A local planner for closed-loop robot

Global motion planners have been proposed for closed-loop robot based on the same paradigm than has been proposed for serial chains. First a sparse representation of the configuration space of the robot is constructed as a set of nodes. This is somewhat more complicated than for serial chain as the closure equations of the mechanism should be satisfied. Then a motion planning query consists simply in connecting the start and goal points through an appropriate set of nodes (usually minimizing the length of the trajectory). But such motion planner should be complemented by a local motion planner that addresses the following issues: \begin{enumerate} \item ensure that two successive nodes belong to the same robot kinematic branch (otherwise connecting these nodes will require to disassemble the robot) \item verify that all poses between nodes satisfy the robot constraints (if possible taking into account the uncertainties in the robot modeling) \item eventually try to shorten the trajectory length \end{enumerate} We present such a local motion planner that addresses all three issues and illustrates its use on a Gough parallel robot

A Local Motion Planner for Closed-loop Robots

Global motion planners have been proposed for closed-loop robot based on the same paradigm than has been proposed for serial chains. First a sparse representation of the configuration space of the robot is constructed as a set of nodes. This is somewhat more complicated than for serial chain as the closure equations of the mechanism should be satisfied. Then a motion planning query consists simply in connecting the start and goal points through an appropriate set of nodes (usually minimizing the length of the trajectory). But such motion planner should be complemented by a local motion planner that addresses the following issues: \begin{enumerate} \item ensure that two successive nodes belong to the same robot kinematic branch (otherwise connecting these nodes will require to disassemble the robot) \item verify that all poses between nodes satisfy the robot constraints (if possible taking into account the uncertainties in the robot modeling) \item eventually try to shorten the trajectory length \end{enumerate} We present such a local motion planner that addresses all three issues and illustrates its use on a Gough parallel robot

Contribution à la modélisation de robots à câbles pour leur commande et leur conception

Cable-Driven Parallel Robots form a new class of parallel robots. Those robots, described by the RRPS architecture of hexapods, use coiled cables for their legs instead of rigid element chains of classical parallel robots. This technology is subject to the specifics of cables, particularly the unilateral aspect of the forces exerted by the cables on the platform, the elasticity, the sagging caused by the flexibility and the mass of the cables. We start by revisiting the model of those robots. We do so by considering the elastic catenary behavior of the cables, suitable for large dimension robots. Then we handle interference detection of such a robot, which concern just as much interference between cables, than with and between objects. Said objects are the platform and arbitrary obstacles. Being a safety matter, interference detection must be guaranteed in front of uncertainties and of the complex shapes of the cables. The detection scheme is issued for the RRPS model and the elastic catenary one. Interval analysis methods are used to deal with uncertainties; hierarchic definitions are used for objects. Lastly, we deal with a design process for those robots. This process aims at fitting a robot that satisfy the expressed needs of a given application. To this end, the process looks for the set of values of parameters of a CDPR generic model. Those values allow the resulting robot to satisfy a set of constraints. Those parameters are subject to their own uncertainties. We guarantee the practical usability of the design both by guaranteeing the suitability of all possible robots given by the intervals of the solutions for the parameters, and with minimal widths.Les robots à câbles (CDPRs) se présentent comme une nouvelle classe de robots parallèles. Ces robots, décrits par l'architecture RRPS des hexapodes, utilisent des câbles enroulés pour leurs jambes plutôt que les chaînes d'éléments rigides des robots parallèles classiques. Cette technologie est dépendante des câbles, donc sujette à l'unilatéralité des efforts exercés par les câbles sur la plate-forme, l'élasticité, ou bien l'affaissement dû à la flexibilité et à la masse. Dans un premier temps nous revisitons la modélisation de ce type de robot, en particulier pour le comportement de type chaînette élastique, approprié pour les robots de grandes dimensions. Dans un second temps nous traitons de la détection de collision, et ce aussi bien entre les câbles, qu'avec et entre les objets que sont la plate-forme et d'éventuels obstacles. S'agissant d'une problématique de sûreté, la détection se doit d'être garantie face aux incertitudes et face à la forme complexe des câbles. Elle est déclinée pour le modèle RRPS et le modèle chaînette élastique. L'analyse par intervalles est utilisée pour traiter les incertitudes, et les objets sont munis de définitions hiérarchiques. Enfin, nous aborderons un processus de conception, qui a pour objectif de répondre au besoin exprimé par une application. À cette fin, il cherche l'ensemble des valeurs des paramètres d'un modèle générique de CDPR, permettant de satisfaire un ensemble de contraintes. Ces paramètres sont toutefois soumis à leurs propres incertitudes. Aussi, on assure la faisabilité de la conception en garantissant et la validité de tous les robots possibles donnés par les intervalles de solutions, et la largeur minimale

Visually Guided Control of Movement

The papers given at an intensive, three-week workshop on visually guided control of movement are presented. The participants were researchers from academia, industry, and government, with backgrounds in visual perception, control theory, and rotorcraft operations. The papers included invited lectures and preliminary reports of research initiated during the workshop. Three major topics are addressed: extraction of environmental structure from motion; perception and control of self motion; and spatial orientation. Each topic is considered from both theoretical and applied perspectives. Implications for control and display are suggested

SPATIAL TRANSFORMATION PATTERN DUE TO COMMERCIAL ACTIVITY IN KAMPONG HOUSE

ABSTRACT Kampung houses are houses in kampung area of the city. Kampung House oftenly transformed into others use as urban dynamics. One of the transfomation is related to the commercial activities addition by the house owner. It make house with full private space become into mixused house with more public spaces or completely changed into full public commercial building. This study investigate the spatial transformation pattern of the kampung houses due to their commercial activities addition. Site observations, interviews and questionnaires were performed to study the spatial transformation. This study found that in kampung houses, the spatial transformation pattern was depend on type of commercial activities and owner perceptions, and there are several steps of the spatial transformation related the commercial activity addition. Keywords: spatial transformation pattern; commercial activity; owner perception, kampung house; adaptabilit