Auto shaft drive system on the fixed section is an important component, the fixed shaft section end, Figure 1 shows. The fixed section 6 Ball manually by the workers to install, less likely to occur loaded situation, if not found quality problems will occur, affecting the normal use of product and corporate reputation. Therefore, according to the factory to design this system, the system uses non-destructive testing, the use of image processing and pattern recognition, image captured on the CCD processing, loading and not drain to drain fitted to judge, and install parts for leakage sound and light alarm.
Figure 1 End section of automotive transmission fixed
1, system components and control process
1. System components
System consists of mechanical parts, electrical parts, control parts. Is mainly mechanical parts to complete the transfer (from the installation location to test location, and then to the next process of the processing location), location (to ensure parts and concentricity of the camera), and removing unqualified parts; electrical part of a sensor, cylinder and other executing agencies; control system adopts PLC and IPC integrated control. Main hardware configuration of computer, programmable controller, CCD camera, image acquisition card, I / O interface board, sensors and other hardware and some peripheral circuits, their structure, shown in Figure 2.
Figure 2 System diagram
2. Control flow
System by the IPC as a host computer, PLC as the next bit plane. Process-control system: IPC to communicate with the PLC to shake hands, that everything is ready; Feeding position sensor detects the workpiece, signaling to the PLC; PLC status under the measuring position sensor measuring position to judge whether the workpiece; If no workpiece measurement position, the PLC signal drive cylinder, open the feed block; Measurement position sensor detects the workpiece has reached, signaling to the PLC; PLC to delay to enable the workpiece stability is conducive to filming, and then send signals to the IPC and delay to enable computer image processing and pattern recognition; IPC implementation procedures uptake by the CCD camera images, real-time image processing by the IPC, to install missing equipment or missing judge the results. The results given PLC; PLC to judge the results, and if the location of all equipment and no artifacts turn, send signals to drive the cylinder block open orientation; if leakage equipment, PLC driver alarm signal lights and buzzers to sound and light alarm manually removed by workers. PLC to judge whether the next trough feeding, if you can then flip the workpiece into the next process. Repeat sequence of the implementation of 2 to 8, reached the system automatically detected. As can be seen from the implementation process, two positions are achieved before and after the interlock. System control process shown in Figure 3.
Figure 3 System Flow
In this system, implemented an integrated industrial computer and PLC control. IPC key to complete the image processing, PLC control signals to complete the site acquisition and implementation of the components of the driver, the communication between them, using I / O cards to achieve. Control the physical structure, shown in Figure 4 show.
Figure 4, the physical structure of control system
Second, the system hardware module
Hardware module consists of data acquisition subsystem, computer basic subsystems, data distribution subsystem and basic I / O system. Structure between them, shown in Figure 5 show.
Figure 5, the composition of the hardware structure
1. Microcomputer basic subsystem
It is the core of the whole system, right throughout the system watchdog, Guan Li, control action, such as complex signal processing, control Juece brings about a special test Xin Hao, control the entire Jianceguocheng Deng Deng. Meanwhile, the use of computer powerful information processing capabilities and high-speed computing power, to achieve command recognition, logical judgments, image processing, the system dynamic characteristics of self-tuning, adaptive functions.
2. Data Acquisition System
And sensors used to detect connected components, to achieve image data acquisition, collation and transmission through interfaces to the computer subsystem processing.
3. Data distribution subsystem
Implementation of the measured part, test signal generators and test operation of the automatic control.
4. Basic I / O subsystem
For the realization of human-computer dialogue, enter or change the system parameters, change the system operation, the output test results, dynamic display of process measurement and control, an alarm signal.
Third, the system software design
Software design is modular and structured programming method, that is, top-down, stepwise refinement of design and the proper division of the module to improve the design and debugging efficiency. The system not only to accept from the sensor, the signal under test piece, but also to accept and process data from the control panel button signal, and image acquisition cards came from the digital signal, but requires a system with real-time processing capabilities. Therefore, the system software have certain requirements for real-time, but also on resource management and scheduling system.
1. Host Computer Software Design
PC monitoring software mainly by the data collection process, testing procedures and control algorithms, interrupt service routines, fault diagnosis and component handling procedures. Modules divided as follows:
(1) to initialize the module Hardware initialization
The hardware resources in the system initialize the state to set clear, including the initialization of the programmable devices, each I / O port set the initial state, the allocation of resources for the system hardware tasks. Software initialization
Including stack initialization, the state variable initialization, the software marks initialization, the variable storage unit initialization, system initialization and other parameters.
(2) Data acquisition module
Control the camera exposure image, the image acquisition card through the completion of A / D conversion, and generate data files to be processed.
(3) detection / control module
On the obtained image data file for analysis, calculation, comparison, detection, identification workpiece is qualified, and to achieve the management of the keyboard.
(4) interrupt management module
For the system s various interrupt sources and the use of the microprocessor s interrupt structure, design the corresponding interrupt processing program modules, including modules and interrupt service interruption management module.
(5) Show Management Module
For real-time updates to display images and data, and manage alarm indicator.
(6) clock management module
Including data sampling cycle time, control the cycle time, dynamic refresh cycle time, and fault monitoring circuit timing signals.
(7) Fault self-diagnosis and treatment module
It is to improve the system reliability and maintainability of the important means, mainly taken the form of self boot, when power on or reset, the system automatically performs a self-test procedures, conduct a test on the hardware circuit. PC monitoring software main program flow, as shown in Figure 6.
Figure 6 Block diagram of PC monitoring program
2. PLC software design
PLC s program uses a modular design, the main program, manual control procedures, troubleshooting procedures module. According to system requirements, PLC s I / O distribution, as shown in Table 1.
(1) input and output signals Table 1 PLC input and output signals
(2) ladder diagram
According to the control process and the preparation of the ladder input and output signals. PLC cyclic scan mode, press the ladder from the top down, from left to right order of implementation. Meanwhile, here are carried out before and after the two parts interlock. Part of the ladder, shown in Figure 7.
Figure 7 Positioning station ladder
R001 is an internal relay that select "Automatic", when the PLC receive signal X010 when the sensor detects a workpiece positioning station, the delay and allow the camera output signal Y000, and then delay 2s (wait for the computer to make judgments) and when the cylinder is not turning in situ and no flip-position the workpiece, the output workpiece positioning station signal can leave. If the PLC received a computer issued "unqualified jobs" signal that the X014, the alarm, press the reset button until the alarm stops.
4, computer and PLC communication
Integration of computer and PLC control system, a key technical issue is the problem computer and PLC communications. In this issue, with regard to communication between computer and PLC, we considered two implementation methods: one is to use serial communication and another by I / O cards to achieve. As the serial communication in real time, reliability, interference immunity and so are not I / O card is good, then the specific circumstances under the factory, finally chose the latter approach. I / O cards that switch input output cards, in this project, we have chosenPCL-724, 24-digit I / O card, transfer rate of 300KB / s. The I / O card with two 8-port (A, B), port address range for the 200H ~ 3FFH, the two ports can be input and output operations during input and output operation, no need for handshake, because data can be written directly or read a set of ports. PLC input and output signals from the table you can see, PLC needed to receive the computer three signals, the computer needs to receive a signal to PLC. They define and address the communication protocol settings, such as shown in Table 2. Table 2 computer and PLC communication protocol definition and the address table
V. Conclusion
The system is integrated PLC and IPC Control of good applications, put into operation, the company has brought considerable economic benefits and social benefits. The control system in the industrial field, especially in the PLC control, with its excellent control and good cost performance, won wide praise users.