A method for early detection of the initiation of sit-to-stand posture transitions

A powered lower extremity orthotic brace can potentially be used to assist frail elderly during daily activities. This paper presents a method for an early detection of the initiation of sit-to-stand (SiSt) posture transition that can be used in the control of the powered orthosis. Unlike the methods used in prosthetic devices that rely on surface electromyography (EMG), the proposed method uses only sensors embedded into the orthosis brace attached to the limb. The method was developed and validated using data from a human study with 10 individuals. Each human trial included different sets of sitting, standing and walking activities originating from various initial postures. Features from the sensor signal were extracted and aggregated in lagged epochs to incorporate the time history. Principal component analysis (PCA) was used to reduce the feature set. The principal components were then used in a leave-one-out manner to train a linear support vector machine (SVM) classifier to perform early detection of the SiSt posture transition. The proposed method achieved the sensitivity of 100% and the specificity 92.94% of trials without false positives. The average detection time (DT) of 0.1341  ±  0.3310 s following the start of transition demonstrated early recognition of the initiation of SiSt transition.

[1]  Xiangrong Shen,et al.  Design and Control of a Pneumatically Actuated Lower-Extremity Orthosis , 2012 .

[2]  Alan Godfrey,et al.  A comparison of methods to detect postural transitions using a single tri-axial accelerometer , 2014, 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[3]  H. van der Kooij,et al.  Design of a series elastic- and Bowden cable-based actuation system for use as torque-actuator in exoskeleton-type training , 2005, 9th International Conference on Rehabilitation Robotics, 2005. ICORR 2005..

[4]  Günter Hommel,et al.  A Human--Exoskeleton Interface Utilizing Electromyography , 2008, IEEE Transactions on Robotics.

[5]  J.K. Hitt,et al.  Control of a Regenerative Braking Powered Ankle Foot Orthosis , 2007, 2007 IEEE 10th International Conference on Rehabilitation Robotics.

[6]  K. Hauer,et al.  Test–retest reliability and minimal detectable change of repeated sit-to-stand analysis using one body fixed sensor in geriatric patients , 2012, Physiological measurement.

[7]  Andreu Català,et al.  Posture transition identification on PD patients through a SVM-based technique and a single waist-worn accelerometer , 2015, Neurocomputing.

[8]  E. S. Sazonov,et al.  A Sensor System for Automatic Detection of Food Intake Through Non-Invasive Monitoring of Chewing , 2012, IEEE Sensors Journal.

[9]  Jerry E. Pratt,et al.  The RoboKnee: an exoskeleton for enhancing strength and endurance during walking , 2004, IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004.

[10]  Yasuhisa Hasegawa,et al.  Sit-to-Stand and Stand-to-Sit Transfer Support for Complete Paraplegic Patients with Robot Suit HAL , 2010, Adv. Robotics.

[11]  Oleksandr Makeyev,et al.  Automatic food intake detection based on swallowing sounds , 2012, Biomed. Signal Process. Control..

[12]  Y. Pai,et al.  Control of body centre of mass momentum during sit-to-stand among young and elderly adults , 1994 .

[13]  Daniel P. Ferris,et al.  Learning to walk with a robotic ankle exoskeleton. , 2007, Journal of biomechanics.

[14]  Kurt Hornik,et al.  The support vector machine under test , 2003, Neurocomputing.

[15]  D. Narayana Dutt,et al.  Computing Fractal Dimension of Signals using Multiresolution Box-counting Method , 2010 .

[16]  Xiangrong Shen,et al.  Sensor sensitivity to posture transitions in a lower-extremity orthotic device , 2015, SoutheastCon 2015.

[17]  K Aminian,et al.  Suitability of commercial barometric pressure sensors to distinguish sitting and standing activities for wearable monitoring. , 2014, Medical engineering & physics.

[18]  Adam Zoss,et al.  On the Biomimetic Design of the Berkeley Lower Extremity Exoskeleton (BLEEX) , 2005, Proceedings of the 2005 IEEE International Conference on Robotics and Automation.

[19]  Jacob Rosen,et al.  A myosignal-based powered exoskeleton system , 2001, IEEE Trans. Syst. Man Cybern. Part A.

[20]  M. Goldfarb,et al.  Preliminary Evaluation of a Powered Lower Limb Orthosis to Aid Walking in Paraplegic Individuals , 2011, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[21]  L Chiari,et al.  Automated approach for quantifying the repeated sit-to-stand using one body fixed sensor in young and older adults. , 2013, Gait & posture.

[22]  A K Bourke,et al.  Activity classification using a single chest mounted tri-axial accelerometer. , 2011, Medical engineering & physics.

[23]  Kamiar Aminian,et al.  Ambulatory Monitoring of Physical Activities in Patients With Parkinson's Disease , 2007, IEEE Transactions on Biomedical Engineering.

[24]  Jay L. Devore,et al.  Probability and statistics for engineering and the sciences , 1982 .

[25]  Toshio Fukuda,et al.  Neuro-fuzzy control of a robotic exoskeleton with EMG signals , 2004, IEEE Transactions on Fuzzy Systems.

[26]  Adam Zoss,et al.  Prototype Medical Exoskeleton for Paraplegic Mobility: First Experimental Results , 2010 .

[27]  Kamiar Aminian,et al.  Measurement of stand-sit and sit-stand transitions using a miniature gyroscope and its application in fall risk evaluation in the elderly , 2002, IEEE Transactions on Biomedical Engineering.

[28]  Chih-Jen Lin,et al.  LIBSVM: A library for support vector machines , 2011, TIST.

[29]  Daisuke Chugo,et al.  Rehabilitation walker system for standing-up motion , 2007, 2007 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[30]  Constantinos Mavroidis,et al.  Control of electro-rheological fluid based resistive torque elements for use in active rehabilitation devices , 2007 .

[31]  H. Herr,et al.  Adaptive control of a variable-impedance ankle-foot orthosis to assist drop-foot gait , 2004, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[32]  K. Kiguchi,et al.  A Study on EMG-Based Control of Exoskeleton Robots for Human Lower-limb Motion Assist , 2007, 2007 6th International Special Topic Conference on Information Technology Applications in Biomedicine.

[33]  Daniel P. Ferris,et al.  A pneumatically powered knee-ankle-foot orthosis (KAFO) with myoelectric activation and inhibition , 2009, Journal of NeuroEngineering and Rehabilitation.

[34]  Eric Loth,et al.  A portable powered ankle-foot orthosis for rehabilitation. , 2011, Journal of rehabilitation research and development.