Robotic Rehabilitation Devices of Human Extremities: Design Concepts and Functional Particularities

International audienceAll over the world, several dozen million people suffer from the effects of post-polio, multiple sclerosis, spinal cord injury, cerebral palsy, etc. and could benefit from the advances in robotic devices for rehabilitation. Thus, for modern society, an important and vital problem of designing systems for rehabilitation of human physical working ability appears. The temporary or permanent loss of human motor functions can be compensated by means of various rehabilitation devices. They can be simple mechanical systems for orthoses, which duplicate the functions of human extremities supplying with rigidity and bearing capacity or more complex mechatronic rehabilitation devices with higher level of control. We attempt to cover all of the major developments in these areas, focusing particularly on the development of the different concepts and their functional characteristics. The robotic devices with several structures are classified, taking into account the actuation systems, the neuromuscular stimulations, and the structural schemes. It is showed that the problems concerning the design of rehabilitation devices are complex and involve many questions in the sphere of biomedicine, mechanics, robot technology, electromechanics and optimal control. This paper provides a design overview of hardware, actuation, sensory, and control systems for most of the devices that have been described in the literature, and it ends with a discussion of the major advances that have been made and should be yet overcome

MoonWalker, a Lower Limb Exoskeleton able to Sustain Bodyweight using a Passive Force Balancer

Abstract-This paper presents MoonWalker, a lower limb exoskeleton able to sustain part of a user's bodyweight. This orthosis can be used for rehabilitation, to help people having weak legs, or to help those suffering from a broken leg, to walk. It can also be used as an assistive device helping people carrying heavy loads. Its main characteristic is that a passive force balancer provides the force to sustain bodyweight. An actuator is also required, but is used only to shift that force the same side as the leg in stance. Consequently, MoonWalker requires very low energy to work on flat terrains. That motor can provide also a part of the energy to climb stairs or slopes. We believe that this approach can help improving energetic autonomy of lower limb exoskeletons

Passive Gravity Balancing with a Self-Regulating Mechanism for Variable Payload

Gravity balancing techniques allow for the reduction of energy consumptions in robotic systems. With the appropriate arrangements, often including springs, the overall potential energy of a manipulator can be made configuration-independent, achieving an indifferent equilibrium for any position. On the other hand, such arrangements lose their effectiveness when some of the system parameters change, including the mass. This paper proposes a method to accommodate different payloads for a mechanism with a single degree-of-freedom (DOF). By means of an auxiliary mechanism including a slider, pulleys and a counterweight, the attachment point of a spring is automatically regulated so as to maintain the system in indifferent equilibrium regardless of the position, even when the overall mass of the system varies. Practical implications for the design of the mechanism are also discussed. Simulation results confirm the effectiveness of the proposed approach

Estudio comparativo de exoesqueletos de miembros superiores de actuación pasiva basados en técnicas de compensación de carga

En este trabajo se desarrolló un estudio comparativo de los principales exoesqueletos industriales de miembros superiores con actuación pasiva desarrollados en la actualidad, los cuales tienen la finalidad de proveer una fuerza de asistencia para minimizar la fatiga del usuario al trabajar en posiciones poco ergonómicas por tiempos prolongados. Estos exoesqueletos se basan en principios o técnicas de compensación de carga, las cuales incorporan distintas configuraciones y mecanismos con actuadores pasivos, tales como resortes acoplados a sistemas de cables y poleas; resortes acoplados a mecanismos de levas con seguidor, entre otros; para finalmente generar una fuerza que equilibre la carga que se desea manipular. En este sentido, primero se realizó una revisión bibliográfica de la tecnología en exoesqueletos, con énfasis en los principales exoesqueletos desarrollados actualmente para ser aplicados en el sector industrial. Se determinó que, para aplicaciones industriales, la alternativa más viable es optar por el desarrollo de exoesqueletos pasivos. Por consiguiente, una vez presentado el panorama actual de la tecnología en exoesqueletos industriales pasivos, se investigaron las principales técnicas de compensación de carga en las cuales se basan los mecanismos de actuación incorporados por estos dispositivos. Esto se realizó con la finalidad de analizar los principios físicos y/o mecánicos de funcionamiento de los mecanismos de actuación pasivos. Finalmente, se procedió a analizar 8 de los principales exoesqueletos industriales de miembros superiores de actuación pasiva, para luego compararlos y determinar las ventajas de las distintas técnicas de compensación de carga aplicadas en el desarrollo de sus mecanismos de actuación.Trabajo de investigació