| With the acceleration of the truck, K6 bogie type has become a main type of railway freight cars, and has met the needs of the overloaded and high-speed requirements of railway trucks. The bolster and side frame in the bogie bear convey and transfer a variety of vertical, horizontal and vertical alternating load when it is running, so their fatigue reliability level affects the entire vehicle's safety in the railway, once something happened, it would result in disastrous consequences. Therefore, to ensure the safe operation of trucks, fatigue testing of bolster and side frame by the bogie dynamic capacity laborating table is needed. According to The People's Republic of China Ministry of Railways industry standard TB / T 1959-2006 requirements, multiple signals drive hydraulic servo valve are needed to work together when the tested products are loaded.The main task of this topic is to design a generator with external synchronization trigger and multi-channel and single-cycle function. In this paper, the DDS Direct Digital Synthesis method is used to design the function generator. It can product an arbitrary waveform ,such as sine wave, triangular wave, square wave and nonstandard wave etc. ; the timer interrupt mode is used to control frequency of the waveform, and each cycle has 256 amplitude values, ensuring no distortion of the waveform; Decoder and A/D converter chip have been used to satisfy the needs of several multiple hydraulic servo valve; at the same time, it's able to use an external trigger to control the load times.This design consists of hardware and software components. Hardware mainly included the function of MCU module, waveform input module, controler output module and man-machine interface module. The software included DDS module and man-machine interface module.The result of the system testing shows that external synchronization trigger, multi-channel, single-cycle function generator's requirements are totally achieved.
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