关键词： 天津大学   机器人学   主任   机构   可重构  

摘要： 2013年2月1日，碧空万里，阳光灿烂，虽然伴随着三四级大风，也让人心情愉悦。为采访天津大学先进机构与机器人学中心主任戴建生教授，记者专门从北京赶往天津。

关键词： Robots   Ants   Pheromones   Robotic behavior   Foraging   Robotics   Animal sociality   Decision making  

摘要： Interactions between individuals and the structure of their environment play a crucial role in shaping self-organized collective behaviors. Recent studies have shown that ants crossing asymmetrical bifurcations in a network of galleries tend to follow the branch that deviates the least from their incoming direction. At the collective level, the combination of this tendency and the pheromone-based recruitment results in a greater likelihood of selecting the shortest path between the colony's nest and a food source in a network containing asymmetrical bifurcations. It was not clear however what the origin of this behavioral bias is. Here we propose that it results from a simple interaction between the behavior of the ants and the geometry of the network, and that it does not require the ability to measure the angle of the bifurcation. We tested this hypothesis using groups of ant-like robots whose perceptual and cognitive abilities can be fully specified. We programmed them only to lay down and follow light trails, avoid obstacles and move according to a correlated random walk, but not to use more sophisticated orientation methods. We recorded the behavior of the robots in networks of galleries presenting either only symmetrical bifurcations or a combination of symmetrical and asymmetrical bifurcations. Individual robots displayed the same pattern of branch choice as individual ants when crossing a bifurcation, suggesting that ants do not actually measure the geometry of the bifurcations when travelling along a pheromone trail. Finally at the collective level, the group of robots was more likely to select one of the possible shorter paths between two designated areas when moving in an asymmetrical network, as observed in ants. This study reveals the importance of the shape of trail networks for foraging in ants and emphasizes the underestimated role of the geometrical properties of transportation networks in general.

关键词： Reinforcement learning   Underwater robotics   Gradient descent algorithms   Actor-Critic algorithms   Model identification  

摘要： This article proposes a field application of a Reinforcement Learning (RL) control system for solving the action selection problem of an autonomous robot in a cable tracking task. The Ictineu Autonomous Underwater Vehicle (AUV) learns to perform a visual based cable tracking task in a two step learning process. First, a policy is computed by means of simulation where a hydrodynamic model of the vehicle simulates the cable following task. The identification procedure follows a specially designed Least Squares (LS) technique. Once the simulated results are accurate enough, in a second step, the learnt-in-simulation policy is transferred to the vehicle where the learning procedure continues in a real environment, improving the initial policy. The Natural Actor-Critic (NAC) algorithm has been selected to solve the problem. This Actor-Critic (AC) algorithm aims to take advantage of Policy Gradient (PG) and Value Function (VF) techniques for fast convergence. The work presented contains extensive real experimentation. The main objective of this work is to demonstrate the feasibility of RL techniques to learn autonomous underwater tasks, the selection of a cable tracking task is motivated by an increasing industrial demand in a technology to survey and maintain underwater structures. (c) 2012 Elsevier B.V. All rights reserved.

关键词： Robotic surgery   da Vinci   gastric bypass   Roux-en-Y gastric bypass   weight loss surgery  

摘要： Robotic surgery for laparoscopic procedures such as advanced gastrointestinal surgery and abdominal malignancies is currently on the rise. The first robotic systems have been used since the 1990s with increasing number of clinical cases and broader clinical applications each year. Although high-evidence-level data are scarce, studies suggest that the technical advantages of robotic surgery result in a clinical value for procedures of advanced complexity such as Roux-en-Y gastric bypass and revisional bariatric surgery. Ultimately, the digital interface of the robotic system with the option to integrate augmented reality and real-time imaging will allow advanced applications particularly in the field of gastrointestinal surgery for malignancies.

关键词： Standard   Service robots   Safety   Performance   Personal care  

摘要： This paper summarizes the recent standardization activities in the field of robotics by ISO (International Organization for Standardization), IEC (International Electrotechnical Commission), OMG (Object Management Group), and other organizations. While the standards in industrial robots have been mainly developed by ISO, the standards on the emerging service robots are initiated by many organizations. One of the goals of this paper is to coordinate the efforts among these groups so that more effective standardization activity can be executed. Standardization in the emerging service robots will eventually promote the proliferation of service robot markets in the near future.

关键词： Algebraic topolgy   Differential topology   Homology invariant   Robot path planning  

摘要： We consider planning problems on Euclidean spaces of the form a"e, where is viewed as a collection of obstacles. Such spaces are of frequent occurrence as configuration spaces of robots, where represent either physical obstacles that the robots need to avoid (e.g., walls, other robots, etc.) or illegal states (e.g., all legs off-the-ground). As state-planning is translated to path-planning on a configuration space, we collate equivalent plannings via topologically-equivalent paths. This prompts finding or exploring the different homology classes in such environments and finding representative optimal trajectories in each such class. In this paper we start by considering the general problem of finding a complete set of easily computable homology class invariants for (N -aEuro parts per thousand 1)-cycles in (a"e. We achieve this by finding explicit generators of the (N -aEuro parts per thousand 1) (st) de Rham cohomology group of this punctured Euclidean space, and using their integrals to define cocycles. The action of those dual cocycles on (N -aEuro parts per thousand 1)-cycles gives the desired complete set of invariants. We illustrate the computation through examples. We then show, for the case when N = 2, due to the integral approach in our formulation, this complete set of invariants is well-suited for efficient search-based planning of optimal robot trajectories with topological constraints. In particular, we show how to construct an 'augmented graph', , from an arbitrary graph in the configuration space. A graph construction and search algorithm can hence be used to find optimal trajectories in different topological classes. Finally, we extend this approach to computation of invariants in spaces derived from (a"eby collapsing a subspace, thereby permitting application to a wider class of non-Euclidean ambient spaces.

关键词： Instrumentation and measurement Medical physics Biological physics Environmental and Earth science Condensed matter: structural   mechanical & thermal  

摘要： This paper investigates fish-like aquatic robotics using flexible bimorphs made of macro-fiber composite (MFC) piezoelectric laminates for carangiform locomotion. In addition to noiseless and efficient actuation over a range of frequencies, geometric scalability, and simple design, bimorph propulsors made of MFCs offer a balance between the actuation force and velocity response for performance enhancement in bio-inspired swimming. The experimental component of the presented work focuses on the characterization of an elastically constrained MFC bimorph propulsor for thrust generation in quiescent water as well as the development of a robotic fish prototype combining a microcontroller and a printed-circuit-board amplifier to generate high actuation voltage for untethered locomotion. From the theoretical standpoint, a distributed-parameter electroelastic model including the hydrodynamic effects and actuator dynamics is coupled with the elongated-body theory for predicting the mean thrust in quiescent water. In-air and underwater experiments are performed to verify the incorporation of hydrodynamic effects in the linear actuation regime. For electroelastically nonlinear actuation levels, experimentally obtained underwater vibration response is coupled with the elongated-body theory to predict the thrust output. The measured mean thrust levels in quiescent water (on the order of similar to 10 mN) compare favorably with thrust levels of biological fish. An untethered robotic fish prototype that employs a single bimorph fin (caudal fin) for straight swimming and turning motions is developed and tested in free locomotion. A swimming speed of 0.3 body-length/second (7.5 cm s(-1) swimming speed for 24.3 cm body length) is achieved at 5 Hz for a non-optimized main body-propulsor bimorph combination under a moderate actuation voltage level.

关键词： Swarm robotics   Review   Swarm engineering  

摘要： Swarm robotics is an approach to collective robotics that takes inspiration from the self-organized behaviors of social animals. Through simple rules and local interactions, swarm robotics aims at designing robust, scalable, and flexible collective behaviors for the coordination of large numbers of robots. In this paper, we analyze the literature from the point of view of swarm engineering: we focus mainly on ideas and concepts that contribute to the advancement of swarm robotics as an engineering field and that could be relevant to tackle real-world applications. Swarm engineering is an emerging discipline that aims at defining systematic and well founded procedures for modeling, designing, realizing, verifying, validating, operating, and maintaining a swarm robotics system. We propose two taxonomies: in the first taxonomy, we classify works that deal with design and analysis methods;in the second taxonomy, we classify works according to the collective behavior studied. We conclude with a discussion of the current limits of swarm robotics as an engineering discipline and with suggestions for future research directions.

关键词： Responsibility in medical robotics   Robo-ethics   Ethical issues concerning rehabilitation robotics   Liability in robotic-assisted surgery   Philosophy of science  

摘要： This article addresses prospective and retrospective responsibility issues connected with medical robotics. It will be suggested that extant conceptual and legal frameworks are sufficient to address and properly settle most retrospective responsibility problems arising in connection with injuries caused by robot behaviours (which will be exemplified here by reference to harms occurred in surgical interventions supported by the Da Vinci robot, reported in the scientific literature and in the press). In addition, it will be pointed out that many prospective responsibility issues connected with medical robotics are nothing but well-known robotics engineering problems in disguise, which are routinely addressed by roboticists as part of their research and development activities: for this reason they do not raise particularly novel ethical issues. In contrast with this, it will be pointed out that novel and challenging prospective responsibility issues may emerge in connection with harmful events caused by normal robot behaviours. This point will be illustrated here in connection with the rehabilitation robot Lokomat.