A wearable inertial sensor system for human motion analysis Tao Liu Robotics and Dynamics Lab Kochi University of Technology th IEEE International Symposium on Computational Intelligence in Robotics and Automation

IntroductionIntroduction Some application fields of human motion analysis Human dynamic analysis Functional electrical stimulation (FES) Humanoid robot

Research Background  Some human motion analysis systems have been developed, but are complicated and expensive for product developments.  In this research, a six-D reaction force sensor had been finished, and the wearable motion analysis system is constructed for the dynamic analysis of human walking.  A more compact measurement system with intelligent computation methods will be the focused problem in this research. IntroductionIntroduction

Methods and Materials Hardware Description Gyro: ENC-03J Accelerometer: ADXL202 A/D converter card with 14 bit resolution

Ay ωyωy Ax ωxωx Y: Gyro X: Gyro Two-axis Accelerometer 70mm 100mm Hardware Description Base board of inertial sensors Methods and Materials

Hardware Description Wearable motion measurement device with inertial sensors Methods and Materials

The Gait Phase Analysis Methods  Gait phases of a normal walking  Physical sense of each gait phase  Introduce the Fuzzy inference system into the detection of gait phases  Post-process of the FIS outputs (Pointer digital filter design)  The optical motion analysis system (In next step to validate above inference) Methods and Materials

The Gait Phase Analysis Methods Toe-rotation Swing Heel-rotation Stance  Gait phases of a normal walking Methods and Materials

The Gait Phase Analysis Methods  Physical sense of each gait phases ωyωy x ωxωx y z ωx: X-Rotational angular velocity ωy: Y-Rotational angular velocity Ax: X-Acceleration Ay: Y-Acceleration If ωx=0 AND ωy =0 AND Ax=0 AND Ay=0 Then ‘Stance Phase’; If ωy<0 AND Ax≠0 AND Ay≠0 Then ‘Swing Phase’; If ωy>0 AND Ax≠0 AND Ay≠0 Then If the case is before the ‘Swing Phase’ of the same walking cycle Then ‘Toe-rotation Phase’ Else ‘Heel-rotation Phase’. Methods and Materials

The Gait Phase Analysis Methods  Introduction of Fuzzy Inference System (FIS) Mamdani method is used in this FIS In this FIS, four inputs and one output were designed Methods and Materials

The Gait Phase Analysis Methods Fuzzy InputDe-fuzzy Output  Introduction of Fuzzy Inference System (FIS) Methods and Materials

The Gait Phase Analysis Methods  Introduction of Fuzzy Inference System (FIS) Rules Designed for the FIS Methods and Materials If ωx=0 AND ωy =0 AND Ax=0 AND Ay=0 Then ‘Stance Phase’; If ωy<0 AND Ax≠0 AND Ay≠0 Then ‘Swing Phase’; If ωy>0 AND Ax≠0 AND Ay≠0 Then If the case is before the ‘Swing Phase’ of the same walking cycle Then ‘Toe-rotation Phase’ Else ‘Heel-rotation Phase’.

The Gait Phase Analysis Methods  Introduction of Fuzzy Inference System (FIS) Results View The FIS is developed by using MATLAB Methods and Materials

The Gait Phase Analysis Methods  Post-process of the FIS outputs (Pointer digital filter design) Output of FIS Last filter result Methods and Materials

The Gait Phase Analysis Methods  The optical motion analysis system Knee marker Heel marker Toe marker Methods and Materials Ankle marker Hi-Dcam High speed camera by NAC

Experiment Study  Data sampling of two-axis Gyroscope and two-axis accelerometer  Gait phases analysis results in two walking tasks  Validating the analysis results using the optical motion analysis system

 Data sampling of two-axis Gyroscope and two-axis accelerometer Experiment Study

 Gait phases analysis results of an object Experiment Study

 Validating the analysis results using the optical motion analysis system Experiment Study

Experimental Results Analysis and Conclusion  The wearable inertial sensors system can be used for foot-motion analysis;  A fuzzy inference system was used on the detection of gait phase.  A digital point filter was design for the results data processing.  The results of gait phases analysis can be used for next step dynamic analysis when a reaction force measurement system is integrated into this analysis system.

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