Kinematics of Gait: New Method for Angle Estimation Based on Accelerometers

School of Electrical Engineering, University of Belgrade, Bulevar kralja Aleksandra 73, Belgrade, Serbia.
Sensors (Impact Factor: 2.25). 12/2011; 11(11):10571-85. DOI: 10.3390/s111110571
Source: PubMed


A new method for estimation of angles of leg segments and joints, which uses accelerometer arrays attached to body segments, is described. An array consists of two accelerometers mounted on a rigid rod. The absolute angle of each body segment was determined by band pass filtering of the differences between signals from parallel axes from two accelerometers mounted on the same rod. Joint angles were evaluated by subtracting absolute angles of the neighboring segments. This method eliminates the need for double integration as well as the drift typical for double integration. The efficiency of the algorithm is illustrated by experimental results involving healthy subjects who walked on a treadmill at various speeds, ranging between 0.15 m/s and 2.0 m/s. The validation was performed by comparing the estimated joint angles with the joint angles measured with flexible goniometers. The discrepancies were assessed by the differences between the two sets of data (obtained to be below 6 degrees) and by the Pearson correlation coefficient (greater than 0.97 for the knee angle and greater than 0.85 for the ankle angle).

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Available from: Nenad Jovicic, Aug 27, 2014
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    • "Some research about gait analysis have reported the joint angles of knee and hip in gait cycle, but these have not described the characterization of events and phases in gait cycle [9,14,19,26]. Djuric-Jovicic et al. [28] reported one method to estimate the joint angles through a system developed with accelerometers which do not need the integration of the acceleration to get the joint angles. The system was evaluated with goniometers and the error was of 6°. "
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    • "Popovic [6] "
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