Modelado y Control de un Exoesqueleto para la Rehabilitación de Extremidad Inferior con dos grados de libertad

[EN] Exoskeletons are robots attached to the extremities of the human body focused on increasing their strength, speed and performance primarily. The applications are in the military, industry and medical. The exoskeleton can be used for the rehabilitation of limbs because of accident or illness that can cause little muscle activity or null. This article presents an exoskeleton of two degrees of freedom that is used to ankle and knee exercise rehabilitation. The design and manufacture of the exoskeleton is based on the instrumentation of a right lower limb orthoses. The exoskeleton contains sensors to estimate the force produced by a human and contains SEA actuators (Serial Elastics Actuators) that used to amplify the human force. Also contains sensors to estimate the position and angular velocity in joints. This paper presents in general: a study of the dynamic model of the exoskeleton and actuators coupled through the singular perturbation method, the design of a control based on the sum of forces generated by the human and the exoskeleton, and the design and manufacture of an experimental prototype. The simulation result shows that the sum of forces between the human and the exoskeleton is controlled to obtain a desired angular position of the joints (knee and ankle). Experimental results show that exist a human force amplification generated by the exoskeleton, providing a reduction in the patient's effort to remain standing and bending exercises. Then force amplification can be increased or decreased as needed in different workouts that will allow the user an evolutionary improvement to achieve a full rehabilitation. [ES] Los exoesqueletos mecánicos son robots acoplados a las extremidades del cuerpo humano enfocados en el incremento de su fuerza, velocidad y rendimiento principalmente. Las principales aplicaciones son en la milicia, en la industria y en la medicina. El exoesqueleto se puede utilizar para la rehabilitación de las extremidades cuando por causas de algún accidente o enfermedad se tiene una actividad muscular reducida o nula. En este artículo se presenta un exoesqueleto de dos grados de libertad para realizar ejercicios de rehabilitación para tobillo y rodilla. El diseño y fabricación del exoesqueleto está basado en la instrumentación de una ortesis del miembro inferior derecho. El Exoesqueleto utiliza sensores que estiman la fuerza producida por el humano y se encuentran incorporados en los actuadores de tipo SEA (Series Elastic Actuator)