ON AN AMBULANCE STRETCHER SUSPENSION CONCERNED WITH THE REDUCTION OF PATIENTS BLOOD-PRESSURE VARIATION

The design process and control of an ambulance stretcher suspension to reduce patient's blood pressure variation (BPV) is discussed. The BPV caused by applying the vehicle brakes may lead to deterioration of a patient's condition. The proposed method can reduce BPV by tilting the stretcher and counterbalancing back-to-front acceleration of the ambu lance with gravity. The experimental results obtained when using a man ually controlled stretcher confirm that BPV is reduced by tilting the stretcher. A continuous control method that varies the tilting angle i s investigated through simulation analysis. The results show that this control method reduces the BPV effectively and achieves safe transpor t of the patient.