Research On Semi-active Control Of Diesel Engine Vibration

The diesel engine is a thermal energy and dynamic machine which is extensively used. It is used as major driving force in many fields such as automobiles, ships, engineering machinery and locomotive. The diesel engine vibration will not only make machine self reliability and life-span come down, but also can great environmental noise pollution. With the development direction of high-speed, high-power, light-weight, diesel engine vibration will further exacerbate. Therefore, new control method and technology adapting to the diesel power set should be studied and explored. It has a great theoretical and practical significance to improve the control of diesel engine vibration.Semi-active control is a hot point in the control research field .It provides a new method to solve the vibration and noise isolation. Using MR damper to achieve a vibration control is an important research direction in the field of structure vibration control. Semi-active control of vibration control is an effective way of structure vibration control .It uses MR dampers to get a variable damping force with high non-linear features.As a nonlinear intelligent control technique, with its special advantages fuzzy control has got extensive development and application in theory and industrial practices. Combining the technique of fuzzy control and the semi-active control, a semi-active fuzzy control base on MR Damper for active diesel engine two-stage vibration isolation is studied in this dissertation.According to the characteristics of the two-stage vibration isolation test-bed, a semi-active fuzzy control model is set up and a fuzzy controller with two inputs and one output is designed. The fuzzy control rules are established based on experiences and theoretical analysis. Use Matlab/Simulink software to study the control model by simulation. The actual dynamic system parameters are the simulation parameters. The semi-active diesel engine vibration isolation and the uncontrolled diesel engine isolation are simulated with periodic signals of different frequencies. Comparing the semi-active control system with the uncontrolled system, the results show that the semi-active control has better control effect. The transition process is short and the effective control can be quickly established.The method of adjusting parameter of fuzzy control automatically is introduced into two-stage vibration isolation, and quantitative factors and scaling factor are revised online. This control stratagem is more adaptive to circumstance than normal fuzzy control which quantitative factors and scaling factor are staid. The simulation of adaptive fuzzy control is made on the model two-stage vibration isolation. Results verify that adaptive fuzzy control method is effective to the active vibration isolation system.