1. Active Ankle-Foot Orthosis
Innovative products and technologies
Carlos Vasconcelos
Mechanical Engineering background, currently working on medical devices for human enhancement.
Active Ankle-Foot Orthosis
Carlos F. Vasconcelos a, Paulo L. Melo, Jorge M. Martins and Miguel T. Silva
IDMEC / IST – Instituto Superior Técnico, Technical University of Lisbon a
Main topics of interest:
Mechatronics, Control, Rehabilitation, Human Enhancement, Medical Devices.
Motivation
Thousands of people are affected every year by disabilities involving the Ankle-Foot complex, such as Drop Foot (National Spinal Cord Injury Statistical Center, United States).
Some disabilities can be corrected by Ankle-Foot Orthoses (AFOs), passive systems that provide enough support when limbs have some functional pathology, but fail to assist when external energy is required.
This absence may be overcome with Active Ankle-Foot Orthoses (AAFO), overcome these limitations by endowing a standard which consists on AFO endowed with sensors and actuators to provide active control of the ankle joint.
Every year, thousands of people are diagnosed with Drop Foot, a gait disability affecting the Ankle-Foot complex.
AFOs can correct Drop foot to some extent, providing only passive and non adaptive support during gait.
Active Ankle-Foot Orthoses (AAFO) overcome these limitations by endowing a standard AFO with sensors and actuators to provide active control of the ankle joint.
Developments
Fig. 1: (a) Active Ankle-Foot Orthosis set with a total mass of 1.7kg (disregarding control unit and power supply), (b) Ankle-Foot Orthosis where sensors and actuator are coupled, (c) Series Elastic Actuator (acting also as a force sensor that allows the calculation of the ankle torque), (d) Rotational Potentiometer to acquire the angle between the foot and shank, (e) Footswitches to detect the gait phases.
Mechanical design of an AAFO fulfilling/(accounting for)that fulfills the biomechanical requirements of an a 70kg individual with 70kg of mass (Fig. 1) during all phases of gait.
A biomechanical model of the ankle-foot complex was developed using ankle’s kinematic and kinetic data to test control strategies.
Different control strategies were simulated to mimic the human control of the ankle joint during gait or assist the ankle movement in a rehabilitation environment.
A Series Elastic Actuator (SEA) was designed purposely to endow the AFO with custom power output, low weight and compact design characteristics (Fig. 1.c).
Parameters identification to obtain the current-force data models for the SEA.
Mechanical design of an AAFO (was performed) to fulfill the biomechanical requirements of a 70 kg individual in all phases of gait.
Active
To mimic natural human control of the ankle, computer simulations were performed to test and optimize different control strategies
support during all phases of gait
Acho que estes dois tópicos podem ser resumido num só.
Portable
Adaptable
A lightweight and compact Series Elastic Actuator was designed(developed/built) to endow the AAFO with muscle-like capabilities.
to different gait pathologies
Autonomous
Fig. 2: Representation of a user endowed of an AAFO with the control unit and power supply on a backpack during the prototype test. At a later stage, all equipment will be coupled to the AFO.
Este último tópico é capaz de já ser um pouco tecnicamente detalhado de mais
Results
Publications
C. F. Vasconcelos et al (2012), "Mechanical Design and Control of an Active Ankle-Foot Orthosis", ESB 2012 – 18th Congress of the European Society of Biomechanics, Instituto Superior Técnico, Technical University of Lisbon, Lisbon, Portugal (accepted, to be presented).
C. F. Vasconcelos et al (2011), "Multibody Dynamics and Control of an Active Orthosis for Ankle Joint Pathologies", Multibody Dynamics 2011 – ECCOMAS Thematic Conference, Université Catholique de Louvain, Brussels, Belgium.
C. F. Vasconcelos et al (2011), "Active Orthosis for Ankle Articulation Pathologies", EUROMECH Colloquium 511 on Biomechanics of Human Motion, Ponta Delgada, Azores, Portugal.
P. L. Melo et al (2011), "Desenvolvimento de uma Ortótese Tornozelo-Pé com Actuação Híbrida para Apoio à Locomoção", 4º Congresso Nacional de Biomecânica, Coimbra, Portugal.
Falta qq coisa na tua frase (gramaticamente)
A fully portable and autonomous AAFO was developed (built) able to support the ankle throughout all gait phases, with human-robot compliance (a parte do due to SEA se calhar nao punha é redundante e nao acrescenta informaçao relevante)
A fully portable and autonomous system (Fig. 2) that assists the ankle movement during all phases of gait, with a human-robotic compliancet functionality due to SEA characteristics and implemented control strategies.
Simulations show that control strategies mitigate foot slap, toe drag and are able to propel the body forward, featuring the ability of assisting different gait pathologies.
The AAFO has been developed for gait correction and rehabilitation environments and is able to adapt to different gait disabilities.
Simulations showed that this system solves Drop Foot’s major problems: foot slap, toe drag and weak foot propulsion.
Acknowledgements: This work was supported by the Portuguese Foundation for Science and Technology (FCT) through the MIT Portugal program project DACHOR – Multibody Dynamics and Control of Hybrid Orthoses (MIT-Pt/BS-HHMS/0042/2008).
E3 Forum 2012, 28th of June, Pavilhão do Conhecimento – Ciência Viva