| Fecal incontinence(FI)is a common clinical symptom that can be repeated and sustained,manifested by the human body’s loss of active control of feces.At present,it is difficult to give a more satisfactory treatment plan for fi in medicine.It is not only difficult to operate,easy to cause postoperative complications and other problems,but also unable to restore the ability of defecation control to the normal level.In recent years,researchers have made a systematic and in-depth study on the artificial anal sphincter(AAS)system,a new fi treatment approach,but the long-term clinical experiments show that the current AAS system is prone to cause intestinal tissue ischemic necrosis,and lack of effective defecation perception function and other defects,so further research is needed.Under the support of NSFC project(no.61673271,no.81601631)and Shanghai Science and technology support project(no.19441910600,no.19441913800,no.19142203800),this paper proposes a new type of AAS system which can optimize the defecation control mode according to the mechanism of human defecation control and defecation reflex mechanism,and realize the defecation perception reconstruction.The main work of this paper includes:1.Design a new type of AAS system in-vivo executive mechanism,imitating the human pubic rectum muscle control mechanism,and drive the rectum through motor drive to form a controllable anorectal angle to help patients achieve autonomous defecation control;The clamping method is changed to the common clamping method of the three swing arms,which increases the contact area between the actuator and the intestine,and provides more pressure detection positions.2.Optimize the distribution design of the flexible pressure sensor module,analyze the contact surface between the actuator and the gut according to the ideal clamping model,embed ten self-developed flexible pressure sensor modules in ten different positions of the three swing arms,and realize the detection of the pressure signals in ten different positions of the contact surface between the actuator and the gut.3.Complete the model of defecation perception reconstruction based on PCA-SVM,and design a comparison model based on feedforward neural network,the pressure data detected by in-vivo executive mechanism from the animal experiment are used to compare the effect of defecation perception prediction,to verify the reliability and accuracy of the model in defecation perception prediction.4.Optimize the design of the control hardware of the system,including improving the previous generation of AAS system,which has the disadvantage of unnecessary power loss of motor-driven related chips,designing the limit protection switch module to improve the real-time and accuracy of the system limit protection function,and increasing the external data storage circuit that can save the detected sensor data.5.Optimize the design of the system control software,including improving the motor drive control,configuring the sensor data detection function,and designing and implementing the sensor data transmission and storage scheme in the low power consumption mode.6.Complete the overall assembly of the new AAS system,and carry out the in vitro simulation experiment and animal in vivo experiment for the test of various functions and effects of the system.Through the experiment,verify the reliability,stability and biocompatibility of various functions when the system is in the in vitro environment and in the animal in vivo environment,and verify according to the pressure sensor data detected in the animal in vivo experiment The ability of the reconstruction module provides reference and basis for the follow-up research. |
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