Roball, the Rolling Robot

Designing a mobile robotic toy is challenging work. The robot must be appealing to children and create interesting interactions while facing the wide variety of situations that can be experienced while playing with a child, and all at a reasonable cost. In this paper we present Roball, a ball-shaped robot that moves by making its external spherical shell rotate. Such design for a mobile robotic toy shows robustness in handling unstructured environments and unconstrained interactions with children. Results show that purposeful movements of the robot, its physical structure and locomotion dynamics generate interesting new games influenced by the environment and the child.     

A Model to Disambiguate Natural Language Parses on the Basis of User Language Proficiency: Design and Evaluation

This paper discusses the design and evaluation of an implemented user model in ICICLE, an instruction system for users writing in a second language. We show that in the task of disambiguating natural language parses, a blended model combining overlay techniques with user stereotyping representing typical linguistic acquisition sequences captures user individuality while supplementing incomplete information with stereotypic reasoning     

Learning from History for Behavior-Based Mobile Robots in Non-Stationary Conditions

Learning in the mobile robot domain is a very challenging task, especially in nonstationary conditions. The behavior-based approach has proven to be useful in making mobile robots work in real-world situations. Since the behaviors are responsible for managing the interactions between the robots and its environment, observing their use can be exploited to model these interactions. In our approach, the robot is initially given a set of behavior-producing modules to choose from, and the algorithm provides a memory-based approach to dynamically adapt the selection of these behaviors according to the history of their use. The approach is validated using a vision- and sonar-based Pioneer I robot in nonstationary conditions, in the context of a multirobot foraging task. Results show the effectiveness of the approach in taking advantage of any regularities experienced in the world, leading to fast and adaptable specialization for the learning robot.     

A model for the consolidation of warp‐knitted reinforced laminates

A model for the consolidation of thermoplastic composites reinforced with a warp‐knitted fabric was developed. The evolution of void content during composite consolidation achieved via film stacking was related to the processing parameters and the material properties. Since the knitting process results in local variations of fiber volume fractions even within a tow, the flow mechanisms are not identical to those occurring in homogeneously dispersed fibers. Two different types of micro‐scale porosities were determined and a unit cell geometry was proposed for modeling. The reduction of the effective pressure due to the gas entrapment was also accounted for. Predictions of the variation of the void content as a function of time, pressure and temperature were compared to experimental data. As a good correlation was found between experiments and predictions, this approach can thus be applied to the consolidation of textile reinforcements in which the tows are locally compressed.     

The packing stress of impregnated fiber mats

The parameters affecting the packing stress of fiber mats for melt impregnation, resin transfer molding and compression molding are systematically investigated. An analytical equation based on local bending of fibers, which was previously derived for non‐impregnated networks, is applied to composite mats of dispersed planar bundles impregnated with molten polypropylene. It is shown that many simultaneous mechanisms interact during packing of impregnated bundle mats, in particular when the mats are needled. These include in‐plane bending of the bundles, compaction of the fibers within a bundle, and buckling, slippage or breakage of the out‐of‐plane fibers. In order to identify and decouple these features, aspect ratio of the bundles, lubrication, needling intensity and packing history are varied. A microstructural experiment is also developed to evaluate the extent of bundle spreading. It is found that dispersed fibers or bundles roughly follow the equation based on local bending, but that needled bundle networks deviate from the power law behavior. Three regions were identified. The first is attributed to self‐loading of the mats and to buckling of the out‐of plane fibers. The second region is due to slippage and breakage of the out‐of‐plane fibers and depends on the loading history and on the needling intensity. The third region is due to packing of the in‐plane bundles, which do not really bend, or spread under load, but are locally compressible, owing to misalignment and waviness of the individual fibers forming the bundles. In compression molding, the influence of the in‐plane reorientation of the initially out‐of‐plane bundles on the packing stress is observed.