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Open AccessFeature PaperArticle

Model-Based Estimation of Ankle Joint Stiffness

Philips Chair for Medical Information Technology, RWTH Aachen University, Pauwelsstrasse 20, 52074 Aachen, Germany
Author to whom correspondence should be addressed.
Sensors 2017, 17(4), 713;
Received: 16 January 2017 / Revised: 22 March 2017 / Accepted: 23 March 2017 / Published: 29 March 2017
(This article belongs to the Special Issue Wearable Biomedical Sensors)
We address the estimation of biomechanical parameters with wearable measurement technologies. In particular, we focus on the estimation of sagittal plane ankle joint stiffness in dorsiflexion/plantar flexion. For this estimation, a novel nonlinear biomechanical model of the lower leg was formulated that is driven by electromyographic signals. The model incorporates a two-dimensional kinematic description in the sagittal plane for the calculation of muscle lever arms and torques. To reduce estimation errors due to model uncertainties, a filtering algorithm is necessary that employs segmental orientation sensor measurements. Because of the model’s inherent nonlinearities and nonsmooth dynamics, a square-root cubature Kalman filter was developed. The performance of the novel estimation approach was evaluated in silico and in an experimental procedure. The experimental study was conducted with body-worn sensors and a test-bench that was specifically designed to obtain reference angle and torque measurements for a single joint. Results show that the filter is able to reconstruct joint angle positions, velocities and torque, as well as, joint stiffness during experimental test bench movements. View Full-Text
Keywords: joint stiffness estimation; body-worn sensors; magnetic, angular rate and gravity sensors; BSN joint stiffness estimation; body-worn sensors; magnetic, angular rate and gravity sensors; BSN
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MDPI and ACS Style

Misgeld, B.J.E.; Zhang, T.; Lüken, M.J.; Leonhardt, S. Model-Based Estimation of Ankle Joint Stiffness. Sensors 2017, 17, 713.

AMA Style

Misgeld BJE, Zhang T, Lüken MJ, Leonhardt S. Model-Based Estimation of Ankle Joint Stiffness. Sensors. 2017; 17(4):713.

Chicago/Turabian Style

Misgeld, Berno J.E.; Zhang, Tony; Lüken, Markus J.; Leonhardt, Steffen. 2017. "Model-Based Estimation of Ankle Joint Stiffness" Sensors 17, no. 4: 713.

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