Harold Martinez

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Grasp stability in the human hand has been resolved by means of an intricate network of mechanoreceptors integrating numerous cues about mechanical events, through an ontogenetic grasp practice. An engineered prosthetic interface introduces considerable perturbation risks in grasping, calling for feedback modalities that address the underlying slip(More)
In the area of bipedal locomotion, the spring-loaded inverted pendulum model has been proposed as a unified framework to explain the dynamics of a wide variety of gaits. In this paper, we present an analysis of the mathematical model and its dynamical properties. We use the perspective of hybrid dynamical systems to study the dynamics and define concepts(More)
The human hand is one of the most complex structures in the body, being involved in dexterous manipulation and fine sensing. Traditional engineering approaches have mostly attempted to match such complexity in robotics without sufficiently stressing on the underlying mechanisms that its morphology encodes. In this work, we propose an artificial skin able to(More)
In this paper we adopt the spring loaded inverted pendulum (SLIP) model as the mathematical framework to represent biped locomotion, but in contrast with previous studies, we redefine the conditions for valid locomotion. As a consequence we identify new ways to produce gait transitions (e.g. change from walking to running) through the control of the angle(More)
Cefaclor [7-(D-2-amino-2-phenylacetamido)-3-chloro-3-cepham-4-carboxy lic acid] crystallizes as the dihydrate. Crystals belong to space group P21, with a = 10.626(3), b = 7.1288(9), c = 14.124(3), and beta = 121.6(2). The structure was solved using direct methods and refined to an R of 0.0535. The bond lengths, angles, and conformation determined are as(More)
Bipedal locomotion is a phenomenon that still eludes a fundamental and concise mathematical understanding. Conceptual models that capture some relevant aspects of the process exist but their full explanatory power is not yet exhausted. In the current study, we introduce the robustness criterion which defines the conditions for stable locomotion when steps(More)
This paper reports studies of the solid-state chemistry of the diammonium salt of moxalactam. The methods employed include X-ray crystallography, molecular mechanics calculations, thermogravimetric analysis, and high-pressure liquid chromatography. The crystal structure shows that the malonic acid amide functionality in crystals of the diammonium salt is(More)
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