In the present paper we propose a generalization of the model developed in Afferrante, L.; Carbone, G.; Demelio, G.; Pugno, N. Tribol. Lett. 2013, 52, 439–447 to take into account the effect of the pre-tension in the tape. A detailed analysis of the peeling process shows the existence of two possible detachment regimes: one being stable and the other being unstable, depending on the initial configuration of the tape. In the stability region, as the peeling process advances, the peeling angle reaches a limiting value, which only depends on the geometry, on the elastic modulus of the tape and on the surface energy of adhesion. Vice versa, in the unstable region, depending on the initial conditions of the system, the tape can evolve towards a state of complete detachment or fail before reaching a state of equilibrium with complete adhesion. We find that the presence of pre-tension in the tape does not modify the stability behavior of the system, but significantly affects the pull-off force which can be sustained by the tape before complete detachment. Moreover, above a critical value of the pre-tension, which depends on the surface energy of adhesion, the tape will tend to spontaneously detach from the substrate. In this case, an external force is necessary to avoid spontaneous detachment and make the tape adhering to the substrate.

We analyse in terms of efficiency and traction capabilities a recently patented traction drive, referred to as the double roller fulltoroidal. variator (DFTV). We compare its performance with the single roller full-toroidal variator (SFTV) and the single roller. half-toroidal variator (SHTV). Modeling of these variators involves challenging tribological issues; the traction and efficiency. performances depend on tribological phenomena occurring at the interface between rollers and disks, where the lubricant. undergoes very severe elastohydrodynamic lubrication regimes. Interestingly, the DFTV shows an improvement of the mechanical. efficiency over a wide range of transmission ratios and in particular at the unit speed ratio as in such conditions in which the DFTV. allows for zero-spin, thus strongly enhancing its traction capabilities.The very highmechanical efficiency and traction performances. of the DFTV are exploited to investigate the performance of a flywheel-based Kinetic Energy Recovery System (KERS), where. the efficiency of the variator plays an important role in determining the overall energy recovery performance. The energy boost. capabilities and the round-trip efficiency are calculated for the three different variators considered in this study.The results suggest. that the energy recovery potential of the mechanical KERS can be improved with a proper choice of the variator.

In this paper, we analyze in terms of efficiency and traction capabilities a recently patented toroidal traction drive variator: the so-called double roller full-toroidal variator (DFTV). By employing a relatively simple model of the elastohydrodynamic contact behavior between the disks and rollers, we compare the performance of the DFTV with classical solutions as the single-roller full-toroidal variator (SFTV) and the single-roller half-toroidal variator (SHTV). Interestingly, the DFTV shows an improvement of the mechanical efficiency over a wide range of transmission ratios, and in particular at the unit speed ratio, as in such conditions the DFTV allows for zero-spin thus strongly enhancing its traction capabilities. The relation between the torque transmission and the operational volume is also investigated for the three toroid geometries. In this case, the better performance is achieved by the SHTV, whereas the other two geometries show a similar behavior.

Normal human gait, described as passive dynamic walking, is neither completely passive nor always dynamic. In this article, we introduce the formulations of Passive Gait Measure (PGM) and Dynamic Gait Measure (DGM) that quantify passivity and dynamicity levels, respectively, of a given biped walking motion. The proposed concepts will be demonstrated through the analysis of human walking experimental data. The PGM measures the relative actuation contribution of the pivot joint of stance leg in the inverted pendulum analogy. The DGM, associated with gait stability, quantifies the effects of inertia in terms of the Zero-Moment Point (ZMP) and the ground projection of center of mass (GCOM). Human walking motion during single and double support phases is reconstructed from raw experimental data, and ZMP and GCOM trajectories during one full step cycle are generated. The calculated PGM values show the passive nature of human walking when the inverted pendulum analogy is adopted. The DGM results verify the dynamic nature of human walking demonstrating their dependence on the walking motion as well as the step phase; the double support phase results a static motion, opposite to the highly dynamic single support phase. The results will benefit the human gait studies and the development of walking robots. Copyright © 2012 by ASME

Normal human walking typically consists of phases during which the body is statically unbalanced while maintaining dynamic stability. Quantifying the dynamic characteristics of human walking can provide better understanding of gait principles. We introduce a novel quantitative index, the dynamic gait measure (DGM), for comprehensive gait cycle. The DGM quantifies the effects of inertia and the static balance instability in terms of zero-moment point and ground projection of center of mass and incorporates the timevarying foot support region (FSR) and the threshold between static and dynamic walking. Also, a framework of determining the DGM from experimental data is introduced, in which the gait cycle segmentation is further refined. A multisegmental foot model is integrated into a biped system to reconstruct the walking motion from experiments, which demonstrates the time-varying FSR for different subphases. The proof-of-concept results of the DGM from a gait experiment are demonstrated. The DGM results are analyzed along with other established features and indices of normal human walking. The DGM provides a measure of static balance instability of biped walking during each (sub)phase as well as the entire gait cycle. The DGM of normal human walking has the potential to provide some scientific insights in understanding biped walking principles, which can also be useful for their engineering and clinical applications. [DOI: 10.1115/1.4024755] Keywords: dynamic gait measure (DGM), dynamic walking, static balance instability, zero-moment point (ZMP)

Method for the identification of the poles and modal vectors of a road or rail vehicle provided with at least two wheels and in working condition, by means of the analysis of the movements or speeds or accelerations (output of the system) acquired in assigned measuring points of said vehicle, wherein said poles and modal vectors are determined by means of the fitting of the data relating to said outputs of the system on the basis of a mathematical model which describes the interaction between road or railway and said vehicle, characterized by hypothesizing that said vehicle moves at constant speed on a rectilinear trajectory or bend with constant radius, hypothesizing that said vehicle moves on a homogeneous and ergodic surface, whose roughness has a Gaussian distribution and that said at least two wheels move on a profile or on a plurality of profiles parallel with respect to each other, hypothesizing that the inlets induced by the road or rail surface on said vehicle cannot be traced back to a sequence of white noises and are correlated with respect to each other in time and/or space.