Vibration Study Of Automotive Seating System Using Semi Active Control System

Abstract

The Automotive Seating System (ASS) plays a vital role in enhancing the ride newlinecomfort, visibility, safety, etc. in a passenger car. Industry is in need of studies newlineto improve the vibration characteristics of ASS. The dynamic characteristics of fourseat newlinemodels, Model-A, Model-B, Model-C, and Model-D were studied by considering newlinethe seat with mannequin and seat without mannequin using natural frequency, newlinemode shape, transmissibility, and random response by Finite Element Analysis (FEA) newlineapproach. The FEA results of four-seat models found that the frequency level was newlinebetween 0 Hz and 80 Hz in lateral, fore-aft, and twist mode shapes. The natural newlinefrequencies extracted from FEA agreed with the test results recognized in the literature, newlineand the correlation level varied from 1.57% to 12%. Also, the natural frequencies of the newlineseat with mannequin fell within the uncomfortable zone of the spine (10-12 Hz) and the newlineabdomen (4-8 Hz) of a human body. An excitation was done at seat mounting locations newlineof ASS with RMS acceleration of 1.0m/s2 along the three directions separately and newlinethe responses were studied at eleven positions. Since the random vibration study was newlinebetter in computing the degree of comfort of the driver and the occupant, the smooth newlineand rough road profiles excited at the mounting locations of ASS.Therefore, the degree newlineof ride comfort of seat occupants can further be enhanced either by modifying the seat newlinestructure or by integrating the semi-active seat suspension system and suitable control newlinepolicies.The newly proposed Model-E ASS had design changes in the seat cushion (side newlinebrackets, hinge brackets, lower rail, upper rail and height adjuster cranks) and seat newlinebackrest (side frame and support rod). A support rod at the thigh region, a spring newlineat the buttock region, and a bracket at the lumbar region were introduced. The first newlinefundamental frequency of the proposed seat design (Model-E) without mannequin mass newlinewas found to be 33.8 Hz which was higher 64% than Model-A (20.58 Hz), 48% higher newlinethan Model-C (22.89 Hz)