Juan C. Moreno

Analysis of the human interaction with a wearable lower-limb exoskeleton

The design of a wearable robotic exoskeleton needs to consider the interaction, either physical or cognitive, between the human user and the robotic device. This paper presents a method to analyse the interaction between the human user and a unilateral, wearable lower-limb exoskeleton. The lower-limb exoskeleton function was to compensate for muscle weakness around the knee joint. It is shown that the cognitive interaction is bidirectional; on the one hand, the robot gathered information from the sensors in order to detect human actions, such as the gait phases, but the subjects also modified their gait patterns to obtain the desired responses from the exoskeleton. The results of the two-phase evaluation of learning with healthy subjects and experiments with a patient case are presented, regarding the analysis of the interaction, assessed in terms of kinematics, kinetics and/or muscle recruitment. Human-driven response of the exoskeleton after training revealed the improvements in the use of the device, while particular modifications of motion patterns were observed in healthy subjects. Also, endurance mechanical tests provided criteria to perform experiments with one post-polio patient. The results with the post-polio patient demonstrate the feasibility of providing gait compensation by means of the presented wearable exoskeleton, designed with a testing procedure that involves the human users to assess the human-robot interaction.

Influence of the robotic exoskeleton Lokomat on the control of human gait: An electromyographic and kinematic analysis

Nowadays there is an increasing percentage of elderly people and it is expected that this percentage will continue increasing, carrying huge organizational costs in rehabilitation services. Recent robotic devices for gait training are more and more regarded as alternatives to solve cost-efficiency issues and provide novel approaches for training. Nevertheless, there is a need to address how to target muscular activation and kinematic patterns for optimal recovery after a neurological damage. The main objective of this work was to understand the underlying principles that the human nervous system employs to synchronize muscular activity during walking assisted by Lokomat. A basic low-dimensional locomotor program can explain the synergistic activation of muscles during assisted gait. As a main contribution, we generated a detailed description of the electromyographic and biomechanical response to variations in robotic assistance in intact humans, which can be used for future control strategies to be implemented in motor rehabilitation.

Feasibility of Submaximal Force Control Training for Robot–Mediated Therapy After Stroke

We investigate the use of submaximal force production as a targeted functionality in a rehabilitation task for early rehabilitation after stroke. We present the detailed assessment of related metrics of force production and position control, their correlation with submaximal force production control learning and their feasibility for robot–mediated therapy after stroke.

Propagación y crecimiento inicial del abarco (Cariniana pyriformis Miers), utilizando semillas silvestres

Se realizo la propagacion de la especie forestal Abarco Cariniana Pyriformis Miers , con el objetivo de analizar su comportamiento en vivero utilizando semillas botanicas no mejoradas. Se utilizo un diseno completamente aleatorio con arreglo factorial compuesto por 10 factores por condicion luminica -luz y sombra- y 45 unidades experimentales. Se utilizaron diferentes combinaciones de sustratos organicos. Las semillas fueron sometidas a un tratamiento pre-germinativo en presencia de un testigo. Las variables evaluadas fueron porcentaje de germinacion, crecimiento en altura y diametro y porcentaje de supervivencia. La especie comenzo la germinacion 13 dias despues de la siembra y se extendio hasta el dia 27. Los resultados del proceso de germinacion fueron de 60 % y 40% a plena exposicion solar y bajo malla poli-sombra, respectivamente. El crecimiento en altura de las plantulas muestra al factor CF con el mejor valor 28,94 cm, bajo condiciones de luz y el factor EF, con 25,56 cm a plena exposicion de sombra. Mientras el incremento en diametro los factores DF y EF registraron valores de 1,04 cm y 0,84 cm, bajo las condiciones sol y sombra respetivamente. Las semillas de esta especie son no-fotoblasticas, es decir que para su germinacion es indiferente la presencia o ausencia de luz. Las plantulas ubicadas en la condicion ambiental sol registraron mejores valores promedios en las variables diametro y altura. Por tanto, esta condicion ejerce efecto positivo para el crecimiento inicial de las plantulas de Abarco C. pyriformis.

Emerging Techniques for Assessment of Sensorimotor Impairments after Spinal Cord Injury

Gait function can be altered after incomplete spinal cord (iSCI) lesions. Muscular weakness, co‐activation of antagonist muscles, and altered muscle mechanics are likely to provoke abnormal gait and postural movements. Functional scales are available for assessment of functional walking in SCI patients, such as walking index for spinal cord injury (WISCI II), timed up and go (TUG) test, 10‐meter walk test (10MWT), and 6‐ minute walk test (6MWT). Novel metrics for a more detailed comprehension of neuromuscular control in terms of degree of voluntary motor control have been recently proposed. This section describes novel techniques based on muscle synergy and frequency domain analysis of electromyographic signals. Such techniques are illustrated as potential tools for assessment of motor function after SCI with experi‐ mental data and a case study describing a diagnostic scenario. This chapter presents a discussion of the current status of the emerging metrics for assessment of sensorimo‐ tor impairments. Conclusions are given with respect to the availability of enriched information about neuromuscular behavior between functional tasks (walking and pedalling) and the potential relevance of these new techniques to improve the efficacy of treatment to improve locomotion after iSCI.

Characterization of a Dual PID-ILC FES Controller for FES-Robot Control of Swing Phase of Walking

Accurate control of neuroprosthesis (NP) to restore walking ability in spinal cord injured people is still challenging due to the non-linear characteristics of neuromuscular tissue. The presence of an external exoskeleton in hybrid configuration (hybrid exoskeleton) that provides joint support and monitoring capabilities, can be exploited for control of the NP. In this work we present the characterization experiments of a dual NP controller, comprised by a proportional-integral-derivative (PID) and an iterative learning algorithm of a hybrid exoskeleton. It is found that non-causal learning allows to overcome the electromechanical delay of knee flexor muscles. Besides, the PID controller decreases stimulation performance.