Header logo is


2015


no image
Modeling interruption and resumption in a smartphone task: An ACT-R approach

Wirzberger, M., Russwinkel, N.

i-com, 14(2), Walter de Gruyter GmbH, 2015 (article)

Abstract
This research aims to inspect human cognition when being interrupted while performing a smartphone task with varying levels of mental demand. Due to its benefits especially in the early stages of interface development, a cognitive modeling approach is used. It applies the cognitive architecture ACT-R to shed light on task-related cognitive processing. The inspected task setting involves a shopping scenario, manipulating interruption via product advertisements and mental demands by the respective number of people shopping is done for. Model predictions are validated through a corresponding experimental setting with 62 human participants. Comparing model and human data in a defined set of performance-related parameters displays mixed results that indicate an acceptable fit – at least in some cases. Potential explanations for the observed differences are discussed at the end.

re

DOI [BibTex]

2015


DOI [BibTex]


Exciting Engineered Passive Dynamics in a Bipedal Robot
Exciting Engineered Passive Dynamics in a Bipedal Robot

Renjewski, D., Spröwitz, A., Peekema, A., Jones, M., Hurst, J.

{IEEE Transactions on Robotics and Automation}, 31(5):1244-1251, IEEE, New York, NY, 2015 (article)

Abstract
A common approach in designing legged robots is to build fully actuated machines and control the machine dynamics entirely in soft- ware, carefully avoiding impacts and expending a lot of energy. However, these machines are outperformed by their human and animal counterparts. Animals achieve their impressive agility, efficiency, and robustness through a close integration of passive dynamics, implemented through mechanical components, and neural control. Robots can benefit from this same integrated approach, but a strong theoretical framework is required to design the passive dynamics of a machine and exploit them for control. For this framework, we use a bipedal spring–mass model, which has been shown to approximate the dynamics of human locomotion. This paper reports the first implementation of spring–mass walking on a bipedal robot. We present the use of template dynamics as a control objective exploiting the engineered passive spring–mass dynamics of the ATRIAS robot. The results highlight the benefits of combining passive dynamics with dynamics-based control and open up a library of spring–mass model-based control strategies for dynamic gait control of robots.

dlg

link (url) DOI Project Page [BibTex]

link (url) DOI Project Page [BibTex]


Comparing the effect of different spine and leg designs for a small bounding quadruped robot
Comparing the effect of different spine and leg designs for a small bounding quadruped robot

Eckert, P., Spröwitz, A., Witte, H., Ijspeert, A. J.

In Proceedings of ICRA, pages: 3128-3133, Seattle, Washington, USA, 2015 (inproceedings)

Abstract
We present Lynx-robot, a quadruped, modular, compliant machine. It alternately features a directly actuated, single-joint spine design, or an actively supported, passive compliant, multi-joint spine configuration. Both spine con- figurations bend in the sagittal plane. This study aims at characterizing these two, largely different spine concepts, for a bounding gait of a robot with a three segmented, pantograph leg design. An earlier, similar-sized, bounding, quadruped robot named Bobcat with a two-segment leg design and a directly actuated, single-joint spine design serves as a comparison robot, to study and compare the effect of the leg design on speed, while keeping the spine design fixed. Both proposed spine designs (single rotatory and active and multi-joint compliant) reach moderate, self-stable speeds.

dlg

link (url) DOI Project Page [BibTex]

link (url) DOI Project Page [BibTex]


no image
Learning from others: Adult and child strategies in assessing conflicting ratings

Hu, J., Lieder, F., Griffiths, T. L., Xu, F.

In Biennial Meeting of the Society for Research in Child Development, Philadelphia, Pennsylvania, USA, 2015 (inproceedings)

re

[BibTex]

[BibTex]


no image
The optimism bias may support rational action

Lieder, F., Goel, S., Kwan, R., Griffiths, T. L.

NIPS 2015 Workshop on Bounded Optimality and Rational Metareasoning, 2015 (article)

re

[BibTex]

[BibTex]


no image
Rational use of cognitive resources: Levels of analysis between the computational and the algorithmic

Griffiths, T. L., Lieder, F., Goodman, N. D.

Topics in Cognitive Science, 7(2):217-229, Wiley, 2015 (article)

re

[BibTex]

[BibTex]


no image
When to use which heuristic: A rational solution to the strategy selection problem

Lieder, F., Griffiths, T. L.

In Proceedings of the 37th Annual Conference of the Cognitive Science Society, 2015 (inproceedings)

re

Project Page [BibTex]

Project Page [BibTex]


no image
Children and adults differ in their strategies for social learning

Lieder, F., Sim, Z., Hu, J., Griffiths, T., Xu, F.

In Proceedings of the 37th Annual Conference of the Cognitive Science Society, 2015 (inproceedings)

re

[BibTex]

[BibTex]


no image
Utility-weighted sampling in decisions from experience

Lieder, F., Griffiths, T. L., Hsu, M.

In The 2nd Multidisciplinary Conference on Reinforcement Learning and Decision Making, 2015 (inproceedings)

re

[BibTex]

[BibTex]


no image
Nachhaltige Effekte simulatorbasierten Trainings auf eine ökologische Fahrweise [Sustainable effects of simulator-based training on ecological driving]

Lüderitz, C., Wirzberger, M., Karrer-Gauß, K.

In VerANTWORTung für die Arbeit der Zukunft, 61st Conference of the Society for Ergonomics and Work Science, GfA Press, Dortmund, 2015 (inproceedings)

re

[BibTex]

[BibTex]


no image
Model-based strategy selection learning

Lieder, F., Griffiths, T. L.

The 2nd Multidisciplinary Conference on Reinforcement Learning and Decision Making, 2015 (article)

re

Project Page [BibTex]

Project Page [BibTex]


no image
Cognitive modeling meets instructional design: Exploring Cognitive Load Theory with ACT-R

Wirzberger, M., Rey, G. D.

In Trends in Neuroergonomics. Proceedings of the 11th Berlin Workshop Human-Machine Systems, pages: 190-193, Universitätsverlag der TU Berlin, Berlin, 2015 (inproceedings)

re

DOI [BibTex]

DOI [BibTex]

2010


Graph signature for self-reconfiguration planning of modules with symmetry
Graph signature for self-reconfiguration planning of modules with symmetry

Asadpour, M., Ashtiani, M. H. Z., Spröwitz, A., Ijspeert, A. J.

In Proceedings of the 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems, pages: 5295-5300, IEEE, St. Louis, MO, 2010 (inproceedings)

Abstract
In our previous works we had developed a framework for self-reconfiguration planning based on graph signature and graph edit-distance. The graph signature is a fast isomorphism test between different configurations and the graph edit-distance is a similarity metric. But the algorithm is not suitable for modules with symmetry. In this paper we improve the algorithm in order to deal with symmetric modules. Also, we present a new heuristic function to guide the search strategy by penalizing the solutions with more number of actions. The simulation results show the new algorithm not only deals with symmetric modules successfully but also finds better solutions in a shorter time.

dlg

DOI [BibTex]

2010


DOI [BibTex]


Roombots - Towards decentralized reconfiguration with self-reconfiguring modular robotic metamodules
Roombots - Towards decentralized reconfiguration with self-reconfiguring modular robotic metamodules

Spröwitz, A., Laprade, P., Bonardi, S., Mayer, M., Moeckel, R., Mudry, P., Ijspeert, A. J.

In Proceedings of the 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages: 1126-1132, IEEE, Taipeh, 2010 (inproceedings)

Abstract
This paper presents our work towards a decentralized reconfiguration strategy for self-reconfiguring modular robots, assembling furniture-like structures from Roombots (RB) metamodules. We explore how reconfiguration by loco- motion from a configuration A to a configuration B can be controlled in a distributed fashion. This is done using Roombots metamodules—two Roombots modules connected serially—that use broadcast signals, lookup tables of their movement space, assumptions about their neighborhood, and connections to a structured surface to collectively build desired structures without the need of a centralized planner.

dlg

DOI [BibTex]

DOI [BibTex]


Roombots: Reconfigurable Robots for Adaptive Furniture
Roombots: Reconfigurable Robots for Adaptive Furniture

Spröwitz, A., Pouya, S., Bonardi, S., van den Kieboom, J., Möckel, R., Billard, A., Dillenbourg, P., Ijspeert, A.

Computational Intelligence Magazine, IEEE, 5(3):20-32, 2010 (article)

Abstract
Imagine a world in which our furniture moves around like legged robots, interacts with us, and changes shape and function during the day according to our needs. This is the long term vision we have in the Roombots project. To work towards this dream, we are developing modular robotic modules that have rotational degrees of freedom for locomotion as well as active connection mechanisms for runtime reconfiguration. A piece of furniture, e.g. a stool, will thus be composed of several modules that activate their rotational joints together to implement locomotor gaits, and will be able to change shape, e.g. transforming into a chair, by sequences of attachments and detachments of modules. In this article, we firstly present the project and the hardware we are currently developing. We explore how reconfiguration from a configuration A to a configuration B can be controlled in a distributed fashion. This is done using metamodules-two Roombots modules connected serially-that use broadcast signals and connections to a structured ground to collectively build desired structures without the need of a centralized planner. We then present how locomotion controllers can be implemented in a distributed system of coupled oscillators-one per degree of freedom-similarly to the concept of central pattern generators (CPGs) found in the spinal cord of vertebrate animals. The CPGs are based on coupled phase oscillators to ensure synchronized behavior and have different output filters to allow switching between oscillations and rotations. A stochastic optimization algorithm is used to explore optimal CPG configurations for different simulated Roombots structures.

dlg

DOI [BibTex]

DOI [BibTex]


Distributed Online Learning of Central Pattern Generators in Modular Robots
Distributed Online Learning of Central Pattern Generators in Modular Robots

Christensen, D. J., Spröwitz, A., Ijspeert, A. J.

In From Animals to Animats 11, 6226, pages: 402-412, Lecture Notes in Computer Science, Springer, Berlin, 2010, author: Doncieux, Stéphan (incollection)

Abstract
In this paper we study distributed online learning of locomotion gaits for modular robots. The learning is based on a stochastic ap- proximation method, SPSA, which optimizes the parameters of coupled oscillators used to generate periodic actuation patterns. The strategy is implemented in a distributed fashion, based on a globally shared reward signal, but otherwise utilizing local communication only. In a physics-based simulation of modular Roombots robots we experiment with online learn- ing of gaits and study the effects of: module failures, different robot morphologies, and rough terrains. The experiments demonstrate fast online learning, typically 5-30 min. for convergence to high performing gaits (≈ 30 cm/sec), despite high numbers of open parameters (45-54). We conclude that the proposed approach is efficient, effective and a promising candidate for online learning on many other robotic platforms.

dlg

DOI [BibTex]

DOI [BibTex]


Automatic Gait Generation in Modular Robots: to Oscillate or to Rotate? that is the question
Automatic Gait Generation in Modular Robots: to Oscillate or to Rotate? that is the question

Pouya, S., van den Kieboom, J., Spröwitz, A., Ijspeert, A. J.

In Proceedings of the 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages: 514-520, IEEE, Taipei, 2010 (inproceedings)

Abstract
Modular robots offer the possibility to design robots with a high diversity of shapes and functionalities. This nice feature also brings an important challenge: namely how to design efficient locomotion gaits for arbitrary robot structures with many degrees of freedom. In this paper, we present a framework that allows one to explore and identify highly different gaits for a given arbitrary- shaped modular robot. We use simulated robots made of several Roombots modules that have three rotational joints each. These modules have the interesting feature that they can produce both oscillatory movements (i.e. periodic movements around a rest position) and rotational movements (i.e. with continuously increasing angle), leading to very rich locomotion patterns. Here we ask ourselves which types of movements —purely oscillatory, purely rotational, or a combination of both— lead to the fastest gaits. To address this question we designed a control architecture based on a distributed system of coupled phase oscillators that can produce synchronized rotations and oscillations in many degrees of freedom. We also designed a specific optimization algorithm that can automatically design hybrid controllers, i.e. controllers that use oscillations in some joints and rotations in others, for fast gaits. The proposed framework is verified by multiple simulations for several robot morphologies. The results show that (i) the question whether it is better to oscillate or to rotate depends on the morphology of the robot, and that in general it is best to do both, (ii) the optimization framework can successfully generate hybrid controllers that outperform purely oscillatory and purely rotational ones, and (iii) the resulting gaits are fast, innovative, and would have been hard to design by hand.

dlg

DOI [BibTex]

DOI [BibTex]


Roombots: Design and Implementation of a Modular Robot for Reconfiguration and Locomotion
Roombots: Design and Implementation of a Modular Robot for Reconfiguration and Locomotion

Spröwitz, A.

EPFL, Lausanne, Lausanne, 2010 (phdthesis)

dlg

DOI [BibTex]

2005


no image
Bruder sein das ist nicht schwer, Schwester sein dagegen sehr?" - Geschlechtsspezifische Betrachtungsweisen zur Situation von Geschwistern behinderter Kinder und Jugendlicher

Wirzberger, M.

Protestant University of Applied Sciences, Bochum, 2005 (thesis)

Abstract
Die Diplomarbeit beschäftigt sich mit der Lebenssituation von Geschwistern behinderter Kinder und Jugendlicher und berücksichtigt hier besonders den Aspekt des Geschlechts. Nach einer Darstellung familiensoziologischer Grundlagen erläutert die Verfasserin den hohen Stellenwert von Geschwisterbeziehungen innerhalb der Familie, sowie deren Entwicklung und Veränderung im Laufe des Lebens. Der Schwerpunkt liegt dabei auf dem Kindes- und Jugendalter. Anschließend werden Grundlagen, Prozesse und Mechanismen geschlechtsspezifischer Sozialisation, und die Auswirkungen des Geschlechts auf die Geschwisterbeziehung thematisiert. Kapitel 3 beschäftigt sich zunächst mit dem Begriff der Behinderung mit Bezug auf das SGB IX und die ICF. Danach beschreibt die Verfasserin, mit welchen spezifischen Belastungen sich die Eltern behinderter Kinder und Jugendlicher konfrontiert sehen. Die Auswirkungen einer Behinderung auf die Geschwister stehen im Mittelpunkt dieser Arbeit und werden anhand von Studien von HACKENBERG und GROSSMAN, sowie Aussagen von ACHILLES ausführlich dargestellt, wobei auch hier der Aspekt des Geschlechts detailliert in die Schilderung der Situation einbezogen wird. Um eine Verbindung von Theorie und Praxis zu gewährleisten, werden zusammenfassende Hypothesen formuliert und anhand von drei Fallgeschichten exemplarisch überprüft. Abschließend erläutert die Verfasserin die Konsequenzen ihrer Diplomarbeit für die heilpädagogische Arbeit.

re

DOI [BibTex]


Adaptation of Central Pattern Generators to Preexisting Mechanical Structure
Adaptation of Central Pattern Generators to Preexisting Mechanical Structure

Spröwitz, A.

Technische Universität Ilmenau, Ilmenau, 2005 (mastersthesis)

dlg

[BibTex]

[BibTex]