1,746 research outputs found
Learning to Segment and Represent Motion Primitives from Driving Data for Motion Planning Applications
Developing an intelligent vehicle which can perform human-like actions
requires the ability to learn basic driving skills from a large amount of
naturalistic driving data. The algorithms will become efficient if we could
decompose the complex driving tasks into motion primitives which represent the
elementary compositions of driving skills. Therefore, the purpose of this paper
is to segment unlabeled trajectory data into a library of motion primitives. By
applying a probabilistic inference based on an iterative
Expectation-Maximization algorithm, our method segments the collected
trajectories while learning a set of motion primitives represented by the
dynamic movement primitives. The proposed method utilizes the mutual
dependencies between the segmentation and representation of motion primitives
and the driving-specific based initial segmentation. By utilizing this mutual
dependency and the initial condition, this paper presents how we can enhance
the performance of both the segmentation and the motion primitive library
establishment. We also evaluate the applicability of the primitive
representation method to imitation learning and motion planning algorithms. The
model is trained and validated by using the driving data collected from the
Beijing Institute of Technology intelligent vehicle platform. The results show
that the proposed approach can find the proper segmentation and establish the
motion primitive library simultaneously
Discovery and recognition of motion primitives in human activities
We present a novel framework for the automatic discovery and recognition of
motion primitives in videos of human activities. Given the 3D pose of a human
in a video, human motion primitives are discovered by optimizing the `motion
flux', a quantity which captures the motion variation of a group of skeletal
joints. A normalization of the primitives is proposed in order to make them
invariant with respect to a subject anatomical variations and data sampling
rate. The discovered primitives are unknown and unlabeled and are
unsupervisedly collected into classes via a hierarchical non-parametric Bayes
mixture model. Once classes are determined and labeled they are further
analyzed for establishing models for recognizing discovered primitives. Each
primitive model is defined by a set of learned parameters.
Given new video data and given the estimated pose of the subject appearing on
the video, the motion is segmented into primitives, which are recognized with a
probability given according to the parameters of the learned models.
Using our framework we build a publicly available dataset of human motion
primitives, using sequences taken from well-known motion capture datasets. We
expect that our framework, by providing an objective way for discovering and
categorizing human motion, will be a useful tool in numerous research fields
including video analysis, human inspired motion generation, learning by
demonstration, intuitive human-robot interaction, and human behavior analysis
Comparative evaluation of approaches in T.4.1-4.3 and working definition of adaptive module
The goal of this deliverable is two-fold: (1) to present and compare different approaches towards learning and encoding movements us- ing dynamical systems that have been developed by the AMARSi partners (in the past during the first 6 months of the project), and (2) to analyze their suitability to be used as adaptive modules, i.e. as building blocks for the complete architecture that will be devel- oped in the project. The document presents a total of eight approaches, in two groups: modules for discrete movements (i.e. with a clear goal where the movement stops) and for rhythmic movements (i.e. which exhibit periodicity). The basic formulation of each approach is presented together with some illustrative simulation results. Key character- istics such as the type of dynamical behavior, learning algorithm, generalization properties, stability analysis are then discussed for each approach. We then make a comparative analysis of the different approaches by comparing these characteristics and discussing their suitability for the AMARSi project
Interactive Imitation Learning of Bimanual Movement Primitives
Performing bimanual tasks with dual robotic setups can drastically increase
the impact on industrial and daily life applications. However, performing a
bimanual task brings many challenges, like synchronization and coordination of
the single-arm policies. This article proposes the Safe, Interactive Movement
Primitives Learning (SIMPLe) algorithm, to teach and correct single or dual arm
impedance policies directly from human kinesthetic demonstrations. Moreover, it
proposes a novel graph encoding of the policy based on Gaussian Process
Regression (GPR) where the single-arm motion is guaranteed to converge close to
the trajectory and then towards the demonstrated goal. Regulation of the robot
stiffness according to the epistemic uncertainty of the policy allows for
easily reshaping the motion with human feedback and/or adapting to external
perturbations. We tested the SIMPLe algorithm on a real dual-arm setup where
the teacher gave separate single-arm demonstrations and then successfully
synchronized them only using kinesthetic feedback or where the original
bimanual demonstration was locally reshaped to pick a box at a different
height
Development of lower-limb rehabilitation exercises using 3-PRS Parallel Robot and Dynamic Movement Primitives
[EN] The design of rehabilitation exercises applied to sprained ankles requires extreme caution, regarding the trajectories and the speed of the movements that will affect the patient. This paper presents a technique that allows a 3-PRS parallel robot to control such exercises, consisting of dorsi/plantar flexion and inversion/eversion ankle movements. The work includes a position control scheme for the parallel robot in order to follow a reference trajectory for each limb with the possibility of stopping the exercise in mid-execution without control loss. This stop may be motivated by the forces that the robot applies to the patient, acting like an alarm mechanism. The procedure introduced here is based on Dynamic Movement Primitives (DMPs).This work has been partially funded by FEDER-CICYT project with reference DPI2017-84201-R financed by Ministerio de Economía, Industria e Innovación (Spain).Escarabajal Sánchez, RJ.; Abu Dakka, FJM.; Pulloquinga Zapata, J.; Mata Amela, V.; Vallés Miquel, M.; Valera Fernández, Á. (2020). Development of lower-limb rehabilitation exercises using 3-PRS Parallel Robot and Dynamic Movement Primitives. Multidisciplinary Journal for Education, Social and Technological Sciences. 7(2):30-44. https://doi.org/10.4995/muse.2020.13907OJS304472Abu-Dakka, F. J., Valera, A., Escalera, J. A., Vallés, M., Mata, V., & Abderrahim, M. (2015). Trajectory adaptation and learning for ankle rehabilitation using a 3-PRS parallel robot. Lecture Notes in Computer Science (Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 9245, 483-494. https://doi.org/10.1007/978-3-319-22876-1_41Atkeson, C. G., Moore, A. W., & Schaal, S. (1997). Locally Weighted Learning. Artificial Intelligence Review, 11(1-5), 11-73. https://doi.org/10.1007/978-94-017-2053-3_2Brockett, C. L., & Chapman, G. J. (2016). Biomechanics of the ankle. Orthopaedics and Trauma, 30(3), 232-238. https://doi.org/10.1016/j.mporth.2016.04.015Dai, J. S., Zhao, T., & Nester, C. (2004). Sprained Ankle Physiotherapy Based Mechanism Synthesis and Stiffness Analysis of a Robotic Rehabilitation Device. Autonomous Robots, 16(2), 207-218. https://doi.org/10.1023/B:AURO.0000016866.80026.d7Díaz-Rodríguez, M., Mata, V., Valera, Á., & Page, Á. (2010). A methodology for dynamic parameters identification of 3-DOF parallel robots in terms of relevant parameters. Mechanism and Machine Theory, 45(9), 1337-1356. https://doi.org/10.1016/j.mechmachtheory.2010.04.007Díaz, I., Gil, J. J., & Sánchez, E. (2011). Lower-Limb Robotic Rehabilitation: Literature Review and Challenges. Journal of Robotics, 2011(i), 1-11. https://doi.org/10.1155/2011/759764Fanger, Y., Umlauft, J., & Hirche, S. (2016). Gaussian Processes for Dynamic Movement Primitives with application in knowledge-based cooperation. IEEE International Conference on Intelligent Robots and Systems, 2016-Novem, 3913-3919. https://doi.org/10.1109/IROS.2016.7759576Gosselin, C., & Angeles, J. (1990). Singularity Analysis of Closed-Loop Kinematic Chains. IEEE Transactions on Robotics and Automation, 6(3), 281-290. https://doi.org/10.1109/70.56660Hesse, S., & Uhlenbrock, D. (2000). A mechanized gait trainer for restoration of gait. Journal of Rehabilitation Research and Development, 37(6), 701-708.Ijspeert, A. J., Nakanishi, J., Hoffmann, H., Pastor, P., & Schaal, S. (2013). Dynamical movement primitives: Learning attractor models formotor behaviors. Neural Computation, 25(2), 328-373. https://doi.org/10.1162/NECO_a_00393Ijspeert, A. J., Nakanishi, J., & Schaal, S. (2002). Movement imitation with nonlinear dynamical systems in humanoid robots. Proceedings - IEEE International Conference on Robotics and Automation, 2, 1398-1403. https://doi.org/10.1109/ROBOT.2002.1014739Liu, G., Gao, J., Yue, H., Zhang, X., & Lu, G. (2006). Design and kinematics simulation of parallel robots for ankle rehabilitation. 2006 IEEE International Conference on Mechatronics and Automation, ICMA 2006, 2006, 1109-1113. https://doi.org/10.1109/ICMA.2006.257780Nakanishi, J., Morimoto, J., Endo, G., Cheng, G., Schaal, S., & Kawato, M. (2004). Learning from demonstration and adaptation of biped locomotion. Robotics and Autonomous Systems, 47(2-3), 79-91. https://doi.org/10.1016/j.robot.2004.03.003Nemec, B., & Ude, A. (2012). Action sequencing using dynamic movement primitives. Robotica, 30(5), 837-846. https://doi.org/10.1017/S0263574711001056Patel, Y. D., & George, P. M. (2012). Parallel Manipulators Applications-A Survey. Modern Mechanical Engineering, 02(03), 57-64. https://doi.org/10.4236/mme.2012.23008Paul, R. P. (1981). Robot Manipulators: Mathematics, Programming, and Control : the Computer Control of Robot Manipulators (p. 279).Reinkensmeyer, D. J., Aoyagi, D., Emken, J. L., Galvez, J. A., Ichinose, W., Kerdanyan, G., Maneekobkunwong, S., Minakata, K., Nessler, J. A., Weber, R., Roy, R. R., De Leon, R., Bobrow, J. E., Harkema, S. J., & Reggie Edgerton, V. (2006). Tools for understanding and optimizing robotic gait training. Journal of Rehabilitation Research and Development, 43(5), 657-670. https://doi.org/10.1682/JRRD.2005.04.0073Safran, M. R., Benedetti, R. S., Bartolozzi, A. R., & Mandelbaum, B. R. (1999). Lateral ankle sprains: A comprehensive review part 1: Etiology, pathoanatomy, histopathogenesis, and diagnosis. In Medicine and Science in Sports and Exercise (Vol. 31, Issue 7 SUPPL., pp. S429-S437).https://doi.org/10.1097/00005768-199907001-00004Saglia, J. A., Tsagarakis, N. G., Dai, J. S., & Caldwell, D. G. (2013). Control strategies for patient-assisted training using the ankle rehabilitation robot (ARBOT). IEEE/ASME Transactions on Mechatronics, 18(6), 1799-1808. https://doi.org/10.1109/TMECH.2012.2214228Schaal, S. (2006). Dynamic Movement Primitives -A Framework for Motor Control in Humans and Humanoid Robotics. In Adaptive Motion of Animals and Machines (pp. 261-280). https://doi.org/10.1007/4-431-31381-8_23Sui, P., Yao, L., Lin, Z., Yan, H., & Dai, J. S. (2009). Analysis and synthesis of ankle motion and rehabilitation robots. 2009 IEEE International Conference on Robotics and Biomimetics, ROBIO 2009, 3, 2533-2538. https://doi.org/10.1109/ROBIO.2009.5420487Tsoi, Y. H., Xie, S. Q., & Graham, A. E. (2009). Design, modeling and control of an ankle rehabilitation robot. Studies in Computational Intelligence, 177, 377-399. https://doi.org/10.1007/978-3-540-89933-4_18Vallés, M., Díaz-Rodrguez, M., Valera, Á., Mata, V., & Page, Á. (2012). Mechatronic development and dynamic control of a 3-dof parallel manipulator. Mechanics Based Design of Structures and Machines, 40(4), 434-452. https://doi.org/10.1080/15397734.2012.687292Xie, S. (2016). Advanced robotics for medical rehabilitation: current state of the art and recent advances. In Springer tracts in advanced robotics (Issue 108). https://doi.org/10.1007/978-3-319-19896-5Yoon, J., Ryu, J., & Lim, K. B. (2006). Reconfigurable ankle rehabilitation robot for various exercises. Journal of Robotic Systems, 22(SUPPL.), 15-33. https://doi.org/10.1002/rob.2015
Isometric Motion Manifold Primitives
The Motion Manifold Primitive (MMP) produces, for a given task, a continuous
manifold of trajectories each of which can successfully complete the task. It
consists of the decoder function that parametrizes the manifold and the
probability density in the latent coordinate space. In this paper, we first
show that the MMP performance can significantly degrade due to the geometric
distortion in the latent space -- by distortion, we mean that similar motions
are not located nearby in the latent space. We then propose {\it Isometric
Motion Manifold Primitives (IMMP)} whose latent coordinate space preserves the
geometry of the manifold. For this purpose, we formulate and use a Riemannian
metric for the motion space (i.e., parametric curve space), which we call a
{\it CurveGeom Riemannian metric}. Experiments with planar obstacle-avoiding
motions and pushing manipulation tasks show that IMMP significantly outperforms
existing MMP methods. Code is available at
https://github.com/Gabe-YHLee/IMMP-public.Comment: 8 pages, 13 figures. This work has been submitted to the IEEE for
possible publicatio
A Posture Sequence Learning System for an Anthropomorphic Robotic Hand
The paper presents a cognitive architecture for posture learning of an anthropomorphic robotic hand. Our approach is aimed to allow the robotic system to perform complex perceptual operations, to interact with a human user and to integrate the perceptions by a cognitive representation of the scene and the observed actions. The anthropomorphic robotic hand imitates the gestures acquired by the vision system in order to learn meaningful movements, to build its knowledge by different conceptual spaces and to perform complex interaction with the human operator
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