High-fidelity patient specific model for blood flow simulation is important in medical applications. In this paper, a software component approach is proposed to perform physics based simulation of blood flow using GPU for general computing. The method comprises three independently developed software components, namely image processing component, object model component and GPU acceleration component. The fluid dynamics of blood flow is simulated using a mesh free modeler based on an improved Smoothed Particle Hydrodynamics method, and the interaction with arterial wall is simulated using a Finite Element modeler based on lumped element approach. Real-time simulation of blood flow has been demonstrated in an application on patients with abdominal aorta aneurysm. The internal fluidic structure and pressure distribution analysis have also been achieved using the proposed method.

This paper describes the reachMAN2, a rehabilitation robot with minimum degrees-of-freedom to train arm reaching and manipulation for typical ADLs, providing assistance in arm flexion/extension, forearm supination/pronation and hand opening/closing. The design, safety, control and performance evaluation of the system are presented. A handle using an innovative cam mechanism enables natural hand opening/closing movements. The interaction force between the device and the subject is measured via four force sensors located on the handle of the device. A preliminary study with healthy subjects was performed to assess the performances of the device.

The effect of hand-eye colocation in performing dexterous fine movements such as microsurgical manipulation is studied under a novel digital stereo microscope. Hand motion data is captured under conditions of hand-eye colocation and separation. Both configurations are tested with monoscopic and stereoscopic vision. A set of microsurgical task abstractions are created to reduce the effect of prior expertise. Finally the captured motion data is analyzed to determine the effect of colocation and stereopsis for surgical motion tasks.

This video presents a fully automated desktop workstation for fabricating tissue engineering (TE) scaffolds by assembling microscopic building blocks of dimension 0.5 × 0.5 × 0.2mm3and 60μm thickness. A TE scaffold is a porous supporting structure made of biodegradable material for cells to attach to and proliferate. TE scaffolds fabricated this way enable 3D control of the cells and agents to promote optimal tissue growth. This video outlines the architecture and control strategies of the workstation, and demonstrates its efficiency. Visual and force feedbacks, as well as a haptic exploration, make the assembly robust to large relative errors in the microparts.

The systems which have been developed are safe, easily transportable and offer various training possibilities. Virtual-reality games have been implemented to increase motivation during the 8 weeks of training with post-stroke subjects. Clinical trials have shown that chronic stroke patients can perform the required tasks and that training improves their motor function.

This paper presents an analysis of a newly developed elastic path controller (EPC) that can be used in assistive devices with human operators. The technique of robust control is also utilized to determine the parameters of the EPC in order to ensure that the EPC can tolerate possible uncertainties or disturbances in the environment. The new EPC is applied to a robotic wheelchair and tested in simulation. The results demonstrate the efficacy of the EPC.

This paper presents a novel type of Elastic Path Controller (EPC) to control and manipulate the assistive devices such as the Collaborative Wheelchair Assistant (CWA). Compared to previous controllers such as Samson’s and Brent’s controller, the proposed EPC is safer and more maneuverable. This paper also proposes the handling of singularity and solutions to backward motion problems of the EPC. Simulation experiments show that the new EPC can fulfill the tasks of path following, obstacle avoiding, singularity handling, backward motion, and so on.

This paper investigates how collaborative robots (cobots) can assist a human by mechanically constraining motion to software-defined guide paths, and introduces simple and efficient tools to design ergonomic paths. Analysis of the movements of seven subjects with the Scooter cobot reveals significant differences between guided movements (GM) and free movements (FM). While FM requires learning for each novel task, movements in GM are satisfying from the first trial, require little effort, are faster, smoother, and with fewer back and forth corrections than in FM. Operators rely on path guidance to rotate the Scooter and direct it along curved trajectories. While these advantages demonstrate the strength of the cobot concept, they do not show how guide paths should be defined. We introduce tools to enable the cobot and its operator to collaboratively learn ergonomic guide paths and adapt to changes in the environment. By relying on the haptic sensing, vision, and planning capabilities of the human operator, we can avoid equipping the cobot with complex sensor processing. Experiments with human subjects demonstrate the efficiency and complementarity of these guide paths design tools

Medical simulators are increasingly being used for surgical training. For interactive surgical simulation involving haptic rendering, the force at the needle tip has to be computed very fast. We are developing biomechanical models for bone needle insertion. The cortical bone can be regarded as a dense form of cancellous bone that can be modeled using a linear elastic material. The porosity of the bone determines the resistance felt as the user inserts the needle into the bone. The bar element method that represents each trabecular bone as a FE beam is most computationally efficient. With 1000 FE elements, the computed force feedback were close to the insertion force measured during experiments. However, the extended bar element method may be the more appropriate choice for taking into consideration the trabecular distribution and hence, inhomogeneous of bone. The simulation studies on bone-needle interaction also showed that a diamond bevel needle may penetrate the bone with less force

An elastic path controller (EPC) is developed in this paper to add "elasticity" to a path following controller and enable dynamic modification of the guiding path for assistive devices based on path guidance. This permits the users to compensate for changes in the environment such as obstacles or error in position sensing. The EPC is demonstrated both on the Scooter cobot and on the collaborative wheelchair assistant (CWA). Simulation results and psychophysical experiments performed with the Scooter suggest that this novel tool is efficient and can help human operators to adapt to environment changes

This paper describes the development and assessment of a collaborative wheelchair assistant (CWA). The concept at the heart of the CWA is to rely on the user's motion planning skills and assist the maneuvering with path guidance. The user decides where to go and controls the speed (including start and stop), while the system guides the wheelchair along software-defined paths. An intuitive path editor allows the user to modify the path on-line and so avoid dangers or obstacles. By using the human sensory and planning systems, complex sensor processing and artificial decision systems are not needed, making the system safe, simple and low-cost. Experimental results demonstrate this concept

The strong impairment of motor functions in stroke survivors affects daily activities such as eating, manipulating objects or writing. Our goal is to induce long lasting improvements in such tasks by having patients perform systematic exercises using haptic interfaces. This paper describes a novel two-degrees-of-freedom interface which we have developed to help stroke patients gradually recover the ability to open and close the hand and manipulate knobs. Different solutions are studied and a design consisting of two parallelogram structures interacting with the fingers is proposed. The mechanical design offers the possibility to adapt the interface to various hand sizes and finger orientations, and to right or left-handed subjects. Design kinematics as well as actuation and system control are described. Several knobs are proposed to interact with patients, especially a cone mechanism to train a complete opening movement from a strongly contracted and closed hand to a large opened position. The interaction force with the subject is measured over four force sensors located close to the output of the interface. A preliminary study has been performed to evaluate the performances of the haptic interface

For use in a Virtual Reality based training system for surgical micromanipulation, we have developed a fast multi-scale FEM algorithm that concentrates detail where needed while still handling global deformations. The resulting 6-to-7-fold speed up is promising for the development of real-time simulation of the mechanical response of a virtual organ or tissue. FEM algorithm uses elements from multiple levels in a hierarchy of mesh similar to the progressive mesh. This algorithm has been integrated with a visual/haptic feedback workstation.

Many wheelchair users have problems in orienting themselves and maneuvering the wheelchair in congested environments. Dependent upon others to push them, they can feel powerless. The collaborative wheelchair assistant introduced in this paper may help these people to regain autonomy by providing motion guidance along software-defined paths corresponding to their ability. It enables the user to travel independently, maneuvering round sharp corners and along narrow passages much more easily without compromising speed or safety. This paper investigates the hardware, kinematics and control of the collaborative wheelchair and presents tools by which the user can easily define guiding paths and personalizes the control to a particular disability. The user can also modify the predefined path 'en route' using an elastic path planner, and so escape from danger using reflexes and anticipation. This low cost assistant can be realized on both manual and powered wheelchairs.