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2017


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Momentum-Centered Control of Contact Interactions

Righetti, L., Herzog, A.

In Geometric and Numerical Foundations of Movements, 117, pages: 339-359, Springer Tracts in Advanced Robotics, Springer, Cham, 2017 (incollection)

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link (url) [BibTex]

2017


link (url) [BibTex]


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SAMP: Shape and Motion Priors for 4D Vehicle Reconstruction

Engelmann, F., Stueckler, J., Leibe, B.

In IEEE Winter Conference on Applications of Computer Vision, WACV, 2017 (inproceedings)

ev

[BibTex]

[BibTex]


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Pattern Generation for Walking on Slippery Terrains

Khadiv, M., Moosavian, S. A. A., Herzog, A., Righetti, L.

In 2017 5th International Conference on Robotics and Mechatronics (ICROM), Iran, August 2017 (inproceedings)

Abstract
In this paper, we extend state of the art Model Predictive Control (MPC) approaches to generate safe bipedal walking on slippery surfaces. In this setting, we formulate walking as a trade off between realizing a desired walking velocity and preserving robust foot-ground contact. Exploiting this for- mulation inside MPC, we show that safe walking on various flat terrains can be achieved by compromising three main attributes, i. e. walking velocity tracking, the Zero Moment Point (ZMP) modulation, and the Required Coefficient of Friction (RCoF) regulation. Simulation results show that increasing the walking velocity increases the possibility of slippage, while reducing the slippage possibility conflicts with reducing the tip-over possibility of the contact and vice versa.

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link (url) [BibTex]

link (url) [BibTex]

2016


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Robust calibration marker detection in powder bed images from laser beam melting processes

zur Jacobsmühlen, J., Achterhold, J., Kleszczynski, S., Witt, G., Merhof, D.

In 2016 IEEE International Conference on Industrial Technology (ICIT), pages: 910-915, March 2016 (inproceedings)

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DOI [BibTex]

2016


DOI [BibTex]


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Phase transitions and optimal algorithms in high-dimensional Gaussian mixture clustering

Lesieur, T., De Bacco, C., Banks, J., Krzakala, F., Moore, C., Zdeborová, L.

In Communication, Control, and Computing (Allerton), 2016 54th Annual Allerton Conference on, pages: 601-608, 2016 (inproceedings)

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Preprint link (url) [BibTex]

Preprint link (url) [BibTex]


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On designing an active tail for legged robots: simplifying control via decoupling of control objectives

Heim, S. W., Ajallooeian, M., Eckert, P., Vespignani, M., Ijspeert, A. J.

Industrial Robot: An International Journal, 43, pages: 338-346, Emerald Group Publishing Limited, 2016 (article)

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Preprint [BibTex]

Preprint [BibTex]


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NimbRo Explorer: Semi-Autonomous Exploration and Mobile Manipulation in Rough Terrain

Stueckler, J., Schwarz, M., Schadler, M., Topalidou-Kyniazopoulou, A., Behnke, S.

Journal of Field Robotics (JFR), 33(4):411-430, Wiley, 2016 (article)

ev

[BibTex]

[BibTex]


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Stochastic search with Poisson and deterministic resetting

Bhat, U., De Bacco, C., Redner, S.

Journal of Statistical Mechanics: Theory and Experiment, 2016(8):083401, IOP Publishing, 2016 (article)

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Preprint link (url) [BibTex]

Preprint link (url) [BibTex]


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ATRIAS: Design and validation of a tether-free 3D-capable spring-mass bipedal robot

Hubicki, C., Grimes, J., Jones, M., Renjewski, D., Spröwitz, A., Abate, A., Hurst, J.

{The International Journal of Robotics Research}, 35(12):1497-1521, Sage Publications, Inc., Cambridge, MA, 2016 (article)

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DOI Project Page [BibTex]

DOI Project Page [BibTex]


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On designing an active tail for body-pitch control in legged robots via decoupling of control objectives

Heim, S. W., Ajallooeian, M., Eckert, P., Vespignani, M., Ijspeert, A.

In ASSISTIVE ROBOTICS: Proceedings of the 18th International Conference on CLAWAR 2015, pages: 256-264, 2016 (inproceedings)

dlg

[BibTex]

[BibTex]


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Multi-Layered Mapping and Navigation for Autonomous Micro Aerial Vehicles

Droeschel, D., Nieuwenhuisen, M., Beul, M., Stueckler, J., Holz, D., Behnke, S.

Journal of Field Robotics (JFR), 33(4):451-475, 2016 (article)

ev

[BibTex]

[BibTex]


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Direct Visual-Inertial Odometry with Stereo Cameras

Usenko, V., Engel, J., Stueckler, J., Cremers, D.

In IEEE International Conference on Robotics and Automation (ICRA), 2016 (inproceedings)

ev

[BibTex]

[BibTex]


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Dynamics of beneficial epidemics

Berdahl, A., Brelsford, C., De Bacco, C., Dumas, M., Ferdinand, V., Grochow, J. A., Hébert-Dufresne, L., Kallus, Y., Kempes, C. P., Kolchinsky, A., others,

arXiv preprint arXiv:1604.02096, 2016 (article)

pio

Preprint [BibTex]

Preprint [BibTex]


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Rare events statistics of random walks on networks: localisation and other dynamical phase transitions

De Bacco, C., Guggiola, A., Kühn, R., Paga, P.

Journal of Physics A: Mathematical and Theoretical, 49(18):184003, IOP Publishing, 2016 (article)

pio

Preprint link (url) [BibTex]

Preprint link (url) [BibTex]


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CPA-SLAM: Consistent Plane-Model Alignment for Direct RGB-D SLAM

Ma, L., Kerl, C., Stueckler, J., Cremers, D.

In IEEE International Conference on Robotics and Automation (ICRA), 2016 (inproceedings)

ev

[BibTex]

[BibTex]


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A Convex Model of Momentum Dynamics for Multi-Contact Motion Generation

Ponton, B., Herzog, A., Schaal, S., Righetti, L.

In 2016 IEEE-RAS 16th International Conference on Humanoid Robots Humanoids, pages: 842-849, IEEE, Cancun, Mexico, 2016 (inproceedings)

Abstract
Linear models for control and motion generation of humanoid robots have received significant attention in the past years, not only due to their well known theoretical guarantees, but also because of practical computational advantages. However, to tackle more challenging tasks and scenarios such as locomotion on uneven terrain, a more expressive model is required. In this paper, we are interested in contact interaction-centered motion optimization based on the momentum dynamics model. This model is non-linear and non-convex; however, we find a relaxation of the problem that allows us to formulate it as a single convex quadratically-constrained quadratic program (QCQP) that can be very efficiently optimized and is useful for multi-contact planning. This convex model is then coupled to the optimization of end-effector contact locations using a mixed integer program, which can also be efficiently solved. This becomes relevant e.g. to recover from external pushes, where a predefined stepping plan is likely to fail and an online adaptation of the contact location is needed. The performance of our algorithm is demonstrated in several multi-contact scenarios for a humanoid robot.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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On the Effects of Measurement Uncertainty in Optimal Control of Contact Interactions

Ponton, B., Schaal, S., Righetti, L.

In The 12th International Workshop on the Algorithmic Foundations of Robotics WAFR, Berkeley, USA, 2016 (inproceedings)

Abstract
Stochastic Optimal Control (SOC) typically considers noise only in the process model, i.e. unknown disturbances. However, in many robotic applications involving interaction with the environment, such as locomotion and manipulation, uncertainty also comes from lack of precise knowledge of the world, which is not an actual disturbance. We analyze the effects of also considering noise in the measurement model, by devel- oping a SOC algorithm based on risk-sensitive control, that includes the dynamics of an observer in such a way that the control law explicitly de- pends on the current measurement uncertainty. In simulation results on a simple 2D manipulator, we have observed that measurement uncertainty leads to low impedance behaviors, a result in contrast with the effects of process noise that creates stiff behaviors. This suggests that taking into account measurement uncertainty could be a potentially very interesting way to approach problems involving uncertain contact interactions.

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link (url) [BibTex]

link (url) [BibTex]


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Momentum Control with Hierarchical Inverse Dynamics on a Torque-Controlled Humanoid

Herzog, A., Rotella, N., Mason, S., Grimminger, F., Schaal, S., Righetti, L.

Autonomous Robots, 40(3):473-491, 2016 (article)

Abstract
Hierarchical inverse dynamics based on cascades of quadratic programs have been proposed for the control of legged robots. They have important benefits but to the best of our knowledge have never been implemented on a torque controlled humanoid where model inaccuracies, sensor noise and real-time computation requirements can be problematic. Using a reformulation of existing algorithms, we propose a simplification of the problem that allows to achieve real-time control. Momentum-based control is integrated in the task hierarchy and a LQR design approach is used to compute the desired associated closed-loop behavior and improve performance. Extensive experiments on various balancing and tracking tasks show very robust performance in the face of unknown disturbances, even when the humanoid is standing on one foot. Our results demonstrate that hierarchical inverse dynamics together with momentum control can be efficiently used for feedback control under real robot conditions.

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link (url) DOI [BibTex]


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Inertial Sensor-Based Humanoid Joint State Estimation

Rotella, N., Mason, S., Schaal, S., Righetti, L.

In 2016 IEEE International Conference on Robotics and Automation (ICRA), pages: 1825-1831, IEEE, Stockholm, Sweden, 2016 (inproceedings)

Abstract
This work presents methods for the determination of a humanoid robot's joint velocities and accelerations directly from link-mounted Inertial Measurement Units (IMUs) each containing a three-axis gyroscope and a three-axis accelerometer. No information about the global pose of the floating base or its links is required and precise knowledge of the link IMU poses is not necessary due to presented calibration routines. Additionally, a filter is introduced to fuse gyroscope angular velocities with joint position measurements and compensate the computed joint velocities for time-varying gyroscope biases. The resulting joint velocities are subject to less noise and delay than filtered velocities computed from numerical differentiation of joint potentiometer signals, leading to superior performance in joint feedback control as demonstrated in experiments performed on a SARCOS hydraulic humanoid.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Stepping Stabilization Using a Combination of DCM Tracking and Step Adjustment

Khadiv, M., Kleff, S., Herzog, A., Moosavian, S. A. A., Schaal, S., Righetti, L.

In 2016 4th International Conference on Robotics and Mechatronics (ICROM), pages: 130-135, IEEE, Teheran, Iran, 2016 (inproceedings)

Abstract
In this paper, a method for stabilizing biped robots stepping by a combination of Divergent Component of Motion (DCM) tracking and step adjustment is proposed. In this method, the DCM trajectory is generated, consistent with the predefined footprints. Furthermore, a swing foot trajectory modification strategy is proposed to adapt the landing point, using DCM measurement. In order to apply the generated trajectories to the full robot, a Hierarchical Inverse Dynamics (HID) is employed. The HID enables us to use different combinations of the DCM tracking and step adjustment for stabilizing different biped robots. Simulation experiments on two scenarios for two different simulated robots, one with active ankles and the other with passive ankles, are carried out. Simulation results demonstrate the effectiveness of the proposed method for robots with both active and passive ankles.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Structured contact force optimization for kino-dynamic motion generation

Herzog, A., Schaal, S., Righetti, L.

In 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages: 2703-2710, IEEE, Daejeon, South Korea, 2016 (inproceedings)

Abstract
Optimal control approaches in combination with trajectory optimization have recently proven to be a promising control strategy for legged robots. Computationally efficient and robust algorithms were derived using simplified models of the contact interaction between robot and environment such as the linear inverted pendulum model (LIPM). However, as humanoid robots enter more complex environments, less restrictive models become increasingly important. As we leave the regime of linear models, we need to build dedicated solvers that can compute interaction forces together with consistent kinematic plans for the whole-body. In this paper, we address the problem of planning robot motion and interaction forces for legged robots given predefined contact surfaces. The motion generation process is decomposed into two alternating parts computing force and motion plans in coherence. We focus on the properties of the momentum computation leading to sparse optimal control formulations to be exploited by a dedicated solver. In our experiments, we demonstrate that our motion generation algorithm computes consistent contact forces and joint trajectories for our humanoid robot. We also demonstrate the favorable time complexity due to our formulation and composition of the momentum equations.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Balancing and Walking Using Full Dynamics LQR Control With Contact Constraints

Mason, S., Rotella, N., Schaal, S., Righetti, L.

In 2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids), pages: 63-68, IEEE, Cancun, Mexico, 2016 (inproceedings)

Abstract
Torque control algorithms which consider robot dynamics and contact constraints are important for creating dynamic behaviors for humanoids. As computational power increases, algorithms tend to also increase in complexity. However, it is not clear how much complexity is really required to create controllers which exhibit good performance. In this paper, we study the capabilities of a simple approach based on contact consistent LQR controllers designed around key poses to control various tasks on a humanoid robot. We present extensive experimental results on a hydraulic, torque controlled humanoid performing balancing and stepping tasks. This feedback control approach captures the necessary synergies between the DoFs of the robot to guarantee good control performance. We show that for the considered tasks, it is only necessary to re-linearize the dynamics of the robot at different contact configurations and that increasing the number of LQR controllers along desired trajectories does not improve performance. Our result suggest that very simple controllers can yield good performance competitive with current state of the art, but more complex, optimization-based whole-body controllers. A video of the experiments can be found at https://youtu.be/5T08CNKV1hw.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Unsupervised Learning of Shape-Motion Patterns for Objects in Urban Street Scenes

Klostermann, D., Osep, A., Stueckler, J., Leibe, B.

In British Machine Vision Conference (BMVC), 2016 (inproceedings)

ev

[BibTex]

[BibTex]


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Step Timing Adjustement: a Step toward Generating Robust Gaits

Khadiv, M., Herzog, A., Moosavian, S. A. A., Righetti, L.

In 2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids), pages: 35-42, IEEE, Cancun, Mexico, 2016 (inproceedings)

Abstract
Step adjustment for humanoid robots has been shown to improve robustness in gaits. However, step duration adaptation is often neglected in control strategies. In this paper, we propose an approach that combines both step location and timing adjustment for generating robust gaits. In this approach, step location and step timing are decided, based on feedback from the current state of the robot. The proposed approach is comprised of two stages. In the first stage, the nominal step location and step duration for the next step or a previewed number of steps are specified. In this stage which is done at the start of each step, the main goal is to specify the best step length and step duration for a desired walking speed. The second stage deals with finding the best landing point and landing time of the swing foot at each control cycle. In this stage, stability of the gaits is preserved by specifying a desired offset between the swing foot landing point and the Divergent Component of Motion (DCM) at the end of current step. After specifying the landing point of the swing foot at a desired time, the swing foot trajectory is regenerated at each control cycle to realize desired landing properties. Simulation on different scenarios shows the robustness of the generated gaits from our proposed approach compared to the case where no timing adjustment is employed.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Scene Flow Propagation for Semantic Mapping and Object Discovery in Dynamic Street Scenes

Kochanov, D., Osep, A., Stueckler, J., Leibe, B.

In IEEE/RSJ Int. Conference on Intelligent Robots and Systems, IROS, 2016 (inproceedings)

ev

[BibTex]

[BibTex]


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Joint Object Pose Estimation and Shape Reconstruction in Urban Street Scenes Using 3D Shape Priors

Engelmann, F., Stueckler, J., Leibe, B.

In Proc. of the German Conference on Pattern Recognition (GCPR), 2016 (inproceedings)

ev

[BibTex]

[BibTex]

2015


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Real-Time Object Detection, Localization and Verification for Fast Robotic Depalletizing

Holz, D., Topalidou-Kyniazopoulou, A., Stueckler, J., Behnke, S.

In IEEE International Conference on Intelligent Robots and Systems (IROS), 2015 (inproceedings)

ev

link (url) [BibTex]

2015


link (url) [BibTex]


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Dense Continuous-Time Tracking and Mapping with Rolling Shutter RGB-D Cameras

Kerl, C., Stueckler, J., Cremers, D.

In IEEE International Conference on Computer Vision (ICCV), Santiago, Chile, 2015, {[video][supplementary][datasets]} (inproceedings)

ev

[BibTex]

[BibTex]


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Perception of Deformable Objects and Compliant Manipulation for Service Robots

Stueckler, J., Behnke, S.

In Soft Robotics: From Theory to Applications, Springer, 2015 (inbook)

ev

link (url) [BibTex]

link (url) [BibTex]


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Large-Scale Direct SLAM with Stereo Cameras

Engel, J., Stueckler, J., Cremers, D.

In IEEE International Conference on Intelligent Robots and Systems (IROS), 2015 (inproceedings)

ev

[BibTex]

[BibTex]


Thumb xl screen shot 2017 06 14 at 3.05.52 pm
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.

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link (url) DOI Project Page [BibTex]

link (url) DOI Project Page [BibTex]


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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.

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link (url) DOI Project Page [BibTex]

link (url) DOI Project Page [BibTex]


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The average number of distinct sites visited by a random walker on random graphs

De Bacco, C., Majumdar, S. N., Sollich, P.

Journal of Physics A: Mathematical and Theoretical, 48(20):205004, IOP Publishing, 2015 (article)

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Preprint link (url) [BibTex]

Preprint link (url) [BibTex]


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The edge-disjoint path problem on random graphs by message-passing

Altarelli, F., Braunstein, A., Dall’Asta, L., De Bacco, C., Franz, S.

PloS one, 10(12):e0145222, Public Library of Science, 2015 (article)

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Code Preprint link (url) Project Page [BibTex]

Code Preprint link (url) Project Page [BibTex]


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Efficient Dense Rigid-Body Motion Segmentation and Estimation in RGB-D Video

Stueckler, J., Behnke, S.

International Journal of Computer Vision (IJCV), 113(3):233-245, 2015 (article)

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Motion Cooperation: Smooth Piece-Wise Rigid Scene Flow from RGB-D Images

Jaimez, M., Souiai, M., Stueckler, J., Gonzalez-Jimenez, J., Cremers, D.

In Proc. of the Int. Conference on 3D Vision (3DV), October 2015, {[video]} (inproceedings)

ev

[BibTex]

[BibTex]


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Kinematic and gait similarities between crawling human infants and other quadruped mammals

Righetti, L., Nylen, A., Rosander, K., Ijspeert, A.

Frontiers in Neurology, 6(17), February 2015 (article)

Abstract
Crawling on hands and knees is an early pattern of human infant locomotion, which offers an interesting way of studying quadrupedalism in one of its simplest form. We investigate how crawling human infants compare to other quadruped mammals, especially primates. We present quantitative data on both the gait and kinematics of seven 10-month-old crawling infants. Body movements were measured with an optoelectronic system giving precise data on 3-dimensional limb movements. Crawling on hands and knees is very similar to the locomotion of non-human primates in terms of the quite protracted arm at touch-down, the coordination between the spine movements in the lateral plane and the limbs, the relatively extended limbs during locomotion and the strong correlation between stance duration and speed of locomotion. However, there are important differences compared to primates, such as the choice of a lateral-sequence walking gait, which is similar to most non-primate mammals and the relatively stiff elbows during stance as opposed to the quite compliant gaits of primates. These finding raise the question of the role of both the mechanical structure of the body and neural control on the determination of these characteristics.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Non-equilibrium statistical mechanics of the heat bath for two Brownian particles : Internal degrees of freedom found where there shouldn’t be (Special Issue on New Challenges in Complex Systems Science)

De Bacco, C., Baldovin, F., Orlandini, E.

理工研報告特集号 : ASTE : advances in science, technology and environmentology : special issue, 11, pages: 111-113, 早稲田大学理工学術院総合研究所 (理工学研究所), March 2015 (article)

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link (url) [BibTex]

link (url) [BibTex]


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Decentralized network control, optimization and random walks on networks

De Bacco, C.

(2015PA112164), Université Paris Sud - Paris XI, sep 2015 (phdthesis)

pio

link (url) [BibTex]

link (url) [BibTex]


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Trajectory generation for multi-contact momentum control

Herzog, A., Rotella, N., Schaal, S., Righetti, L.

In 2015 IEEE-RAS 15th International Conference on Humanoid Robots (Humanoids), pages: 874-880, IEEE, Seoul, South Korea, 2015 (inproceedings)

Abstract
Simplified models of the dynamics such as the linear inverted pendulum model (LIPM) have proven to perform well for biped walking on flat ground. However, for more complex tasks the assumptions of these models can become limiting. For example, the LIPM does not allow for the control of contact forces independently, is limited to co-planar contacts and assumes that the angular momentum is zero. In this paper, we propose to use the full momentum equations of a humanoid robot in a trajectory optimization framework to plan its center of mass, linear and angular momentum trajectories. The model also allows for planning desired contact forces for each end-effector in arbitrary contact locations. We extend our previous results on linear quadratic regulator (LQR) design for momentum control by computing the (linearized) optimal momentum feedback law in a receding horizon fashion. The resulting desired momentum and the associated feedback law are then used in a hierarchical whole body control approach. Simulation experiments show that the approach is computationally fast and is able to generate plans for locomotion on complex terrains while demonstrating good tracking performance for the full humanoid control.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Super-Resolution Keyframe Fusion for 3D Modeling with High-Quality Textures

Maier, R., Stueckler, J., Cremers, D.

In International Conference on 3D Vision (3DV), October 2015, {[slides] [poster]} (inproceedings)

ev

[BibTex]

[BibTex]


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Humanoid Momentum Estimation Using Sensed Contact Wrenches

Rotella, N., Herzog, A., Schaal, S., Righetti, L.

In 2015 IEEE-RAS 15th International Conference on Humanoid Robots (Humanoids), pages: 556-563, IEEE, Seoul, South Korea, 2015 (inproceedings)

Abstract
This work presents approaches for the estimation of quantities important for the control of the momentum of a humanoid robot. In contrast to previous approaches which use simplified models such as the Linear Inverted Pendulum Model, we present estimators based on the momentum dynamics of the robot. By using this simple yet dynamically-consistent model, we avoid the issues of using simplified models for estimation. We develop an estimator for the center of mass and full momentum which can be reformulated to estimate center of mass offsets as well as external wrenches applied to the robot. The observability of these estimators is investigated and their performance is evaluated in comparison to previous approaches.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Reconstructing Street-Scenes in Real-Time From a Driving Car

Usenko, V., Engel, J., Stueckler, J., Cremers, D.

In Proc. of the Int. Conference on 3D Vision (3DV), October 2015 (inproceedings)

ev

[BibTex]

[BibTex]

2014


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Roombots: A hardware perspective on 3D self-reconfiguration and locomotion with a homogeneous modular robot

Spröwitz, A., Moeckel, R., Vespignani, M., Bonardi, S., Ijspeert, A. J.

{Robotics and Autonomous Systems}, 62(7):1016-1033, Elsevier, Amsterdam, 2014 (article)

Abstract
In this work we provide hands-on experience on designing and testing a self-reconfiguring modular robotic system, Roombots (RB), to be used among others for adaptive furniture. In the long term, we envision that RB can be used to create sets of furniture, such as stools, chairs and tables that can move in their environment and that change shape and functionality during the day. In this article, we present the first, incremental results towards that long term vision. We demonstrate locomotion and reconfiguration of single and metamodule RB over 3D surfaces, in a structured environment equipped with embedded connection ports. RB assemblies can move around in non-structured environments, by using rotational or wheel-like locomotion. We show a proof of concept for transferring a Roombots metamodule (two in-series coupled RB modules) from the non-structured environment back into the structured grid, by aligning the RB metamodule in an entrapment mechanism. Finally, we analyze the remaining challenges to master the full Roombots scenario, and discuss the impact on future Roombots hardware.

dlg

DOI [BibTex]

2014


DOI [BibTex]


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Rough Terrain Mapping and Navigation using a Continuously Rotating 2D Laser Scanner

Schadler, M., Stueckler, J., Behnke, S.

Künstliche Intelligenz (KI), 28(2):93-99, Springer, 2014 (article)

ev

link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Adaptive Tool-Use Strategies for Anthropomorphic Service Robots

Stueckler, J., Behnke, S.

In Proc. of the 14th IEEE-RAS International Conference on Humanoid Robots (Humanoids), 2014 (inproceedings)

ev

link (url) [BibTex]

link (url) [BibTex]


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Nonequilibrium statistical mechanics of the heat bath for two Brownian particles

De Bacco, C., Baldovin, F., Orlandini, E., Sekimoto, K.

Physical review letters, 112(18):180605, APS, 2014 (article)

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Preprint link (url) [BibTex]

Preprint link (url) [BibTex]


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Automatic Generation of Reduced CPG Control Networks for Locomotion of Arbitrary Modular Robot Structures

Bonardi, S., Vespignani, M., Möckel, R., Van den Kieboom, J., Pouya, S., Spröwitz, A., Ijspeert, A.

In Proceedings of Robotics: Science and Systems, University of California, Barkeley, 2014 (inproceedings)

Abstract
The design of efficient locomotion controllers for arbitrary structures of reconfigurable modular robots is challenging because the morphology of the structure can change dynamically during the completion of a task. In this paper, we propose a new method to automatically generate reduced Central Pattern Generator (CPG) networks for locomotion control based on the detection of bio-inspired sub-structures, like body and limbs, and articulation joints inside the robotic structure. We demonstrate how that information, coupled with the potential symmetries in the structure, can be used to speed up the optimization of the gaits and investigate its impact on the solution quality (i.e. the velocity of the robotic structure and the potential internal collisions between robotic modules). We tested our approach on three simulated structures and observed that the reduced network topologies in the first iterations of the optimization process performed significantly better than the fully open ones.

dlg

DOI [BibTex]

DOI [BibTex]


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Dense Real-Time Mapping of Object-Class Semantics from RGB-D Video

Stueckler, J., Waldvogel, B., Schulz, H., Behnke, S.

Journal of Real-Time Image Processing (JRTIP), 10(4):599-609, Springer, 2014 (article)

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Local Multi-Resolution Surfel Grids for MAV Motion Estimation and 3D Mapping

Droeschel, D., Stueckler, J., Behnke, S.

In Proc. of the 13th International Conference on Intelligent Autonomous Systems (IAS), 2014 (inproceedings)

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link (url) [BibTex]

link (url) [BibTex]