The Vibration Isolation Performance And Control Method Research Of ERF Semi-active Engine Mount

For that engine is the main vibration source and noise source in automobile, so how to isolate and attenuate the vibration of the engine is critical to the improvement of the automobile ride comfort. Mount is a connect part between engine and chassis, and also is a transfer part of engine vibration. Hign performance engine mount not only can effectively isolate and attenuate the vibration that is transmitted from engine to vehicle chassis, reduce the vibration and noise in body room, improve the ride comfort and also can protect the engine. Conventional passive mounts can not commendably satisfy the using need of people for their limits of the capability. While active control mounts' structure complexity, needing to consume a great deal outside energy and high costs make them can not be widely used. So semi-active control mount which only need partly change of mount's structure and lesser outside energy to realize the characteristics' modulation and control become the emphases of people's research.The intelligent control ERF engine mount which is studied in this dissertation is a kind of typical semi-active control mount. Intelligent control ERF engine mount is a semi-active control mount which can change the fluid of ERF through control outside electric field to realize characteristics' modulation. This dissertation, analyze the ER effect principle, yield shearing stress and mechanical characteristics of ERF; confect two kinds of ERF; study the structure design, bond graph model's set up and the dynamic characteristics of ERF mount; simulate and compare the isolation characteristics of two degree ERF mount using three different intelligent methods; design the single chip controller of ERF mount; and research the modeling, simulation analysis and test-bed of ERF engine mounting system. The work of this desertation is the detected research of ERF engine mount's development, main research content as follows:This paper analyzes the build up of the ERF, the principle of electrorheological effect and mechanical characteristics of ERF. Three elements nanometer compound ERF of kaolin, dimethylsulfoxide, Hydroxymethylstarch and alumina ERF two kinds of ERF are confected. HAKKE electrorheological equipment is used to test the rheological characteristics of this two ERF. The result that alumina ERF is better than three elements nanometer compound ERF is received through analyzing the test datum. The relation expression of shearing stress and electric field is received through fitting the test datum.The structure and working principle of typical ERF mount is analyzed. One kind of ERF mount is designed and manufactured. Bond graph theory modeling method is introduced. Bond graph modeling of ERF mount is built up based on its physical model. Frequency changing expression of ERF mount's dynamic stiffness and damping lagging angle is deduced. Meanwhile structure and characteristic parameters of ERF mount's influence to dynamic characteristics is analyzed. The dynamic characteristics of ERF mount samples with different dimensions in dissimilar electric fields are tested by using INSTRON dynamic equipment. The test datum is compared with simulation results, and they are similar. This indicates that the dynamic charactiristics' expression is correct.The two degree system mechanical model and bond graph of engine and body considering stiffness and damping of ERF mount and suspension are built up. The simulation model of this two degree system is set up by using Simulink module of MATLAB software. Three different intelligent control methods-Fuzzy control, fuzzy neural network control and wavelet fuzzy neural network control are used to control the ERF mount. The velocity and acceleration time domain variational curves of engine and body in different working conditions are simulated through software. The isolation effects of these three methods are compared, and the resit that the fuzzy neural network control method is better sutiable for application is achieved. The system function and compose of single-chip fuzzy neural network controller is analyzed. The ATmega16L type AVR single-chip made by Atmel is chosed to develop the single-chip controller of ERF mount based on the Comparation of different products made by different company in the market. The exploitation tool of AVR single-chip, and the chip pin, whole structure and central processing unit of ATmegal6L are introduced. The hardware and software structure of ERF mount's single-chip fuzzy neural network controller is designed.The bond graph model of ERF engine mounting system is built up based on the structure of it. And simulation model of ERF engine mounting system is set up by using Simulink module of MATLAB software, this simulation model can simulate isolation characteristics of ERF engine mounting system in different working situations. Fuzzy neural network control program is writed using MATLAB language. The sinusoidal excitation signal is used to simulate second order inertia force of four-cylinder-four-stroke engine. The isolation characteristics of ERF engine mounting system in 10Hz and idle working condition is simulated. The results indicate that intelligent control ERF engine mount relative to normal hydraulic mount is more effective to isolate and attenuation the vibration transfer from engine to body both in 10Hz and idle working condition. It improves the ride comfort of automobile.The hardware test-bed of intelligent control ERF engine mount is built up. The engine vibration excitation is simulated through electromotor, gear box, eccentric block and tranducer. The revolving velocity of electromotor is modulate by transducer to realize the simulation of engine excitation in different vibration frequency. The vibration signal collection of engine and body and the output of control signal are finished by ERF engine mount single-chip controller, acceleration sensor, charger amplifier and power amplifier, alteriorly through controlling high voltage source to modulate the characteristics of ERF mount. This test-bed can finish dynamic simulation of ERF engine mounting system in different working condition indoor, this economizes the exploitation costs and shorten the exploitation period. The test results show that the effectiveness of intelligent control ERF mount for reducing the vibration transmittion from engine to body. Meanwhile it validates the correctness of the simulation results.ERF engine mount is one kind of semi-active control engine mount having good prospect of application. Its research in china is still in the earlier phase of development. Some relevant key technologies are not solved yet. The study of this paper has reference value and guiding action for the exploitation of ERF semi-active control engine mount.