The DACHOR Project: Multibody Dynamics and Control of Hybrid Active Orthoses

O engenheiro biomédico Paulo de Melo, de 29 anos, venceu o concurso Fraunhofer Portugal Challenge 2014 na categoria de doutoramento com um dispositivo para ajudar pessoas com problemas motores. A ideia foi premiada com 3000 euros e destina-se a ajudar doentes que sofrem com o chamado “pé pendente”. O novo produto chama-se ISTim Modular Stimulation System e baseia-se na investigação de doutoramento de Paulo de Melo, realizada Instituto Superior Técnico (IST) e intitulada “A Novel Functional Electrical Stimulation System and Strategies for Motor Rehabilitation”. Arrastar o pé ou caminhar tocando no chão primeiro com a parte da frente do pé (em vez do calcanhar) são algumas das características do pé pendente. Esta patologia consiste na perda de controlo de um grupo de músculos da parte de baixo da perna que controla o movimento do pé. “Quando balançamos a perna para ir de um passo para o outro e levantá-la do chão, esses músculos funcionam e puxam para cima o pé para não batermos com o pé no chão. A falta de activação desses músculos faz com que o pé arraste ou bata no chão”, explicou Paulo ao P3. É aqui que entra este dispositivo, um sistema modular de estimulação eléctrica para reabilitação motora, que promete ajudar o doente a ter uma mobilidade mais próxima do normal, actuando ao longo das diversas fases da marcha. Como? O dispositivo, colocado na própria perna do doente (debaixo do joelho), baseia-se na estimulação eléctrica funcional dos músculos associados à perda de função, actuando em certas fases da marcha através de pequenos choques eléctricos em determinadas localizações da perna e que fazem o pé mexer-se normalmente. Para o efeito, é necessário um estimulador eléctrico funcional, mas também uma rede de sensores para saber o que se passa no pé, se está em contacto com o chão ou o qual o ângulo que está a fazer enquanto a pessoa anda. Para quê? Para conseguir adequar-se correctamente e corrigir com um estímulo diferente. Dispositivo “portátil” e “adaptável” Eis aqui uma das características que Paulo de Melo acredita ser distintiva face a outros dispositivos que já existem no mercado. “É bastante flexível em termos de adaptação às necessidades concretas da patologia. Modelamos matematicamente a perna do doente e o pé e como reagem face aos estímulos eléctricos e, por isso, podemos dar estimulações dos músculos muito mais fisiológicas do que os [dispositivos] que estão no mercado, que são simplesmente cegos a este princípio. [Estes] dão o mesmo tipo de estímulo independentemente do que se passa no pé ou no meio que o envolve, se há perturbações, [por exemplo, ou] se alguma coisa bate no pé ou há uma pedra”, garante. Para além de “adaptativo”, o dispositivo é também “portátil”, “leve”, “confortável” e “flexível”, pois pode utilizado para outras patologias, garante o vencedor do prémio. “Esse sistema, agora, está a funcionar para o pé pendente, mas sendo modular e flexível, através destas unidades modulares de estimulação, conseguimos escalá-lo para outras patologias até mais complicadas, a nível do tornozelo e joelho ou mesmo para a ambulação de paraplégicos. O sistema actual já está preparado para isso. Desenvolvemos esta plataforma de estimulação e fizemo-la o suficientemente genérica para termos agora a liberdade de integrá-la a problemas mais complexos”, esclarece. Antes de chegar ao mercado, o dispositivo médico necessita ainda de ser certificado, um processo que ainda pode demorar alguns anos. Já as unidades modulares de estimulação — uma das componentes do dispositivo — “estão mais próximas do mercado”. Paulo afirma que uma parte do prémio será investida no desenvolvimento dos protótipos (já existentes) destas unidades modulares e na sua comercialização. Este trabalho é o resultado de uma tese de doutoramento, à qual Paulo se dedicou durante quatro anos. Integra-se, ainda, no projecto DACHOR(Multibody Dynamics and Control of Hybrid Active Orthoses), do programa MIT Portugal. Doutorado em Bioengenharia pelo MIT Portugal/IST, Paulo pretende que o seu futuro continue a passar pelas áreas da biomecânica e da performance humana. O Fraunhofer Portugal Challenge é um concurso que, desde 2010, premeia “as melhores ideias científicas desenvolvidas em Portugal”, em duas categorias (mestrado e doutoramento). Na categoria de doutoramento foram ainda distinguidos, nesta edição, dois investigadores da Universidade do Porto: em segundo lugar, Gilberto Bernardes, com um “software” que auxilia músicos na manipulação de sinais áudio em contextos criativos e Pydi Ganga, em terceiro, com uma plataforma para desenvolver circuitos integrados com tecnologias a-GIZO TFT. Os prémios foram de 1500 e 1000 euros, respectivamente. http://www.mitportugal.org/

MONDAY, 30 AUGUST 2010

In recent years, Portugal has developed strong biological sciences and emerging bioengineering activities that serve as the foundation for knowledge-based innovation in the medical devices field.  Similarly, advances in new materials, micro/nanosensors, and microactuators technologies are leading to a new class of promising products, normally referred to as smart devices, able to monitor their environment and perform accordingly. Among other possibilities, such types of behavior can be obtained by the use of novel materials whose physical properties can change significantly with the surrounding environment or by active biological agents. The opportunities in the field of medical devices are vast, both at the research, innovation and product development levels. The development of the particular skill set required to take advantage of these opportunities is a core goal of the MIT Portugal Program, more specifically in the MDIP (Material & Design-Inspired Products) Targeted Research Application Area. Within MDIP the MIT Portugal Program has been developing a number of projects in collaboration with industrial partners, using an integrated approach to build innovative products. Within the medical devices field, one of MIT Portugal research projects consists in building an Ankle-Foot Orthosis, aimed at enhancing mobility of cystic fibrosis patients and some amputees, which applies both muscle stimulation and mechanical actuators to improve the mobility and usability of available prostheses that will allow patients to walk with greater comfort and mobility than ever before. “Advances in robotics technology, computer technology, and materials science are enabling the development of hybrid human-machine technologies that allow humans to perform at higher levels, to function in extreme environments, and to recover from or compensate for injury better.” – Prof. Dava Newman (Professor of Aeronautics and Astronautics and Engineering Systems, Director of Technology and Policy Program, MIT) The DACHOR project is an inter-institutional venture that joins together two MIT Portugal participating institutions (Instituto Superior Técnico-Technical University of Lisbon and the University of Minho), MIT and a Portuguese company focused in creating innovative solutions in the fields of Research, Sports and Health Care (PLUX). Prof. Miguel Tavares da Silva (Biomechatronics Research Group/IDMEC, Instituto Superior Técnico) has led the DACHOR Project team of researchers since January 2009. Prof. Jorge Martins (IST), Prof. Paulo Flores (University of Minho), Prof. Dava Newman and Prof. Hugh Herr from MIT are also part of the team. OttoBock Portugal, a company specializing in the development of technologies for prostheses, orthoses, rehabilitation, wheel chairs and neuro-stimulation, also collaborates with the DACHOR Project. In addition, the Biomechanics Laboratory at IST has been a key resource for the analysis of pathological and non-pathological human movement. “What we can achieve with this type of technologies is that one can really maximize the performance of ortho-prosthetic products and the quality of life of people with reduced mobility. And that’s what really matters to us.” - Dr. Ricardo Marcelino (Prosthetist/Orthotist, Otto Bock Portugal) This Project began with the need to respond to different pathologies.  For that reason, medical teams from the Medical School of University of Lisbon, Santa Maria and D. Estefânia Hospitals initiated contact with MIT Portugal researchers in order to work to find solutions together. The DACHOR project proposes the development of an innovative powered Ankle-Foot Orthosis (AFO) to aid individuals with reduced mobility and neuromuscular disabilities of the locomotion apparatus, providing not only the support for general gait disabilities but also the rehabilitation of the musculoskeletal apparatus. The hybrid nature of this powered orthosis is due to an external mechanical actuation that is complemented by Functional Electrical Stimulation (FES). Development of a Hybrid Active AFO The DACHOR project relies on multibody dynamics methodologies to model and optimize altered human gait and on adaptive control architectures to distribute the control forces between both actuators. It is expected that the highlighted innovations contribute to an improved locomotion and muscular rehabilitation, to an increased autonomy and to a reduction in power, size and weight of the external actuators. The outcomes of the project span from new computational modeling tools and control methods to new mechanical designs and prototypes for hybrid human-machine systems. The results from the computational modeling provide know-how to the development of a prototype of an active ankle-foot orthosis with the devised control architecture. In 2011 physical prototypes will be implemented and MIT Portugal researchers expect to develop prototypes for the mechanical orthosis and for the electro-stimulation orthosis by the end of this year. Also, in 2011 MIT Portugal researchers expect to produce a prototype for a hybrid orthosis, gathering the mechanical and the electro-stimulation components. The most important result expected from the DACHOR project is a novel orthotic device that helps individuals with general gait disabilities. Patients will have access to a better orthotic device that will provide locomotion support as well as muscular rehabilitation, significantly improving their quality of life. This is possible by means of novel hybrid adaptive biorobotic technology that is in a first stage implemented computationally using advanced 3D multibody integrated models, and in a later stage materialized in a physical prototype. Computational models Another important result is reflected in the results obtained from physiotherapy programs in which a new tool will be available that can help physiatrists to devise new and more efficient treatment plans, allowing faster patient recovery with improved results. From the scientific point of view the outcomes of this project are twofold. The most important is to provide conditions to enlarge the research community so that even more advanced orthotic devices can be envisaged in the near future. The other repercussion is to allow team researchers with teaching responsibilities to spread knowledge and motivate new students to enroll research in this important topic. From the industry point of view, and considering the participation in the project of a startup company with experience in technology transfer, the team expects to create spinoff products, such as a new FES device, and eventually a new spin-off company. The DACHOR Project highlights the human enhancement component by working to assist people with locomotion disabilities and improving their quality of life in the near future. This will have a major impact in peoples’ lives, enabling them to have greater mobility with less effort and fatigue. Moreover, patients will be able to manipulate and use a wide range of everyday objects that otherwise would constitute barriers to them. DACHOR’s impact on the self-esteem and integration of disabled people makes this project a potentially significant application of research and technology to contemporary challenges in society.