Research Of Co-Driver’s Backrest Active Adjustment System

Car seats are important component of passengers restraint system. To meet thecomfort requirement, the backrests are often designed adjustable, especially for thepassengers at the co-driver seat side since their primary concern is relaxation and thebackrest angle is often adjusted larger than design value. Currently, however, all thevehicle crash tests mandate that the backrest angel to be set to the design value beforetesting, making the test results unable to represent all the real crash accidents. so it isnecessary to investigate the influence of enlarging backrest angel on passenger crashsafety.Firstly, a co-driver’s occupant restraint system was established and validatedwith HYPERMESH and PRIMER. LS-DYNA was employed to evaluate the passengerinjury in frontal impacts with different backrest angles. The result indicates that thepassenger injury, especially the head and neck injury, increased with the increase ofbackrest angle. Injuries in other areas showed a similar pattern, but they are within thehigh performance criteria in C-NCAP. Hence, it would benefit the co-driver occupantsto reduce the oversized backrest angle.Based on the simulation above, the backrests active adjustable system design isproposed. A high speed motor was applied to the existing car seat electro adjustingsystem and a place measurement apparatus was employed. When possible danger wasdetected, the backrest would be automatically adjusted to a safe position and it wouldbe automatically returned to the former comfort position once the danger alarm wasrelieved. The system can be controlled manually and comfort positions can be storedto save time adjusting it every time.A control system hardware circuit was designed based on the adjusting syste mdesigned. The circuit has four primary modules: electro-control module, memorymodule, position detection module, power module. The hardware selection for eachmodule and circuit design were explained in detail; Altium Designer6.9was used forthe design. based on the characteristic of hardware circuit, a full set of C languageprogram was written using CodeWarrior and the program process as well as the subprograms was described in detail. Finally, the various functions of the control systemwere tested by experiments.