Vibration Analysis And Parameters Optimization Of The Cab-Seat Mounting On Scrap Handler

With the improvement of production technology and increasing importance attached to the Human-oriented concept by people, increasing demand has been put forward for the working environment. With more and more prevalent of engineering construction, accordingly more and more extensive application of construction machinery products, the requirement for their working environment by the construction machinery drivers also gets higher and higher, where the damping effect on cab is one of the main factors for concerning, thereby the manufacture attaches more and more importance to the damping on cab.The evaluation standard and recommended limited values have been established for the whole-body vibration of scrap handler's cab based on the conclusion on the evaluation standard and limited value of whole-body vibration in various environments available. Under the experiment conditions jointly provided by a construction machinery factory and Southwest Jiaotong University, the measurement on vibration of w-type scrap handler is conducted according to work conditions on site and it is found that the whole-body vibration of this scrap handler's cab has exceeded the recommended limits by evaluation as a result..This paper made analysis for the promoting and vibration characteristics of the seat suspension system in this scrap handler's cab according to the vibration signals obtained from measurement of its various parts. Based on analyzing, the cause for strong vibration is that too low fixed frequency has been set in vibration mode of the system with vertical cab vibration prevailed, resulting in magnification of frequency composition for human sensitivity during promoting. It is known that the promoting characteristic of the system is mainly distributed into the low frequency both at the direction z and y.By the way,the mainly promoting is at the direction z.Moreover this paper simplifies the seat suspension system of the cab to the vibration system with double mass and 12-degree-of freedom in accordance with the seat structure of this cab. The derivation of equation vibration with double mass and 12-degree-of freedom based on the micro-vibration and superposition of two centers of mass of rigid body conditions as well as approximate calculation formula for the distribution percentage of natural frequency, vibration mode and energy of the system are made in the thesis. The research on float encoding genetic algorithm is carried out in the thesis. Also the optimized target function is established and 30 variable parameters are set on the theoretical basis of decoupling theory and classical vibration isolation theory to optimize the seat suspension system in the cab. The optimized parameter obtained by programming optimization program in MATLAB will be used to build a model in the ADAMS software, which will be used to calculate the transmissibility function of the model. Combining with the measured acceleration signal of platform, it is found that the weighted vibration level here is within the range of recommended values by using numerical algorithm to estimate the vertical and transverse weighted vibration level at the cab and seat .after optimization.,and the weighted vibration level of the seat will be reduced by 10dB.Based on that,The weighted vibration level of the seat will be reduced by 6dB when the disc spring A100 has been used.Accordingly, it is proven that the use of the method in the thesis is feasible and effective for analyzing and optimizing the seat suspension system of scrap handler.