title: New generation of wearable goniometers for motion capture systems.
abstract: BACKGROUND
  Monitoring joint angles through wearable systems enables human posture and gesture to be reconstructed as a support for physical rehabilitation both in clinics and at the patient's home. A new generation of wearable goniometers based on knitted piezoresistive fabric (KPF) technology is presented.
  
  
  METHODS
  KPF single-and double-layer devices were designed and characterized under stretching and bending to work as strain sensors and goniometers. The theoretical working principle and the derived electromechanical model, previously proved for carbon elastomer sensors, were generalized to KPF. The devices were used to correlate angles and piezoresistive fabric behaviour, to highlight the differences in terms of performance between the single layer and the double layer sensors. A fast calibration procedure is also proposed.
  
  
  RESULTS
  The proposed device was tested both in static and dynamic conditions in comparison with standard electrogoniometers and inertial measurement units respectively. KPF goniometer capabilities in angle detection were experimentally proved and a discussion of the device measurement errors of is provided. The paper concludes with an analysis of sensor accuracy and hysteresis reduction in particular configurations.
  
  
  CONCLUSIONS
  Double layer KPF goniometers showed a promising performance in terms of angle measurements both in quasi-static and dynamic working mode for velocities typical of human movement. A further approach consisting of a combination of multiple sensors to increase accuracy via sensor fusion technique has been presented.
authors.affiliation: Research Center "E,Piaggio", University of Pisa, Via Diotisalvi 2, Pisa, Italy. a.tognetti@centropiaggio.unipi.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Tognetti
authors.forename: Federico
authors.initials: F
authors.lastname: Lorussi
authors.forename: Gabriele Dalle
authors.initials: GD
authors.lastname: Mura
authors.forename: Nicola
authors.initials: N
authors.lastname: Carbonaro
authors.forename: Maria
authors.initials: M
authors.lastname: Pacelli
authors.forename: Rita
authors.initials: R
authors.lastname: Paradiso
authors.forename: Danilo De
authors.initials: DD
authors.lastname: Rossi
mesh_terms: D053587:Arthrometry, Articular / Q000295:instrumentation*; D006801:Humans; D018670:Monitoring, Ambulatory / Q000295:instrumentation*
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