A new validation technique for estimations of body segment inertia tensors: Principal axes of inertia do matter. Issue 16 (8th December 2016)

• Record Type: Journal Article
• Authors: Rossi, Marcel M.; Alderson, Jacqueline; El-Sallam, Amar; Dowling, James; Reinbolt, Jeffrey; Donnelly, Cyril J.
• Is Part Of: Journal of biomechanics. Volume 49:Issue 16(2016)
• Page Start: 4119
• Page End: 4123
• Publication Date: 2016-12-08
• Subjects: CP Compound Pendulum: method to estimate experimentally the moments of inertia and the inertia tensor of an object under suspended oscillation -- DA Deviation Angle: angle measured between two sampled angular velocity vectors, one from experimental and other from simulated data -- GF Geometric Formulae: Formulae using dimensions of homogeneous objects with perfect geometry to compute the moments of inertia and the inertia tensor of the object -- CCS Cylinder Coordinate System: reference frame with respect to which the inertia tensor of the cylinder was estimated.; Validation -- Simulation -- Compound pendulum -- Criterion method -- Anthropometry -- Airborne motion; Animal mechanics -- Periodicals; Biomechanics -- Periodicals; Biomechanics -- Periodicals; Mécanique animale -- Périodiques; Biomécanique -- Périodiques; Electronic journals; 571.4305
• DOI: 10.1016/j.jbiomech.2016.10.006
• Languages: English
• ISSNs: 0021-9290

Abstract

Abstract: The aims of this study were to: (i) establish a new criterion method to validate inertia tensor estimates by setting the experimental angular velocity data of an airborne objects as ground truth against simulations run with the estimated tensors, and (ii) test the sensitivity of the simulations to changes in the inertia tensor components. A rigid steel cylinder was covered with reflective kinematic markers and projected through a calibrated motion capture volume. Simulations of the airborne motion were run with two models, using inertia tensor estimated with geometric formula or the compound pendulum technique. The deviation angles between experimental (ground truth) and simulated angular velocity vectors and the root mean squared deviation angle were computed for every simulation. Monte Carlo analyses were performed to assess the sensitivity of simulations to changes in magnitude of principal moments of inertia within ±10% and to changes in orientation of principal axes of inertia within ±10° (of the geometric-based inertia tensor). Root mean squared deviation angles ranged between 2.9° and 4.3° for the inertia tensor estimated geometrically, and between 11.7° and 15.2° for the compound pendulum values. Errors up to 10% in magnitude of principal moments of inertia yielded root mean squared deviation angles ranging between 3.2° and 6.6°, and between 5.5° and 7.9° when lumped with errors of 10° in principal axes of inertia orientation. The proposed technique can effectively validate inertia tensors from novel estimation methods of body segment inertial parameter. Principal axes of inertia orientation should not be neglected when modelling human/animal mechanics.