CN111451898B

CN111451898B - Grinding and polishing robot for weld joints at pipe ends of spiral steel pipes

Info

Publication number: CN111451898B
Application number: CN202010128811.5A
Authority: CN
Inventors: 张瑾宇; 王林军; 刘伟; 马利; 刘晨
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: 2022-02-08
Anticipated expiration: 2040-02-28
Also published as: CN111451898A

Abstract

The grinding and polishing robot for the weld joint at the pipe end of the spiral steel pipe adopts a two-degree-of-freedom fine grinding actuating mechanism provided with a laser profilometer and arranged at an actuating end of a multi-degree-of-freedom manipulator, improves the grinding precision and the polishing precision of the manipulator while simplifying motion control, and overcomes the defect that the quality of the weld joint at the pipe end of the spiral steel pipe 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. 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

Grinding and polishing robot for weld joints at pipe ends of spiral steel pipes

Technical Field

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

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 of the spiral welded pipe in the length range of at least 150mm from the pipe end is removed, namely, the axial grinding elongation 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 is carried out only by adopting 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 addition, in some key pipeline construction, the requirement of smooth transition between the polished welding seam and the parent metal is also provided for polishing the welding seam at the pipe end, namely the welding seam surplus height is 0. Therefore, in order to realize the automatic polishing and grinding of the weld reinforcement of 0 on the basis of solving the grinding problems of high precision and high grinding ratio of the weld reinforcement of the pipe end, the following improved technical scheme is provided

Disclosure of Invention

The technical problems solved by the invention are as follows: the grinding and polishing robot for the weld joints at the ends of the spiral steel pipes has the advantages that a two-degree-of-freedom fine grinding actuating mechanism is mounted at the actuating end of a multi-degree-of-freedom manipulator, so that the motion control of the manipulator is simplified, the grinding precision of the actuating end of the manipulator is improved, and the grinding ratio is improved; and the polishing function of the polishing manipulator with multiple degrees of freedom after polishing is realized.

The technical scheme adopted by the invention is as follows: the grinding and polishing robot for the weld joint at the end of the spiral steel pipe is provided with a two-degree-of-freedom grinding and polishing platform for performing abrasive belt grinding on the horizontal fixed mounting of the tail end of a multi-degree-of-freedom manipulator; the two-degree-of-freedom grinding and polishing platform is provided with a frame with a horizontal aluminum alloy hollow frame 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 a polishing mechanism and drives the grinding mechanism and the polishing mechanism to vertically displace in a normal straight line; and the laser contourgraph is fixedly installed on the outer side of the grinding mechanism and carries out linear displacement of the laser contourgraph relative to the horizontal axis and the vertical normal of 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 and polishing platform is fixedly provided with a left limit proximity switch, a zero point proximity switch I and a right limit proximity switch by taking a rack as a carrier; and the normal mechanism is fixedly provided with an upper limit proximity switch, a zero point proximity switch II 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 and polishing 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 and polishing platform at the executing 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 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 and polishing platform is designed for reliability, stability, light weight, compactness and miniaturization: the two-degree-of-freedom grinding and polishing platform is provided with a rack with a hollow frame structure, and the bottom end of the inner side of the axial horizontal rack body of the rack 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 sliding blocks are fixedly connected with an inverted L-shaped horizontal sliding block connecting plate respectively; the front and rear inverted L-shaped horizontal slider 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; the vertical screw rod sliding block is fixedly connected with the back side of the vertical substrate through an L-shaped adapter plate fixedly connected with the vertical screw rod sliding block in a switching way so as to drive the vertical substrate to vertically displace in a normal direction; the grinding mechanism is fixedly arranged on the front surface 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.

Aiming at the residual height of the welding seam, the polishing function of realizing the smooth transition of the residual height of the welding seam and the parent metal is used as follows: the normal mechanism is provided with a vertical substrate which is lifted in the normal vertical direction relative to the axial mechanism; the vertical substrate is fixedly provided with a polishing mechanism through a cuboid installation frame; a guard plate is arranged on the outer side of the polishing mechanism; the polishing mechanism is provided with a pair of micro cylinders which synchronously and parallelly execute lifting action in the vertical direction, and the top ends of the micro cylinders are fixedly connected with the lower bottom surface of the cuboid mounting frame into a whole; the micro cylinder is fixedly connected with the execution end facing downwards vertically and pushes the motor supporting plate to move up and down, and the motor supporting plate supports the installation of the polishing motor; the polishing motor is connected with the polishing wheel and drives the polishing wheel to rotate for polishing. Cuboid installation frame 1001 uses screw fastening as an organic whole through the horizontal screw hole that this system of frame was made and perpendicular base plate body through-hole.

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 and an adjusting wheel frame; 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 a grinding and polishing robot for a weld joint at the end of a spiral steel pipe, 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 a weld bead at the end of the spiral steel pipe 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. according to the scheme, the grinding function and the polishing function are integrated, and the manipulator is used as a carrier at the manipulator execution tail end, so that two-degree-of-freedom accurate displacement adjustment of the manipulator execution tail end grinding mechanism or polishing mechanism is realized; the subsequent manual accurate grinding and polishing steps can be omitted, and the high-precision polishing use after the high-precision full-automatic polishing of the inner and outer welding seams of the spiral steel pipe is finished is realized; the surface of the weld joint after grinding and polishing does not damage the parent metal; the grinding surface is smooth and flat, and no depression phenomenon exists; the pipe end can be smoothly butted for use;

2. this scheme high accuracy two degree of freedom grinding and polishing 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, and the allowable value is far higher than the requirement of the extra-high precision of the welding seam, so that the realization of high-precision and high-quality welding seam grinding is ensured;

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

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 two-degree-of-freedom grinding and polishing platform 4 in the scheme has precise, stable and reliable 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 and polishing platform on the adjustment of the axial and normal displacement mechanisms for accurate, stable and reliable polishing 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 two-degree-of-freedom grinding and polishing platform 4 and the execution end of the multi-degree-of-freedom manipulator are integrally installed, so that the universality 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; reliable guarantee is provided for the accuracy and timeliness of data acquisition;

12. when the polishing mechanism polishes, based on the ground welding seam surplus height data acquired by the vision system, the polishing mechanism is carried by the two-degree-of-freedom moving mechanism to move in the axial normal direction according to the trajectory route planned by the mechanical arm during grinding, the pipe end welding seam surplus height is polished accurately, the polishing precision is reliable, and the accurate grinding polishing of the welding seam can be completed by replacing manpower.

Drawings

FIG. 1 is a front perspective view of the sharpening mechanism of the present invention;

FIG. 2 is a rear perspective view of the sharpening mechanism;

FIG. 3 is a back front view of the sharpening mechanism;

FIG. 4 is a front perspective view of the other side of the sharpening mechanism;

FIG. 5 is an adjustment schematic of a hand wheel adjustment mechanism of the adjustment wheel;

FIG. 6 is a front view of a hand wheel adjustment mechanism for an adjustment wheel;

FIG. 7 is a perspective view of a hand wheel adjustment mechanism of the adjustment wheel;

FIG. 8 is a schematic diagram of the cylinder tensioning of the grinding wheel in the sharpening mechanism;

FIG. 9 is a front view of the grinding wheel with the three-axis cylinder removed;

FIG. 10 is a cross-sectional view of the mounting structure of the grinding wheel of FIG. 9;

FIG. 11 is a perspective view of the grinding wheel of FIG. 9;

FIG. 12 is a perspective view of the two-degree-of-freedom grinding and polishing platform axial displacement mechanism after the proximity switch is installed;

FIG. 13 is a front view of the sharpening mechanism with proximity switches mounted to the normal displacement mechanism at the back of the sharpening mechanism;

FIG. 14 is a flow chart of the grinding and polishing process of the present invention;

FIG. 15 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. 16 is a graph of the trajectory in three dimensions of the actual helical weld of the present invention of FIG. 15;

FIG. 17 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. 18 is a two-dimensional view of the visual scanning result of the weld seam at the end of the spiral steel pipe according to the present invention;

FIG. 19 is a two-dimensional view of a visual scan result after the weld grinding of the present invention;

FIG. 20 is a bottom perspective view of the two-degree-of-freedom grinding and polishing platform of the present invention with the upper polishing mechanism mounted thereon;

FIG. 21 is a right side view of the two degree-of-freedom grinding and polishing platform of the present invention with the polishing mechanism mounted thereon;

FIG. 22 is a schematic view of a rectangular parallelepiped mounting frame mounted on the back side of a vertical substrate in accordance with the polishing mechanism of the present invention;

FIG. 23 is a perspective view of the polishing mechanism of the present invention;

FIG. 24 is a perspective view of a rectangular parallelepiped mounting frame of the present invention;

FIG. 25 is a bottom view of a rectangular parallelepiped mounting frame of the present invention.

Detailed Description

Specific embodiments of the present invention are described below in conjunction with fig. 1-25. 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 grinding and polishing robot for the weld joints at the ends of the spiral steel pipes 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-degree-of-freedom grinding and polishing platform 4 is horizontally fixed and installed at the tail end of the multi-degree-of-freedom manipulator and is ground by using an abrasive belt; the two-degree-of-freedom grinding and polishing platform 4 is provided with a frame 41 with a horizontal aluminum alloy hollow frame 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 the polishing mechanism 10 and drives the grinding mechanism 3 and the polishing mechanism 10 to vertically displace in a normal straight line; the laser contourgraph 5 is fixedly installed on the outer side of the grinding mechanism 3, and the laser contourgraph 5 is carried to linearly displace in the horizontal axial direction and the vertical normal direction relative to the rack 41.

The grinding method of the grinding and polishing robot for the weld joint at the pipe end of the spiral steel pipe comprises the following steps:

step S001, determining the position of the steel pipe: the steel pipe end welding seam grinding and polishing robot comprises an upper computer, a PLC, a motion control card, a manipulator, a non-contact laser profiler 2 and a two-degree-of-freedom grinding and polishing platform 4 carrying a grinding mechanism 3 and vertically moving along axial and normal spaces, wherein the steel pipe diameter is input into the upper computer of the spiral steel pipe end welding seam grinding and polishing robot, the manipulator is controlled by the upper computer, the two-degree-of-freedom grinding and polishing platform 4 fixedly carried by an execution end of the manipulator moves from a zero position to an initial position, and the laser profiler 5 scans and determines the position of a detected steel pipe;

it should be noted that: the upper computer is used for issuing and controlling control instructions of the mechanical arm and each mechanism on the two-degree-of-freedom grinding and polishing platform 4; and the upper computer uses LABVIEW to develop a friendly graphical user interface, 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 coping mechanism 3 carried by the two-degree-of-freedom grinding and polishing 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 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 circle of the steel pipe and the highest point of the steel pipe according to the diameter of the steel pipe, records coordinate information of specific points by an upper computer and establishes a coordinate system of the steel pipe to be polished, so that the circular arc track of the manipulator concentrically moves around the outer circumferential surface of the steel pipe to be polished is planned;

step S003, pipe end searching: after the manipulator carries a two-degree-of-freedom grinding and polishing platform 4 and translates to a position right above the 12 th highest point of the steel pipe under the guidance of a laser profiler 5, the manipulator 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 and polishing platform 4 drives an axial mechanism 7 to drive a coping 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 mechanical arm and a two-degree-of-freedom grinding and polishing platform 4; the PLC controls a manipulator to drive the two-degree-of-freedom grinding and polishing 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 spiral angle of the grinding mechanism 3;

step S005, scanning start point: the PLC controls the Y-shaped roller for lifting the steel pipe to rotate, and the laser profiler 5 searches for a welding seam while rotating to determine a welding seam 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: (as shown in fig. 15), according to the scanning result of the laser profiler 5, the grinding mechanism 3 in the two-degree-of-freedom grinding and polishing platform 4 drives the axial mechanism 7 to drive the grinding mechanism 3 to move horizontally by the X-axis horizontal speed reducing motor 6 in the two-degree-of-freedom grinding and polishing platform 4, and the two-degree-of-freedom grinding and polishing platform 4 cooperates with a manipulator to move concentrically around the central axis of the spiral steel pipe according to a planned circular arc track (see fig. 15); the two-degree-of-freedom grinding and polishing 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 to drive the two-degree-of-freedom grinding and polishing 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. 17); because the manipulator moves in an arc shape concentric with the steel pipe, and simultaneously, the characteristic points of the welding seam are recorded according to the scanning data of the laser profiler 5 (as shown in figure 18); the axial horizontal speed reducing motor of the two-degree-of-freedom grinding and polishing 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 and polishing 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 and polishing 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 and polishing platform 4 controls the X-axis horizontal speed reducing motor 6 to drive the axial mechanism 7 to drive the grinding mechanism 3 to axially and horizontally move, so that the grinding mechanism 3 moves to the initial position when the laser contourgraph 5 scans a welding line, 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 manipulator and the two-degree-of-freedom grinding and polishing 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 manipulator moves according to the planned circular arc track, the axial mechanism 7 of the two-degree-of-freedom grinding and polishing platform 4 moves at a matched speed, and the Z-axis vertical speed reducing motor 8 in the two-degree-of-freedom grinding and polishing 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 17 and 18); under the coordinated motion of the horizontal motor, the vertical motor and the manipulator, the whole two-degree-of-freedom grinding and polishing 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 and polishing 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, thereby simplifying control and improving grinding precision. 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, carrying out second scanning detection on the welding seam: after the first grinding is finished, stopping the grinding head of the grinding mechanism 3, and scanning by a laser profiler 5 to detect the weld reinforcement;

step S009, polishing by a polishing mechanism: the double micro cylinders 1003 of the polishing mechanism 10 synchronously execute a pushing extension action, the polishing motor 1005 and the polishing wheel 1006 fixedly mounted on the pushing motor supporting plate 1004 vertically descend to a polishing position, and based on the data of the weld reinforcement height obtained by scanning of the laser profiler 5 in the step S008, the polishing operation is started under the planned path provided by the manipulator, the axial mechanism and the normal mechanism until the polishing height of the weld reinforcement height is 0.

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 the mechanical arm and each mechanism on the two-degree-of-freedom grinding and polishing 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 coping mechanism 3 and the polishing mechanism 1 carried by the two-degree-of-freedom grinding and polishing 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 and polishing platform 4 controls the X-axis horizontal speed reducing motor 6 to drive the axial mechanism 7 to drive the grinding mechanism 3 to axially and horizontally move, so that the grinding mechanism 3 moves to the initial position when the laser contourgraph 5 scans a welding line, and the PLC controls the X-axis horizontal speed reducing motor 6 to move to complete position compensation. During polishing, the two-degree-of-freedom grinding and polishing platform 4 controls the X-axis horizontal speed reducing motor 6 to drive the axial mechanism 7 to drive the polishing mechanism 10 to axially and horizontally move according to the welding seam surplus height data acquired by the laser profiler 5, and polishes the welding seam surplus height until the welding seam and the base metal are in smooth transition.

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 and polishing 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 and polishing 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, thereby simplifying control and improving grinding precision. 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 laser profiler 5 welding seam detection tracking visual algorithm in the grinding and polishing robot for the 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. The algorithm is also suitable for the use of the secondary scanning of the welding seam before the polishing of the polishing mechanism; to provide coordinate data support for high precision polishing.

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 and polishing platform 4 is fixedly provided with a left limit proximity switch 71, a zero point proximity switch I72 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 II 92 and a lower limit proximity switch 93.

When in use, the two-degree-of-freedom grinding and polishing platform 4 cooperates with the zero proximity switches I and II and the left and right or upper and lower proximity switches to act together; reliable guarantee is provided for the multi-degree-of-freedom manipulator to execute two-degree-of-freedom grinding at the tail end and the polishing platform 4 to precisely position and polish the spiral weld at the pipe 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. And in the cooperative polishing step, the smoothness and the flatness of the surface of the welding line of the parent metal can be retained to the maximum extent, and the use requirement of smooth butt joint of pipelines with special purposes is met.

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 (as shown in fig. 1) is fastened and integrated 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. 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 and polishing platform is designed for light weight and beautification: the frame 41 is made of aluminum alloy; the frame 41 includes a left and a right frames 411 (as shown in fig. 20) with a hollow structure, a supporting frame 412 fixedly connected between the left and the right frames 411 for front and rear horizontal supporting, and a cover casing 413 enclosing the top of the left and the right frames 411 and the supporting frame 412; wherein the outer side of the supporting frame 412 is covered with a layer of aluminum alloy skin; a manipulator connecting seat 414 (shown in fig. 12) with a hollow right-angled triangle structure is fixedly arranged 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 and polishing platform 4 at the end of the robot. 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 and polishing platform 4; the structure is compact, the appearance is attractive, and the support is stable and reliable; the requirements of the two-degree-of-freedom grinding and polishing platform 4 on the light-weighted, compact, stable and reliable horizontal fixed support installation of the tail end of the multi-degree-of-freedom manipulator are met; 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 and polishing 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 precise, stable and reliable grinding displacement of the two-degree-of-freedom grinding and polishing platform 4 can be met.

In the above embodiment, further: the axial and normal displacement mechanism of the two-freedom grinding and polishing platform is designed for reliability, stability, light weight, compactness and miniaturization: (as shown in fig. 12), the two-degree-of-freedom grinding and polishing platform 4 has a frame 41 with a hollow frame structure, and the bottom end of the inner side of the axial horizontal frame body of the frame 41 is slidably matched with two groups of horizontal guide rail sliders 43 through two groups of horizontal guide rails 42 which are parallel front and back; two groups of horizontal guide rail sliders 43 are fixedly connected with inverted L-shaped horizontal slider connecting plates 44 respectively; the front and rear inverted L-shaped horizontal slider connecting plates 44 are fixedly connected with the front and rear vertical mounting side plates 301 of the sharpening mechanism 3 respectively; a pair of vertical slide rails 302 (as shown in fig. 13) 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 slide blocks 303 in a sliding manner, one side of each vertical guide rail slide block 303 is fixedly connected with a vertical lead screw slide block 304, and the vertical lead screw slide blocks 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; the vertical screw rod sliding block 304 which is driven by the Z-axis vertical speed reducing motor 307 to move and vertically displace is fixedly connected with the back side of the vertical base plate 309 through the connection of an L-shaped adapter plate 308 fixedly connected with the vertical screw rod sliding block 304 so as to drive the vertical base plate 309 to vertically displace in the normal direction; the grinding mechanism 3 is fixedly arranged on the front surface of the vertical substrate 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 and the polishing mechanism 10 fixedly installed on the front surface of the vertical base plate 309 to vertically displace relative to the vertical slide rails 302 fixedly installed on the inner side plates of the front and rear vertical installation side plates 301 (as shown in fig. 20); 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; 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 installation side plates 301 and the coping mechanism 3 to horizontally and axially displace relative to the two groups of horizontal guide rails 42.

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 and the polishing mechanism 10 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 and the polishing mechanism 10 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 (as shown in fig. 1, 2, 3 and 4) 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. 5); 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 and an adjusting wheel frame 339; 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: (as shown in fig. 5, 6 and 7) 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 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 installation abrasive belt 34 (as shown in fig. 4); 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 ball bearing II 3206 is matched with a retainer ring 3207 for a mounting hole and an end cover 3208 of the shaft end. 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. 9, 10 and 11) the grinding wheel adopts upper and lower wheel axle grooves 3204 of upper and lower mounting

frames

3201 and 3203 to clamp and horizontally and fixedly mount a grinding wheel axle 3202 in an upper and lower opposite clamp manner by using upward lower fastening bolts 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 a grinding and polishing robot for a weld joint at the end of a spiral steel pipe, 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 a weld bead at the end of the spiral steel pipe 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, the scheme adds the two-degree-of-freedom grinding and polishing platform 4 at the execution end of the multi-degree-of-freedom manipulator, 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.

On the basis, the grinding method adopts a set of two-degree-of-freedom grinding and polishing platform with machine vision horizontally arranged at the execution end of the multi-degree-of-freedom manipulator. 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 and polishing platform adopts a horizontal installation mode at the tail end execution end of the multi-degree-of-freedom manipulator, so that the grinding of the outer weld joint of the 508 spiral welded pipe with the outer diameter can be adapted, and the grinding of the inner weld joint of the spiral steel pipe can be realized: in addition, the whole two-degree-of-freedom grinding and polishing platform is designed to be small and light; 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 and polishing platform at the tail end of the manipulator are realized, and the structural stability of the two-degree-of-freedom grinding and polishing platform during grinding is ensured.

The two-degree-of-freedom grinding and polishing 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 the grinding welding line is guaranteed.

The two-degree-of-freedom grinding and polishing platform frame 41 is designed to be hollowed out on a structural part and a 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 and polishing platform is installed in a modular design, so that the whole system is more convenient to disassemble, assemble and maintain.

The zero proximity switch is additionally arranged at the specific position of the two-degree-of-freedom grinding and polishing 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 and polishing platform with manipulator and execution end level fixed mounting, there are feed mechanism and axial translational movement mechanism that can be translated along the normal direction in the two-degree-of-freedom grinding and polishing platform, and is furnished with the high-accuracy laser profile appearance of machine vision system of high-accuracy weld joint detection, through the upper computer control system taking movement control card as core, and grating sensor, magnetic grating sensor realize the position control of the closed loop totally, the speed control adopts the Blend Motion mode, through the vision detection algorithm developed by oneself, finish the two-degree-of-freedom grinding of inner, outer weld joint of the spiral welded tube and polish the linear displacement regulation in horizontal axis and vertical normal direction of the platform carrying the abrasive belt type grinding head, and then realize the inclined compound movement of the abrasive belt type grinding head along the spiral weld joint of the spiral steel tube; and realizing the accurate grinding and polishing operation of the spiral weld joint of the steel pipe.

In summary, the following steps: the manipulator real-time control of the invention is guided by the laser profiler 5 in real time, 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 and polishing 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 and polishing 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 transmission of the two-degree-of-freedom grinding and polishing 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 and polishing platform on the adjustment of the axial and normal displacement mechanisms for 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 and polishing platform 4 and the execution end of the multi-degree-of-freedom manipulator are integrally installed, and the universality is ideal. 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. Spiral steel pipe end welding seam coping polishing robot which characterized in that: the two-degree-of-freedom grinding and polishing platform (4) is arranged at the tail end of the multi-degree-of-freedom manipulator for horizontally fixing and installing and sanding by using a sanding belt; the two-degree-of-freedom grinding and polishing platform (4) is provided with a frame (41) with a horizontal aluminum alloy hollow frame 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 a grinding mechanism (3) and a polishing mechanism (10), and drives the grinding mechanism (3) and the polishing mechanism (10) to vertically displace in a normal straight line; the laser contourgraph (5) is fixedly installed on the outer side of the grinding mechanism (3), and the laser contourgraph (5) is carried to linearly displace in the horizontal axial direction and the vertical normal direction relative to the rack (41); 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; 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 and polishing platform (4) at the execution tail end of the manipulator; the bottom end of the inner side of the axial horizontal frame 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 fixedly connected with an inverted L-shaped horizontal sliding block connecting plate (44) respectively; the inverted L-shaped horizontal sliding block connecting plate (44) is fixedly connected with the front vertical mounting side plate (301) and the rear vertical mounting side plate (301) of the coping 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 side of each vertical guide rail slide block (303) is fixedly connected with a vertical lead screw slide block (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; the vertical screw rod sliding block (304) which is driven by the Z-axis vertical speed reducing motor (307) to vertically displace moves, and the vertical screw rod sliding block (304) is fixedly connected with the back side of the vertical base plate (309) in a switching way through an L-shaped switching plate (308) fixedly connected with the vertical screw rod sliding block so as to drive the vertical base plate (309) to vertically displace in a normal direction; the grinding mechanism (3) is fixedly arranged on the front surface of the vertical substrate (309), and the polishing mechanism (10) is fixedly arranged on the back surface of the vertical substrate; 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 the vertical screw rod sliding block (304) to drive the vertical base plate (309) to carry and fixedly mount the coping mechanism (3) and the polishing mechanism (10) through the Z-axis vertical speed reducing motor (307) to vertically displace relative to the vertical sliding rail (302) fixedly mounted on the inner side plate body of the front and rear vertical mounting side plate (301); 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), the grinding mechanism (3) and the polishing mechanism (10) to horizontally and axially displace relative to the two groups of horizontal guide rails (42).

2. The grinding and polishing robot for the weld joints at the ends of the spiral steel pipes according to claim 1, is characterized in that: the axial mechanism (7) of the two-degree-of-freedom grinding and polishing platform (4) is fixedly provided with a left limit proximity switch (71), a zero point proximity switch I (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 II (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.

3. The grinding and polishing robot for the weld joints at the ends of the spiral steel pipes according to claim 1, is characterized in that: 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.

4. The grinding and polishing robot for the weld joints at the ends of the spiral steel pipes according to claim 1, is characterized in that: the normal mechanism (9) is provided with a vertical base plate (309) which can lift in the normal vertical direction relative to the axial mechanism (7); the vertical substrate (309) is fixedly provided with a polishing mechanism (10) through a cuboid mounting frame (1001); a guard plate (1002) is arranged on the outer side of the polishing mechanism (10); the polishing mechanism (10) is provided with a pair of micro cylinders (1003) which synchronously and parallelly execute lifting action in the vertical direction, and the top ends of the micro cylinders (1003) are fixedly connected with the lower bottom surface of the cuboid mounting frame (1001) into a whole; the actuating end of the micro cylinder (1003) facing downwards is fixed and pushes a motor supporting plate (1004) to move up and down, and the motor supporting plate (1004) supports the installation of a polishing motor (1005); the polishing motor (1005) is connected with the polishing wheel (1006) and drives the polishing wheel to rotate for polishing.

5. The grinding and polishing robot for the weld joints at the ends of the 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) and an adjusting wheel frame (339); 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).

6. The grinding and polishing robot for the weld joints at the ends of the 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 the mounting hole and a shaft end cover (3208).

7. The grinding and polishing robot for the weld joints at the ends of the 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).