Research On Sleep Monitoring Of Smart Mattress Based On Piezoceramic Signal

With the rapid development of society and economy in china,people's living standard is enhanced and life rhythm is speeded up.Since sleep becomes an important factor affecting the quality of people's life and work,the increasing number of people have been concerned about sleep.At present,the existing sleep monitoring equipment in the market is mostly used in medical institutions,which has high price and is difficult to operate,while the design of similar equipment for the home users is relatively rare.Therefore,based on the objective demand,this paper studies the non-contact and multi-functional sleep monitoring system applicable to the family.The research contents of this paper are as follows:(1)A multifunctional mattress sleep monitoring system is designed based on piezoceramic sensor.On the basis of the traditional mattress,the system includes 5 functional modules:sleep signal acquisition module,signal amplification and filtering module,signal processing module,wireless signal transmission module and physiological information display module.In the acquisition of sleep signal,to improve the accuracy and comprehensiveness of physiological signal capture,multichannel piezoceramic sensors are used to collect physiological signals and body motion signals during sleep.In the aspect of physiological signal processing,combining with sleep signal characteristics,theoretical research and experimental analysis select suitable signal processing methods to improve the scientificity of signal processing.In the aspect of wireless signal transmission,real-time transmission of physiological information is carried out using low-power Bluetooth and WIFI mode,and remote monitoring is realized through handheld devices and PC.(2)The complex piezoelectric signal processing generated by physiological activities in the sleep state of human body to extracts various life characteristics information.Based on the least square method and mathematical morphology filtering algorithm,operations such as removing the trend items,smoothing the signal and framing signal preprocessing have been done.This paper proposes a regional short-time energy distribution algorithm to recognize the posture of human body turning over and getting off bed.With the usage of the autoregressive model power spectrum,it has analyzed the respiration rate in the sleep signal,and compensated the respiratory rate by the improved short time mean difference function when the body is in moving state.Combined with the characteristics of human physiological activity and the characteristics of piezoelectric signal,it is proposed to transform the vibration displacement signal into the acceleration signal method so as to suppress the respiratory components in the sleep signal.This method can effectively separate the heartbeat signal.The Fast Ensemble Empirical Mode Decomposition algorithm is used to extract heartbeat components in the signal,and then the envelope is extracted by Hilbert transform algorithm.Next,an adaptive algorithm has been proposed to identify the characteristic waves in the Ballistocardiogram and a formula has been given for calculating the heart rate.Finally,a comprehensive experiment of sleep monitoring system is designed based on the ECG monitor of medical devices.The experimental results show that the presented sleep monitoring system in accuracy,stability and real time the three aspects are conform to the requirements of the sleep monitoring system,and it can meet of demand of the daily sleep monitoring and health management.