System Introduction
Automobile Aggregate Function Performance Detection System (AAFPDS) is an automobile detection system that uses modern detection technology, electronic technology and computer application technology to detect and diagnose automobiles without disassembly. It can detect and diagnose all the parameters and possible faults to evaluate the performance of automobiles.

AAFPDS not only inspects the dynamics, economy, reliability, environment and safety management of automobiles, but also evaluates the servicing quality and technical status of active automobiles. The testing devices for weighing, braking, speed, exhaust gas and smoke, light and sound are connected to industrial PCs. All the signals from testing devices are collected and converted into digital signals which will be transmitted to the host and stored. The test report is made according to the obtained data, and the functions of data-query analysis and statistics are provided. The whole system realizes the automated management and information sharing of automobile safety inspection.

Operating Principles
The test line is divided into three working phases. The task of the first phase is to test the speed, exhaust gas and chassis of the automobile while the second phase is to test braking performance on axis-weight measurement platform and braking testing platform. The test items in the third phase mainly include sideslip, lighting, sound level and so on. When the automobile is being tested on the test line, the driver is required to operate according to the prompts on the LED dot-matrix screen. Test trigger signals are provided by photoelectric switches.

The test flow is shown as follows. Firstly, all the automobiles to be tested need to be logged in to the computer for queuing. If the first station is idle, it will suggest testing an automobile. When the driving axle reaches the speed test bench, the lifter will be lowered down by the main control computer and speed test prompts will be displayed on the screen. Normally, a 40km/h test is given, where the driver is required to adjust the speed to 40km/h, and the exact speed is recorded by the computer. After the test, the tires will be released by the lifter, allowing the automobile to enter the next station. The second station mainly involves the braking test, the main device of which is the single axle roller opposite forces type brake tester, and the motor is driven by the electrical cabinet that is controlled by the signals from the main control computer. The third station mainly involves the lighting test, which is done by a lighting tester. The sideslip test is performed when the automobile is driven out. After all tests are done, the main control computer will transmit all the data to the data processing computer, which will print out the data in a given format and store it in the database for future retrieval. More than one automobile can be tested simultaneously for higher efficiency.

System Diagram


Functions of the Parts:
1) Login subsystem
As the start of the computer network test system, the login function is mainly to register the automobiles to be tested and provide necessary parameters for the tests.
2) Comparison function for appearance query
The appearance test station is mainly to check the appearance of the automobiles according to the requirements of GA468-2004. The appearance and dynamic items of the chassis are tested one by one and all the results are stored in the computer.
3) Online scheduling function
After login, the online scheduling function will schedule the automobiles having logged in and passed appearance test, and complete corresponding test items.
4) Measurement and control function for test items
Measurement and control software is the core unit on the test line. Its function is to identify on-off input and output, control mechanical actions, condition signals, acquire data and so on. The software can test and control the speed meter, exhaust gas, smoke opacity, headlights, sound level, sideslip, axis weight, braking, chassis and other items according to GA468-2004 and GB7258-2004. With the software, the operator is guided through auxiliary operation and determines test results in a real-time manner.
5) Main control function
The main control function is normally fulfilled by the main control industrial computer, usually of high performance, which also serves as test line The main control function is primarily to control and schedule the whole test line, synthesize and store data.
6) Data management
Data management mainly involves the query and statistics of test data as well as system setup.
7) Flexible calibration function
The computer network testing system shall be provided with flexible measurement and inspection function and each subsystem shall be able to conduct self-calibration. The calibration program mainly provides the measured values of controlled testing devices with calibration interfaces, on which the zero point output, A/D value and calibration value of each analog output channel of each controlled device are displayed, and provides zero calibration and recovery operation.
8) Fault self-diagnosis, analysis and indication
The computer network testing system shall find its own faults in time, analyze and indicate them and help users in troubleshooting. The system, when running, shall conduct self-diagnosis and indication of the faults in smart card, photoelectric switches, sensors and circuits for smooth operation of the testing system.
9) Monitoring function
The monitoring function is primarily to monitor the working status of each station and the testing status of the automobiles, so that automobile owners and the management department can be informed of the testing process.
10) Data input function for road test
If the automobile cannot be tested directly on the test line or the test result is controversial, a road test will be carried out. Information such as braking distance, MFDD, coordination time, braking stability and road test checker will be entered into the computer and stored in the database.

System Configuration
Host Computer
Login computer, management computer

System Evaluation
AAFPDS achieves the networking of automobile test, making the sharing of information, hardware and software resources possible. All the automobile aggregate function performance detection stations across the country are connected to form a wide area network so that traffic administrations are timely informed of the automobile information in different regions.