Online Robot Introspection via Wrench-based Action Grammars

Robotic failure is all too common in unstructured robot tasks. Despite well-designed controllers, robots often fail due to unexpected events. How do robots measure unexpected events? Many do not. Most robots are driven by the sense-plan act paradigm, however more recently robots are undergoing a sense-plan-act-verify paradigm. In this work, we present a principled methodology to bootstrap online robot introspection for contact tasks. In effect, we are trying to enable the robot to answer the question: what did I do? Is my behavior as expected or not? To this end, we analyze noisy wrench data and postulate that the latter inherently contains patterns that can be effectively represented by a vocabulary. The vocabulary is generated by segmenting and encoding the data. When the wrench information represents a sequence of sub-tasks, we can think of the vocabulary forming a sentence (set of words with grammar rules) for a given sub-task; allowing the latter to be uniquely represented. The grammar, which can also include unexpected events, was classified in offline and online scenarios as well as for simulated and real robot experiments. Multiclass Support Vector Machines (SVMs) were used offline, while online probabilistic SVMs were are used to give temporal confidence to the introspection result. The contribution of our work is the presentation of a generalizable online semantic scheme that enables a robot to understand its high-level state whether nominal or abnormal. It is shown to work in offline and online scenarios for a particularly challenging contact task: snap assemblies. We perform the snap assembly in one-arm simulated and real one-arm experiments and a simulated two-arm experiment. This verification mechanism can be used by high-level planners or reasoning systems to enable intelligent failure recovery or determine the next most optima manipulation skill to be used.Comment: arXiv admin note: substantial text overlap with arXiv:1609.0494

Synesthetic Sensor Fusion via a Cross-Wired Artificial Neural Network.

The purpose of this interdisciplinary study was to examine the behavior of two artificial neural networks cross-wired based on the synesthesia cross-wiring hypothesis. Motivation for the study was derived from the study of psychology, robotics, and artificial neural networks, with perceivable application in the domain of mobile autonomous robotics where sensor fusion is a current research topic. This model of synesthetic sensor fusion does not exhibit synesthetic responses. However, it was observed that cross-wiring two independent networks does not change the functionality of the individual networks, but allows the inputs to one network to partially determine the outputs of the other network in some cases. Specifically, there are measurable influences of network A on network B, and yet network B retains its ability to respond independently

Using Agent-Based Modeling to Evaluate UAS Behaviors in a Target-Rich Environment

The trade-off between accuracy and speed is a re-occurring dilemma in many facets of military performance evaluation. This is an especially important issue in the world of ISR. One of the most progressive areas of ISR capabilities has been the utilization of Unmanned Aircraft Systems (UAS). Many people believe that the future of UAS lies in smaller vehicles flying in swarms. We use the agent-based System Effectiveness and Analysis Simulation (SEAS) to create a simulation environment where different configurations of UAS vehicles can process targets and provide output that allows us to gain insight into the benefits and drawbacks of each configuration. Our evaluation on the performance of the different configurations is based on probability of correct identification, average time to identify a target after it has deployed in the area of interest, and average time to identify all targets in an area

GRASP News Volume 9, Number 1

A report of the General Robotics and Active Sensory Perception (GRASP) Laboratory

Planning in subsumption architectures

A subsumption planner using a parallel distributed computational paradigm based on the subsumption architecture for control of real-world capable robots is described. Virtual sensor state space is used as a planning tool to visualize the robot's anticipated effect on its environment. Decision sequences are generated based on the environmental situation expected at the time the robot must commit to a decision. Between decision points, the robot performs in a preprogrammed manner. A rudimentary, domain-specific partial world model contains enough information to extrapolate the end results of the rote behavior between decision points. A collective network of predictors operates in parallel with the reactive network forming a recurrrent network which generates plans as a hierarchy. Details of a plan segment are generated only when its execution is imminent. The use of the subsumption planner is demonstrated by a simple maze navigation problem

\u3cem\u3eGRASP News\u3c/em\u3e: Volume 9, Number 1

The past year at the GRASP Lab has been an exciting and productive period. As always, innovation and technical advancement arising from past research has lead to unexpected questions and fertile areas for new research. New robots, new mobile platforms, new sensors and cameras, and new personnel have all contributed to the breathtaking pace of the change. Perhaps the most significant change is the trend towards multi-disciplinary projects, most notable the multi-agent project (see inside for details on this, and all the other new and on-going projects). This issue of GRASP News covers the developments for the year 1992 and the first quarter of 1993

Differentiable world programs

L'intelligence artificielle (IA) moderne a ouvert de nouvelles perspectives prometteuses pour la création de robots intelligents. En particulier, les architectures d'apprentissage basées sur le gradient (réseaux neuronaux profonds) ont considérablement amélioré la compréhension des scènes 3D en termes de perception, de raisonnement et d'action. Cependant, ces progrès ont affaibli l'attrait de nombreuses techniques ``classiques'' développées au cours des dernières décennies. Nous postulons qu'un mélange de méthodes ``classiques'' et ``apprises'' est la voie la plus prometteuse pour développer des modèles du monde flexibles, interprétables et exploitables : une nécessité pour les agents intelligents incorporés. La question centrale de cette thèse est : ``Quelle est la manière idéale de combiner les techniques classiques avec des architectures d'apprentissage basées sur le gradient pour une compréhension riche du monde 3D ?''. Cette vision ouvre la voie à une multitude d'applications qui ont un impact fondamental sur la façon dont les agents physiques perçoivent et interagissent avec leur environnement. Cette thèse, appelée ``programmes différentiables pour modèler l'environnement'', unifie les efforts de plusieurs domaines étroitement liés mais actuellement disjoints, notamment la robotique, la vision par ordinateur, l'infographie et l'IA. Ma première contribution---gradSLAM--- est un système de localisation et de cartographie simultanées (SLAM) dense et entièrement différentiable. En permettant le calcul du gradient à travers des composants autrement non différentiables tels que l'optimisation non linéaire par moindres carrés, le raycasting, l'odométrie visuelle et la cartographie dense, gradSLAM ouvre de nouvelles voies pour intégrer la reconstruction 3D classique et l'apprentissage profond. Ma deuxième contribution - taskography - propose une sparsification conditionnée par la tâche de grandes scènes 3D encodées sous forme de graphes de scènes 3D. Cela permet aux planificateurs classiques d'égaler (et de surpasser) les planificateurs de pointe basés sur l'apprentissage en concentrant le calcul sur les attributs de la scène pertinents pour la tâche. Ma troisième et dernière contribution---gradSim--- est un simulateur entièrement différentiable qui combine des moteurs physiques et graphiques différentiables pour permettre l'estimation des paramètres physiques et le contrôle visuomoteur, uniquement à partir de vidéos ou d'une image fixe.Modern artificial intelligence (AI) has created exciting new opportunities for building intelligent robots. In particular, gradient-based learning architectures (deep neural networks) have tremendously improved 3D scene understanding in terms of perception, reasoning, and action. However, these advancements have undermined many ``classical'' techniques developed over the last few decades. We postulate that a blend of ``classical'' and ``learned'' methods is the most promising path to developing flexible, interpretable, and actionable models of the world: a necessity for intelligent embodied agents. ``What is the ideal way to combine classical techniques with gradient-based learning architectures for a rich understanding of the 3D world?'' is the central question in this dissertation. This understanding enables a multitude of applications that fundamentally impact how embodied agents perceive and interact with their environment. This dissertation, dubbed ``differentiable world programs'', unifies efforts from multiple closely-related but currently-disjoint fields including robotics, computer vision, computer graphics, and AI. Our first contribution---gradSLAM---is a fully differentiable dense simultaneous localization and mapping (SLAM) system. By enabling gradient computation through otherwise non-differentiable components such as nonlinear least squares optimization, ray casting, visual odometry, and dense mapping, gradSLAM opens up new avenues for integrating classical 3D reconstruction and deep learning. Our second contribution---taskography---proposes a task-conditioned sparsification of large 3D scenes encoded as 3D scene graphs. This enables classical planners to match (and surpass) state-of-the-art learning-based planners by focusing computation on task-relevant scene attributes. Our third and final contribution---gradSim---is a fully differentiable simulator that composes differentiable physics and graphics engines to enable physical parameter estimation and visuomotor control, solely from videos or a still image

A Framework For Abstracting, Designing And Building Tangible Gesture Interactive Systems

This thesis discusses tangible gesture interaction, a novel paradigm for interacting with computer that blends concepts from the more popular fields of tangible interaction and gesture interaction. Taking advantage of the human innate abilities to manipulate physical objects and to communicate through gestures, tangible gesture interaction is particularly interesting for interacting in smart environments, bringing the interaction with computer beyond the screen, back to the real world. Since tangible gesture interaction is a relatively new field of research, this thesis presents a conceptual framework that aims at supporting future work in this field. The Tangible Gesture Interaction Framework provides support on three levels. First, it helps reflecting from a theoretical point of view on the different types of tangible gestures that can be designed, physically, through a taxonomy based on three components (move, hold and touch) and additional attributes, and semantically, through a taxonomy of the semantic constructs that can be used to associate meaning to tangible gestures. Second, it helps conceiving new tangible gesture interactive systems and designing new interactions based on gestures with objects, through dedicated guidelines for tangible gesture definition and common practices for different application domains. Third, it helps building new tangible gesture interactive systems supporting the choice between four different technological approaches (embedded and embodied, wearable, environmental or hybrid) and providing general guidance for the different approaches. As an application of this framework, this thesis presents also seven tangible gesture interactive systems for three different application domains, i.e., interacting with the In-Vehicle Infotainment System (IVIS) of the car, the emotional and interpersonal communication, and the interaction in a smart home. For the first application domain, four different systems that use gestures on the steering wheel as interaction means with the IVIS have been designed, developed and evaluated. For the second application domain, an anthropomorphic lamp able to recognize gestures that humans typically perform for interpersonal communication has been conceived and developed. A second system, based on smart t-shirts, recognizes when two people hug and reward the gesture with an exchange of digital information. Finally, a smart watch for recognizing gestures performed with objects held in the hand in the context of the smart home has been investigated. The analysis of existing systems found in literature and of the system developed during this thesis shows that the framework has a good descriptive and evaluative power. The applications developed during this thesis show that the proposed framework has also a good generative power.Questa tesi discute l’interazione gestuale tangibile, un nuovo paradigma per interagire con il computer che unisce i principi dei più comuni campi di studio dell’interazione tangibile e dell’interazione gestuale. Sfruttando le abilità innate dell’uomo di manipolare oggetti fisici e di comunicare con i gesti, l’interazione gestuale tangibile si rivela particolarmente interessante per interagire negli ambienti intelligenti, riportando l’attenzione sul nostro mondo reale, al di là dello schermo dei computer o degli smartphone. Poiché l’interazione gestuale tangibile è un campo di studio relativamente recente, questa tesi presenta un framework (quadro teorico) che ha lo scopo di assistere lavori futuri in questo campo. Il Framework per l’Interazione Gestuale Tangibile fornisce supporto su tre livelli. Per prima cosa, aiuta a riflettere da un punto di vista teorico sui diversi tipi di gesti tangibili che possono essere eseguiti fisicamente, grazie a una tassonomia basata su tre componenti (muovere, tenere, toccare) e attributi addizionali, e che possono essere concepiti semanticamente, grazie a una tassonomia di tutti i costrutti semantici che permettono di associare dei significati ai gesti tangibili. In secondo luogo, il framework proposto aiuta a concepire nuovi sistemi interattivi basati su gesti tangibili e a ideare nuove interazioni basate su gesti con gli oggetti, attraverso linee guida per la definizione di gesti tangibili e una selezione delle migliore pratiche per i differenti campi di applicazione. Infine, il framework aiuta a implementare nuovi sistemi interattivi basati su gesti tangibili, permettendo di scegliere tra quattro differenti approcci tecnologici (incarnato e integrato negli oggetti, indossabile, distribuito nell’ambiente, o ibrido) e fornendo una guida generale per la scelta tra questi differenti approcci. Come applicazione di questo framework, questa tesi presenta anche sette sistemi interattivi basati su gesti tangibili, realizzati per tre differenti campi di applicazione: l’interazione con i sistemi di infotainment degli autoveicoli, la comunicazione interpersonale delle emozioni, e l’interazione nella casa intelligente. Per il primo campo di applicazione, sono stati progettati, sviluppati e testati quattro differenti sistemi che usano gesti tangibili effettuati sul volante come modalità di interazione con il sistema di infotainment. Per il secondo campo di applicazione, è stata concepita e sviluppata una lampada antropomorfica in grado di riconoscere i gesti tipici dell’interazione interpersonale. Per lo stesso campo di applicazione, un secondo sistema, basato su una maglietta intelligente, riconosce quando due persone si abbracciano e ricompensa questo gesto con uno scambio di informazioni digitali. Infine, per l’interazione nella casa intelligente, è stata investigata la realizzazione di uno smart watch per il riconoscimento di gesti eseguiti con oggetti tenuti nella mano. L’analisi dei sistemi interattivi esistenti basati su gesti tangibili permette di dimostrare che il framework ha un buon potere descrittivo e valutativo. Le applicazioni sviluppate durante la tesi mostrano che il framework proposto ha anche un valido potere generativo

Ultra high frequency (UHF) radio-frequency identification (RFID) for robot perception and mobile manipulation

Personal robots with autonomy, mobility, and manipulation capabilities have the potential to dramatically improve quality of life for various user populations, such as older adults and individuals with motor impairments. Unfortunately, unstructured environments present many challenges that hinder robot deployment in ordinary homes. This thesis seeks to address some of these challenges through a new robotic sensing modality that leverages a small amount of environmental augmentation in the form of Ultra High Frequency (UHF) Radio-Frequency Identification (RFID) tags. Previous research has demonstrated the utility of infrastructure tags (affixed to walls) for robot localization; in this thesis, we specifically focus on tagging objects. Owing to their low-cost and passive (battery-free) operation, users can apply UHF RFID tags to hundreds of objects throughout their homes. The tags provide two valuable properties for robots: a unique identifier and receive signal strength indicator (RSSI, the strength of a tag's response). This thesis explores robot behaviors and radio frequency perception techniques using robot-mounted UHF RFID readers that enable a robot to efficiently discover, locate, and interact with UHF RFID tags applied to objects and people of interest. The behaviors and algorithms explicitly rely on the robot's mobility and manipulation capabilities to provide multiple opportunistic views of the complex electromagnetic landscape inside a home environment. The electromagnetic properties of RFID tags change when applied to common household objects. Objects can have varied material properties, can be placed in diverse orientations, and be relocated to completely new environments. We present a new class of optimization-based techniques for RFID sensing that are robust to the variation in tag performance caused by these complexities. We discuss a hybrid global-local search algorithm where a robot employing long-range directional antennas searches for tagged objects by maximizing expected RSSI measurements; that is, the robot attempts to position itself (1) near a desired tagged object and (2) oriented towards it. The robot first performs a sparse, global RFID search to locate a pose in the neighborhood of the tagged object, followed by a series of local search behaviors (bearing estimation and RFID servoing) to refine the robot's state within the local basin of attraction. We report on RFID search experiments performed in Georgia Tech's Aware Home (a real home). Our optimization-based approach yields superior performance compared to state of the art tag localization algorithms, does not require RF sensor models, is easy to implement, and generalizes to other short-range RFID sensor systems embedded in a robot's end effector. We demonstrate proof of concept applications, such as medication delivery and multi-sensor fusion, using these techniques. Through our experimental results, we show that UHF RFID is a complementary sensing modality that can assist robots in unstructured human environments.PhDCommittee Chair: Kemp, Charles C.; Committee Member: Abowd, Gregory; Committee Member: Howard, Ayanna; Committee Member: Ingram, Mary Ann; Committee Member: Reynolds, Matt; Committee Member: Tentzeris, Emmanoui