Implementation Of Portable Gait Analysis Software Based On Android

Gait analysis is a subject widely used in many fields.Its work often depends on large equipment,so it is mostly carried out in specific places such as hospitals,which affects the practicability of these equipment to a certain extent.In order to enable those in need to analyze gait at any time in their daily life without the limitation of place,a portable gait analysis system based on ergonomics and biomechanics is designed in this paper.It uses the six axis inertial sensor to collect the acceleration and angular velocity of the upper and lower positions of the foot and knee joint,and sends them to the mobile phone through the Bluetooth device.The gait analysis algorithm designed in this paper is used to calculate the gait characteristics and the angle change of the knee joint.Compared with larger gait analysis devices,this portable gait analysis device has wearability,which can make users no longer limited by the place when conducting gait analysis.At the same time,the portable gait analysis system helps to realize the online gait monitoring of users,and can help rehabilitated patients see their own rehabilitation effect and form positive psychological hints.The main research contents are as follows:（1）A method to calculate the gait parameters of human body is designed.The calculation of gait parameters in this system is mainly based on the acceleration and angular velocity data measured by inertial sensors.In terms of time parameters,the start and end of a gait cycle and the time of support phase and swing phase are judged by finding the gait key points in the angular velocity curve.In terms of gait parameter measurement,the Euler angle change during the walking process of the tester is calculated by data fusion of acceleration and angular velocity,the acceleration in three different directions is obtained by means of Euler angle,the gait information such as the step size of the tester is calculated by integration,and the speed offset in the walking process is eliminated by means of zero speed update method.The system uses the acceleration information measured by two sensors on the thigh and lower leg to calculate the change of knee joint angle during walking.Experiments show that the software has high accuracy in calculating gait parameters.（2）A mobile phone software for gait analysis is designed and implemented.The mobile phone software is based on Android operating system,and uses the human gait data analysis method designed in this paper to analyze the subjects’ gait.The mobile phone software includes login and registration module,Bluetooth connection module,animation display module,data display module,data recording module and information management module.It provides users with the function of login and registration,uses Bluetooth equipment to collect the original data of inertial sensor,and analyzes the user’s step length,gait cycle,Gait parameters such as support phase ratio and knee angle were calculated.The calculated data will be stored in the Bmob cloud.In general,the software system can complete the measurement of gait parameters under the condition of portability and accuracy.Compared with other wearable gait analysis systems,it can not only measure the time and space parameters in the process of walking,but also measure and display the knee angle of the subject in real time.