Broadband measurement of translational and angular vibrations using a single continuously scanning laser Doppler vibrometer

• Published in: The Journal of the Acoustical Society of America Vol. 132; no. 3; pp. 1384 - 1391
• Main Authors: Salman, Muhammad, Sabra, Karim G.
• Format: Journal Article
• Language: English
• Published: Melville, NY Acoustical Society of America 01.09.2012; American Institute of Physics
• Subjects: Adult; Biomechanical Phenomena; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Gelatin; Hand; Humans; Laser-Doppler Flowmetry - instrumentation; Linear Models; Male; Measurement and testing methods; Muscle Contraction; Muscle Fatigue; Muscle, Skeletal - physiopathology; Phantoms, Imaging; Physics; Reproducibility of Results; Signal Processing, Computer-Assisted; Solid mechanics; Structural and continuum mechanics; Tremor - physiopathology; Vibration; Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...); Measurement; Laser dopplerometry; Vibration; Wide band; Vibrometer
• ISSN: 0001-4966; 1520-8524; 1520-8524
• DOI: 10.1121/1.4740473

A continuous scanning laser Doppler velocimetry (CSLDV) technique is used to measure the low frequency broadband vibrations associated with human skeletal muscle vibrations (typically f < 100 Hz) by continuously varying the orientation of laser beam over distances that are short compared to the characteristic wavelengths of the vibrations. The high frequency scan (compared to the vibration frequency) enables the detection of broadband translational and angular velocities at a single point using amplitude demodulation of the CSDLV signal. For instance, linear scans allow measurement of the normal surface velocity and one component of angular velocity vector, while circular scans allow measurement of an additional angular velocity component. This CSLDV technique is first validated here using gel samples mimicking soft tissues and then applied to measure multiple degrees of freedom (DOF) of a subject’s hand exhibiting fatigue-induced tremor. Hence this CSLDV technique potentially provides a means for measuring multiple DOF of small human body parts (e.g., fingers, tendons, small muscles) for various applications (e.g., haptic technology, remote surgery) when the use of skin-mounted sensors (e.g. accelerometers) can be problematic due to mass-loading artifacts or tethering issues.