A new approach to accurate measurement of uniaxial joint angles based on a combination of accelerometers and gyroscopes

A new method of measuring joint angle using a combination of accelerometers and gyroscopes is presented. The method proposes a minimal sensor configuration with one sensor module mounted on each segment. The model is based on estimating the acceleration of the joint center of rotation by placing a pair of virtual sensors on the adjacent segments at the center of rotation. In the proposed technique, joint angles are found without the need for integration, so absolute angles can be obtained which are free from any source of drift. The model considers anatomical aspects and is personalized for each subject prior to each measurement. The method was validated by measuring knee flexion-extension angles of eight subjects, walking at three different speeds, and comparing the results with a reference motion measurement system. The results are very close to those of the reference system presenting very small errors (rms=1.3, mean=0.2, SD=1.1 deg) and excellent correlation coefficients (0.997). The algorithm is able to provide joint angles in real-time, and ready for use in gait analysis. Technically, the system is portable, easily mountable, and can be used for long term monitoring without hindrance to natural activities.

[1]  C. Myles,et al.  Knee joint functional range of movement prior to and following total knee arthroplasty measured using flexible electrogoniometry. , 2002, Gait & posture.

[2]  Angela Shiratsu,et al.  Reliability and accuracy of different sensors of a flexible electrogoniometer. , 2003, Clinical biomechanics.

[3]  K. Aminian,et al.  Evaluation of an ambulatory system for gait analysis in hip osteoarthritis and after total hip replacement. , 2004, Gait & posture.

[4]  Kamiar Aminian,et al.  Capturing human motion using body‐fixed sensors: outdoor measurement and clinical applications , 2004, Comput. Animat. Virtual Worlds.

[5]  J D Moorehead,et al.  Instant center of rotation estimation using the Reuleaux technique and a Lateral Extrapolation technique. , 2003, Journal of biomechanics.

[6]  A. Heyn,et al.  The kinematics of the swing phase obtained from accelerometer and gyroscope measurements , 1996, Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[7]  A. Lundberg,et al.  A new method for estimating the axis of rotation and the center of rotation. , 1999, Journal of biomechanics.

[8]  D. H. Titterton,et al.  The alignment of ship launched missile IN systems , 1990 .

[9]  L. Schutte,et al.  An index for quantifying deviations from normal gait. , 2000, Gait & posture.

[10]  R. B. Davis,et al.  A gait analysis data collection and reduction technique , 1991 .

[11]  Heinrich M. Overhoff,et al.  Total knee arthroplasty: coordinate system definition and planning based on 3-D ultrasound image volumes , 2001, CARS.

[12]  H. Boom,et al.  Real-time gait assessment utilizing a new way of accelerometry. , 1990, Journal of biomechanics.

[13]  László Kocsis,et al.  Joint kinematics and spatial-temporal parameters of gait measured by an ultrasound-based system. , 2004, Medical engineering & physics.

[14]  John Weston,et al.  Strapdown Inertial Navigation Technology , 1997 .

[15]  Dejan B. Popovic,et al.  Comprehensive gait analysis in spinal cord injured patients with functional electrical stimulation , 1994, Proceedings of 16th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[16]  Kamiar Aminian,et al.  Spatio-temporal parameters of gait measured by an ambulatory system using miniature gyroscopes. , 2002, Journal of biomechanics.

[17]  M H Granat,et al.  A practical gait analysis system using gyroscopes. , 1999, Medical engineering & physics.

[18]  J R Morris,et al.  Accelerometry--a technique for the measurement of human body movements. , 1973, Journal of biomechanics.

[19]  Peter H Veltink,et al.  Accelerometer and rate gyroscope measurement of kinematics: an inexpensive alternative to optical motion analysis systems. , 2002, Journal of biomechanics.