Research On Human Body Piezoelectric Signal Control Of Wearable Exercise Aids

Wearable motion AIDS are the current research hotspots,and have applied prospects in the field of military and medical rehabilitation.An important indicator of Wearable motion AIDS is to predict human motion accurately and maintain the same motion with the corresponding joint.Therefore,if human walking is the main research object,it is very important to know the gait behavior of others in advance,and it is very important to control the wearable motion AIDS of the lower limbs.The gait recognition algorithm needs motion parameters as reference,and there are many kinds of parameters,including EMG signal,foot pressure signal and so on.The collection of EMG signal based on EMG signal includes two kinds: a kind of needle electrode is used to stab it into the human muscle,and the EMG signal is obtained directly from the muscle fiber,and it is intrusive;The surface electrodes can be used to collect electrical signals directly from the surface of the muscles and not damage the tissues of the human body.However,no matter which means of EMG signal acquisition,it is easily affected by the effects of the skin conductivity,electrocardiogram,body temperature and individual physique of the testers,while the foot pressure signal is easily affected by the terrain.And can not fully reflect the relevant muscle movement information.In the course of walking,the movement of lower extremities is driven by the muscles of the lower extremities.The muscles of the lower extremities change periodically with the change of gait.The surface pressure that controls the resulting surface pressure of the muscle group varies with the gait.It can be used as an important gait data to analyze the correlation between the pressure signal of the muscle surface and the phase of the gait.The human gait phase is identified by the pressure signal on the muscle surface.Therefore,it is necessary to reclassify the gait phase according to the change of the surface pressure signal of the muscle,and then recognize the gait by using the detected data.Because of the delay in the motion of the auxiliary equipment and the acquisition process of the sensor,it is necessary to predict the human gait in order to realize the behavior of the wearable motion AIDS in real time.Firstly,according to the characteristics of muscle surface pressure,PVDF flexible piezoelectric material is chosen as the main material for making sensors.Based on the study of the characteristics of PVDF films and related sensors,a suitable sensor is designed for the acquisition of muscle surface pressure signals based on the properties of PVDF films.A matched filter amplifying signal is designed to facilitate subsequent signal analysis.Then the muscle surface pressure signal of the tester is collected,and the information of the foot sensor is used to identify the phase of the human gait in the test process.Starting from the pressure signal on the muscle surface,the correlation of the side gait phase with the ipsilateral pressure data and contralateral pressure data was analyzed.The gait cycle is redivided according to the relationship between the two,and the relationship between the gait phase and the muscle surface pressure is studied,and the recognition of the gait phase is accomplished according to the signal of the muscle surface pressure.At last,in order to realize the gait prediction,a prediction algorithm based on adaptive filter is designed to predict the muscle surface pressure signal,and then the gait phase is predicted.The prediction results show that the system can realize the recognition and prediction of the lower limb muscle surface pressure and the gait phase,and provide a guarantee for the control of the wearable motion AIDS.