The Research On Measuring And Controlling System Of Engine Test Bed Based On DSP

Higher engine test bed is required, because social development has an urgent demand that the engine needs improvement in the place of reduce energy consumption and harmful gas emissions. By analyzing home and abroad engine measure and control techniques, this paper proposes an advanced test program which is controlled by digital signal processor. Meanwhile, we use fuzzy PID algorithms to realize automation in engineer test bed. This solution is simple, but it provides not only powerful function, high control precision, good stability, but also good application value and reference value.According to the function and the targrt of this system, DSP2812 is used as the core controller. And we use the electric eddy current dynamometer to simulate engine load. The system places emphasis on the speed characteristics testing, load characteristics testing, universal characteristics testing and other kinds of dissertation testing.From the aspect of dynamics, we build the mathematical model of the engine test bed, including mathematical model of the absorption torque of the dynamometer, dynamometer excitation current, the engine-dynamometer transmission system, and the engine effective torque. In this paper, we also study the theory of PID control and fuzzy control, and then we design a fuzzy PID controller with two input and three output based on the two theroies mentioned above.The controller can achieve engine dynamometers'fast stability control. At last, we test the superior dynamic and steady-state control performance of the fuzzy PID controller through the MATLAB simulation.On the hardware side, this thesis has designed a DSP system and its peripheral circuits, and then complete the design of accelerograph driven circuit and eddy driven circuit. A brief introduction of the driven principle of DC torque motor is given in this paper. The motor realize full-bridge driven by using IPM(Intelligent Power Module) in the accelerograph driven circuit which has high reliability,high integration and good driving ability. Measuring principles are also analyzed to finish the signal processing circuit, such as speed, torque, temperature, pressure, current. When it comes to software, we focus on the main function program, subroutines, such as PWM module, communication module, signal capture module, ADC sampling modules in the DSP system. The program flow charts of modules are given. At last, we introduce the software architecture diagrams and running flow chart of system software of the host computer system.Finally we test this system. As a result, this system shows us its favorable function.