Design and implementation of motion control system for plate cutting machine based on PLC

Li-xin TIAN

(Intelligence and Information Engineering College, Tangshan University, Tangshan 063020, China)

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Design and implementation of motion control system for plate cutting machine based on PLC

Li-xin TIAN*

(IntelligenceandInformationEngineeringCollege,TangshanUniversity,Tangshan063020,China)

In practice, many cutting equipments have low cutting precision and the automation level is not high enough. To meet the requirements of increasing cutting quality and accuracy, the development of automatic cutting machine with high precision, high intelligent is imperative. In this design, PLC, motion controller, servo drive system as well as position detection devices were used to build motion control system for the plate cutting machine to complete the trajectory control. The system can realize arbitrary graph cutting to meet the demand of various occasions. Touch screen was made as the HMI to complete the upper machine control with displaying the cutting status. It has advantages of vivid image and strong operability. The control system can improve the machining quality and the level of processing automation so as to improve the product quantity.

Cutting machine, PLC, Touch screen, Motion control

1 Introduction

In modern society, it often needs to cut plates into various shapes in engineering to meet different production requirements, so it needs all kinds of cutting equipments [1]. Plate cutting equipments are divided into two main categories: the metal cutting machine and the nonmetallic cutting machine. The metal cutting machine can be used in ship building, automobile, engineering machinery, boiler and other metal processing manufacturing occasions, while the nonmetallic cutting machine is mainly used in packaging design, clothing proofing, shoe sample making and so on. The core of the cutting equipment is the automatic control system and. At present, some of the cutting machine control systems mainly make the single chip microcomputer, ARM or DSP as the core of control [2-6]. The open CNC cutting machine system based on PC and motion controller has become one of the mainstreams in the automation industry. It integrates the information processing ability of the PC and the trajectory control ability of the motion controller [7-9]. But at present in our country the development of motion controllers is relatively backward. Some of the controllers have relatively weaker openness and extensibility.

PLCs as a kind of industrial control computer with high reliability, strong anti-interference ability and short development cycle are widely used in industrial control field. So in modern industry some cutting machines make PLC as the core of the automatic control system. The trajectory control system can be constructed by matured control components, such as programmable terminal, PLC, motion control unit and servo drive system [10]. Using this system the quality of workpiece, degree of automation of the machine and the operational performance can be greatly improved [10]. This type of control system has advantages of obvious economy and good practicability with broad market prospects [11].

In this design, it makes the PLC as the control core of the plate cutting machine. It inputs all kinds of operation commands to the lower computer PLC by the touch screen which also displays the various operational parameters and data. PLC sends signal commands to the servo motors to drive the movements of each axis. The strokes of the two axes are limited by the position detecting sensors. The lifting position of the cutting torch is controlled by the position detection switches and the pressure relay. The control system can realize the automatic control mode and the manual control mode, meanwhile, the user can choose two kinds of cutting forms- flame cutting and plasma cutting.

2 Control system structure and function

The system consists of five major components: Mitsubishi FX2N series programmable controller PLC FX2N-32MR, FX2N-20GM positioning unit, GT1050-QBBD-C touch screen, AC servo motor and servo driver. As man-machine interface the touch screen realizes the upper computer control, parameters inputting and status displaying. The FX2N-32MR PLC is the core controller and the FX2N-20GM is used for controlling the two axes moving in coordination to realize the linear interpolation and the circular interpolation. The Servo motor is used to drive the two axes motion in the horizontal plane to complete arbitrary planar graph cutting. The hardware structure diagram of the cutting machine control system is shown in Fig.1.

Fig.1 Control System Hardware Structure Diagram

The control system requires a total of 10 inputs and 14 outputs. The I/O address allocation is shown in Table 1.

Table 1 I/O Address Allocation

InputI/ObitNameOutputI/ObitNameX000emergencystopcommandY000greenindicatorlightX001XaxisleftlimitY001redindicatorlightX002XaxisrightlimitY002buzzerX003YaxisleftlimitY003contactorofservopowerX004YaxisrightlimitY006startingsignalofplasmaX005XaxisservoreadyY007electromagneticvalveofcuttingtorchupX006YaxisservoreadyY010electromagneticvalveofcuttingtorchdownX007arcfeedbacksignalY011electromagneticvalveforcompressingworkpieceX010compressedsig-nalY012electromagneticvalveforlooseningworkpieceX011signalofputtingtheguninplaceY013gassolenoidvalveY014preheatoxygensolenoidvalveY015cuttingoxygensolenoidvalveY016ignitiongassolenoidvalveY017Ignitionelec-tromag-neticvalve

3 Software design of the control system

As the core of control system, PLC is mainly used for realizing the manual control and the automatic control. Automatic control involves programming for all kinds of cutting path to complete the corresponding cutting function.

3.1 Manual control program design

Manual control is mainly for system debugging of the installation of the production line in order to test whether all of the equipments can operate normally. When choose the manual cutting mode, pressing the manual button on the control panel will have the corresponding action. For example, when pressing the “torch up” button the rising electromagnetic valve of the torch is powered on and pressing the “work pressing” button then the work pressing electromagnetic valve is powered on and so on. The manual operation panel is shown in Fig.2.

Fig.2 Manual Operation Panel

3.2 Automatic control mode

After the system is powered on, in the automatic mode, the working starting point is defined artificially. The cutting gun is ignited at the defined origin point, and then it will work according to the select plasma or flame cutting mode and the graph cutting form. Fig.3 gives the programming flow chart of the automatic control mode. After the cutting form is chose, it will call the 20GM procedures, namely the VPS program, and then input the corresponding cutting parameters. PLC controls the cutting of the required trajectory according to the setting. After the cutting of the graphics trajectory, the cutting gun goes back to the original position. The control process of the triangle cutting is shown in Fig.4.

Fig. 3 Flow Chart of the Automatic Control Mode

Fig.4 Flow chart of triangular cutting control process

The cutting patterns involve the triangular, quadrilateral, circular trajectory cutting and so on. Different locus needs different cutting parameters. The triangular cutting needs to set the side lengthL1, side lengthL2 and the angleβbetween the two sides, while the circular cutting requires inputting the parameter of radiusR.

4 Examples of application

In this paper, it make triangular cutting as the example to introduce the control process. The user can input the parameters by the touch screen which is shown in Fig.5, and the PLC calls the triangle data calculation procedures to calculate the required triangular trajectory parameters.

Fig.5 Triangular parameter inputting screen

The triangle data calculation program segment is shown in Fig.6. The input angleβand lengthL1 are converted into floating point numbers, and the angleβis changed to radian, then through the corresponding operation algorithm to obtain the height of the trianglehand the foot pointd. Converthanddinto the corresponding real numbers to form the vertex coordinates of the triangle which are given to VPS program of the positioning module 20 GM .The equations ofhanddare as follow.

h=L1*sinβ

d=L1*cosβ

Fig. 6 Triangle data calculation procedures

After the choice of the cutting modes it calls the triangle VPS procedures. The triangular data parameters including the second edgeL2 and the height of the trianglehwith the foot pointdare written into the corresponding storage units of the VPS. The corresponding program segment is shown in Fig.7.

Fig.7 Procedures of writing parameters and calling VPS for a triangle

The Triangular VPS program is shown in Fig.8. The DRV command is used to realize the high-speed positioning. The setting value of the target coordinate location relative to theXaxis is specified by the (DD200), in which DD200 is stored with the triangle side lengthL2. The operation speed ofXaxis is specified by the “fx”. LINE is the “linear interpolation positioning”, which can make the two axesXandYmove to the target coordinate (x,y) along with a linear path. The “f” is the vector velocity. The coordinates of the two vertices of the cutting triangle are respectively (DD202, DD204) and (DD206, DD208). Under the control function of PLC and the positioning module, the cutting machine can complete the cutting of the triangle of any shape according to the predetermined parameters.

Fig.8 No.2 triangle cutting positioning program

5 Conclusions

The motion control system for cutting machine has adopted the control mode of PLC with the motion controller which has strong ability of resisting disturbance and high working stability. With the application of the servo control system it reduced the system motion error. In the system the locus of the cutting graphic was completed by the motion control unit and with this way it saved the algorithm programming of linear and circular interpolation for PLC. The system has the advantages of friendly interface and strong interactivity by using the touch screen as human-machine interface to realize the selection of arbitrary shapes, the inputting of various parameters and the displaying of the field operation data. The application of this control system for plate cutting machine can greatly improve the level of automation, the cutting precision and the work stability.

Acknowledgement

This paper is supported by Key Laboratory Project of Tangshan College (No.140080312).

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摘要：通過燒結銅纖維和微溝槽銅板制造得到了一種具有高孔隙率的新型溝槽燒結纖維復合毛細芯多孔材料。通過對溝槽燒結纖維復合毛細芯多孔材料進行拉伸性能測試，研究了纖維參數和燒結參數對拉伸性能的影響。通過大量的拉伸實驗數據得到了溝槽燒結纖維復合毛細芯多孔材料的典型的應力應變圖。對于在相同的燒結參數下制造得到的相同質量的溝槽燒結纖維復合毛細芯多孔材料，其抗拉強度隨著孔隙率和直徑的增加而減少。測試結果表明：當燒結溫度低于1083 ℃時，抗拉強度隨著燒結溫度和燒結時間的增加而增加。

關鍵詞：復合毛細芯；微溝槽；銅纖維；拉伸性能

10.3969/j.issn.1001-3881.2015.24.018 Document code: A

TP273

基于PLC的平板切割機運動控制系統的設計與實現

田麗欣*

唐山學院 智能與信息工程學院, 河北 唐山063000

在實際應用中，很多切割設備存在切割精度不夠、自動化水平不高的弊端，為滿足對切割質量和切割精度不斷提高的要求，發展高精度、高智能化的自動切割機勢在必行。采用PLC、運動控制器和伺服驅動系統配以位置檢測裝置等構建板材切割機運動控制系統，完成運動軌跡控制，實現平面任意圖形切割，可滿足各種不同場合的切割需求。以觸摸屏作為HMI，完成上位機控制以及切割狀態顯示，畫面生動，可操作性強。該控制系統可提高加工工件的質量以及加工自動化程度，從而提高產品數量。

切割機; PLC; 觸摸屏; 運動控制

溝槽燒結纖維復合毛細芯多孔材料的拉伸性能研究

陶素連*

廣東水利電力職業技術學院 機械工程學院, 廣州510925

28 February 2015; revised 10 May 2015;

Li-xin TIAN, Lecturer.

E-mail: yupoosilon@163.com

accepted 21 July 2015

Hydromechatronics Engineering

http://jdy.qks.cqut.edu.cn

E-mail: jdygcyw@126.com