Christof Schröter

An Approach to Multi-modal Human-Machine Interaction for Intelligent Service Robots

Abstract The paper describes a multi-modal scheme for human–robot interaction suited for a wide range of intelligent service robot applications. Operating in un-engineered, cluttered, and crowded environments, such robots have to be able to actively contact potential users in their surroundings and to offer their services in an appropriate manner. Starting from a real application scenario, the usage of a robot as mobile information kiosk in a home store, some reliable methods for vision-based interaction, sound analysis and speech output have been developed. These methods are integrated into a prototypical interaction cycle that can be assumed as a general approach to human–machine interaction. Experimental results demonstrate the strengths and weaknesses of the proposed methods.

Finding the adequate resolution for grid mapping - Cell sizes locally adapting on-the-fly

For robot mapping occupancy grid maps are the most common representation of the environment. However, most existing algorithms for creating such maps assume a fixed resolution of the grid cells. In this paper we present a novel mapping technique that chooses the resolution of each cell adaptively by merging and splitting cells depending on the measurements. The splitting of the cells is based on a statistical measure that we derive in this paper. In contrast to other approaches the adaption of the resolution is done online during the mapping process itself. Additionally, we introduce the Nd-Tree, a generalization of quadtrees and octrees that allows to subdivide any d-dimensional volume recursively with Nd children per node. Using this data structure our approach can be implemented in a very generic way and allows the creation of 2D, 3D and even higher dimensional maps using the same algorithm. Finally, we show results of our proposed method for 2D and 3D mapping using different kinds of range sensors.

Interactive mobile robots guiding visitors in a university building

This paper presents an architectural overview of a robot-based visitor information system in a university building. Two mobile robots serve as mobile information terminals providing information about the employees, labs, meeting rooms, and offices in the building and are able to guide the visitors to these points of interest. The paper focuses on the different software components needed to meet the requirements of the multi-story office building. Furthermore, the integration of a multi-hypotheses person tracker is outlined, which helps the robots to interact with the people in their near surrounding. Besides first observations on interaction, the further development is outlined as well.

Konrad and Suse, Two Robots Guiding Visitors in a University Building

This paper presents an overview of the hard- and software architecture of a mobile visitor information system for the Konrad Zuse building of the School of Computer Science and Automation at the Ilmenau University of Technology. Two mobile robots serve as mobile information terminals with capabilities for generating way descriptions and guiding the visitor to the points of interest (labs, meeting rooms, offices, employees) in the building. The paper focuses on the constraints resulting from the challenging environment in this multi-floor building, as well as on the integration aspects of various skills for navigation and human–robot interaction. Besides first experience with the system, the further development is outlined as well.

Smart Fur Tactile Sensor for a Socially Assistive Mobile Robot

Close natural interaction is assumed to be a key feature for a socially assistive service robot, if the user is expected to develop an emotional bond to the robot system and accept it as a companion over a prolonged period. One particularly intuitive way of affective interaction, seen e.g. between people and pets, is physical touch in the form of stroking or smacking. In order to support the companion robot’s role of an intelligent pet-like buddy, we aim to equip the robot with the capabilities to recognize such physical interaction behavior and react accordingly. In this paper, we present a low cost smart fur sensor which encourages tactile interaction by the user and recognizes different touch patterns relating to various kinds of emotional expressions. Special emphasis is put on the simple and robust classification of touch patterns emerging from such tactile interaction to distinguish the respective inputs for the robot.

Can't take my eye off you: Attention-driven monocular obstacle detection and 3D mapping

Robust and reliable obstacle detection is an important capability for mobile robots. In our previous works we have presented an approach for visual obstacle detection based on feature based monocular scene-reconstruction. Most existing feature-based approaches for visual SLAM and scene reconstruction select their features uniformly over the whole image based on visual saliency only. In this paper we present a novel attention-driven approach that guides the feature selection to image areas that provide the most information for mapping and obstacle detection. Therefore, we present an information theoretic derivation of the expected information gain that results from the selection of new image features. Additionally, we present a method for building a volumetric representation of the robots environment in terms of an occpancy voxel map. The voxel map provides top-down information that is needed for computing the expected information gain. We show that our approach for guided feature selection improves the quality of the created voxel maps and improves the obstacle detection by reducing the risk of missing obstacles.

Low-Cost Whole-Body Touch Interaction for Manual Motion Control of a Mobile Service Robot

Mobile service robots for interaction with people need to be easily maneuverable by their users, even if physical restrictions make a manual pushing and pulling impossible. In this paper, we present a low cost approach that allows for intuitive tactile control of a mobile service robot while preserving constraints of a differential drive and obstacle avoidance. The robots enclosure has been equipped with capacitive touch sensors able to recognize proximity of the users hands. By simulating forces applied by the touching hands, a desired motion command for the robot is derived and combined with other motion objectives in a local motion planner (based on Dynamic Window Approach in our case). User tests showed that this haptic control is intuitively understandable and outperforms a solution using direction buttons on the robots touch screen.

Detection of lounging people with a mobile robot companion

This paper deals with the task of searching for people in home environments with a mobile robot. The robust estimation of the users position is an important prerequisite for human robot interaction. While detecting people in an upright pose is mainly solved, most of the users various poses in living environments are hard to detect. We present a visual approach for the detection of people resting at previously known seating places in arbitrary poses, e.g. lying on a sofa. The method utilizes color and gradient models of the environment and a color model of the users appearance. Evaluation is done on real-world experiments with the robot searching for the user at different places.

Multimodale Mensch-Maschine-Interaktion für Servicerobotik-Systeme

Die Frage der Mensch-Roboter-Interaktion wird fur zukunftige erfolgreiche Applikationen von Servicerobotern eine wesentliche, wenn nicht die zentrale Rolle spielen. Vor diesem Hintergrund beschreibt der vorliegende Beitrag ein Konzept zur multimodalen Mensch-Maschine-Kommunikation und dessen Realisierungsstand anhand eines konkreten Einsatzszenarios, der Entwicklung eines intelligenten, interaktiven und mobilen Informationskiosks im Baumarkt. Obwohl sich das vorgestellte Konzept an den konkreten Erfordernissen dieses Szenarios orientiert, stellt es einen generischen Ansatz dar, der sich auf eine Vielzahl weiterer Applikationen ubertragen lasst.