CN112338988A

CN112338988A - Robot-based control method for sheet lamination forming production line

Info

Publication number: CN112338988A
Application number: CN201910721817.0A
Authority: CN
Inventors: 陈明达; 刘�东; 祝颖丹; 王涛; 冯雄峰; 涂丽艳; 赵秀兰
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS
Priority date: 2019-08-06
Filing date: 2019-08-06
Publication date: 2021-02-09

Abstract

The invention discloses a control method of a robot-based sheet lamination forming production line, wherein the production line comprises a feeding deviation rectifying frame, a cutting bed, a robot, a vision system station and a lamination preforming platform, and the control method comprises the following steps: after the robot runs to the initial position, a starting signal is sent to the cutting bed; cutting the sheet material by the cutting bed according to the pattern to be cut; after cutting, the robot sucks a cut material pattern in vacuum and carries the material pattern to a station of a vision system, the vision system acquires data of the pattern, the data comprises an X-axis coordinate, a Y-axis coordinate and an included angle A between the edge of the upper end of the pattern and the X-axis direction, the included angle A is compared with an original stored image, and deviation values delta X, delta Y and delta A are sent to the robot; the robot carries the material pattern to the lamination preforming platform, and in the process, coordinate position and angle adjustment is completed according to the deviation values delta X, delta Y and delta A; and repeating the steps to finish the lamination molding of the sheet.

Description

Robot-based control method for sheet lamination forming production line

Technical Field

The invention relates to the technical field of automatic production lines, in particular to a control method of a robot-based sheet lamination forming production line.

Background

Industrial automation is a trend of widely adopting automatic control and automatic adjustment devices in industrial production to replace manual operation machines and machine systems for processing production. Under industrial production automation conditions, humans only take care and supervise machines indirectly to produce. The industrial automation can be divided into the following stages according to the development stages: (1) semi-automatic. I.e. partly by automatic control and automation, and partly by manually operated machines. (2) The method is full-automatic. The whole process in the production process, including feeding, blanking, loading and unloading, does not need a person to directly carry out production operation (the person only indirectly supervises and supervises the operation of the machine), and the machine continuously and repeatedly produces one or a batch of products automatically.

In the field of industrial automation, a traditional control system experiences the development process of a relay-based ground type pneumatic instrument control system, an electric unit combined type analog instrument control system, a centralized digital control system and a Distributed Control System (DCS).

With the development of control technologies, computers, communications, networks, and other technologies, the field of information interaction and communication is rapidly covering from the field device layer of a factory to each layer of control and management. An industrial control machine system is a generic term for an automatic technical tool (including an automatic measuring instrument and a control device) for measuring and controlling an industrial production process, electromechanical equipment and process equipment thereof. Today, the simplest understanding of automation also translates into: a wide range of machines, including computers, are used to partially or fully replace or exceed human physical strength.

With the development of society and the improvement of the level of automatic production, people have higher and higher dependence on production automation manufacturing. At the present stage, the automation degree of the composite material manufacturing is low, and most of work is completed manually. The traditional processing and manufacturing method relying on manual work not only has high labor intensity, but also is difficult to ensure the consistency of products, and especially for the processing and manufacturing of composite materials such as glass fiber and carbon fiber, the dust and harmful gas which are generated in the manufacturing process can not be avoided, and the health of people can not be influenced anytime and anywhere.

Disclosure of Invention

Aiming at the defects in the field, the invention provides the control method of the robot-based sheet lamination molding production line, which can be used for manufacturing parts with different specifications, can realize the processing and manufacturing of different products by only setting a software program, and does not need to purchase new equipment again.

A control method based on a robot sheet lamination forming production line comprises a feeding deviation rectifying frame, a cutting bed, a robot, a vision system station and a lamination preforming platform, and specifically comprises the following control steps:

a) after the robot is controlled to run to the initial position, the robot is switched to an internal automatic state and sends a starting signal to the cutting bed;

b) the cutting bed resets after receiving the starting signal, and a beam on the cutting bed returns to the front original point;

c) the feeding deviation correcting frame sends the sheet to the cutting bed, the cutting bed cuts the sheet according to the pattern to be cut, after the cutting is finished, the cross beam on the cutting bed returns to the back original point and sends a cutting finishing signal to the robot, after the robot receives the cutting finishing signal, the robot resets a starting signal, a control system of the cutting bed enables the cutting bed to be disconnected, and the cutting bed enters a waiting state;

d) the robot sucks the cut material pattern from the cutting position of the cutting bed in vacuum;

e) the robot carries the cut material pattern to a visual system station, a visual system on the visual system station carries out data acquisition on the pattern, the pattern comprises an X-axis coordinate, a Y-axis coordinate and an included angle A between the edge of the upper end of the pattern and the X-axis direction, the included angle A is compared with an original stored image, and deviation values delta X, delta Y and delta A are sent to the robot;

f) the robot carries the cut material patterns from the visual system station to the lamination preforming platform, and in the process, coordinate position and angle adjustment of the material patterns are completed according to the deviation values delta X, delta Y and delta A;

g) and d) repeating the steps d) to f) to finish the lamination forming of the sheets.

In order to prevent the cross beam on the cutting bed and the sucker on the robot from colliding with each other in the cutting bed cutting and robot material taking processes to damage equipment, preferably, the control system of the cutting bed can control the cutting bed to move correspondingly only after receiving a signal that the robot sends the cutting bed to move on the safe premise. The cutting bed is at the back initial point of cutting completion back crossbeam retreat to safety, sends the cutting and accomplishes the signal for the robot, and the robot just allows to get on the cutting bed workstation and gets the material after receiving the cutting and accomplish the signal of cutting bed, and the robot cancels the condition of the permitted motion of cutting bed and the signal that the cutting bed reset the cutting and accomplish simultaneously immediately.

The sheet material is a unidirectional prepreg, the strength of the material in different directions is different, and the material patterns with the same size are used for superposition in different directions according to the strength required in different directions.

Preferably, the cutting bed automatically vacuum-adsorbs the sheet material on the surface. In order to cut smoothly, a cutting bed must be ensured to perform good vacuum adsorption fixation on a cut material, and a buckling phenomenon, particularly the buckling of the material at the beginning of the cut material, is inevitable due to a cut sheet (such as a unidirectional prepreg). The vacuum of the cutting bed is difficult to completely ensure the suction leveling and fixing of the sheet, so that the cutting bed cannot cut. Preferably, the cutting device on the cutting bed comprises a knife and a pen, the bottom of the pen is a hemispherical pressing plate, the hemispherical pressing plate at the bottom of the pen is firstly driven to perform auxiliary cutting movement when the cutting bed performs cutting, the auxiliary pressing plate movement process is used for flattening the warping generated at the cutting edge, and then the knife cutting movement of the pattern is performed.

When the sheet is one-way prepreg, the one-way prepreg is formed by uniformly arranging and combining single fibers, certain slippage exists in the relative cutting knife feeding direction of fiber tows in the cutting process, the phenomenon of lotus root broken filaments connection often exists at a corner, and a robot cannot normally take materials. In order to cut off the pattern smoothly, the cutting bed preferably cuts the sheet material 2-3 mm at the corner of the pattern of the material.

Preferably, the robot determines the material taking position according to the relative position of the material pattern and the front origin and the relative position of the front origin and the robot, and the material taking position is specifically as follows: the robot carries the cut material from the worktable of the cutting bed, firstly calculates the position (Xc, Yc, Zc, Ac, Bc, Cc) of the front origin of the cutting bed relative to the world coordinates of the robot, and then calculates the relative position of the material pattern relative to the front origin to be superposed, thus determining the material taking position of the robot.

Preferably, a camera, a lens, a light source and a polarizer are arranged on the visual system station and used for collecting material patterns conveyed by the robot from the cutting bed;

controlling the robot to enable the material pattern to be parallel to the camera, wherein the color of the material pattern is obviously contrasted with the background color of the suction surface of the robot;

and calibrating the size of the camera pixel by using calibration paper, converting the pixel value into millimeter units, and moving the robot to enable the increment direction of the camera to be consistent with the increment direction of the robot.

Preferably, the robot clears the deviation values Δ X, Δ Y, and Δ a after completing one transportation, and then performs the next transportation. This way, the deviation caused by the cutting bed in the cutting process and the robot sucker in the process of grabbing the material pattern can be effectively compensated.

Compared with the prior art, the invention has the main advantages that: the invention can be used for manufacturing parts with different specifications, can realize the processing and manufacturing of different products only by setting a software program, and does not need to purchase new equipment again.

Drawings

FIG. 1 is a schematic structural diagram of a robot-based sheet material lamination and forming line apparatus according to an embodiment;

FIG. 2 is a diagram of a pattern to be cut drawn on a computer of a cutting bed according to an embodiment;

FIG. 3 is a sequence diagram of the robot picking material from the cutting bed to the lamination of the lamination preforming platform according to the embodiment;

FIG. 4 is a schematic structural view of a cutting device on a beam of the cutting bed according to the embodiment;

FIG. 5 is a schematic diagram of a cut of an embodiment;

FIG. 6 is a schematic view of a visual sample of an embodiment;

FIG. 7 is a schematic view of a visual calibration of an embodiment;

fig. 8 is a schematic view of the visual working principle of the embodiment.

Detailed Description

The invention is further described with reference to the following drawings and specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The following examples are conducted under conditions not specified, usually according to conventional conditions, or according to conditions recommended by the manufacturer.

The structure of the robot-based sheet lamination forming production line device of the embodiment is shown in fig. 1, and comprises a feeding deviation rectifying frame 7, a cutting bed 2, a robot 1, a vision system station 5 and a lamination preforming platform 6.

The table surface of the cutting bed 2 has an automatic vacuum adsorption function, a beam 8 is arranged above the cutting bed, and a cutting device is arranged on the beam 8. The structure of the cutting device is shown in fig. 4, and comprises a knife 18 and a pen 17 which are arranged on the same fixing plate, and the bottom of the pen 17 is a hemispherical pressing plate. The rolling felt 10 is arranged below the unidirectional prepreg 19 and is vacuum-adsorbed on the cutting bed 2 together with the unidirectional prepreg. When cutting, the knife 18 and the pen 17 move together in the same direction, the pen 17 follows the knife 18, and the hemispherical pressing plate at the bottom of the pen 17 flattens and cuts the warp 11 generated on the edge of the unidirectional prepreg 19. The cutting bed 2 is also provided with two movable ends of a beam 8, namely a front original point position 4 and a rear original point position 3.

The robot 1 is a six-axis robot, and a vacuum adsorption and spot welding gun device 9 is arranged on a sixth axis and used for carrying and welding laminated unidirectional prepreg 19. The bottom of the vacuum adsorption and spot welding gun device 9 is provided with a suction cup 16.

The work flow of the robot-based sheet material lamination forming production line comprises the following steps: automatic pay-off is rectified and is placed preimpregnation reel sheet on the frame 7, under the function effect is rectified in the automatic tracking, automatic vacuum adsorption cutting bed 2 pulls and unreels preimpregnation reel sheet, one-way preimpregnation material 19 vacuum adsorption and automatic back that cuts on automatic vacuum adsorption cutting bed 2, the vacuum adsorption of robot 1, spot welding gun device 9 absorb and receive the material, carry to vision system station 5 and carry out the adjustment of size position and fibre angle direction, on moving to stromatolite preforming platform 6 at last, carry out the stromatolite spot welding.

The method can realize the whole process of automatic unreeling, cutting, robot carrying, visual positioning and spot welding of the composite prepreg, and particularly, the flexible manufacturing can be realized only by reprogramming and setting related parameters in a production line, thereby avoiding the repeated investment of factories and improving the utilization rate of equipment.

The control method of the robot-based sheet lamination forming production line comprises the following specific steps:

a) when the robot 1 selects a required program, the robot 1 is switched to an internal automatic state after the robot 1 is operated to an initial position (BCO position), and the robot 1 sends a setting starting signal to the cutting machine 2.

b) After receiving the set starting signal of the robot 1, the cutting bed 2 is clicked on the operation interface of the cutting bed 2 to reset, the cutting bed 2 automatically resets and changes, and the beam 8 on the cutting bed 2 returns to the front original point 4 of the equipment.

c) The feeding deviation rectifying frame 7 sends the unidirectional prepreg 19 to the cutting bed 2, patterns needing to be cut are drawn on a computer of the cutting bed 2, files are printed, the cutting bed 2 starts to cut, the device beam 8 returns to the back original point 3 after the cutting bed 2 finishes cutting, and the cutting bed 2 sends a cutting completion signal to the robot 1. After the robot 1 which is always in the signal receiving waiting state receives the cutting completion signal of the cutting bed 2, the robot 1 immediately resets the starting signal to the cutting bed 2, and the control system of the cutting bed 2 is enabled to be disconnected and is always in the waiting state.

d) The robot 1 starts to vacuum-suck the cut material pattern from the position where the cutting bed 2 cuts.

e) The robot 1 carries the cut material pattern from the cutting bed 2 to a vision system station 5, a vision system on the vision system station 5 carries out data acquisition on the pattern, the data acquisition comprises an X-axis coordinate, a Y-axis coordinate and an included angle A between the edge of the upper end of the pattern and the X-axis direction, the included angle A is compared with an original stored image, and deviation values delta X, delta Y and delta A are sent to the robot 1;

f) the robot 1 carries the cut material pattern from the vision system station 5 to the lamination preforming table 6 and, in the process, performs coordinate position and angle adjustment of the material pattern according to the deviation values Δ X, Δ Y and Δ a.

g) And d) repeating the steps d) to f) to finish the lamination molding of the unidirectional prepreg 19.

The unidirectional prepreg has different strengths in different directions, and material patterns with the same size are used for superposition in different directions according to the required strengths in different directions. For example, in step c), the cut specimens drawn on the cutting bed 2 according to a certain product requirement are shown in fig. 2, and the specimens a1, a2, A3, a4, a5 and a6 have the same shape. In fig. 2, 1# to 8# represent the cutting sequence of the cutting bed 2 in one cycle cutting process. The number 1 is the action executed by the cutting bed 2 firstly in the process of one cycle, and the like, and the number 8 is the action executed by the cutting bed 2 finally in the process of one cycle. The center coordinate position of the pattern a1 is O1, the spatial position with respect to the front origin 4 of the cutting bed is (O1x, O1y, O1z), the center coordinate position of the pattern a6 is O6 by analogy, and the spatial position with respect to the front origin 4 of the cutting bed is (O6x, O6y, O6 z). The dotted line of the pattern is the material direction of the unidirectional prepreg.

The order of stacking the swatches in FIG. 2 is shown in FIG. 3, A1+ A2+ A3+ A4+ A5+ A6. The robot 1 firstly takes a material A1 to the laminated preforming platform 6, the robot 1 rotates 90 degrees to take a material A2 to the laminated preforming platform 6 for the second time, and the like, and finally the robot rotates 90 degrees to take a material A6 to the laminated preforming platform 6, the material A1, the material A2, the material A3, the material A4, the material A5 and the material A6 are stacked on the laminated preforming platform 6 sequentially from bottom to top, the material A1, the material A2, the material A3683, the material A5 and the material A6 are all the same, 1# represents an auxiliary motion track of a pen on a cutting bed, the motion sequence is 1, 2# represents a motion track of a cutting knife of the cutting bed, the motion sequence is 2, the same sequence is 3-8 # represents a motion track of a cutting knife of the cutting bed, the motion sequence is 3-8 respectively, and auxiliary motions of a pressing plate track and 1# of an increasing pen mechanism are mainly used for solving.

As shown in fig. 5, the unidirectional prepreg 19 is formed by uniformly arranging and combining single fibers, has a specific texture 14, and the fiber tows slide in the feeding direction of the cutter 18 in the cutting process to a certain extent, so that the coupling and disconnection phenomena often occur at the

corners

12 and 13, and the robot 1 cannot take materials normally. In order to cut the pattern smoothly, the sheet is cut by the knife 18 of the cutting bed 2 at the

corners

12 and 13 of the pattern of the material by 2-3 mm.

The robot 1 determines the material taking position according to the relative position of the material pattern and the front origin 4 and the relative position of the front origin 4 and the robot 1, and the material taking position is as follows: the robot 1 carries the cut material from the table of the cutting bed 2, and calculates the position (Xc, Yc, Zc, Ac, Bc, Cc) of the front origin 4 of the cutting bed 2 with respect to the world coordinates of the robot 1, so that in fig. 2,

the world coordinates of the central position O1 of the image a1 with respect to the robot 1 can be calculated to obtain Pa 1: (Xc + O1x, Yc + O1y, Zc + O1z, Ac + O1a, Bc + O1b, Cc + O1 c);

the center position O2 of the image a2 is relative to the world coordinates Pa2 of the robot 1: (Xc + O2x, Yc + O2y, Zc + O2z, Ac + O1a +90, Bc + O1b, Cc + O1 c);

the center position O3 of the image a3 is relative to the world coordinates Pa3 of the robot 1: (Xc + O3x, Yc + O3y, Zc + O3z, Ac + O1a +90, Bc + O1b, Cc + O1 c);

the center position O4 of the image a4 is relative to the world coordinates Pa4 of the robot 1: (Xc + O4x, Yc + O4y, Zc + O4z, Ac + O1a, Bc + O1b, Cc + O1 c);

the center position O5 of the image a5 is relative to the world coordinates Pa5 of the robot 1: (Xc + O5x, Yc + O5y, Zc + O5z, Ac + O1a +90, Bc + O1b, Cc + O1 c);

the center position O6 of the image a6 is relative to the world coordinates Pa6 of the robot 1: (Xc + O6x, Yc + O6y, Zc + O6z, Ac + O1a +90, Bc + O1b, Cc + O1 c).

Therefore, the position of the front original point 4 of the cutting bed 2 relative to the world coordinate of the robot 1 only needs to be accurately obtained, and the material taking position of the robot 1 for cutting other points of the pattern on the cutting bed 2 can be directly obtained through the position of the front original point 4 of the cutting image relative to the cutting bed 2.

And a camera, a lens, a light source and a polarizer are arranged on the vision system station 5 and used for collecting material patterns conveyed by the robot from the cutting bed. In step e), before data acquisition, the position of the material 15 sucked by the robot 1 relative to the camera needs to be adjusted. In the vision system station 5, as shown in fig. 6, the material 15 grabbed by the robot 1 is kept as parallel as possible to the camera, the material 15 is tightly attached to the suction cup 16, and the edges are not warped unevenly so as to avoid deformity. The color of the material 15 is clearly contrasting with the background of the suction cup 16, if the material 15 is white, the background of the suction cup 16 is black. As shown in fig. 7, the camera pixels are sized using calibration paper, the pixels of the camera pixel values are converted into millimeters, and the robot 1 is moved so that the incremental directions of 6 cameras are kept consistent with the coordinate incremental direction of the robot 1.

In step g), when repeating steps d) to f), the robot 1 completes one transportation, clears the deviation values Δ X, Δ Y and Δ a, and then carries out the next transportation. This way, the deviation caused by the cutting bed in the cutting process and the robot sucker in the process of grabbing the material pattern can be effectively compensated.

In step E), the principle of the visual operation is shown in fig. 8, where the original pattern stored in the camera is E, the center point So of the original pattern is F, the center point So of the newly acquired pattern is So1, and the deviations of the newly acquired pattern from the original pattern are Δ X, Δ Y, and Δ a.

The specific process of step e) is as follows:

1) the robot 1 absorbs material patterns at a position point Pa1 where the cutting bed 2 cuts the patterns, and then carries the material patterns to a point Ps of a visual system station 5, the robot 1 sends a visual processing request to a Siemens PLC, the Siemens PLC triggers an image acquisition and processing signal to the visual system, the visual system compares the material patterns absorbed by the robot 1 with standard patterns originally stored in a camera memory, calculates corresponding deviation values delta X, delta Y and delta A, and transmits the deviation values delta X, delta Y and delta A to a position register corresponding to the PLC;

2) the PLC converts the deviation values delta X, delta Y and delta A into high and low values and sends the high and low values to corresponding registers of the robot 1, the robot 1 carries out corresponding offset processing and then reaches an actual position Pm1(Xm + delta X, Ym + delta Y, Zm, Am + delta A, Bm and Cm) of the lamination preforming platform 6, the vacuum adsorption is released, lamination is carried out, and then the robot returns to the position above the cutting bed 2 for next material suction.

Furthermore, it should be understood that various changes and modifications can be made by one skilled in the art after reading the above description of the present invention, and equivalents also fall within the scope of the invention as defined by the appended claims.

Claims

1. The robot-based sheet lamination forming production line is characterized by comprising a feeding deviation rectifying frame, a cutting bed, a robot, a vision system station and a lamination pre-forming platform, and the specific control steps comprise:

2. The method as claimed in claim 1, wherein the cutting bed is controlled to move only when the control system receives a signal that the robot sends out the cutting bed movement on the premise of safety.

3. The method as claimed in claim 1, wherein in step c), the cross beam moves back to a safe rear origin after the cutting of the cutting bed is completed, the robot sends a cutting completion signal to the cutting bed, the robot allows the cutting bed to take materials on the worktable after receiving the cutting completion signal of the cutting bed, and the robot simultaneously cancels the condition of allowing the cutting bed to move and the signal of resetting the cutting bed to complete the cutting.

4. The method of claim 1, wherein the sheet material is a unidirectional prepreg and the material patterns of the same size are used for different directions of superposition according to the strength required in different directions.

5. The method as claimed in claim 1, wherein the cutting machine automatically vacuum-adsorbs the surface of the sheet, the cutting device on the cutting machine includes a knife and a pen, the bottom of the pen is a hemispherical pressing plate, the cutting machine first drives the hemispherical pressing plate at the bottom of the pen to perform a cutting auxiliary motion during cutting, the pressing plate auxiliary motion is used for flattening the warpage generated at the cutting edge, and then performs a knife cutting motion of the pattern.

6. The robot-based sheet material lamination molding line control method according to claim 1, wherein the cutting bed cuts the sheet material by 2-3 mm relative over-cutting at the corners of the material pattern.

7. A method for controlling a robot-based sheet material lamination molding line as recited in claim 1, wherein the robot determines the material take-out position based on the relative position of the material pattern to the front origin and the relative position of the front origin to the robot.

8. The robot-based control method for the sheet material lamination molding production line according to claim 1, wherein a camera, a lens, a light source and a polarizer are mounted on the vision system station and used for collecting the material patterns conveyed by the robot from the cutting bed;

9. The method according to claim 1, wherein the robot clears the deviation values Δ X, Δ Y, and Δ a after completing one transportation and performs the next transportation.