Research System Features Pneumatic Artificial Muscles Buffer Ambulance Stretcher

Ambulance is a medical equipment which is used to convey patients orwounded to hospital，and it equipped with first-aid equipment and stretcher，etc，in the way to hospital，we can implement the patients with necessary advancetreatment. With the development of society and medical industry，the patients’requirement of comfort for ambulance stretcher is also improving.Many ambulance is refitted based on the light truck or sports utility vehiclechassis，and stretcher vibration isolation system is passive buffer system，whichconsists of elastic element and shock absorber，then its damping effect is notgood. So ambulance chassis does not suit to alter，then in order to improve thecomfort of patients on ambulance stretcher，the development of stretchervibration isolation device is becomes more important.Pneumatic artificial muscle (PAM，the Mckibben type PAM was used inthis paper) is a bionics pneumatic actuator，it consists two sections，one is themiddle rubber sleeve which external encapsulated by fiber mesh grid；another isthe joints connecting two ends of PAM. The followings are merits of PAM：simple structure；high ratio of output force and weight；free of adhesion andcreeping；variable stiffness；response rapidly；action smoothly. Mckibben typePAM was used in stretcher vibration isolation system in this paper，and vibrationisolation platform was built based on PAM，then stretcher can locked onplatform rigidity and rapidly，based on this，the vibration transferred fromambulance body to stretcher can attenuated.The6degrees of freedom“ambulance-stretcher system”vibration modeland9degrees of freedom“ambulance-stretcher-prone position patients”vibrationmodel were established，in Matlab/Simulink，fuzzy PID control and BP neuralnetwork PID control were used to control the two vibration system respectively.For the6degrees of freedom“ambulance-stretcher system”vibration model，takestretcher’s vertical acceleration and pitch angular acceleration as evaluationstandard；For the9degrees of freedom“ambulance-stretcher-prone positionpatients”vibration model，take vertical acceleration of prone position patients’head、buttock and leg as evaluation standard. Simulation results show that under the two control strategies，for the two vibration models，the correspondingevaluation standard all decreased greatly，then the comfort of patients improvedsignificantly.