Synthesis, dynamic modeling, prototyping and control of a handheld rotational inertia generator.

This paper explores the design and experimental validation of a three-degree-of-freedom variable inertia generator. An inertia generator is a handheld haptic device that renders a prescribed inertia. In the mechanism proposed in this paper, three-dimensional torque feedback is achieved by accelerating three pairs of flywheels mounted on orthogonal axes. While the primary objective of this work is to design an inertia generator, this study also includes developing other functionalities for the device that exploit its torque generation capabilities. These include the ability to generate a predefined torque profile and to simulate a viscous environment through damping, which are both utilized to assess the device's performance. The device proved to accurately render the necessary torques for every functionality while presenting some limitations for damping and rendering an inertia smaller than the device's inherent inertia.

Mechanical design of a new device to assist eating in people with movement disorders.

Many people living with neurological disorders, such as cerebral palsy, stroke, muscular dystrophy or dystonia, experience upper limb impairments (muscle spasticity, loss of selective motor control, muscle weakness or tremors) and are unable to eat independently. This article presents the development of a new device to assist with eating, aimed at stabilizing the movement of people who have movement disorders. The design was guided by insights gathered through focus groups, with occupational therapists and engineers, about the challenges faced by individuals who have movement disorders and difficulty in eating autonomously. The proposed assistive device prototype is designed to be fixed on a table and to support a spoon. The mechanism is designed so that the spoon maintains a position parallel to the ground for the user. Dampers and inertia allow stabilizing the user's motion. A preliminary trial with five individuals living with cerebral palsy is presented to assess the prototype's performance and to guide future iterations of the prototype. Task completion time generally decreased and movement fluidity generally improved when using the assistive device prototype. The prototype showed good potential in stabilizing the spoon for the user and improving movement fluidity.

Analysis and synthesis of assistive tools for insertion tasks.

This article studies two types of assembly tasks, namely snap-fit insertions and press-fit hose insertions. Experimental data and theoretical modelling of a snap-fit assembly are used to design a tool that can perform the snap-fit task effectively. The design process of the tool is presented and experimental tests developed to validate its effectiveness are described. Hose insertion experiments are then performed and the results are analyzed in order to develop strategies for the effective insertion of press-fit components in assembly tasks. A motion primitive strategy is first explored, followed by a vibration oriented strategy. Finally, a video demonstrating the experiments accompanies this paper.

Preliminary Design of an Active Stabilization Assistive Eating Device for People Living with Movement Disorders.

This paper presents the development of a new active assistive eating device, which aims to stabilize the movements of people living with movement disorders, such as spasticity and ataxia. Many people living with upper-body incapacities are unable to eat on their own, due to movement disorders (ex. tremors, spastic motions, lack of muscular tone), resulting from various ailments like Cerebral palsy, Parkinson's disease, Dystonia, Multiple sclerosis, strokes, and Muscular dystrophy). Our past work focused on the development of a purely mechanical device, which involved damping of the system via passive mechanical dampers. This paper extends said work by using active stabilization of user movements. The active assistance enables the design of intelligent algorithms that can assist human movements more efficiently. This active version has the benefits of being easily adjustable; the level of damping can be adjusted in real-time, depending on the user movement; different control modes are offered, and the guiding of user movements is also allowed. Firstly, the mechanical design of the device is presented, followed by the damping arrangement, the electronic design, the control algorithms and finally, the preliminary experiments are mentioned.

On the development of a walking rehabilitation device with a large workspace.

Rehabilitation therapy aiming at helping a person to regain or improve the ability to walk is a labour-intensive activity. In this context, the patient is often limited to very restricted walking spaces. This paper presents a device that can support the weight of a person walking freely over a large workspace. The device is based on an overhead gantry mechanism combined with a cable routing that decouples the vertical motion from the horizontal displacements of the person. The mechanical architecture is first presented and it is shown that the principle can be applied to the design of a completely passive device in which the portion of the weight to be supported can be adjusted. A simplified dynamic model is also derived in order to highlight the characteristics of the device. A powered version of the device is then discussed. Finally, a prototype of a passive device built at full scale is presented and discussed. A video accompanying the paper illustrates the experimental tests underway with the prototype.

A first semimanual device for clinical intramuscular repetitive cell injections.

Intramuscular cell transplantation in humans requires so far meticulous repetitive cell injections. Performed percutaneously with syringes operated manually, the procedure is very time consuming and requires a lot of concentration to deliver the cells exactly in the required region. This becomes impractical and inaccurate for large volumes of muscle. In order to accelerate this task, to render it more precise, and to perform injections more reproducible in large volumes of muscle, we developed a specific semimanual device for intramuscular repetitive cell injections. Our prototype delivers very small quantities of cell suspension, homogeneously throughout several needles, from a container in the device. It was designed in order to deliver the cells as best as possible only in a given subcutaneous region (in our case, skeletal muscles accessible from the surface), avoiding wasting in skin and hypodermis. The device was tested in monkeys by performing intramuscular allotransplantations of beta-galactosidase-labeled myoblasts. During transplantations, it was more ergonomic and considerably faster than manually operated syringes, facilitating the cell graft in whole limb muscles. Biopsies of the myoblast-injected muscles 1 month later showed abundant beta-galactosidase-positive myofibers with homogeneous distribution through the biopsy sections. This is the first device specifically designed for the needs of intramuscular cell transplantation in a clinical context.