CN111775006B

CN111775006B - Automatic grinding robot for spiral weld joints at ends of spiral steel pipes

Info

Publication number: CN111775006B
Application number: CN202010128815.3A
Authority: CN
Inventors: 原小红; 张瑾宇; 朱雅光; 尹志远; 马利; 王林军
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: 2022-03-25
Anticipated expiration: 2040-02-28
Also published as: CN111775006A

Abstract

The automatic grinding robot for the spiral weld at the pipe end of the spiral steel pipe is characterized in that a two-degree-of-freedom fine grinding executing mechanism provided with a laser profilometer is arranged at an executing end of a multi-degree-of-freedom manipulator, the grinding precision of the manipulator is improved while the motion control is simplified, and the problem that the quality of the weld bead at the pipe end of the spiral steel pipe after being ground by the multi-degree-of-freedom grinding manipulator in the prior art cannot meet the process index requirements specified by API Spec5L standard and GBT 97111-1997 standard is overcome; the technical problem of manual secondary grinding is still needed. The invention can be used for polishing the outer weld of the spiral steel pipe and the inner weld of the spiral steel pipe, and the parent metal is not damaged by polishing; the minimum residual height after grinding can be less than or equal to 0.1mm and is far higher than the requirements of API Spec5L standard and GBT 97111-1997 standard; the laser profiler cooperates with a special detection algorithm to realize high-precision scanning detection with the precision of less than 0.05 mm; powerful technical support is provided for high-precision weld grinding.

Description

Automatic grinding robot for spiral weld joints at ends of spiral steel pipes

Technical Field

The invention belongs to the technical field of operation, transportation, grinding and polishing, and particularly relates to an automatic grinding robot for spiral weld joints at pipe ends of spiral steel pipes.

Background

The spiral steel pipe is a pipe which is formed by rolling a strip steel coil plate serving as a raw material by adopting a spiral welding process. For spiral steel pipes, in order to meet the welding quality of the next steel pipe butt-ring welding at the end of the spiral steel pipe, the API Spec5L standard and the GBT 97111-1997 standard are both specified: taking the grinding of the weld joint at the end of the spiral steel pipe with the diameter specification of 508mm as an example: firstly, the weld reinforcement height of the spiral welded pipe within the length range of at least 150mm from the pipe end is removed, namely the axial grinding depth length of the pipe end of the spiral steel pipe is required; secondly, the welding bead after grinding treatment cannot be lower than the outer circumferential surface of the pipe body base metal, namely the base metal cannot be damaged by grinding the welding seam; furthermore, the residual height of the weld bead exceeding the surface of the steel pipe after grinding treatment is less than 0.5mm, so that the durable use requirement of uniform radial stress distribution of the steel pipe is met to the maximum extent. In addition, in terms of appearance quality requirements, the surface of the welded seam after grinding is smooth and flat.

However, in the prior art, in the market, the grinding precision of the equipment which directly carries the grinding head by means of the manipulator to complete automatic grinding is generally insufficient, so that the welding bead residual height after grinding is too high, the welding bead residual height still needs to be manually secondarily ground or the base metal of the welded pipe is damaged, and the steel pipe is scrapped, namely, the fully automatic grinding precision and technical index requirements which are in accordance with the specification of the API Spec5L standard and the GBT 97111-1997 standard cannot be realized.

Take a robot polishing system with three-dimensional vision disclosed in publication No. CN109483369A and a control method thereof, and a robot polishing system with three-dimensional vision disclosed in publication No. CN109483369A and a control method thereof as examples: 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 and reliable automatic polishing of the weld joint at the end of the spiral steel pipe with the inner weld bead within 0.5mm height after high-precision smooth polishing without damaging the base metal can not 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 manipulator motion trajectory planning and the additional corner increment generated by the joint due to the elastic deformation of each joint trajectory sensor, the displacement generated by the corner increment will be 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 met by manual polishing cannot be completely replaced. In addition, 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. In view of the above, the following improved technical scheme is proposed

Disclosure of Invention

The technical problems solved by the invention are as follows: the automatic grinding robot for the spiral weld at the pipe end of the spiral steel pipe is characterized in that a two-degree-of-freedom fine grinding actuating mechanism is arranged at the actuating end of a multi-degree-of-freedom manipulator, so that on one hand, the motion control of the manipulator can be simplified, and meanwhile, the grinding precision of the actuating end of the manipulator is improved; the quality of a weld bead at the end of a spiral steel pipe, which is polished by a multi-degree-of-freedom polishing manipulator in the prior art, can not meet the process index requirements specified by the API Spec5L standard and the GBT 97111-1997 standard; the technical problem of manual secondary grinding is still needed.

The technical scheme adopted by the invention is as follows: the automatic grinding robot for the spiral weld at the end of the spiral steel pipe is provided with a two-freedom-degree grinding platform which is used for horizontally and fixedly mounting a horizontal structure at the tail end of a multi-freedom-degree manipulator and grinding by using an abrasive belt; the two-degree-of-freedom grinding platform is provided with a rack with a horizontal aluminum alloy hollow structure; an axial mechanism which horizontally displaces relative to the axial direction of the rack is arranged on the inner side of the rack; a normal mechanism is arranged at an axial horizontal displacement executing end of the axial mechanism; a normal vertical linear displacement executing end of the normal mechanism is fixedly provided with a grinding mechanism and drives the grinding mechanism to vertically displace in a normal straight line; a laser contourgraph is fixedly installed on the outer side of the grinding mechanism; the laser profilometer linearly displaces along with the horizontal axis or the vertical normal direction of the coping mechanism relative to the rack.

In the above technical solution, further: in order to ensure the accuracy, stability and reliability of accurate grinding: the axial mechanism of the two-degree-of-freedom grinding platform is fixedly provided with a left limit proximity switch, a zero point proximity switch and a right limit proximity switch by taking a rack as a carrier; the normal mechanism is fixedly provided with an upper limit proximity switch, a zero point proximity switch and a lower limit proximity switch by taking a front vertical installation side plate and a rear vertical installation side plate which are arranged on the normal mechanism as carriers.

In the above technical solution, further: the frame of the two-degree-of-freedom grinding platform is designed for light weight and beautification: the frame is made of aluminum alloy; the frame comprises a left frame and a right frame with hollow structures, a supporting frame fixedly connected between the left frame and the right frame and used for front and back horizontal supporting, and a sealing cover shell for packaging the left frame, the right frame and the top of the supporting frame; wherein the outer side of the supporting frame is coated with a layer of aluminum alloy skin; a manipulator connecting seat with a hollowed-out right-angled triangular structure is fixedly arranged on the horizontal left side of the rack; the manipulator connecting seat is used for horizontally installing the two-degree-of-freedom grinding platform at the execution tail end of the manipulator.

In the above technical solution, preferably: in order to guarantee the polishing precision: the axial mechanism and the normal mechanism 9 respectively comprise a stable and reliable rotation and linear displacement conversion mechanism consisting of a double guide rail, a double guide rail slide block, a screw rod and a screw rod slide block.

In the above technical solution, further: the axial and normal displacement mechanism of the two-freedom grinding platform is designed for reliability, stability, light weight, compactness and miniaturization: the two-degree-of-freedom grinding platform is provided with a rack with a hollow frame structure, and the bottom end of the inner side of a rack body of the rack axial horizontal rack body is matched with two groups of horizontal guide rail sliding blocks in a sliding manner through two groups of horizontal guide rails which are parallel front and back; two groups of horizontal guide rail sliders are respectively and fixedly connected with two front and rear inverted L-shaped horizontal slider connecting plates in a front-rear axial symmetry manner; the front and rear inverted L-shaped horizontal sliding block connecting plates are fixedly connected with the front and rear vertical mounting side plates of the grinding mechanism respectively; the inner side plate bodies of the front and rear vertical installation side plates are vertically parallel and symmetrically provided with a pair of vertical slide rails, the vertical slide rails are respectively matched with a pair of vertical guide rail slide blocks in a sliding manner, one side of each vertical guide rail slide block is fixedly connected with a vertical lead screw slide block, and the vertical lead screw slide blocks are matched with vertical lead screws in a screwing manner; the vertical screw rod is rotatably supported and installed on the inner side of the installation side plate through a vertical screw rod installation seat fixedly connected with the installation side plate, and a power input end of the vertical screw rod is coaxially and fixedly connected with a Z-axis vertical speed reducing motor fixedly installed by taking the installation side plate as a support; a vertical screw rod sliding block driven by a Z-axis vertical speed reducing motor to vertically displace is fixedly connected with the back side of a vertical substrate through an L-shaped adapter plate, and a grinding mechanism is fixedly arranged on the front side of the vertical substrate; wherein, a driving wheel polishing motor of a polishing mechanism is arranged at the back side of the vertical substrate plate body; the vertical base plate drives a vertical lead screw slider through a Z-axis vertical speed reducing motor to drive a grinding mechanism fixedly arranged on the front surface of the vertical base plate to vertically displace relative to vertical sliding rails fixedly arranged on inner side plate bodies of the front and rear vertical installation side plates; the outer sides of the front and rear vertical mounting side plate bodies are fixedly connected with horizontal screw rod sliding blocks; the horizontal screw rod sliding block is screwed and matched with the horizontal screw rod; the horizontal screw rod is horizontally and rotatably arranged on the inner side of the frame body through a horizontal screw rod mounting base, and the horizontal screw rod is horizontally arranged above the horizontal guide rail sliding block in parallel; the power input end of the horizontal screw rod is coaxially and fixedly connected with an X-axis horizontal speed reducing motor; the X-axis horizontal speed reducing motor drives the horizontal screw rod sliding block to drive the front and rear vertical installation side plates and the grinding mechanism to horizontally and axially displace relative to the two groups of horizontal guide rails.

Among the above-mentioned technical scheme, for compact, miniaturized, stable, lightweight design grinding mechanism to make things convenient for the change in abrasive band: the grinding mechanism is provided with a driving wheel, a grinding wheel and an adjusting wheel which are distributed in a triangular shape, and the driving wheel, the grinding wheel and the adjusting wheel are externally wrapped with a tensioning installation abrasive belt; the polishing wheel is driven by a three-axis cylinder to realize linear tensioning displacement adjustment of the polishing wheel in the Z-axis direction; the adjusting wheel pushes one end of an adjusting wheel shaft to rotate around a hinge point at the other end of the adjusting wheel shaft by rotating a hand wheel so as to prevent the abrasive belt wrapped on the adjusting wheel from deviating; the adjusting mechanism of the adjusting wheel consists of a hand wheel, a bolt, a nut, a joint bearing, an adjusting wheel shaft, a ball bearing I, a retainer ring for a bearing hole, a cylindrical pin, an adjusting wheel frame and an adjusting wheel; one end of an adjusting wheel shaft is hinged and rotatably connected with an adjusting wheel frame through a cylindrical pin, and the other end of the adjusting wheel shaft is connected with the output end of a joint bearing; the input end of the joint bearing is connected with a screw pair of a screw nut consisting of a nut, a bolt and a hand wheel.

In the above technical solution, further: for the installation and the change of conveniently polishing wheel: the grinding mechanism is provided with a driving wheel, a grinding wheel and an adjusting wheel which are distributed in a triangular shape; and the driving wheel, the grinding wheel and the adjusting wheel are wrapped outside the tensioning installation abrasive belt; the grinding wheel is provided with an inverted U-shaped upper mounting frame; the top end of the upper mounting frame is fixedly connected with an execution end of a three-axis cylinder which is vertically and downwards mounted; a lower mounting frame used for clamping and fixedly mounting the polishing wheel shaft up and down is arranged opposite to the upper mounting frame up and down; the opposite clamping ends of the upper mounting frame and the lower mounting frame are respectively provided with a wheel axle groove matched with the grinding wheel axle in size; shaft bodies at two ends of the polishing wheel shaft are horizontally and fixedly installed in a clamping manner by using two lower fastening bolts respectively in upper and lower wheel shaft grooves of the upper and lower mounting frames; the middle part of the polishing wheel shaft body is coaxially and rotatably supported and provided with a polishing wheel through a ball bearing II; a rubber layer is arranged on the outer circumference of the grinding wheel body; and the shaft end of the ball bearing II is matched with the retainer ring for the mounting hole and the shaft end cover.

In the above technical solution, preferably: to ensure the reliability of the visual data acquisition: the grinding mechanism is provided with a driving wheel, a grinding wheel and an adjusting wheel which are distributed in a triangular shape; wherein the grinding wheel is positioned at the bottom end of the triangle, and the laser profile instrument is fixedly installed at the outer side of the fixed supporting structure of the grinding wheel.

Compared with the prior art: the invention designs an automatic grinding robot for spiral weld joints at the ends of spiral steel pipes, which adopts a two-degree-of-freedom fine grinding actuating mechanism arranged at the actuating end of a multi-degree-of-freedom manipulator, improves the grinding precision of the manipulator by simplifying motion control, and overcomes the defect that the quality of weld beads at the ends of the spiral steel pipes ground by the multi-degree-of-freedom grinding manipulator in the prior art cannot meet the process index requirements specified by API Spec5L standard and GBT 97111-1997 standard; the technical problem of manual secondary grinding is still needed.

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

1. the scheme can save the subsequent manual fine grinding and polishing steps, and realize the high-precision full-automatic polishing and use of the inner and outer welding seams of the spiral steel pipe; the surface of the weld joint is polished without damaging the parent metal; the minimum residual height after grinding can be less than or equal to 0.1mm and is higher than the requirements of API Spec5L standard and GBT 97111-1997 standard; the polished surface is smooth and flat and has no hollow phenomenon;

2. the high-precision two-degree-of-freedom grinding platform 4 of the scheme comprises: the allowable value of the axial control error of the grinding platform where the grinding head is located is less than 0.05mm, the allowable value of the normal control error is less than 0.01mm, and the allowable value is far higher than the precision requirement of the residual height of the welding seam, so that the realization of the grinding of the welding seam with high precision and high quality is ensured;

3. the scheme adopts abrasive belt grinding to replace grinding wheel grinding and grinding ratio to be improved by 4-10 times, and has high production efficiency, low replacement cost and high machine tool power utilization rate;

4. according to the scheme, the triangular grinding mechanism 3 adopts pneumatic vertical tensioning to adjust the height of the grinding 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;

5. 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; the abrasive belt 34 is prevented from deviating; the structure is simple, the adjustment is convenient, and the device is economical and practical;

6. according to the scheme, the grinding wheel is clamped and horizontally and fixedly mounted by upper and lower mounting frames (3201 and 3203), and grinding wheel shaft assemblies including a check ring 3207 for a hole and a ball bearing II 3206 of a shaft end cover 3208 are convenient and convenient to disassemble, replace and mount; the maintenance is convenient; the structure is stable and reliable;

7. the transmission of the two-degree-of-freedom grinding platform 4 is precise, stable and reliable; the guide support structure of the double-sliding-rail sliding block is cooperated to act together; the requirements of the two-degree-of-freedom grinding platform on the adjustment of the axial and normal displacement mechanisms for accurate, stable and reliable grinding displacement can be met;

8. the aluminum alloy frame 41 is adopted in the scheme, the structure is compact, and light weight, reliability and stability in carrying of the manipulator execution end are realized; the appearance is beautiful, and the support is stable and reliable; the universality of the two-degree-of-freedom grinding platform 4 and the integrated installation of the execution end of the multi-degree-of-freedom manipulator is ideal; mounting of a carrying grinding head through a horizontal extension part of the frame 41; the polishing and using requirements of the external spiral weld joint can be met; the inner spiral welding line can extend into the opening of the steel pipe to realize polishing of the inner spiral welding line;

9. the axial and normal displacement mechanisms cooperate with the zero point, left and right and upper and lower proximity switches; reliable guarantee is provided for high-precision finish grinding; the residual height of the welded seam after grinding can be controlled within 0-0.5 mm; is far higher than the requirements of API Spec5L standard and GBT 97111-1997 standard;

10. the scheme 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;

11. according to the scheme, the laser contourgraph 5 is fixed at the bottom of the grinding mechanism 3; and reliable guarantee is provided for the accuracy and timeliness of data acquisition.

Drawings

FIG. 1 is a view showing a state of the automatic spiral weld grinding robot for the end of a spiral steel pipe in use according to the present invention;

FIG. 2 is a perspective view of the two-degree-of-freedom grinding table of FIG. 1;

FIG. 3 is a left side view of the two-degree-of-freedom grinding platform of FIG. 2 with the robot connecting seat removed;

FIG. 4 is a perspective view of the internal structure of the two-degree-of-freedom grinding platform of FIG. 2;

FIG. 5 is a perspective view of the two-degree-of-freedom grinding table of FIG. 4;

FIG. 6 is a front perspective view of the sharpening mechanism;

FIG. 7 is a rear perspective view of the sharpening mechanism;

FIG. 8 is a back front view of the sharpening mechanism;

FIG. 9 is a top perspective view of the sharpening mechanism;

FIG. 10 is an adjustment schematic of a hand wheel adjustment mechanism of the adjustment wheel;

FIG. 11 is a front view of a hand wheel adjustment mechanism of the adjustment wheel;

FIG. 12 is a perspective view of a hand wheel adjustment mechanism of the adjustment wheel;

FIG. 13 is a schematic diagram of the cylinder tensioning of the grinding wheel in the sharpening mechanism;

FIG. 14 is a front view of the grinding wheel with the three-axis cylinder removed;

FIG. 15 is a cross-sectional view of the mounting structure of the grinding wheel of FIG. 14;

FIG. 16 is a perspective view of the grinding wheel of FIG. 14;

FIG. 17 is a perspective view of the two-degree-of-freedom grinding platform axial displacement mechanism after the proximity switch is installed;

FIG. 18 is a front view of the two-degree-of-freedom grinding platform normal displacement mechanism after installation of proximity switches;

FIG. 19 is a perspective view of a two-degree-of-freedom grinding platform mounted on a manipulator of the automatic grinding robot for spiral weld joints at the ends of spiral steel pipes according to the invention;

FIG. 20 is a main control interface diagram of an upper computer of the automatic grinding robot for spiral weld joints at the pipe ends of the spiral steel pipes;

FIG. 21 is a program interface diagram of a scanning part of the laser profiler of the automatic grinding robot for spiral weld at the end of a spiral steel pipe according to the present invention;

FIG. 22 is a program interface diagram of a manipulator control part of the automatic grinding robot for spiral weld joints at the pipe ends of spiral steel pipes according to the invention;

FIG. 23 is a LABVIEW program block diagram of the automatic sharpening robot for the spiral weld at the pipe end of the connecting spiral steel pipe;

FIG. 24 is a first flowchart of a servo control section according to the present invention;

FIG. 25 is a second flowchart of a servo control section according to the present invention;

FIG. 26 is a process flow chart of the automatic grinding robot grinding method for spiral weld at the end of a spiral steel pipe according to the invention;

FIG. 27 is a power supply diagram of the present invention using DC24V and DC48V power supplies;

FIG. 28 is an electrical layout of the main power supply circuit of the present invention;

FIG. 29 is an electrical wiring diagram of the encoder, power and brake of the horizontal axial reduction motor of the present invention;

FIG. 30 is a graph of the spatial trajectory of the spiral weld, the manipulator, the laser profiler (machine vision) of the spiral steel tube of the present invention;

FIG. 31 is a graph of the trajectory in three dimensions of the actual weld spiral of the present invention of FIG. 30;

FIG. 32 is a three-dimensional view showing the visual scanning result of the weld joint at the end of the spiral steel pipe according to the present invention;

FIG. 33 is a two-dimensional view of the visual scanning result of the weld joint at the end of the spiral steel pipe according to the present invention;

FIG. 34 is a main control interface diagram of the automatic grinding robot for spiral weld joints at the ends of spiral steel pipes after scanning by an upper computer;

FIG. 35 is a two-dimensional view of the visual scan results of the invention after weld grinding.

Detailed Description

Specific embodiments of the present invention are described below in conjunction with fig. 1-35. 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.

Automatic sharpening robot for spiral weld joints at the ends of spiral steel pipes, and it is understood that the robot is applied to the following steps: the device also comprises a power supply, an upper computer, a PLC and a motion control card. The method is characterized in that: the two-freedom-degree grinding platform 4 is horizontally and fixedly provided with a horizontal structure at the executing tail end of the multi-freedom-degree manipulator 1 and is used for grinding by using an abrasive belt; the two-degree-of-freedom grinding platform 4 is provided with a frame 41 with a horizontal aluminum alloy hollow structure; an axial mechanism 7 which horizontally displaces relative to the axial direction of the frame 41 is arranged on the inner side of the frame; a normal mechanism 9 is arranged at the axial horizontal displacement executing end of the axial mechanism 7; the normal vertical linear displacement executing end of the normal mechanism 9 is fixedly provided with the grinding mechanism 3 and drives the grinding mechanism 3 to vertically displace in a normal straight line; a laser contourgraph 5 is fixedly installed on the outer side of the grinding mechanism 3; the laser profiler 5 linearly displaces along the horizontal axis or the vertical normal direction of the coping mechanism 3 relative to the frame 41.

The grinding method of the automatic grinding robot for the spiral weld at the pipe end of the spiral steel pipe comprises the following steps: (see FIG. 1 in conjunction with the flow diagrams) the techniques described herein are also described in the flow diagrams. 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.

Step S001, determining the position of the steel pipe: the method comprises the following steps of (1) inputting the diameter of a steel pipe into an upper computer (see figure 20) of the spiral steel pipe end spiral weld automatic grinding robot comprising the upper computer, a PLC (programmable logic controller), a motion control card, a manipulator 1, a non-contact laser contourgraph 2 and a two-degree-of-freedom grinding platform 4 carrying a grinding mechanism 3 to vertically move along axial and normal spaces, controlling the manipulator 1 by the upper computer, moving the two-degree-of-freedom grinding platform 4 fixedly carried by an execution end of the manipulator 1 to an initial position from a zero position, and scanning by a laser contourgraph 5 to determine the position of the detected steel pipe;

it should be noted that: the upper computer is used for issuing and controlling control instructions of all mechanisms on the manipulator 1 and the two-degree-of-freedom grinding platform 4; and the upper computer uses LABVIEW to develop a friendly graphical user interface (as shown in figure 20), so that not only can various instruments and equipment be controlled in real time, but also various information can be comprehensively displayed, and the use and the operation personnel can conveniently master the real-time situation. The PLC is used for controlling the rotation of the spiral steel pipe; the motion control card is used for controlling and executing the motion tracks of the axial and normal displacement mechanisms of the polishing mechanism 3 carried by the two-degree-of-freedom grinding platform 4; meanwhile, the laser contourgraph 5 carried by the grinding mechanism 3 synchronously displaces along with the displacement of the axial displacement mechanism and the normal displacement mechanism so as to accurately acquire elevation data of the spiral welding seam and establish three-dimensional and two-dimensional coordinates of the welding seam data.

Step S002, planning a trajectory: the manipulator 1 determines the translational motion of the detected position of the steel pipe according to the scanning of the laser profiler 5, calculates the center of the steel pipe and the highest point of the steel pipe according to the diameter of the steel pipe, and records the coordinate information of a specific point and establishes a coordinate system of the steel pipe to be polished by an upper computer, so that the circular arc track of the manipulator 1 concentrically moves around the outer circumferential surface of the steel pipe to be polished is planned.

Step S003, pipe end searching: after the manipulator 1 carries the two-degree-of-freedom grinding platform 4 and translates to a position right above the 12-point highest point of the steel pipe under the guidance of the laser profiler 5, the manipulator 1 translates along the axial direction of the steel pipe to search and position the end of the steel pipe;

step S004, identifying the pipe end: an X-axis horizontal speed reducing motor 6 in the two-degree-of-freedom grinding platform 4 drives an axial mechanism 7 to drive a grinding mechanism 3 to translate to a grinding section distance which is as deep as 180mm from the axial depth of a pipe end; specifically, after the pipe end is found, the height position of a concentric circle is fixed above a point 12 away from the steel pipe through a PLC control manipulator 1 and a two-degree-of-freedom grinding platform 4; the PLC controls the mechanical arm 1 to drive the two-degree-of-freedom grinding platform 4 to translate 180mm towards the inner side of the steel pipe, wherein 180mm is larger than the left-right linear distance of the helical angle of the grinding mechanism 3;

step S005, scanning start point: the PLC controls a Y-shaped roller for lifting the steel pipe to rotate (see figure 1), and the laser profiler 5 searches for a welding line while rotating to determine a welding line grinding starting point; after the laser profilometer 5 finds the welding seam, the PLC controls the Y-shaped roller for lifting the steel pipe, and the driving roller of the Y-shaped roller is controlled to extend and stop rotating according to the diameter of the steel pipe and the linear speed delay of the Y-shaped roller driven by the roller speed reducing motor, so that the middle point of one half of the inclination length of the spiral welding seam stops at the position of 12 points of the steel pipe.

Step S006, weld joint tracking scanning and tracking scanning end: according to the scanning result of the laser contourgraph 5, the polishing mechanism 3 in the two-degree-of-freedom grinding platform 4 drives the axial mechanism 7 to drive the polishing mechanism 3 to move horizontally by an X-axis horizontal speed reducing motor 6 in the two-degree-of-freedom grinding platform 4, and the two-degree-of-freedom grinding platform 4 and the mechanical arm 1 do concentric circular motion around the central axis of the spiral steel pipe as the center of a circle according to a planned circular arc track (see fig. 30); the two-degree-of-freedom grinding platform 4 positions and tracks the weld according to a weld detection and tracking visual algorithm of the laser profiler 5, and records weld characteristic point information and weld reinforcement and toe point information: specifically, the upper computer controls the mechanical arm 1 to drive the two-degree-of-freedom grinding platform 4 to move concentrically relative to the center line of the steel pipe in the direction of 12 points of the steel pipe; a point is taken at the left side of the highest point of the spiral welding line through data collected and fed back by the laser profiler 5, and the coordinate of the point in the coordinate system of the manipulator robot is obtained; taking a point on the right side of the highest point, acquiring the coordinate of the point in a manipulator robot coordinate system, feeding data back to an upper computer through the coordinates of the two points and the known outer diameter of the spiral steel pipe, calculating the coordinate of the center point of the steel pipe circle by using a mathematical algorithm, and defining the point as a specific user coordinate system origin, wherein the three directions of the coordinate system are still the same as the directions of the manipulator robot coordinate system; generating a 3D image of the weld by software (see fig. 32); because the manipulator 1 moves in an arc shape concentric with the steel pipe, and simultaneously records the characteristic points of the welding seam according to the scanning data of the laser profiler 5 (as shown in figure 33); the axial horizontal speed reducing motor of the two-degree-of-freedom grinding platform 4 is guided and controlled by the characteristic information obtained by calculation, so that the laser profiler 5 carried by the two-degree-of-freedom grinding platform 4 moves in the horizontal direction, the laser profiler 5 is always kept right above the weld joint, the weld joint is continuously tracked and scanned, the whole scanning of the weld joint is completed, and the tracking and scanning are finished until the two-degree-of-freedom grinding platform 4 detects and tracks the weld joint to the end point of the weld joint at the pipe end.

Furthermore, the following steps are carried out: in step S006, the PLC obtains a position difference between the polishing working points of the laser profiler 5 and the polishing mechanism 3; the two-degree-of-freedom grinding platform 4 controls the X-axis horizontal speed reducing motor 6 to drive the axial mechanism 7 to drive the grinding mechanism 3 to move axially and horizontally, so that the grinding mechanism 3 moves to the initial position when the laser contourgraph 5 scans a weld joint, and the PLC controls the X-axis horizontal speed reducing motor 6 to move to complete position compensation.

Step S007, finishing weld grinding and grinding: the mechanical arm 1 and the two-degree-of-freedom grinding platform 4 return to the initial point of the welding seam through the axial mechanism 7, the grinding head of the grinding mechanism 3 is started and moves to the initial point of the welding seam, the mechanical arm 1 moves according to a planned circular arc track, the axial mechanism 7 of the two-degree-of-freedom grinding platform 4 moves at a matched speed, and the Z-axis vertical speed reducing motor 8 in the two-degree-of-freedom grinding platform 4 drives the normal mechanism 9 to drive the grinding head of the grinding mechanism 3 to feed to the surface of the welding seam to carry out welding seam grinding operation;

it should be noted that: in the step, the PLC controls the X-axis horizontal speed reducing motor 6 to move along the track when the welding seam is scanned, and simultaneously the PLC controls the Z-axis vertical speed reducing motor 8 to drive the normal mechanism 9 to drive the grinding head of the grinding mechanism 3 to automatically adjust the grinding height according to the welding seam height information obtained by scanning (as shown in figures 32 and 33); under the coordinated motion of the horizontal motor, the vertical motor and the manipulator, the whole two-degree-of-freedom grinding platform carries the grinding head of the grinding mechanism 3, and the welding line is ground under the driving of the grinding head motor, so that the requirement of high-precision grinding is met. Has the advantages that: the two-degree-of-freedom grinding platform 4 can self-adaptively search for the spiral weld seam through the coordinated work of machine vision, a horizontal motor and a vertical motor without knowing the spiral angle of the weld seam, so that the grinding precision is improved while the control is simplified. Moreover, the grinding mechanism 3 is a triangular abrasive belt and is provided with a three-axis cylinder for tensioning, so that the three-axis cylinder not only provides convenience for replacing the abrasive belt, but also facilitates tensioning after replacing the abrasive belt; meanwhile, the three-axis cylinder can also realize flexible grinding of the grinding mechanism 3; the polishing precision is high, the surface quality is good, and the parent metal is not damaged. Specifically, during flexible sanding, the triaxial cylinder may be equipped with a pressure sensor. The working principle of the flexible grinding is based on the prior art, and is not limited herein.

Step S008, secondary grinding operation: and after the first grinding is finished, stopping the grinding head of the grinding mechanism 3, scanning by the laser profiler 5 to detect the extra height of the welding line, and carrying out secondary grinding operation if the extra height of the welding line is more than 0.5 mm.

Regarding the method of scanning and polishing the weld, it should be noted that: the upper computer is used for issuing and controlling control instructions of all mechanisms on the manipulator 1 and the two-degree-of-freedom grinding platform 4; and the upper computer uses an LABVIEW to develop a friendly graphical user interface, controls various instruments and equipment in real time, comprehensively displays various information, and is convenient to use and an operator to master real-time conditions. The PLC is used for controlling the rotation of the spiral steel pipe; the motion control card is used for controlling and executing the motion tracks of the axial and normal displacement mechanisms of the polishing mechanism 3 carried by the two-degree-of-freedom grinding platform 4; meanwhile, the laser contourgraph 5 carried by the grinding mechanism 3 synchronously displaces along with the displacement of the axial displacement mechanism and the normal displacement mechanism so as to accurately acquire elevation data of the spiral welding seam and establish three-dimensional and two-dimensional coordinates of the welding seam data. The PLC obtains the position difference between the polishing working points of the laser contourgraph 5 and the polishing mechanism 3; the two-degree-of-freedom grinding platform 4 controls the X-axis horizontal speed reducing motor 6 to drive the axial mechanism 7 to drive the grinding mechanism 3 to move axially and horizontally, so that the grinding mechanism 3 moves to the initial position when the laser contourgraph 5 scans a weld joint, and the PLC controls the X-axis horizontal speed reducing motor 6 to move to complete position compensation.

It should be noted that: the PLC controls the X-axis horizontal speed reducing motor 6 to move along the track of the laser profiler 5 when scanning the weld joint, and simultaneously controls the Z-axis vertical speed reducing motor 8 to drive the normal mechanism 9 to drive the grinding head of the grinding mechanism 3 to automatically adjust the grinding height according to the weld joint height information obtained by scanning the laser profiler 5; under the coordinated motion of the horizontal motor, the vertical motor and the manipulator, the whole two-degree-of-freedom grinding platform carries the grinding head of the grinding mechanism 3, and the welding line is ground under the driving of the grinding head motor, so that the requirement of high-precision grinding is met. Has the advantages that: the two-degree-of-freedom grinding platform 4 can self-adaptively search for the spiral weld seam through the coordinated work of machine vision, a horizontal motor and a vertical motor without knowing the spiral angle of the weld seam, so that the grinding precision is improved while the control is simplified. Moreover, the grinding mechanism 3 is a triangular abrasive belt and is provided with a three-axis cylinder for tensioning, so that the three-axis cylinder not only provides convenience for replacing the abrasive belt, but also facilitates tensioning after replacing the abrasive belt; meanwhile, the three-axis cylinder can also realize flexible grinding of the grinding mechanism 3; the polishing precision is high, the surface quality is good, and the parent metal is not damaged. Specifically, during flexible sanding, the triaxial cylinder may be equipped with a pressure sensor. The working principle of the flexible grinding is based on the prior art, and is not limited herein.

Further, it should be noted that: the welding seam detection tracking visual algorithm of the laser contourgraph 5 in the automatic grinding robot for the spiral welding seam at the end of the spiral steel pipe comprises the following steps: the method comprises the steps of firstly, filtering acquired laser profilometer data; and (3) algorithm II: fitting the filtered data and solving the square sum of the residual errors of the filtered data; and (3) algorithm III: if the sum of the squares of the residual errors is smaller than the welding seam identification threshold value, the welding seam does not exist in the area; if the sum of the squares of the residual errors is larger than the welding seam identification threshold value, the welding seam exists in the area; and (4) algorithm four: if the welding seam exists, averaging the data collected in the area where the welding seam is located to divide the welding seam area; and (5) algorithm five: after the welding seam area is divided, the welding seam characteristic point area and the welding seam turning point area are obtained; and (6) algorithm six: judging straight lines in the turning point area to determine characteristic points and left and right toe points of the welding line; and (3) an algorithm is seven: and (4) calculating the weld reinforcement according to the straight line judgment of the weld turning point region, the characteristic points and the left and right toe points of the weld, and ending the algorithm.

In the above embodiment, further: in order to ensure the accuracy, stability and reliability of accurate grinding: the axial mechanism 7 of the two-degree-of-freedom grinding platform 4 is fixedly provided with a left limit proximity switch 71, a zero point proximity switch 72 and a right limit proximity switch 73 by taking the frame 41 as a carrier; the normal mechanism 9 uses the front and rear vertical installation side plates 301 as a carrier to fixedly install an upper limit proximity switch 91, a zero point proximity switch 92 and a lower limit proximity switch 93.

When in use, the two-degree-of-freedom grinding platform 4 cooperates with the zero proximity switch and the left and right or up and down proximity switches to act together; the two-degree-of-freedom grinding platform 4 at the tail end of the multi-degree-of-freedom manipulator provides reliable guarantee for high-precision positioning and precision grinding of the spiral weld at the end of the spiral steel pipe; the residual height of the welded seam after grinding can be controlled within +0-0.5 mm; is far higher than the requirements of API Spec5L standard and GBT 97111-1997 standard.

Moreover, the horizontal and vertical moving mechanisms are respectively provided with limit proximity switches to limit the horizontal and vertical directions, so that the motion of the horizontal and vertical motors is effectively protected, the grinding head provided with the contourgraph cannot impact on the structural frame of the frame 41, and the overall safety of the structure is ensured.

Specifically, the laser profiler 5 is fixedly connected with the upper mounting rack 3201 of the grinding wheel 32 of the sharpening mechanism 3 or the outer side wall of the cylinder body of the three-axis cylinder 321 of the grinding wheel 32 through the profiler mounting rack 501 of an L-shaped structure (as shown in FIG. 9). And the scanning end of the laser contourgraph 5 is positioned below the outer side of the grinding mechanism 3 and always synchronously moves with the horizontal and vertical displacement of the grinding mechanism 3. When in use, the laser contourgraph 5 is fixedly connected with a supporting structure of the grinding wheel 32 at the bottom end of the grinding mechanism 3 into a whole and moves horizontally along with the grinding mechanism 3 in the axial direction and the normal direction; and reliable guarantee is provided for the accuracy and timeliness of the near-end scanning data acquisition.

In the above embodiment, further: the frame of the two-degree-of-freedom grinding platform is designed for light weight and beautification: the frame 41 is made of aluminum alloy; the frame 41 includes a left frame 411 and a right frame 411 (as shown in fig. 5 and fig. 4) with a hollow structure, a supporting frame 412 fixedly connected between the left frame 411 and the right frame 411 for front-back horizontal supporting, and a cover casing 413 for enclosing the top of the left frame 411, the top of the supporting frame 412 and the right frame 411; wherein the outer side of the supporting frame 412 is covered with a layer of aluminum alloy skin 4131 (as shown in fig. 1 and 2); a manipulator connecting seat 414 (shown in fig. 4 and 5) with a hollow right-angled triangle structure is fixedly installed on the horizontal left side of the rack 41; the robot connecting base 414 is used to horizontally mount the two-degree-of-freedom grinding table 4 at the end of the robot 1 (see fig. 1). The hollow design is carried out on the structural part and the bearing part, so that the structural weight is greatly reduced, and the lightweight of the system is facilitated. Mounting of a carrying grinding head through a horizontal extension part of the frame 41; the polishing and using requirements of the external spiral weld joint can be met; the device can also extend into the pipe orifice of the steel pipe to realize the polishing use of the internal spiral weld joint.

Therefore, the aluminum alloy frame 41 is adopted to support the installation of the two-degree-of-freedom grinding platform 4; the structure is compact, the appearance is attractive, and the support is stable and reliable; the horizontal fixed support installation of the two-degree-of-freedom grinding platform 4 at the tail end of the multi-degree-of-freedom manipulator is light, compact, stable and reliable in structure; the universality of the integrated installation of the execution end of the multi-degree-of-freedom manipulator is ideal.

In the above embodiment, preferably: in order to guarantee the polishing precision: the axial mechanism 7 and the normal mechanism 9 respectively form a stable and reliable rotation and linear displacement conversion mechanism by a double guide rail, a double guide rail slide block, a screw rod and a screw rod slide block. Furthermore, as described later: the two-degree-of-freedom grinding platform 4 adopts screw pair transmission of a screw rod nut, and the transmission is precise, stable and reliable; the support device can cooperate with the reliable support of the parallel double-slide rail and double-slide block; the accurate, stable and reliable polishing displacement of the two-degree-of-freedom grinding platform 4 can be met.

In the above embodiment, further: the axial and normal displacement mechanism of the two-freedom grinding platform is designed for reliability, stability, light weight, compactness and miniaturization: (as shown in fig. 5) the two-degree-of-freedom grinding platform 4 has a frame 41 with a hollow frame structure, and the bottom end of the inner side of the frame body of the axial horizontal frame body of the frame 41 is slidably matched with two groups of horizontal guide rail sliders 43 (as shown in fig. 4 and 5) through two groups of horizontal guide rails 42 which are parallel front and back; two groups of horizontal guide rail sliding blocks 43 are respectively and fixedly connected with two front and rear inverted L-shaped horizontal sliding block connecting plates 44 in a front-rear axial symmetry manner; the front and rear inverted-L-shaped horizontal sliding block connecting plates 44 are fixedly connected with the front and rear vertical mounting side plates 301 of the grinding mechanism 3 respectively; a pair of vertical slide rails 302 (as shown in fig. 8) are vertically and parallelly and symmetrically mounted on the inner side plate body of the front and rear vertical mounting side plates 301, the vertical slide rails 302 are respectively matched with a pair of vertical guide rail sliders 303 in a sliding manner, one side of each vertical guide rail slider 303 is fixedly connected with a vertical lead screw slider 304, and the vertical lead screw sliders 304 are matched with vertical lead screws 305 in a screwing manner; the vertical screw 305 is rotatably supported and mounted on the inner side of the mounting side plate 301 through a vertical screw mounting seat 306 fixedly connected with the mounting side plate 301, and a power input end of the vertical screw 305 is coaxially and fixedly connected with a Z-axis vertical speed reducing motor 307 fixedly mounted by taking the mounting side plate 301 as a support; a vertical screw rod sliding block 304 driven by a Z-axis vertical speed reducing motor 307 to vertically displace is fixedly connected with the back side of a vertical base plate 309 through an L-shaped adapter plate 308, and the grinding mechanism 3 is fixedly installed on the front side of the vertical base plate 309; wherein, a driving wheel polishing motor 3101 of a polishing mechanism 3 is arranged at the back side of the plate body of the vertical base plate 309; the vertical base plate 309 drives the vertical screw rod slide block 304 through the Z-axis vertical speed reduction motor 307 to drive the sharpening mechanism 3 fixedly mounted on the front surface of the vertical base plate 309 to vertically displace relative to the vertical slide rails 302 fixedly mounted on the inner side plates of the front and rear vertical mounting side plates 301 (as shown in fig. 6, 7 and 8); the outer sides of the plate bodies of the front and rear vertical mounting side plates 301 are fixedly connected with horizontal screw rod sliding blocks 45 (as shown in FIG. 5); the horizontal screw rod sliding block 45 is screwed and matched with the horizontal screw rod 46; the horizontal screw rod 46 is horizontally and rotatably arranged on the inner side of the frame body of the frame 41 through a horizontal screw rod mounting seat 47, and the horizontal screw rod 46 is horizontally arranged above the horizontal guide rail sliding block 43 in parallel; the power input end of the horizontal screw rod 46 is coaxially and fixedly connected with the X-axis horizontal speed reducing motor 6; the X-axis horizontal speed reducing motor 6 drives the horizontal screw rod sliding block 45 to drive the front and rear vertical mounting side plates 301 and the coping mechanism 3 to horizontally and axially displace relative to the two groups of horizontal guide rails 42 (see fig. 5).

The advantages are that: the axial mechanism and the normal mechanism respectively adopt double-sliding-rail sliding blocks, the double-sliding-rail sliding blocks provide linear guide on one hand, and the double-sliding-rail sliding blocks play a role in bearing on the other hand. The X-axis horizontal speed reducing motor 6 drives the horizontal screw rod 46 to do rotary motion, the horizontal screw rod sliding block 45 converts the rotary motion into left-right linear motion, and the front vertical installation side plate 301 and the rear vertical installation side plate 301 are connected with the horizontal screw rod sliding block 45, so that the whole triangular grinding head grinding mechanism 3 is driven to do horizontal motion. The front and rear vertical mounting side plates 301 are respectively fixed on the front and rear groups of horizontal guide rail sliders 43 by the front and rear L-shaped horizontal slider connecting plates 44 axially symmetric with the grinding mechanism 3, so that the weight of the whole triangular grinding head grinding mechanism 3 is transferred to the front and rear horizontal guide rails 42. The horizontal guide rail 42 functions as a load bearing guide. In the same way: the Z-axis vertical speed reduction motor 307 drives the vertical screw 305 to make a rotational motion, the vertical screw slider 304 converts the rotational motion into an up-and-down linear motion, and the vertical screw slider 304 is fixedly connected with the vertical base plate 309 through an L-shaped adapter plate 308, so as to drive the triangular grinding head grinding mechanism 3 mounted on the vertical base plate 309 to make an up-and-down motion.

Briefly, in use: the two parallel high-precision guide rails are respectively installed in the horizontal direction and the vertical direction, a high-precision lead screw is used in a matched mode, the motion straightness accuracy of the linear displacement mechanism driven by the vertical speed reducing motor and the horizontal speed reducing motor is good, the precision of a motor transmission system is greatly improved, and the high-precision requirement of polishing welding seams is met.

In the above embodiment, the grinding mechanism is designed for compactness, miniaturization, stability and light weight, and the abrasive belt is convenient to replace: the sharpening mechanism 3 (shown in fig. 6, 7, 8 and 9) has a driving wheel 31, a sharpening wheel 32 and an adjusting wheel 33 which are distributed in a triangular shape, and the driving wheel 31, the sharpening wheel 32 and the adjusting wheel 33 are externally wrapped with a tensioning installation abrasive belt 34; the grinding wheel 32 is driven by a three-axis cylinder 321 to realize linear tensioning displacement adjustment of the grinding wheel 32 in the Z-axis direction; the adjusting wheel 33 pushes one end of the adjusting wheel shaft 332 to rotate around a hinge point at the other end of the adjusting wheel shaft 332 by rotating the hand wheel 331 so as to prevent the abrasive belt 34 wrapped on the adjusting wheel 33 from deviating (as shown in fig. 10); the adjusting mechanism of the adjusting wheel 33 consists of a hand wheel 331, a bolt 334, a nut 335, a knuckle bearing 336, an adjusting wheel shaft 332, a ball bearing I337, a retainer ring 333 for a bearing hole, a cylindrical pin 338, an adjusting wheel frame 339 and an adjusting wheel 332; one end of the adjusting wheel shaft 332 is hinged and rotatably connected with an adjusting wheel frame 339 through a cylindrical pin 338, and 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 joint bearing 336 is connected with a screw pair of a feed screw nut consisting of a nut 335, a bolt 334 and a hand wheel 331.

When in use: the adjusting wheel (as shown in fig. 10) 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; the highest point of the adjusting wheel mounted on the adjusting wheel shaft 332 through the bearing rotating support is coincided with the center of the abrasive belt, so that the abrasive belt 34 wrapped on the adjusting wheel 33 is prevented from deviating; the hand wheel 331 is limited and fixed relative to the top end of the adjusting wheel frame 339 and can only rotate; the bolt 334 screwed with the hand wheel 331 and the nut 335 vertically displaces relative to the adjusting wheel frame 339, and drives the right end of the adjusting wheel shaft 332 to swing upwards or downwards around the cylindrical pin 338 at the left end of the adjusting wheel shaft 332 through the knuckle bearing 336 fixedly connected with the bottom end of the bolt 334, so that the abrasive belt 34 wrapped on the adjusting wheel 33 is prevented from deviating; simple structure, convenient adjustment, economy and practicality.

When in use: the grinding of the abrasive belt 34 is adopted to replace grinding wheel grinding, and compared with grinding wheel grinding, the grinding ratio of the abrasive belt 34 is 4-10 times of that of the grinding wheel, so that the abrasive belt 34 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 3 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.

In the above embodiment, further: to facilitate installation and replacement of the grinding wheel 32: the grinding mechanism 3 is provided with a driving wheel 31, a grinding wheel 32 and an adjusting wheel 33 which are distributed in a triangular shape; and the driving wheel 31, the grinding wheel 32 and the adjusting wheel 33 are externally wrapped with a tension mounting abrasive belt 34 (as shown in fig. 14, 15 and 16); the grinding wheel 32 has an inverted U-shaped upper mounting frame 3201; the top end of the upper mounting rack 3201 is fixedly connected with the execution end of the triaxial cylinder 321 which is vertically and downwards mounted; a lower mounting rack 3203 for clamping and fixedly mounting the grinding wheel shaft 3202 up and down is arranged opposite to the upper mounting rack 3201 up and down; the opposite clamping ends of the upper mounting frame 3201 and the lower mounting frame 3203 are respectively provided with an axle groove 3204 matched with the grinding axle 3202 in size; shafts at two ends of the grinding wheel shaft 3202 are clamped, clamped and horizontally and fixedly installed in upper and lower wheel shaft grooves 3204 of upper and lower mounting frames 3201 and 3203 by two lower fastening bolts 3205 respectively; the middle part of the grinding wheel shaft 3202 is coaxially and rotatably supported and provided with a grinding wheel 32 through a ball bearing II 3206; a rubber layer is arranged on the outer circumference of the wheel body of the grinding wheel 32; and the shaft end of the ball bearing II 3206 is matched with a retainer ring 3207 for a mounting hole and a shaft end cover 3208. Namely, the sanding wheel tensions the sanding belt 34 through the three-axis cylinder 321; 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.

When in use: (see fig. 15) the grinding wheel adopts an upper wheel shaft groove 3204 and a lower wheel shaft groove 3204 of an upper mounting frame 3201 and a lower mounting frame 3203 to clamp up and down and horizontally and fixedly mount a grinding wheel shaft 3202 by using an upward lower fastening bolt 3205; a grinding wheel 32 is coaxially and rotatably supported and mounted on the grinding wheel shaft 3202 through a ball bearing II 3206; the polishing wheel is 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.

In the above embodiment, preferably: to ensure the reliability of the visual data acquisition: the grinding mechanism 3 is provided with a driving wheel 31, a grinding wheel 32 and an adjusting wheel 33 which are distributed in a triangular shape; wherein the grinding wheel 32 is located at the bottom end of the triangle, and the laser profiler 5 is fixedly installed outside the fixed supporting structure of the grinding wheel 32.

Compared with the prior art: the invention designs an automatic grinding robot for spiral weld joints at the ends of spiral steel pipes, which adopts a two-degree-of-freedom fine grinding actuating mechanism arranged at the actuating end of a multi-degree-of-freedom manipulator, improves the grinding precision of the manipulator by simplifying motion control, and overcomes the defect that the quality of weld beads at the ends of the spiral steel pipes ground by the multi-degree-of-freedom grinding manipulator in the prior art cannot meet the process index requirements specified by API Spec5L standard and GBT 97111-1997 standard; the technical problem of manual secondary grinding is still needed. Moreover, according to the scheme, the two-degree-of-freedom grinding platform 4 is additionally arranged at the execution end of the multi-degree-of-freedom manipulator, complex cloud computing is not needed, and the two-degree-of-freedom grinding platform has the advantages of high precision, high strength, intelligent detection, real-time feedback, high response speed and the like.

On the basis, the polishing method adopts a two-degree-of-freedom grinding platform with machine vision which is horizontally arranged at the execution end of the multi-degree-of-freedom manipulator 1. When the grinding precision is improved, the motion control of the mechanical arm is relatively simple. Wherein, the laser profiler 5 is a scanControl2900/2950/2910 series 3D laser profiler of Mi Iridium company.

The invention has the advantages that: the two-degree-of-freedom grinding platform adopts a horizontal installation mode at the tail end execution end of the multi-degree-of-freedom manipulator, can adapt to polishing of the outer weld joint of the 508 spiral welded pipe with the outer diameter, and can also realize polishing of the inner weld joint of the spiral steel pipe: in addition, the whole two-degree-of-freedom grinding platform is designed in a small and light manner; the miniaturization installation is achieved; the polishing of the inner welding seam in the narrow space of the inner welding seam is met.

And then, the high-strength aluminum alloy structural part is matched with a high-strength firm connecting bolt, so that firm support and reliable horizontal installation of the two-degree-of-freedom grinding platform at the tail end of the manipulator are realized, and the structural stability of the two-degree-of-freedom grinding platform during grinding is ensured.

The two-degree-of-freedom grinding platform is respectively provided with two parallel high-precision guide rails in the horizontal direction and the vertical direction, a high-precision lead screw is used in a matched manner, the straightness of the motor motion is good, the precision of a motor transmission system is greatly improved, and the high-precision requirement of grinding a welding line is guaranteed.

The two-degree-of-freedom grinding platform frame 41 is designed in a hollow mode on the structural part and the bearing part, so that the structural weight is greatly reduced, and the light weight of the system is facilitated. The whole two-degree-of-freedom grinding platform is installed in a modular design, so that the whole system is more convenient to disassemble, assemble and maintain.

The zero-position proximity switch is additionally arranged at the specific position of the two-degree-of-freedom grinding platform, so that the horizontal and vertical motors have accurate initial positions in movement, and the precision is further guaranteed; the horizontal and vertical moving mechanisms are respectively provided with limit proximity switches for limiting the horizontal and vertical directions, so that the motion of the horizontal and vertical motors is effectively protected, the grinding head provided with the contourgraph cannot impact on the structural frame of the frame 41, and the overall safety of the structure is ensured.

The working principle is as follows: the invention is by the two-degree-of-freedom grinding platform horizontally and fixedly installed with manipulator and execution end, there are feed mechanism and axial translational movement mechanism that can be translated along the normal direction in the two-degree-of-freedom grinding platform, and is furnished with the high-accuracy laser profilometer of machine vision system of high-accuracy weld detection, realize the position control of the closed loop totally through the upper computer control system taking movement control card as core, grating sensor, magnetic grating sensor, the speed control adopts the Blend Motion mode, through the vision detection algorithm developed by oneself, finish the inner, outer weld two-degree-of-freedom grinding platform of the spiral welded pipe and carry the linear displacement regulation of the abrasive belt type grinding head in horizontal axial direction and vertical normal direction, and then realize the inclined compound movement of the abrasive belt type grinding head along the spiral weld of the spiral welded pipe; and realizing the accurate grinding and polishing operation of the spiral weld joint of the steel pipe.

In summary, the following steps: the manipulator 1 is controlled in real time and guided by the laser profiler 5 in real time, so that the real-time track can be continuously corrected, and the tracking precision is improved as much as possible, thereby providing reliable guarantee for further improving the grinding precision of the welding seam; high-precision two-degree-of-freedom grinding platform 4: the allowable value of the axial control error of the grinding platform where the grinding head is located is less than 0.05mm, the allowable value of the normal control error is less than 0.01mm, the requirement of the residual weld height is far higher than the requirement of the weld height, and the realization of high-precision and high-quality weld grinding is ensured. On the basis of machine grinding, the subsequent manual fine grinding and polishing steps can be omitted, and the high-precision full-automatic polishing and polishing of the welding seam of the spiral steel pipe can be realized; the surface of the weld joint is polished without damaging the parent metal; the minimum residual height after grinding can be less than or equal to 0.1mm and is higher than the requirements of API Spec5L standard and GBT 97111-1997 standard; and the polished surface is smooth and flat without hollow phenomenon. The laser profiler 5 cooperates with a special detection algorithm, and compared with the detection equipment sold in the market, the highest precision of the detection equipment is 0.1mm, the detection with the precision of less than 0.05mm (measured value) is realized; powerful detection technical support is provided for high-precision weld grinding; moreover, the real-time control of the manipulator is guided by the laser profiler 5 in real time, so that the real-time track can be continuously corrected, and the tracking precision is improved as much as possible, thereby providing reliable guarantee for further improving the grinding precision of the welding seam; high-precision two-degree-of-freedom grinding platform 4: 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. The triangular grinding mechanism 3 adopts pneumatic vertical tensioning to adjust the height of the grinding 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 simple and convenient to replace. 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; the abrasive belt 34 is prevented from deviating; simple structure, convenient adjustment, economy and practicality. The grinding wheel is clamped and horizontally and fixedly mounted by adopting upper and lower mounting frames (3201 and 3203), and grinding wheel shaft components including a check ring 3207 for a hole and a ball bearing II 3206 of a shaft end cover 3208 are convenient and convenient to disassemble, assemble, replace and mount; the maintenance is convenient; the structure is stable and reliable. The two-degree-of-freedom grinding platform 4 is precise, stable and reliable in transmission; the guide support structure of the double-sliding-rail sliding block is cooperated to act together; the requirements of the two-degree-of-freedom grinding platform on the adjustment of the axial and normal displacement mechanisms on the accurate, stable and reliable grinding displacement can be met. The aluminum alloy frame 41 has a compact structure, attractive appearance and stable and reliable support; the two-degree-of-freedom grinding platform 4 and the execution end of the multi-degree-of-freedom manipulator are ideal in universality in integrated installation. The axial displacement mechanism and the normal displacement mechanism cooperate with the zero point, the left and right proximity switches and the upper and lower proximity switches; reliable guarantee is provided for high-precision finish grinding; the residual height of the welded seam after grinding can be controlled within 0-0.5 mm; is far higher than the requirements of API Spec5L standard and GBT 97111-1997 standard. 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. The laser contourgraph 5 is fixed at the bottom of the grinding mechanism 3; and reliable guarantee is provided for the accuracy and timeliness of data acquisition.

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, which are not intended to limit the scope of the present invention, and therefore, all equivalent changes made by the contents of the claims of the present invention should be included in the claims of the present invention.

Claims

1. Automatic coping robot of spiral steel pipe end spiral weld, its characterized in that: the two-freedom-degree grinding platform (4) is horizontally and fixedly provided with a horizontal structure at the executing tail end of the multi-freedom-degree manipulator (1) and is used for grinding by using an abrasive belt; the two-degree-of-freedom grinding platform (4) is provided with a frame (41) with a horizontal aluminum alloy hollow structure; an axial mechanism (7) which horizontally displaces relative to the axial direction of the rack (41) is arranged on the inner side of the rack; a normal mechanism (9) is arranged at the axial horizontal displacement executing end of the axial mechanism (7); a normal vertical linear displacement executing end of the normal mechanism (9) is fixedly provided with the grinding mechanism (3) and drives the grinding mechanism (3) to vertically displace in a normal straight line; a laser contourgraph (5) is fixedly installed on the outer side of the grinding mechanism (3); the laser contourgraph (5) linearly displaces along the horizontal axis or the vertical normal direction of the coping mechanism (3) relative to the rack (41);

an axial mechanism (7) of the two-degree-of-freedom grinding platform (4) is fixedly provided with a left limit proximity switch (71), a zero point proximity switch (72) and a right limit proximity switch (73) by taking a rack (41) as a carrier; the normal mechanism (9) is fixedly provided with an upper limit proximity switch (91), a zero point proximity switch (92) and a lower limit proximity switch (93) by taking a front vertical installation side plate (301) and a rear vertical installation side plate (301) which are arranged on the normal mechanism as carriers;

the frame (41) is made of aluminum alloy; the rack (41) comprises a left frame (411) and a right frame (411) which are of hollow structures, a supporting frame (412) which is fixedly connected with the left frame (411) and the right frame and is used for horizontally supporting front and back, and a sealing cover shell (413) for sealing the tops of the left frame (411), the right frame (411) and the supporting frame (412); wherein the outer side of the supporting frame (412) is coated with a layer of aluminum alloy skin (4131); a manipulator connecting seat (414) with a hollow right-angled triangle structure is fixedly arranged on the horizontal left side of the rack (41); the manipulator connecting seat (414) is used for horizontally installing the two-degree-of-freedom grinding platform (4) at the execution tail end of the manipulator (1);

the axial mechanism (7) and the normal mechanism (9) respectively form a stable and reliable rotation and linear displacement conversion mechanism by a double guide rail, a double guide rail slide block, a screw rod and a screw rod slide block.

2. The automatic grinding robot for spiral weld joints at the pipe ends of spiral steel pipes according to claim 1 is characterized in that: the two-degree-of-freedom grinding platform (4) is provided with a rack (41) with a hollow frame structure, and the bottom end of the inner side of the axial horizontal rack body of the rack (41) is matched with two groups of horizontal guide rail sliding blocks (43) in a sliding manner through two groups of horizontal guide rails (42) which are parallel front and back; two groups of horizontal guide rail sliding blocks (43) are respectively and fixedly connected with two front and rear inverted L-shaped horizontal sliding block connecting plates (44) in a front-rear axial symmetry manner; the front and rear inverted L-shaped horizontal sliding block connecting plates (44) are fixedly connected with front and rear vertical mounting side plates (301) of the grinding mechanism (3) respectively; the inner side plate bodies of the front and rear vertical installation side plates (301) are vertically parallel and symmetrically provided with a pair of vertical slide rails (302), the vertical slide rails (302) are respectively matched with a pair of vertical guide rail slide blocks (303) in a sliding manner, one sides of the vertical guide rail slide blocks (303) are fixedly connected with vertical lead screw slide blocks (304), and the vertical lead screw slide blocks (304) are matched with vertical lead screws (305) in a screwing manner; the vertical screw rod (305) is rotatably supported and mounted on the inner side of the mounting side plate (301) through a vertical screw rod mounting seat (306) fixedly connected with the mounting side plate (301), and a power input end of the vertical screw rod (305) is coaxially and fixedly connected with a Z-axis vertical speed reducing motor (307) fixedly mounted by taking the mounting side plate (301) as a support; a vertical screw rod sliding block (304) driven by a Z-axis vertical speed reducing motor (307) to vertically displace is fixedly connected with the back side of a vertical base plate (309) through an L-shaped adapter plate (308), and a grinding mechanism (3) is fixedly installed on the front side of the vertical base plate (309); wherein, a driving wheel polishing motor (3101) of a polishing mechanism (3) is arranged at the back side of the plate body of the vertical substrate (309); the vertical base plate (309) drives a vertical screw rod sliding block (304) to drive a grinding mechanism (3) fixedly installed on the front surface of the vertical base plate (309) to vertically displace relative to a vertical sliding rail (302) fixedly installed on the inner side plate body of the front and rear vertical installation side plates (301) through a Z-axis vertical speed reducing motor (307); the outer sides of the plate bodies of the front and rear vertical mounting side plates (301) are fixedly connected with a horizontal screw rod sliding block (45); the horizontal screw rod sliding block (45) is screwed and matched with the horizontal screw rod (46); the horizontal screw rod (46) is horizontally and rotatably arranged on the inner side of the frame body of the rack (41) through a horizontal screw rod mounting seat (47), and the horizontal screw rod (46) is horizontally arranged above the horizontal guide rail sliding block (43) in parallel; the power input end of the horizontal screw rod (46) is coaxially and fixedly connected with an X-axis horizontal speed reducing motor (6); the X-axis horizontal speed reducing motor (6) drives the horizontal screw rod sliding block (45) to drive the front and rear vertical installation side plates (301) and the grinding mechanism (3) to horizontally and axially displace relative to the two groups of horizontal guide rails (42).

3. The automatic grinding robot for spiral weld joints at the pipe ends of spiral steel pipes according to claim 1 is characterized in that: the grinding mechanism (3) is provided with a driving wheel (31), a grinding wheel (32) and an adjusting wheel (33) which are distributed in a triangular shape, and an abrasive belt (34) is arranged outside the driving wheel (31), the grinding wheel (32) and the adjusting wheel (33) in a wrapping and tensioning mode; the grinding wheel (32) is driven by a three-axis cylinder (321) to realize linear tensioning displacement adjustment of the grinding wheel (32) in the Z-axis direction; the adjusting wheel (33) pushes one end of the adjusting wheel shaft (332) to rotate around a hinge point at the other end of the adjusting wheel shaft (332) by rotating the hand wheel (331) so as to prevent the abrasive belt (34) wrapped on the adjusting wheel (33) from deviating; the adjusting mechanism of the adjusting wheel (33) consists of a hand wheel (331), a bolt (334), a nut (335), a knuckle bearing (336), an adjusting wheel shaft (332), a ball bearing I (337), a retainer ring (333) for a bearing hole, a cylindrical pin (338), an adjusting wheel frame (339) and the adjusting wheel (33); one end of the adjusting wheel shaft (332) is hinged and rotatably connected with the adjusting wheel frame (339) through a cylindrical pin (338), and 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 a screw pair of a screw nut and a screw nut consisting of a nut (335), a bolt (334) and a hand wheel (331).

4. The automatic grinding robot for spiral weld joints at the pipe ends of spiral steel pipes according to claim 1 is characterized in that: the grinding mechanism (3) is provided with a driving wheel (31), a grinding wheel (32) and an adjusting wheel (33) which are distributed in a triangular shape; and the driving wheel (31), the grinding wheel (32) and the adjusting wheel (33) are wrapped with a tensioning installation abrasive belt (34); the grinding wheel (32) is provided with an upper mounting rack (3201) in an inverted U shape; the top end of the upper mounting frame (3201) is fixedly connected with the execution end of the vertically downward-mounted triaxial cylinder (321); a lower mounting rack (3203) used for clamping and fixedly mounting the grinding wheel shaft (3202) up and down is arranged opposite to the upper mounting rack (3201) up and down; the opposite clamping ends of the upper mounting frame (3201) and the lower mounting frame (3203) are respectively provided with an axle groove (3204) matched with the grinding axle (3202) in size; shafts at two ends of the grinding wheel shaft (3202) are clamped horizontally and fixedly installed in upper and lower opposite clamping modes in upper and lower wheel shaft grooves (3204) of upper and lower mounting frames (3201, 3203) by using two lower fastening bolts (3205) respectively; the middle part of the shaft body of the grinding wheel shaft (3202) is coaxially and rotatably supported and provided with a grinding wheel (32) through a ball bearing II (3206); a rubber layer is arranged on the outer circumference of the wheel body of the grinding wheel (32); and the shaft end of the ball bearing II (3206) is matched with a retainer ring (3207) for a mounting hole and a shaft end cover (3208).

5. The automatic grinding robot for spiral weld joints at the pipe ends of spiral steel pipes according to claim 1 is characterized in that: the grinding mechanism (3) is provided with a driving wheel (31), a grinding wheel (32) and an adjusting wheel (33) which are distributed in a triangular shape; wherein the grinding wheel (32) is positioned at the bottom end of the triangle, and the laser profile instrument (5) is fixedly arranged at the outer side of the fixed supporting structure of the grinding wheel (32).