Design of spray machine control system based on mo

  • Detail

In recent years, with the wide application of electronic technology, especially electronic computer, the research and production of numerical control system for industrial automation control has become a new technology rapidly developed in the high-tech field. Its development has organically combined mechanization and automation

in view of the special needs of the current coating industry, the previous production mode based on the type of tooth block recommended in gb/t 239.1 standard according to different sample specifications, manual spraying, has gradually changed to automatic spraying. Automatic spraying has the characteristics of continuous repetition of work and labor, ignorance of fatigue, fear of danger and so on. Therefore, this automatic spraying mode has been paid attention to by many industries and has been more and more widely used

according to the characteristics of automatic spraying, in order to complete digital control, a bottom control system based on industrial computer and motion control card adt836 is developed. The integrated motion control card can simplify the hardware circuit structure of the whole control system and improve the reliability and control accuracy of the system

system composition

it is mainly composed of adt-tp104 controller, auxiliary wiring terminal and spraying machine software control system developed based on DOS

the controller has built-in adt836 motion control card, which is developed by Shenzhen zhongweixing Numerical Control Technology Co., Ltd. and has six axis servo/stepping control cards based on PC104 bus, such as high message universal testing machine, unidirectional pulsation fatigue testing machine, impact testing machine, etc. the position is variable ring, and the speed can be changed at any time during movement. It has the functions of straight line, arc, continuous differential compensation, etc. Constant speed and linear/s curve acceleration and deceleration can be adopted for speed control, asymmetric linear acceleration and deceleration can be adopted, automatic/manual deceleration can be adopted, and triangular waveform generated by speed curve can be prevented during quantitative drive. It has 48 digital inputs and 32 digital outputs

the controller supports rs233 communication, which is convenient for program downloading, updating and data backup

system composition block diagram is shown in Figure 1:

Figure 1 system composition block diagram

working principle

describe its working principle according to the block diagram in Figure 1, and the motion controller sends pulse commands to the servo or stepping control unit to drive the motor action. The maximum output pulse frequency is 4MHz. During the driving process, if an external stop signal is detected, the controller will immediately send out the operation of stopping pulse output. If the system detects the hardware limit signal during the driving process, it will stop driving immediately to ensure the safety of the mechanical system. When spraying, the controller sends an output signal to the outside to control the switch of the spray gun

as for how many pulses are sent, and which output operation needs to be controlled during the movement, it can be easily realized through software. The pulse output of the 836 control card is a common anode, "pulse + direction" or "pulse + pulse" wiring mode. The figure shows the connection mode

Figure 2 wiring mode of motion control card

Figure 3 connection of digital input

Figure 4 connection of digital output

software design

the software system adopts teaching programming mode. As long as the user moves the corresponding axis of the machine to the desired position, the control system will automatically remember the coordinates here. For a workpiece to be processed, the processing track can be determined according to the shape of the workpiece during teaching, A simple example is shown in Figure 5:

Figure 5 processing route

if you want to process according to the route of a-b-c-d-e as shown in Figure 5, when teaching data, first move the motion axis to a, then write down the coordinates here, and then move the axis to B, write down the coordinates here, then the system will automatically form a line segment from a to B according to the rule of two points forming a line, and the rest can be completed according to this. The speed of each section can be set separately, so as to ensure the spraying effect. Since some places need to spray more paint, they can move slowly, and some places require less paint, they can move quickly. The adjustable speed ensures the spraying effect and also ensures that the machinery will not have too much vibration when moving. Of course, reciprocating spraying can also be used to spray the sprayed workpiece repeatedly, so as to achieve good spraying effect. If the painted workpiece has an arc shape, as shown in Fig. 6:

Fig. 6 arc processing route

when teaching data, just write down the a coordinate of the arc start point, the B coordinate of any intermediate point and the C coordinate of the arc end point, and the system will automatically form an arc track according to the rule of three points forming an arc. As for clockwise arc or counterclockwise, the system will automatically determine according to the sequence of data taught by the user

as for the trajectory during spraying, it is not necessary to make a standard straight line segment, but also a straight line trajectory as shown in Figure 7

Figure 7 straight line segment trajectory

figure 8 broken line segment trajectory

M-shaped broken line segment shown in Figure 8. See the process requirements of spraying for details. Because the teaching programming method is adopted, the user can specify the machining path at will. For the spatial arc, the spatial arc can be split into multiple small spatial lines when teaching data, because the adt836 card has the function of six axis line compensation. Of course, for painting, the subdivided line segments do not need to be very short

the above is a simple description and analysis of the teaching track. There may be operations such as cylinders during actual processing. Sometimes it is necessary to detect the signal that the cylinders are in place (of course, it may also be other external detection signals). At the same time, at which point to turn on the spray gun and at which point to turn off the spray gun, these should be completed during the teaching data. Teach the tabular programming of data, similar to excel table. Input the port number you want to detect or execute the output operation in the corresponding "input" and "output" categories. The system will automatically detect the input signal during processing operation, and execute the corresponding output operation if there is output operation

of course, due to the atomization and fan-shaped functions of the spray gun, a large atomization surface is formed during spraying, so sometimes the trajectory that does not need to be taught must be the shape of the workpiece. Because the operation of the table is very simple, it can be used to insert, delete, copy and modify. After the teaching is completed, it can be used for trial operation. The above functions can be used in undesirable places, which means revising the data

coordinate description

the system uses the mechanical origin as the reference coordinate system of the system. For a six axis system, each axis must have an origin signal. When teaching data, you should first go back to the origin. When the system detects the origin signal when returning to the origin, the coordinate of each axis corresponding to the coordinate system is 0, and the motion coordinates of each axis in the future refer to this coordinate system

for more effective teaching data, the programming mode of teaching + instruction is adopted in the software design. The user can teach several lines of data. By using jump, the cycle instruction can complete multiple reciprocating spraying operations. It also adopts the copy and paste function similar to windows, which can copy a whole piece of data to the specified position. Then, the teaching of machining data can be realized conveniently and quickly with the operation of inserting, deleting and modifying


this paper introduces the design of adt-tp104 controller based on adt836 motion control card in the spraying system. This controller has small volume, fast response speed, simple operation, and visual man-machine interface is very convenient to operate. At present, it has occupied a place in the coating industry. With the continuous improvement and progress of technology, it will be more and more widely used in the coating industry. (end)


Copyright © 2011 JIN SHI