Robotique collective et auto-assemblage:une étude mécatronique

We present a study of collective robotics by including a mechatronics point of view. In the field it is usually claimed that collective robots are simple and relatively cheap because they are produced in large quantities. Instead in our study we show that collective robots are not simple because they need sensors and actuators for additional work. Our experience in designing robots and producing them allows us to analyze the manufacturing costs of different collective robots . We present in this work four robots developed prior and during to this thesis. Chapter 2 concerns the e-puck robot. This is a robot designed for education, however, it is used in research to experiment collective behaviors. The s-bot robot is presented in Chapter 3. This is a robot that has the collective ability to self-assemble to form larger structures and increase its performance. In Chapter 4 we present the marXbot robot. It is a modular robot developed in the laboratory to meet the needs of different research hubs. One of its modules allows it to self-assemble with its teammates and with the robot handbot presented in Chapter 5. The handbot is a robot that can climb and handle objects. It can climb for example a shelf to grasp a book. On the ground it is transported by marXbot. In Chapter 6 the performance of robots are presented. We expose a study of their performance gain when the robots are self-assembled. Finally we compare in Chapter 7 the four robots from the mechatronics point of view and in respect to their cost

Recent atmospheric Pb deposition at a rural site in southern Germany assessed using a peat core and snowpack, and comparison with other archives

In a peat bog from Black Forest, Southern Germany, the rate of atmospheric Pb accumulation was quantified using a peat core dated by 210Pb and 14C. The most recent Pb accumulation rate (2.5 mg m−2 y−1) is similar to that obtained from a snowpack on the bog surface, which was sampled during the winter 2002 (1 to 4 mg m−2 y−1). The Pb accumulation rates recorded by the peat during the last 25 yr are also in agreement with published values of direct atmospheric fluxes in Black Forest. These values are 50 to 200 times greater than the “natural” average background rate of atmospheric Pb accumulation (20 μg m−2 y−1) obtained using peat samples from the same bog dating from 3300 to 1300 cal. yr B.C. The isotopic composition of Pb was measured in both the modern and ancient peat samples as well as in the snow samples, and clearly shows that recent inputs are dominated by anthropogenic Pb. The chronology and isotopic composition of atmospheric Pb accumulation recorded by the peat from the Black Forest is similar to the chronologies reported earlier using peat cores from various peat bogs as well as herbarium samples of Sphagnum and point to a common Pb source to the region for the past 150 years. In contrast, Pb contamination occurring before 1850 in southwestern Germany, differs from the record published for Switzerland mainly due to the mining activity in Black Forest. Taken together, the results show that peat cores from ombrotrophic bogs can yield accurate records of atmospheric Pb deposition, provided that the cores are carefully collected, handled, prepared, and analysed using appropriate methods

Autonomous Construction with Compliant Building Material

In this paper, we develop an autonomous construction system in which a self-contained ground robot builds a protective barrier by means of compliant pockets (i.e., filled bags). We present a stochastic control algorithm based on two biological mechanisms (stigmergy and templates) that takes advantage of compliant pockets for autonomous construction. The control algorithm guides the robot to build the structure without relying on any external motion capture system or external computer. We propose a statistical model to represent the structures built with the compliant pockets, and we provide a set of criteria for assessing the performance of the proposed system. To demonstrate the feasibility of the proposed system, real-robot experiments were carried out. In each experiment, the robot successfully built the structure. The results show the viability of the proposed autonomous construction system

Autonomous Self-assembly in a Swarm-bot

Multi-robot systems have been studied in tasks that require the robots to be physically linked. In such a configuration, a group of robots may navigate a terrain that proves too difficult for a single robot. On the contrary, many collective tasks can be accomplished more efficiently by a group of independent robots. This paper is about swarm-bot, a robotic system that can operate in both configurations and autonomously switch from one to the other. We examine the performance of a single robot and of groups of robots selfassembling with an object or another robot. We assess the robustness of the system with respect to different types of rough terrain. Finally, we evaluate the performance of swarms of 16 physical robots. At present, for self-assembly in autonomous, mobile robotics, swarm-bots is the state of the art for what concerns reliability, robustness and speed

A Programming Workshop using the Robot "Thymio II": The Effect on the Understanding by Children

Robots are both fascinating objects for the general public and devices whose conception, understanding and pro- gramming involve many fields. This unique combination makes them an ideal tool for introducing science and technology to children. This paper presents the outcome of a programming workshop held on the occasion of the 2011 EPFL Robotics Festival. This workshop introduced programming using the robot “Thymio II”. The participants enjoyed this workshop very much, and their attitudes suggest that the public is attracted to such events out of interest rather than pure fun or educational concerns. Children appreciated the supervision, characterized by a high staff-per-child ratio of 1/3. We also show that in an hour of tutorial, children were able to acquire concepts such as the sensor or the loading of a program on the robot because they practised these enough. More theoretical and less practised concepts, such as the sensory-motor loop or the programming details, were not well understood. These findings now enable us to create better edutainment material

Cooperation through self-assembly in multi-robot

This article illustrates the methods and results of two sets of experiments in which a group of mobile robots, called s-bots, are required to physically connect to each other, that is, to self-assemble, to cope with environmental conditions that prevent them from carrying out their task individually. The first set of experiments is a pioneering study on the utility of self-assembling robots to address relatively complex scenarios, such as cooperative object transport. The results of our work suggest that the s-bots possess hardware characteristics which facilitate the design of control mechanisms for autonomous self-assembly. The control architecture we developed proved particularly successful in guiding the robots engaged in the cooperative transport task. However, the results also showed that some features of the robots’ controllers had a disruptive effect on their performances. The second set of experiments is an attempt to enhance the adaptiveness of our multi-robot system. In particular, we aim to synthesise an integrated (i.e., not-modular) decisionmaking mechanism which allows the s-bot to autonomously decide whether or not environmental contingencies require self-assembly. The results show that it is possible to synthesize, by using evolutionary computation techniques, artificial neural networks that integrate both the mechanisms for sensory-motor coordination and for decision making required by the robots in the context of self-assembly

Towards an Autonomous Evolution of Non-Biological Physical Organisms

We propose an experimental study where simplistic organ- isms rise from inanimate matter and evolve solely through physical interactions. These organisms are composed of three types of macroscopic building blocks floating in an agitated medium. The dynamism of the medium allows the blocks to physically bind with and disband from each other. This results in the emergence of organisms and their reproduction. The process is governed solely by the building blocks' local interactions in the absence of any blueprint or central command. We demonstrate the feasibility of our approach by realistic computer simulations and a hardware prototype. Our results suggest that an autonomous evolution of non-biological organisms can be realized in human-designed environments and, potentially, in natural environments

Bringing robotics into formal education using the Thymio open source hardware robot

Mobile robots are valuable tools for education because of both the enthusiasm they raise and the multidisciplinary nature of robotics technology. Mobile robots give access to a wide range of fields, such as complex mechanics, sensors, wireless transmission, mathematics, and computer science. However, despite their potential as educational tools, robots are still not as widespread in schools as they could be. In this article, we identify five key reasons: lack of diversity, high cost, noninclusive design, lack of educational material, and lack of stability over time. Then, we describe our answers to these problems, as we implemented them in the Thymio project: a mature mass-produced open-hardware robot, at a low price, with a multiage and gender-neutral feature set, and with a design promoting creativity, facilitating learning, and providing a wide range of interaction possibilities from built-in behaviors to text programming, passing through different visual programming environments. We highlight some neglected key issues that differentiate open-source hardware from open-source software, for instance the legal uncertainty of designing open hardware using professional computer-aided design (CAD) tools and the difficulty to distribute the development. Our solution to these being to increase the awareness of CAD editors to open-source hardware and to provide a two-layer development model for hardware

Design of Magnetic Switchable Device (MSD) and applications in climbing robot

A Magnetic Switchable Device (MSD) is a ferromagnetic circuit using permanent magnets where the flux can circulate between different paths when its configuration is changed. This routes or cancels the flux through specific surfaces, and thus turns on or off adhesion forces.We present classic and innovative magnetic configuration to realize powerful MSD. We designed and prototyped some miniature systems and give their characteristics. Finally various robotics applications for gripper, anchor and climbing robot are unveiled where the MSD solution has proved to be advantageous