The obtained results show that the integrated system is sensitive to the contact points, their number, location, the properties of the surfaces in contact and the orthosis characteristics in terms of mass properties and strap adjustment (or pre-tension) between the orthosis and the lower limb. The presented results also provide means for a better understanding of the interface phenomena and suggest that the proposed model may now be used to perform the sensitivity analysis of the system to specific design parameters and also its numerical optimization in order to achieve optimal orthosis designs.
Objectives & Motivation Our collaborative research in biomedical devices aims to significantly enhance human mobility. The DACHOR (Dynamics and Control of Hybrid Active Orthoses) project contributes multibody dynamics and control modeling for the development of an innovative powered Ankle-Foot Orthosis (AFO) with hybrid actuation to aid individuals with reduced mobility and neuromuscular disabilities. The project includes several innovative aspects: analysis of the musculoskeletal dynamics of an integrated biomechanical model of the patient and orthosis; the development of a hybrid actuation solution with dynamic scaling of the control authority between a functional mechanical actuation provided by an external power drive and functional electrical stimulation (FES) of selected muscles; and the development of an adaptive control law that dynamically regulates the amount of support and rehabilitation provided by the orthotic device. Our innovations strive to improve locomotion and enhance muscular rehabilitation, while providing wearable sensing and devices that realize power, size and weight benefits. Faculty from multiple Portuguese universities, a Portugal biomedical startup, and MIT are successfully leveraging their experience and passion to dream about the possibility of a world without disability, where everybody is abled through human-machine hybrid devices and designs.
Main Scientific Achievements 1. Development of advanced computational models for the integrated design of the hybrid AFO This project developed several computational models, using a multibody formulation with fully Cartesian coordinates, to provide insight into the development of the physical prototypes. These models encompassed: i) The development of a control architecture for the control of a partial multibody model of the human ankle joint by providing the proper set of muscle activations to a group of Hill-type muscle actuators:
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