Currently, robotics has shown that it can increase the efficiency in the specific rehabilitation of some of the limbs of the human body, in this case assisting people who have suffered a stroke, by using devices such as exoskeletons, to provide continuous, smooth and controlled movements. Stroke is the result of a shortage of the brain that leads in just a few minutes to cell death, causing severe damage to the human body, even death of the patient. People who have suffered a stroke have difficulty rising from a chair. An exoskeleton is a mechanical structure designed to be used on the human body as a garment, it serves as a support and is used to assist movements or accentuate strength as a support in a person. Lower extremity exoskeleton can assist patients with hemiplegia to get up or sit on a chair, thus avoiding muscle atrophy and possible spasticity. This paper proposes the use of a robust Generalized Proportional Integral (GPI) controller for trajectory tracking for controlling a six degrees of freedom exoskeleton, to assist patients when getting up and sitting down from a chair. Simulation results obtained with the virtual prototype of the exoskeleton, under the environment of the MSC Adams software in co-simulation with Matlab are presented.

En este trabajo se propone implementar la técnica de identificación algebraica para desarrollar identificadores de los parámetros físicos de un sistema térmico gobernado por la ley de enfriamiento de Newton. Los identificadores algebraicos se derivan a partir del modelo dinámico del sistema térmico y se emplean para estimar el parámetro de enfriamiento k, la temperatura ambiente Tₐ y la temperatura inicial del cuerpo T₀, utilizando únicamente la señal de temperatura en función del tiempo como dato de entrada. Los resultados obtenidos muestran que los identificadores algebraicos propuestos permiten determinar adecuadamente los parámetros físicos del sistema térmico, incluso en presencia de ruido en la señal de alimentación. Asimismo, se observa que el filtro invariante implementado favorece la convergencia del proceso de identificación cuando la señal de temperatura está afectada por ruido.

The vibration control in structural design has long been a critical area of study, particularly in mitigating undesirable resonant vibrations using dynamic vibration absorbers (DVAs). Traditional approaches to tuning DVAs have relied on complex mathematical models based on Newtonian or Euler–Lagrange equations, often leading to intricate systems requiring simplification of the analysis of multi-degree-of-freedom structures. This paper introduces a novel modeling approach for analyzing DVAs based on the concept of global admittance, which stems from mechanical admittance and network simplifications. This model streamlines the representation of structures with DVAs as one-degree-of-freedom systems coupled with a global admittance function, which emulates additional damping coupled to the primary structure. In this work, global admittance functions are determined by the independent analysis of the mechanical networks of the DVA, restructuring the process of obtaining the system’s transfer function. The model was validated using different classical DVA configurations, demonstrating total accuracy in its applicability across designs concerning conventional modeling. Our most remarkable finding was that the dimensionless function, ${\gamma }_g\left(\mathsf{\Omega }\right)$, resulting from the global admittance, partially decouples the dynamics of the DVAs from the primary structure, facilitating the implementation of passive vibration control strategies in more realistic structural models. Additionally, this work establishes a significant advancement in vibration control analysis, providing a flexible tool for control strategies in real-world structural systems.