title: Wearable Goniometer and Accelerometer Sensory Fusion for Knee Joint Angle Measurement in Daily Life.
abstract: Human motion analysis is crucial for a wide range of applications and disciplines. The development and validation of low cost and unobtrusive sensing systems for ambulatory motion detection is still an open issue. Inertial measurement systems and e-textile sensors are emerging as potential technologies for daily life situations. We developed and conducted a preliminary evaluation of an innovative sensing concept that combines e-textiles and tri-axial accelerometers for ambulatory human motion analysis. Our sensory fusion method is based on a Kalman filter technique and combines the outputs of textile electrogoniometers and accelerometers without making any assumptions regarding the initial accelerometer position and orientation. We used our technique to measure the flexion-extension angle of the knee in different motion tasks (monopodalic flexions and walking at different velocities). The estimation technique was benchmarked against a commercial measurement system based on inertial measurement units and performed reliably for all of the various tasks (mean and standard deviation of the root mean square error of 1:96 and 0:96, respectively). In addition, the method showed a notable improvement in angular estimation compared to the estimation derived by the textile goniometer and accelerometer considered separately. In future work, we will extend this method to more complex and multi-degree of freedom joints.
authors.affiliation: Research Center E.Piaggio, University of Pisa, Largo L. Lazzarino 1, 56126 Pisa, Italy. a.tognetti@centropiaggio.unipi.it.|Information Engineering Department, University of Pisa, Via G. Caruso 16, 56122 Pisa, Italy. a.tognetti@centropiaggio.unipi.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Tognetti
authors.affiliation: Research Center E.Piaggio, University of Pisa, Largo L. Lazzarino 1, 56126 Pisa, Italy. f.lorussi@ing.unipi.it.
authors.forename: Federico
authors.initials: F
authors.lastname: Lorussi
authors.affiliation: Research Center E.Piaggio, University of Pisa, Largo L. Lazzarino 1, 56126 Pisa, Italy. nicola.carbonaro@centropiaggio.unipi.it.
authors.forename: Nicola
authors.initials: N
authors.lastname: Carbonaro
authors.affiliation: Research Center E.Piaggio, University of Pisa, Largo L. Lazzarino 1, 56126 Pisa, Italy. d.derossi@centropiaggio.unipi.it.|Information Engineering Department, University of Pisa, Via G. Caruso 16, 56122 Pisa, Italy. d.derossi@centropiaggio.unipi.it.
authors.forename: Danilo
authors.initials: D
authors.lastname: de Rossi
mesh_terms: D061725:Accelerometry / Q000379:methods*; D053587:Arthrometry, Articular / Q000295:instrumentation* / Q000379:methods*; D001696:Biomechanical Phenomena; D004867:Equipment Design; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D016138:Walking / Q000502:physiology
keywords: accelerometers; data fusion; human motion analysis; joint angle measurements; knee joint; knitted piezoresistive fabrics; sensor to segment alignment; smart textiles; wearable goniometers