This paper presents study review on control method for two-mass systems either in speed control or position control. The systems should be modeled as two-mass or multi-mass systems when flexible couplings or long shaft with low stiffness are used to connect the actuator with other elements. Due to this, the finite but small elasticity of the shaft gets magnified and has a vibrational effect on the load position which may reduce positioning accuracy. This vibration gives the unstable performance response of the plant. Many control method have been developed to solve this problem are studied. On the other hand, one-mass system is only applicable in the case a rigid coupling with high stiffness is used and there are no flexible elements. Fundamental concept of two-mass systems and their control method are reviewed and explained either in linear or rotary systems.

A modeling through sensitivity analysis is one of the promising methods to investigate the dynamic characteristics of complex mechanical parts. This study aimed to investigate the effect of sensitivity based on mass and stiffness modification in automobile crankshaft as a function of natural frequency. Verification for the crankshaft model that is used in the experiment and simulation was done and both results showed good agreement and small errors percentage. The modification was also done by reducing the different percentage of crankshaft’s mass and stiffness. Partial differential analysis was used in the sensitivity analysis in order to figure out the natural frequency after every set of modification. According to the results, we also found that there were changes of sensitivity value by changes in mass value but the stiffness value remains unchanged. However, there is no significant effect of stiffness reduction on vibration was found in this research.

The paper presents a method for analysis of the mechanical behaviour of a crankshaft in a four-cylinder internal combustion engine. The purpose of the analysis was to study the characteristics of the shaft in which the pin and arm parts were assumed to have a uniform section in order to simplify the modal analysis. The results of the natural frequency transfer function and mode shape were compared with those obtained by experimental work. The results obtained from the comparison showed good agreement with each other and consequently verified the analysis model. Furthermore, a prediction of crankshaft characteristics under the firing condition, by using the model, was performed. The study describes a new method for analysing the dynamic behaviour of crankshaft vibrations in the frequency domain based on the initial firing stages. The new method used root mean square values to calculate the energy at each bearing journal and balancer shape modification under the operating conditions. stage. Consideration of the load history in the time Seoul, South Korea. email: amenmy@ domain [2] under running conditions is obviously important, but the high-frequency components of yahoo.com D10304

Under excitation of the engine and road surface, the vibration energy of the exhaust system which will result in the vibration of the body and produce the structure noise transfers to the body from the hanger. In view of these problems will cause noise, vibration and harshness (NVH) performance of the vehicle. A method called averaged driving DOF displacement (ADDOFD) is used to determine and optimize the exhaust hanger locations in this paper. Based on a sample vehicle, the Hyper Mesh and MSC. Nastrans oftware are adopted for meshing and calculation in the FEM modeling and vibration modal analysis of the exhaust system. Exhaust systems free-free mode and sum of its eigenvectors are offered using MSC. Nastran. Hanger locations are recommended at the position where the ADDOFD is relatively lower. Then static analysis and dynamic analysis of the exhaust system are done, and finally hanger locations of the exhaust system are selected. When the reasonable hanger positions have been decided, the vibration level of the body and the internal noise would have been decreased. This method can effectively select better NVH performance hanger locations in the earlier vehicle development process and can be extended to other types of vehicle, thus is instructive for saving both the time and the cost of operation.

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