A Review of Pneumatic Actuators Used for the Design of Medical Simulators and Medical Tools

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A multi-level architecture controlling robots from autonomy to teleoperation

International audienceThis paper presents a specific architecture based on a multilevel formalism to control either autonomous or teleoperated robots that have been developed in the laboratory vision and robotics. This formalism separates precisely each robot functionalities (hardware and software) and provides a global scheme to position them and to model data exchanges among them. Our architecture was originally built from the classical control loop. Two parts can thus be defined: the Perception part which manages the processing and the models construction of incoming data (the sensor easurements), and the Action part which manages the processing of controlled outputs. These two parts are divided in several levels and depending on the robot, the control loops that have to be performed are located at different levels: from the basic one (i.e. level 0) composed by the jointed mechanical structure and level 1 which performs actuators servoing, to the highest one (i.e. level 5) which manages the various missions of the robot. The higher the level is, the shorter the loop reaction time has to be. Each level clusters, for their respective part, specific modules which perform their own goals. This general scheme permits to integrate different modules issued from various robot control theories. This architecture has been designed to model and control autonomous robots. Furthermore, a third part, called "teleoperated part", can be added and structured in levels similarly to the two other parts. Distant from the robot, this teleoperated part is managed by a human operator who controls the robot at various levels: i.e. from the first level (the basic remote control) to the upper one (where the operator only controls the robot mission). Hence, this architecture merges two antagonist concepts of robotics, i.e. teleoperation and autonomy, and allows a sharp distribution between these two fields. Finally, this architecture can be used as a main frame to build its own control architecture, using only a few clusters with dedicated modules. Some examples and experimental results are given in this paper to validate the proposed formalism

Framework for modular robot control architecture

International audienceThis paper presents a multi-level formalism to achieve a hierarchical control architecture of a robot being either autonomous or tele-operated. This formalism is based on a graphical representation which allows to precisely distinguish each feature of a given robotic application. We have identified five possible levels of control for the autonomous mode and as much for the tele-operated mode. When taking into account these two modes the designer has the ability to directly integrate a human operator action within any level of the proposed structure. Once the architecture is defined for a given robot, the implantation is performed using the chosen hardware and software environment (e.g. operating system, real-time kernel, programming language...). Two examples of mobile and tele-operated robots, designed and developed, validate experimentally the proposed architecture

An Hybrid Motion Controller for a Real Car-Like Robot Evolving in a Multi-Vehicle Environment

This paper addresses the problem of the interface between a map-based path/trajectory planner and a physical mobile robot with under servo control. The connection between these two entities must match virtual motions of a modeled robot in the map-world of the path/trajectory planner and real robot motions in its physical world. We lead research works on motion controllers which are able to join these virtual and physical worlds. We develop these controllers for an autonomous car project, called Praxitele. In the first part of this paper, we present Praxitele project. After, we discuss about motion controller, and the need to obtain a real autonomous vehicle. The third and the fourth parts of this paper describes two motion controllers : a fuzzy one and another one issuing from local navigation with Escape Lines. The last part and the conclusion deals with the fusion of fuzzy logic and Escape Lines in a hybrid motion controller. 1 Praxitele Project Figure 1: One of the two PRAXITELE Pro..

Direct Model Navigation issue shifted in the continuous domain by a predictive control approach for mobile robots

International audienceThis paper presents a new navigation method for mobile robots, based on direct kinematics model and predictive control approach. It is adaptable to all types of robots taking into account their specific constraints. The research of the optimal trajectory is shifted in the continuous parameters space, which enables the exploitation of all of the robot's capabilities. The use of a stochastic algorithm enables the determination of obstacle bypass trajectories, and simulation results show that the navigation in cluttered environment is improved

Direct Model Navigation issue shifted in the continuous domain by a predictive control approach for mobile robots

International audienceThis paper presents a new navigation method for mobile robots, based on direct kinematics model and predictive control approach. It is adaptable to all types of robots taking into account their specific constraints. The research of the optimal trajectory is shifted in the continuous parameters space, which enables the exploitation of all of the robot's capabilities. The use of a stochastic algorithm enables the determination of obstacle bypass trajectories, and simulation results show that the navigation in cluttered environment is improved

Omni-directional robot with spherical orthogonal wheels: concepts and analyses

International audienceThis article addresses the omni directional mechanical architectures problematic for mobile robots using 3 motorized axles with 2 spherical orthogonal wheels. These wheels transmit a power torque according to a direction and are completely free with respect to the two others. They are used on 2 mechanical structures: SM1 and SM2. The complete kinematic study emphasizes the facility of controlling such omni-directional robots, and examines the problems involved in the transition of the wheel-to-floor contact on each axle. From this double study emerges an optimal theoretical architecture, but difficult to realize mechanically. We then present a controller which compensates for the errors related to the simplest mechanical structure; and it is validated on a mobile robot ROMNI using mechanical structure SM

Singularity avoidance in a robotized ultrasound scan

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