Research On Rotating Speed Control System Of Automotive Power Train System Test-bed

The traditional engine test-bed is hard to meet the needs of scientific research, production and teaching, because of the shortcomings such as poor stability, low measurement precision, single function, etc. Now the set of automatic engine test bed experiment has already been developed. However, because of the high price, it's only used in professional research units, large enterprises. If introducing new equipment, the original equipment would have to be eliminated, which would cost a lot of money. Based on this situation, we need to find a convenient and efficient method which makes full use of the existing equipment conditions of each unit, and can accomplish engine test-bed modification and extension, so as to meet the needs of operators during research and production, and decrease investment and waste as well.Based on traditional engine test-bed, a rotating speed control system of automotive power train system test-bed is developed in this paper. Making the throttle angle of diesel engine and the field current of electric eddy current dynamometer as control project, it can realize that the power train system runs stably in the set speed. The system will greatly improve the operation conditions, the accuracy and precision. The main work of this paper is followed:1) The test-bed structure is analysed, and the diesel engine throttle control model and the engine-dynamometer model is established.2) The requirements of the system is analysed, and the control scheme is designed. The rotating speed control system is based on single-chip microcomputer ATmegal6, and consists of several circuit modules such as Power supply, crystal oscillator, JTAG debugging, reset, serial communication, voltage signal output of throttle control, numerical input and display, eddy current dynamometer excitation current power drive, alarm and so on.3) This control system adopts the fuzzy-PID control algorithm, and the fuzzy-PID controller is designed. The Simulink simulation results show that fuzzy-PID control meets the design requirements, with higher control precision and quicker response compared to traditional control method.4) The software of the control system is designed. The speed control system can realize two control methods:speed-throttle control mode, which usually used in tests of external characteristics and load performance; speed-torque control mode, which usually used in variable condition test. For the software part, which mainly includes keyboard input and display module, fuzzy-PID control algorithm module, modularization design concept is adopted to facilitate the programming and debugging.