title: A Two-Axis Goniometric Sensor for Tracking Finger Motion.
abstract: The study of finger kinematics has developed into an important research area. Various hand tracking systems are currently available; however, they all have limited functionality. Generally, the most commonly adopted sensors are limited to measurements with one degree of freedom, i.e., flexion/extension of fingers. More advanced measurements including finger abduction, adduction, and circumduction are much more difficult to achieve. To overcome these limitations, we propose a two-axis 3D printed optical sensor with a compact configuration for tracking finger motion. Based on Malus' law, this sensor detects the angular changes by analyzing the attenuation of light transmitted through polarizing film. The sensor consists of two orthogonal axes each containing two pathways. The two readings from each axis are fused using a weighted average approach, enabling a measurement range up to 180 ∘ and an improvement in sensitivity. The sensor demonstrates high accuracy (±0.3 ∘ ), high repeatability, and low hysteresis error. Attaching the sensor to the index finger's metacarpophalangeal joint, real-time movements consisting of flexion/extension, abduction/adduction and circumduction have been successfully recorded. The proposed two-axis sensor has demonstrated its capability for measuring finger movements with two degrees of freedom and can be potentially used to monitor other types of body motion.
authors.affiliation: Wolfson Centre for Magnetics, School of Engineering, Cardiff University, Cardiff CF24 3AA, Wales, UK. WangL54@cardiff.ac.uk.
authors.forename: Lefan
authors.initials: L
authors.lastname: Wang
authors.affiliation: Wolfson Centre for Magnetics, School of Engineering, Cardiff University, Cardiff CF24 3AA, Wales, UK. Meydan@cardiff.ac.uk.
authors.forename: Turgut
authors.initials: T
authors.lastname: Meydan
authors.affiliation: Wolfson Centre for Magnetics, School of Engineering, Cardiff University, Cardiff CF24 3AA, Wales, UK. WilliamsPI1@cardiff.ac.uk.
authors.forename: Paul Ieuan
authors.initials: PI
authors.lastname: Williams
mesh_terms: D001696:Biomechanical Phenomena; D005384:Finger Joint; D005385:Fingers; D006801:Humans; D009068:Movement; D016059:Range of Motion, Articular
keywords: 3D printing; abduction/adduction; angle measurement; finger motion tracking; flexion/extension; glove-based systems; optical sensor