5 research outputs found

    Advances in Robot Navigation

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    Robot navigation includes different interrelated activities such as perception - obtaining and interpreting sensory information; exploration - the strategy that guides the robot to select the next direction to go; mapping - the construction of a spatial representation by using the sensory information perceived; localization - the strategy to estimate the robot position within the spatial map; path planning - the strategy to find a path towards a goal location being optimal or not; and path execution, where motor actions are determined and adapted to environmental changes. This book integrates results from the research work of authors all over the world, addressing the abovementioned activities and analyzing the critical implications of dealing with dynamic environments. Different solutions providing adaptive navigation are taken from nature inspiration, and diverse applications are described in the context of an important field of study: social robotics

    Prosthetic mitral valve orientation and its impact on the flow dynamics in the left ventricle

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    Severe mitral regurgitation is a complication that reduces the quality of life of those affected and left untreated, it can lead to heart failure and potential death. With the recent success of transcatheter aortic valve replacement surgery reducing the risk associated with open heart surgery, attention has been focused on performing a similar approach for mitral valve replacement. Transcatheter mitral valve replacement has proven to be more challenging; one of the associated complications is the potential misalignment of the mitral valve that alters the flow dynamics occurring in the left ventricle. An in-vitro experiment was performed to study the change in the flow dynamics associated with increasing misalignment severity. Three different valve orientations were investigated: a healthy case to use as a baseline, a slightly angled case such that the valve is aligned with the apical septal wall and a highly angled case that has the valve aligned in the basal septal wall. Each valve orientation was tested over a range of heart rates corresponding to 40, 60, 80, 100 and 120 beats per minute while maintaining a constant stroke volume. A Eulerian analysis was performed on fluid mechanics properties including the kinetic energy, viscous energy dissipation and circulation. The healthy case was determined to minimize viscous energy dissipation and maximize systolic kinetic energy. Circulation in the altered valve orientations had a reversed direction relative to the healthy case. A Lagrangian analysis was completed to quantify the amount of stasis, which was determined to be minimized in the healthy case
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