In this paper, stability analysis of walking gaits and robustness analysis are developed for a five-link and four-actuator biped robot. Stability conditions are derived by studying unactuated dynamics and using the Poincaré map associated with periodic walking gaits. A stable gait is designed by an optimization process satisfying physical constraints and stability conditions. Also, considering...

We analyze the stability of naturally curved, inextensible elastic ribbons. In experiments, we first show that a loop formed using a metallic strip can become unstable if its radius is smaller than its natural radius of curvature (undercurved case): the loop then folds onto itself into a smaller, multiply-covered loop. Conversely, a multi-covered, overcurved metallic strip can unfold dynamicall...

In the present study, small scale effect on critical buckling loads of triangular nano- composite plates under uniform in-plane compression is studied. Since at nano-scale the structure of the plate is discrete, the size dependent nonlocal elasticity theory is employed to develop an equivalent continuum plate model for this nanostructure incorporating the changes in its mechanical behavior. The...

The structural, elastic, and electronic properties of the high-pressure FeTiO3 polymorphs and their relative phase stability under pressure are investigated using hybrid exchange density functional theory. For the currently known phases the computed structural and elastic parameters are in good agreement with those observed, as is the predicted stability of the phases. The transformation of the...

Negative bulk modulus and possibility of loss of elastic stability near tricritical transitions in thin films on substrates A. P. Levanyuk, S. A. Minyukov & I. B. Misirlioglu To cite this article: A. P. Levanyuk, S. A. Minyukov & I. B. Misirlioglu (2016) Negative bulk modulus and possibility of loss of elastic stability near tricritical transitions in thin films on substrates, Ferroelectrics, 5...

Using an unbiased structure searching method, a new orthorhombic Cmmm structure consisting of ZrIr12 polyhedron building blocks is predicted to be the thermodynamic ground-state of stoichiometric intermetallic Ir₂Zr in Ir-Zr systems. The formation enthalpy of the Cmmm structure is considerably lower than that of the previously synthesized Cu₂Mg-type phase, by ~107 meV/atom, as demonstrated by t...

in this paper, the stability of a functionally graded magneto-electro-elastic (fg-mee) micro-beam under actuation of electrostatic pressure is studied. for this purpose euler-bernoulli beam theory and constitutive relations for magneto-electro-elastic (mee) materials have been used. we have supposed that material properties vary exponentially along the thickness direction of the micro-beam. gov...

Aerial vehicles are difficult to stabilize, especially when acted upon by external forces. A hovering vehicle in contact with objects and surfaces must maintain flight stability while subject to forces imparted to the airframe through the point of contact. These forces couple with the motion of the aircraft to produce distinctly different dynamics from free flight. While external contact is gen...