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Poor stability, low measurement accuracy, and features a single drawback to the traditional engine test stand equipment, it is difficult to meet the demand of scientific research, production, and teaching; engine has developed a complete set of automatic monitoring and control of test systems are expensive, the only limitations for professional research units of large enterprises. If the introduction of new equipment, existing equipment will be eliminated, and this will cause a large capital investment. Therefore, for this case, you need to find a convenient way to make full use of existing equipment conditions of the various units, the renovation and expansion of the engine test stand equipment, in order to achieve both meet the specific requirements of the operator, to adapt scientific research and production needs, but also reduce the investment and waste. In this thesis, the traditional engine test stand based on improved diesel engine throttle opening and eddy current dynamometer current control, speed control system for the study of the target, making the test bench set speed automotive powertrain test bench under stable operation, so as to improve the operating conditions, and improve the experimental accuracy and stability. This article is mainly carried out research in the following areas: 1) analysis of the structure of the test bench, diesel engine throttle control model and engine - dynamometer model. 2) analysis and control system requirements, design control programs. ATmega16 microcontroller as the core control system hardware design, including a single-chip power supply circuit, crystal oscillator circuit, JTAG debug circuit, reset circuit, serial communication unit, a the throttle voltage signal analog unit and a keyboard input and display, eddy current dynamometer excitation current drive, alarm unit circuit module design 3) control algorithm design and simulation. The fuzzy PID control for the characteristics of the control system, the completion of the Fuzzy-PID controller design and simulation. Comparing the simulation results, fuzzy PID control faster response than conventional PID system, small overshoot, high control accuracy, good dynamic and static performance, comply with the design requirements. 4) system software design. Demand for different experimental set two control modes: speed - throttle control method, commonly used in the outer characteristics, load characteristics and test; speed - torque control method, commonly used in the trials of variable conditions. In order to facilitate the writing and debugging the program, the software part of the modular design method, mainly to complete the overall flow chart sub flow chart of the two control modes, as well as keyboard input and display module, control flow design fuzzy PID controller algorithm module.
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