The Design & Implementation Of Fixture Control System

The companies which produce car electronics demand high in reliability and security. Therefore, test equipment is needed for testing the performance of the electronics. A complete test equipment includes a fixture, a load bank and a test machine. The fixture is used for fixing the products that need to be tested, and the load bank is used for providing the products with some load to simulate the car parts which connect with the products, while the test machine is used for testing the performance of the electronic products. The fixture control system is used for the real-time control of the implementation of the fixture, testing and the indicator. E.g. it has to control the test machine to do a real-time inspection for the electronic products and deal with the feedback signals and also give out a result; besides, it has to control the electromagnetic valve, the cylinder and sorts of indicator on the fixture. The traditional fixture control system is basically manual-controlled through testing, which is complex, up to one's neck in work, high in price and poor in stability. Therefore, it could not meet the demands of the electronic product test.This issue comes up with a new control system on the basis of analyzing the current fixture control system, it puts forward a proposal that the control of the implementation of the fixture and the testing machine could be realized by combining the MCU (Microcontroller Unit) and the electromagnetic valve. The research is mainly reflected on the hardware and software of the system control. In terms of hardware, the paper analyzes the function and the features of the fixture control system to set the basic framework of the fixture control system. The hardware of the system controls the position of the cylinder with the electromagnetic valve ,which ensures the accuracy and stability of cylinder on fixture;Secondly, use the electronic sensor to do a real-time inspection on the existence of the products to be tested, the location of the cylinder position to be advanced and the advancement of the cylinder position on the fixture, which simplifies the structure of the hardware of the system. As for the software of the system, it adopts C and assembly language to compile software and use uVision4 written by Keil Software to the compilation. The problems can be solved by this issue are listed as follows:1. To control the actions of the cylinder by combining the MCU and the electromagnetic valve. E.g. using the cylinder on the fixture controlled by the electromagnetic valve to lock and unlock the products to be tested in the process of testing, and also using the cylinder on general station to forward and backward the fixture. Besides, to do a real-time inspection on the location of cylinders by using sensors not only saves the hardware equipment, improves the stability and reliability of the system, but also simplifies the program of the MCU.2. Illustrate and analyze the basic requirements in practical application. Firstly, the software design flowchart of the control system should be provided according to the practical testing when designs. Secondly, the software of each function module should be concreted and modularized. Finally, the software control program of the entire fixture control system can be integrated on the basis of the software control program that is specifically compiled.In the process of the software & hardware design, the new system takes reliability and stability fully into account, and also extensibility of the function is taken into consideration. Inspection and operation of the fixture control system indicates that the new system can control the car electronics in the testing process by automation, and can improve the efficiency of the products testing. In this way, the quality of the car electronics is guaranteed and the production efficiency is impressively improved.