Design and Analysis of Passive Components-Supported SLS-VI Mechanism for the Control of Road-Induced Stretcher Vibrations During Ambulance Movement

Purpose The road-induced vibrations affect the comfort and health of the patient in the ambulances. Depending on the sudden changes in the ambulance and road conditions, high amplitude and frequency vibrations occur on the stretcher in the ambulance. In this study, a new passive components-supported SLS-VI mechanism has been developed between the ambulance base and the stretcher to suppress the road-induced vibrations on the stretcher. This is the first study in which the SLS-based vibration isolation mechanism was applied as stretcher's vibration suspension system in an ambulance. Methods The suspension performance of the traditional SLS-VI system is enhanced by additional passive elements such as spring and dampers. The mathematical model of the developed system is derived using the Lagrange energy method, and the coefficients of the spring and dampers were determined for maximum damping performance. After that, the vibration damping performance was analyzed by simulations and experiments for different road conditions. The experimental and simulation results are evaluated in time and frequency domains and with some statistical methods. Results The results show that the developed SLS-VI based system successfully suppresses road-induced vertical vibrations at different frequencies. For higher frequencies, it has better damping performance and it has been observed that the amplitudes of the base vibrations are damped by more than 50% in the vertical direction for all cases. Conclusion According to all these results, it is seen that the use of the SLS-VI system increases the comfort/health of the patient and makes the patient transport safer.