 2 and a Z-direction straight weld grinding platform 3; inputting the diameter of the steel pipe into an upper computer, namely a computer, of the automatic grinding robot for the weld at the end of the straight weld steel pipe, and providing a basis for the height of a mechanical arm; the upper computer controls the mechanical arm 1, the Z-direction straight weld grinding platform 3 fixedly carried by the executing end of the mechanical arm 1 moves to an initial position, namely a position with a certain height above the steel pipe, and the laser profiler 2 scans to determine the position of the detected steel pipe; the laser profiler 2 is fixedly installed on the outer side of the lower part of the platform by taking a Z-direction straight weld grinding platform 3 as a carrier;

it should be noted that: controlling a mechanical arm; MOTOCOM32 software is integrated in LABVIEW software, and the mechanical arm is controlled off-line to plan a proper circular arc track and move stably at a constant speed according to the grinding flow requirements. Except for parameter setting programs of the roller motor and the Z-direction speed reducing motor, all control programs are written and controlled by LABVIEW. The laser profiler selects a German iridium (scanning control) scanCONTROL2900/2950/2910 two-dimensional line laser profile scanning sensor for scanning so as to accurately acquire elevation data of the straight welding line and be used for establishing a straight welding line two-dimensional coordinate waveform diagram. The upper computer display has a graphical user interface which is developed and friendly by using LABVIEW, is used for controlling various instruments and equipment in real time, comprehensively displays information data including the diameter of the steel pipe, a two-dimensional oscillogram of a welding seam scanning result and the like, and is convenient for operators to master real-time conditions and operate and modify information such as the diameter of the steel pipe. The PLC is used for controlling the rotation of the steel pipe roller motor 4; and is also used for controlling the adjustment of the axial height of the Z-direction straight weld grinding platform 3; the motion control card is used for planning the motion trail of the mechanical arm.

Step S002, planning a trajectory: the mechanical arm 1 determines the translation motion of the detected position of the steel pipe from the position of a certain height right above the 12 point of the steel pipe according to the scanning of the laser profiler 2, namely the center of the steel pipe and the highest point of the steel pipe are obtained according to the calculation of the pipe diameter of the steel pipe, the upper computer records the coordinate information of the specific point and establishes a coordinate system of the steel pipe to be polished, so that the upper computer plans a concentric motion circular arc track of the constant height of the mechanical arm 1 around the outer circumferential surface of the steel pipe to be polished by a Motorman robot Motorom 32 component of the upper computer

(see fig. 20, 21);

step S003, pipe end searching: after the mechanical arm 1 carries the Z-direction straight weld grinding platform 3 and translates to a position right above the highest point 12 of the steel pipe, the mechanical arm 1 carries the Z-direction straight weld grinding platform 3 and translates along the axial direction of the steel pipe so as to find and position the end of the steel pipe; the method for identifying the end of the steel pipe comprises the following steps: if more than one third of the number of the laser points of the linear laser projected by the laser profiler 2 falls to the steel pipe, the mechanical arm 1 carries the Z-direction straight weld grinding platform 3 to stop moving axially, and the mechanical arm 1 finds the pipe end;

step S004, identifying the pipe end: the mechanical arm 1 carries the Z-direction straight weld grinding platform 3 to move to a position with a fixed concentric circle height above the steel pipe 11 point, and the position is stopped and positioned; carrying a Z-direction straight weld grinding platform 3 on the upper computer control mechanical arm 1, and axially translating to a grinding section which is deeper than the pipe end in the axial direction by a width d of an abrasive belt 3-303 by taking the height position point of the 11-point fixed concentric circle as a starting point to prepare for grinding of a straight weld at the pipe end welding seam starting end of the abrasive belt width in the first pass;

step S005, scanning start point: the PLC controls a roller motor 4 for driving the steel pipe to rotate to work, and the laser profiler 2 judges and searches a welding seam starting point according to laser points which are steeply increased on the outer surface of the steel pipe so as to determine a welding seam grinding starting point; after the welding line is found, the upper computer sends a signal for stopping the rotation of the roller motor 4 to the PLC, and the PLC controls the roller motor 4 to stop rotating; and the straight weld of the steel pipe is rotated to the position of 12 points of the steel pipe;

it should be noted that: the roller motor 4 lifts the steel pipe through the Y-shaped roller lifting mechanism, and the driving roller rotates through the driving of the driving roller fixedly connected with the power output shaft of the roller motor 4 (the position is referred to as a roller speed reduction motor) in the Y-shaped roller, and the driving roller shifts the steel pipe to rotate through the friction force between the driving roller body made of rubber and the outer circumferential side wall of the steel pipe. In addition, PLC can be according to steel pipe diameter data, 4 linear velocities of running roller motor to laser profile appearance 2 detects the steel pipe welding seam and is trigger signal when reaching 12 dot positions, triggers PLC control running roller motor 4 stall to rotate the steel pipe welding seam and stop to 12 dot positions department.

Step S006, establishing a user coordinate system: the mechanical arm 1 carries the Z-direction straight weld grinding platform 3 and moves to the direction of a point 12 of the steel pipe, and the upper computer reads the position information of the mechanical arm 1 at the highest point of the steel pipe and reads the coordinate of the point in a robot coordinate system; establishing a user coordinate system according to the diameter data of the steel pipe and the real-time height of the laser profiler 2 from the steel pipe;

it should be noted that: through the establishment of a user coordinate system, the motion control of the manipulator is simplified, and simultaneously: when polishing, the manipulator only needs to follow the planned circular arc track

Repeatedly reciprocating; when one pass is finished, the manipulator only needs to move horizontally by half the axial feeding displacement of the width d of the abrasive belt according to the axial depth of the steel pipe; namely, the motion control of the multi-degree-of-freedom manipulator only needs the alternate repetition of the two actions of axial feeding displacement and circular arc reciprocating motion, and the use requirement of the polishing planning track of the Z-direction straight weld grinding platform 3 can be met; moreover, by establishing a user coordinate system, on one hand, the motion control of the mechanical arm is simplified, and the reduction influence of polishing precision caused by the accumulation of motion errors of the mechanical arm is avoided; on the other hand, by establishing a user coordinate system and cooperating with the adjustment of the linear polishing height of the abrasive belt by the mechanical arm execution end Z-direction straight weld grinding platform 3, the accurate adjustment control of the normal lifting displacement of the Z-direction straight weld grinding platform 3 is achieved, and therefore the purpose of accurate polishing of straight welds in multiple passes is achieved.

Step S007, weld joint tracking scanning and tracking scanning end: an upper computer control mechanical arm 1 carries a Z-direction straight weld grinding platform 3 along a planning circular arc concentric with a steel pipe

Radial movement (as in fig. 20); meanwhile, the laser profiler 2 is fixedly carried by the Z-direction straight weld grinding platform 3, the laser profiler 2 emits linear laser CD (see figure 17 and combined with figure 22) which extends along the axial direction of the steel pipe in a fixed length, and the linear laser CD emitted by the laser profiler 2 is along a planning circular arc concentric with the steel pipe

While moving radially, the linear laser edge

And scanning the straight weld of the steel pipe by using the circular arc, acquiring the straight weld of the steel pipe according to a weld tracking algorithm, and dividing the straight weld into two-dimensional oscillogram characteristic data corresponding to each pass of the straight weld of a plurality of passes (see fig. 23).

It should be noted that: when the grinding length L of the straight welding seam of the pipe end is less than the length of the linear laser CD emitted by the laser profiler 2: the tracking scanning of the straight weld joint of the steel pipe can be completed only by one-time tracking scanning of the step S007; and when the grinding length L of the straight welding seam of the pipe end is larger than the length of the linear laser CD emitted by the laser profiler 2: after the first tracking scanning is finished, the mechanical arm 1 firstly carries the Z-direction straight weld grinding platform 3 and translates a distance of a laser axial linear length CD along the axial depth of the steel pipe; then, repeating the step S007 to finish the straight weld seam tracking scanning of the length of the linear laser CD emitted by the laser profiler 2 for the second time; repeating the operation of the step S007 after the mechanical arm 1 carries the Z-direction straight weld grinding platform 3 to translate one laser axial linear length CD along the axial depth of the steel pipe; and (4) tracking and tracking through multiple times of straight weld scanning, wherein the tracking and scanning are not finished until all straight welds with the length of L are scanned.

Step S008, position compensation: controlling the mechanical arm 1 to move relatively according to the fixed position difference between the laser profiler 2 and the grinding working point of the Z-direction straight weld grinding platform 3, so that the grinding working point of the Z-direction straight weld grinding platform 3 moves to the initial position of the laser profiler 2 for scanning the weld, and completing position compensation; through position compensation, a foundation is laid for accurate positioning of a linear working point of the grinding head in a user coordinate system;

step S009, first straight weld grinding: (as shown in FIG. 17) the upper computer controls a grinding head motor 3-301 of the Z-direction straight weld grinding platform 3 to start for grinding; the upper computer controls the mechanical arm 1 to follow a planning circular arc concentric with the steel pipe

Radial movement (see fig. 2)2) Meanwhile, the upper computer controls a Z-direction vertical speed reduction motor 3-302 of the Z-direction straight weld grinding platform 3 to scan the obtained weld height information according to the laser profiler 2 (as shown in fig. 23 in combination with fig. 17: the height is the weld coordinate of the highest point on the width d of the abrasive belt) to automatically adjust the Z-direction height of the triangular grinding mechanism 3-3, and precisely grinding the axial length straight weld of the shaft end with the width d of the abrasive belt 3-303 under the drive of a grinding head motor 3-301 (as shown in figure 17);

step S009, second pass straight weld grinding: the upper computer controls the mechanical arm 1 to follow a planning circular arc concentric with the steel pipe

Radially retreating and resetting to a point A, carrying out axial feed displacement (such as an abrasive belt at the position of a dotted line in FIG. 17) of half of the width d of an abrasive belt 3-303 along the axial feed of a steel pipe straight weld by a mechanical arm 1 after retreating and resetting to the point A, and carrying out axial feed displacement of a Z-direction straight weld grinding platform 3 along the axial feed of the steel pipe straight weld; the upper computer controls the mechanical arm 1 to follow a planning circular arc concentric with the steel pipe

Repeating the radial movement, automatically adjusting the Z-direction height of the triangular grinding mechanism 3-3 by a Z-direction vertical speed reducing motor 3-302 of the Z-direction straight weld grinding platform 3 according to the weld height information (in a combined figure 17, the height is half of the width d of the abrasive belt, namely the weld coordinate of the highest point of the axial straight weld on the rear half section of the abrasive belt) obtained by scanning of the laser contourgraph 2, and precisely grinding the axial straight weld of one half of the width d of the abrasive belt 3-303 under the driving of a grinding head motor 3-301;

it should be noted that: after the second pass of polishing is finished, the upper computer controls the mechanical arm 1 to follow a planning circular arc concentric with the steel pipe

Radially returning and resetting to the point A; after returning to the point A, the mechanical arm 1 carries the Z-direction straight weld grinding platform 3 to move by half the axial feed displacement of the width d of the abrasive belt 3-303 along the axial feed of the straight weld of the steel pipe; preparing grinding for the third pass;

step S010, grinding the straight welding seam of the Nth pass: each edge of the mechanical arm 1 is concentric with the steel pipeOf

Performing radial movement once, namely finishing Z-direction vertical lifting accurate grinding of a straight welding seam with the width d of one half of the abrasive belt 3-303 and the axial length d; namely, the process of step S009 is repeated;

step S011, finishing polishing: when the value of (N-1) × (d/2) + d is larger than the standard axial depth length L of the weld at the end of the steel pipe after the Nth-time straight weld is polished, N is the minimum natural number which meets the relational expression of (N-1) × (d/2) + d larger than L; and finishing grinding.

It should be noted that: regarding the grinding of the straight weld seam with the axial L length of the straight weld seam at the pipe end, when the diameter of the steel pipe and the width d of the abrasive belt are determined: and N is obtained by calculation. Calculation of grinding pass N: the relation between N and the axial depth L of the straight weld seam at the pipe end (the general depth length L corresponds to the diameter of the steel pipe) of the abrasive belt width d satisfies that: (N-1) (d/2) + d > L; and N is the smallest natural integer of (N-1) × (d/2) + d > L.

In the above embodiment, further: the laser profiler 2 seam tracking algorithm of the automatic straight-seam steel pipe end seam grinding robot in the step S007 comprises the following steps: the method comprises the steps of firstly, filtering acquired laser profilometer data; and (3) algorithm II: and (3) carrying out difference operation on the filtered data: and (3) algorithm III: determining left and right toe points of the welding line according to the difference operation result; and (4) algorithm four: performing arc fitting on the steel pipe data except for the left and right toe points; during arc fitting, the required grinding pass N is calculated according to the length L of a welding seam and the width d of an abrasive belt for fitting each pass; dividing the two-dimensional data of the straight welding seam with the length of L into N sections corresponding to the number of the grinding passes N along the axial direction according to the grinding passes N; then, arc fitting is carried out on the N sections of welding seam height data in a segmented mode; fifthly, taking arc fitting data as surplus height data of the welding seam; it should be noted that: and when the segmental arc fitting is used as the weld reinforcement data: taking the weld joint height coordinate of the highest point in the abrasive belt width d direction EF all the time in the abrasive belt width d direction of each section as the weld joint residual height data of abrasive belt linear grinding, and adjusting the grinding height of the grinding head according to the weld joint height coordinate of the highest point in the abrasive belt width d direction EF; and sixthly, taking the residual height data as Z-direction height feeding data of the grinding head of the Z-direction vertical speed reducing motor 3-302 adjusting triangular grinding mechanism 3-3 during weld grinding, and ending the algorithm. The mode of multi-pass grinding in a way of being perpendicular to the axial length direction of the welding seam in a way of multiple passes is adopted, so that on one hand, the motion control is simplified, and the grinding precision is improved; on the other hand, the grinding ratio is favorably improved, the grinding utilization rate of the grinding mechanism is improved, and the cost of grinding consumables is reduced.

In summary, the following steps: compared with the prior art, the invention has the greatest improvement that: the invention provides a robot for automatically grinding a weld joint at the end of a straight weld steel pipe, which comprises the following steps: installing a sand belt grinding type Z-direction straight weld grinding platform at the execution end of the manipulator; compared with the prior art: adopting abrasive belt grinding with higher grinding ratio to replace grinding wheel grinding; and the abrasive belt grinding type Z-direction straight weld grinding platform reciprocates along a planned circular arc track in a direction perpendicular to the weld joint to carry out multi-pass grinding; the abrasive belt rotating at high speed in the vertical plane and the axial straight welding are carried out in a line contact grinding mode as shown in figure 17; and finishing the accurate grinding of the straight welding line with certain axial depth by multi-pass grinding. The grinding ratio is improved, the motion control of the manipulator is simplified, and meanwhile, the Z-direction lifting adjusting function of the grinding head is carried by the Z-direction straight weld grinding platform, so that the grinding precision of the straight weld ground by the execution end of the multi-degree-of-freedom manipulator is improved; the technical problems of high precision, high reliability, automatic identification and automatic grinding are solved, and the straight welding seam with a certain axial depth at the end of the straight welding seam steel pipe does not damage a parent metal. Moreover, the abrasive belt of the triangular grinding mechanism in the abrasive belt grinding type Z-direction straight weld grinding platform has an abrasive belt tensioning adjusting function and an abrasive belt deviation rectifying function; the grinding ratio polishing efficiency is improved, and the cost of grinding consumables is reduced; the problems of convenient and simple maintenance, adjustment and replacement of the abrasive belt in the future are solved; the automatic grinding machine can completely meet the requirements of high-precision, high-efficiency and high-reliability automatic grinding of straight welding seams at the ends of steel pipes. The automatic polishing machine has the advantages of high precision, high reliability, intelligent detection, real-time feedback, high response speed, high polishing efficiency, high speed and the like. And can realize the polishing use of the straight welding seam in the pipe end.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

The above-mentioned embodiments are merely preferred embodiments of the present invention, and not intended to limit the scope of the invention, so that equivalent changes made by the claims of the present invention should be included in the claims of the present invention.

Claims

1. Automatic coping robot of straight welding seam steel pipe end welding seam, its characterized in that: the Z-direction straight weld grinding platform (3) is fixedly connected with the execution end of the multi-degree-of-freedom manipulator (1) and is polished by adopting an abrasive belt; the Z-direction straight weld grinding platform (3) consists of a flange mounting rack (3-1), an X-direction rack (3-2) and a sand belt type triangular grinding mechanism (3-3) which vertically ascends and descends in the Z direction relative to the X-direction rack (3-2); the flange mounting rack (3-1) is of a spatial three-dimensional hollow right-angled triangle structure; the top end face of one horizontal right-angle side is fixedly connected with the execution tail end of the six-degree-of-freedom manipulator (1) into a whole in the horizontal plane through a horizontal flange plate (3-11), and the other vertical right-angle side is fixedly connected with the horizontal left end of the X-direction rack (3-2) into a whole; a triangular grinding mechanism (3-3) which vertically ascends and descends in the Z direction relative to the X-direction rack (3-2) is arranged at the horizontal right end of the X-direction rack (3-2); the laser contourgraph (2) is fixedly installed at the bottom of the outer side of the horizontal right end of the triangular polishing mechanism (3-3); the flange mounting rack (3-1) and the X-direction rack (3-2) are made of aluminum alloy;

the triangular grinding mechanism (3-3) comprises a pair of front and rear vertical installation side plates (301); a pair of vertical slide rails (302) are respectively vertically and symmetrically arranged on the plate body on the inner side of the front vertical installation side plate (301) and the inner side plate body of the rear vertical installation side plate (301), the vertical slide rails (302) are respectively matched with a pair of vertical guide rail slide blocks (303) in a sliding mode, and the outer sides of the pair of vertical guide rail slide blocks (303) are fixedly connected with the back sides of the plate bodies of the vertical base plates (309) at the same time; a lead screw sliding block (304) is fixedly connected to the inner side of a block body of one of the vertical guide rail sliding blocks (303), and the lead screw sliding block (304) is screwed and matched with a vertical lead screw (305); the upper end and the lower end of the vertical screw rod (305) are rotatably supported and fixedly mounted on the vertical inner side wall of a plate body of one of the vertical mounting side plates (301) through a screw rod mounting seat assembly (306) respectively; the power input end at the top end of the vertical screw rod (305) is coaxially and fixedly connected with a Z-direction vertical speed reducing motor (3-302), and the Z-direction vertical speed reducing motor (3-302) is fixedly installed by taking the top of the inner side wall of a vertical plate body of one vertical installation side plate (301) as a support; the Z-direction vertical speed reducing motor (3-302) drives the vertical screw rod (305) to rotate to realize vertical displacement of the screw rod sliding block (304), and the screw rod sliding block (304) is fixedly connected with a plate body at one end of the L-shaped adapter plate (308); a plate body at the other end of the L-shaped adapter plate (308) is fixedly connected with the back side of the vertical base plate (309), and a grinding mechanism is fixedly arranged on the front side of the plate body of the vertical base plate (309); a Z-axis vertical speed reducing motor (3-302) drives a vertical base plate (309) to drive the coping mechanism to vertically displace in the Z direction relative to the front and rear vertical mounting side plates (301); in addition, the outer sides of the plate bodies of the front and rear vertical installation side plates (301) are fixedly connected with the vertical inner side wall of the plate body at the horizontal right end of the X-direction rack (3-2) into a whole;

the triangular grinding mechanism (3-3) is provided with a driving wheel (31), an adjusting wheel (33) and a grinding wheel (32), wherein the driving wheel is externally tensioned and wraps the abrasive belt (3-303) and is distributed on the outer side of the vertical base plate (309) in a triangular manner;

the grinding wheel (32) is coaxially and rotatably supported at a high speed by a plurality of groups of ball bearings II (3206), hole retainer rings (3207) and shaft end covers (3208) and is arranged in the middle of the grinding wheel shaft (3202); the axial two ends of the shaft body of the grinding wheel shaft (3202) are respectively clamped and clamped by lower fastening bolts (3205) vertically penetrating through the shaft body and wheel shaft grooves (3204) which are symmetrically formed on the upper and lower mounting frames (3201 and 3203) up and down, so that the grinding wheel shaft (3202) can be detachably, horizontally and fixedly clamped and mounted in the wheel shaft grooves (3204) of the frame bodies of the upper and lower mounting frames (3201 and 3203); the upper and lower mounting frames (3201, 3203) are composed of an inverted U-shaped upper mounting frame (3201) and a pair of lower mounting frames (3203) clamping plate bodies; the horizontal top of the outer side of the upper mounting frame (3201) is fixedly connected with the execution tail end of the Z-direction triaxial cylinder (321); wherein the Z-direction three-axis cylinder (321) is fixedly installed by taking a plate body on the outer side of the vertical base plate (309) as a carrier; the outer side of the cylinder body of the Z-direction triaxial cylinder (321) is fixedly supported and provided with a laser contourgraph (2) through a contourgraph mounting seat (201); a rubber layer is arranged on the outer circumference of the wheel body of the grinding wheel (32);

and an upper limit proximity switch (91), a zero point proximity switch (92) and a lower limit proximity switch (93) which are just opposite to the detection of the vertical guide rail sliding block (303) are fixedly arranged on the inner side of one of the front and rear vertical installation side plates (301).

2. The automatic grinding robot for the weld joint at the end of the straight weld steel pipe according to claim 1 is characterized in that: the grinding wheel (32) is arranged below the driving wheel (31) and the adjusting wheel (33); the polishing wheel (32) is driven by a Z-direction three-axis cylinder (321) to realize linear tensioning displacement adjustment of the polishing wheel (32) in the Z-axis direction; the adjusting wheel (33) adjusts the pitch angle of the adjusting wheel (33) in the horizontal axial direction by rotating the hand wheel (331) so as to prevent the abrasive belt (3-303) from deviating.

3. The automatic grinding robot for the weld joint at the end of the straight weld steel pipe according to claim 2 is characterized in that: the adjusting wheel (33) has a wheel body which supports the wheel body to rotate at a high speed on the adjusting wheel shaft (332) through a plurality of groups of ball bearings I (337) and a retaining ring (333) for a bearing hole; one end of the adjusting wheel shaft (332) is rotatably connected with an adjusting wheel frame (339) through a cylindrical pin (338); the other end of the adjusting wheel shaft (332) is connected with the output end of the joint bearing (336); the input end of the joint bearing (336) is connected with the vertical linear displacement execution end of a screw pair of a screw nut consisting of a nut (335), a bolt (334) and a hand wheel (331); one end of an adjusting wheel shaft (332) is pushed to rotate around a hinge point of a cylindrical pin (338) at the other end of the adjusting wheel shaft (332) in a pitching manner through the rotation of a hand wheel (331) and the transmission of a screw pair of a screw rod nut (334) through a nut (335) so as to prevent an abrasive belt (3-303) outside the wheel body of the adjusting wheel (33) from deviating.

4. The automatic grinding robot for the weld joint at the end of the straight weld steel pipe according to claim 1 is characterized in that: the triangular grinding mechanism (3-3) is provided with a Z-direction vertical speed reducing motor (3-302); a motor shield (3-21) used for hiding the motor installation is arranged on the outer side of the Z-direction vertical speed reducing motor (3-302); the triangular grinding mechanism (3-3) is provided with an external tensioning wrapping abrasive belt (3-303), a driving wheel (31), an adjusting wheel (33) and a grinding wheel (32) which are distributed in a triangular shape; wherein, the upside of the outer sides of the driving wheel (31) and the adjusting wheel (33) at the upper part is provided with inverted grinding head shields (3-22).