Humans and other animals walk in a way that minimizes energy consumption. We take advantage of inertial passive dynamics and elastic energy storage and return to create a walking pattern that is extremely economical [1]. A reduction in energy consumption during walking might be achieved by supplying external mechanical power to the joints of the lower limbs. With additional mechanical power app...

This paper deals with force and impedance control of series elastic actuators for driving the joints of an exoskeleton for lower limbs. Series elastic actuators are devices where elastic components are introduced between the motor’s output and the load. From the deflection of these components, it is possible to measure the force applied to the load and to control it. Also, the mechanical impeda...

The optimal path planning for two flexible cooperating manipulators carrying a solid object on a prescribed tip trajectory has been studied using kinematic resolution. The formulation has been derived using the Pontryagin minimum principle that results in a two-point boundary value problem. Also, a numerical technique based on converting the abstract optimization to parametric optimization prob...

Abstract. This paper deals with robust H∞ force and impedance control of series elastic actuators. It is considered that the series elastic actuators are subject to parametric uncertainties and external disturbances. Robust controllers based on the H∞ criterion have been widely used among robotic applications for guaranteeing good disturbance rejection properties. The H∞ force and impedance con...

In this paper, we identify optimal swimming strategies for drag-dominated swimmers with a passive elastic joint. We use resistive force theory (RFT) to obtain the dynamics of system. then frequency domain analysis relate motion joint actuated couple elements geometric framework introduced in our previous work aimed at identifying useful gaits systems drag dominated environments, speed-maximizin...

This work deals with a methodology to assess the influence of the spherical clearance joints in spatial multibody systems. The methodology is based on the Cartesian coordinates, with the dynamics of the joint elements modeled as impacting bodies and controlled by contact forces. The impacts and contacts are described by a continuous contact force model that accounts for geometric and mechanical...

Fractures are planar discontinuities, i.e. interruption of the rock physical continuity, due to stresses. The geological fractures occur at every scale, so that any large volume of rock has some or many. These discontinuities are related to sudden elastic relaxation of elastic energy stored in the rock. The geological fractures have their economic importance. The loss of continuity in intact ro...

• Computational nonlinear homogenization of refractory masonry is performed. Effects joints closure/reopening on the mechanical behavior are considered. Computationally efficient homogenized elastic-viscoplastic model developed. Dry close and reopen due to cyclic loading unloading. The response orthotropic nonlinear. Refractory with dry widely used in steel-making industry for linings several h...