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Learning of Parameters in Behavior Trees for Movement Skills

Mayr, Matthias LU orcid ; Ahmad, Faseeh LU ; Chatzilygeroudis, Konstantinos ; Nardi, Luigi LU and Krueger, Volker LU orcid (2021) IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 2021 p.7572-7572
Abstract
Reinforcement Learning (RL) is a powerful mathematical framework that allows robots to learn complex skills by trial-and-error. Despite numerous successes in many applications, RL algorithms still require thousands of trials to converge to high-performing policies, can produce dangerous behaviors while learning, and the optimized policies (usually modeled as neural networks) give almost zero explanation when they fail to perform the task. For these reasons, the adoption of RL in industrial settings is not common. Behavior Trees (BTs), on the other hand, can provide a policy representation that a) supports modular and composable skills, b) allows for easy interpretation of the robot actions, and c) provides an advantageous low-dimensional... (More)
Reinforcement Learning (RL) is a powerful mathematical framework that allows robots to learn complex skills by trial-and-error. Despite numerous successes in many applications, RL algorithms still require thousands of trials to converge to high-performing policies, can produce dangerous behaviors while learning, and the optimized policies (usually modeled as neural networks) give almost zero explanation when they fail to perform the task. For these reasons, the adoption of RL in industrial settings is not common. Behavior Trees (BTs), on the other hand, can provide a policy representation that a) supports modular and composable skills, b) allows for easy interpretation of the robot actions, and c) provides an advantageous low-dimensional parameter space. In this paper, we present a novel algorithm that can learn the parameters of a BT policy in simulation and then generalize to the physical robot without any additional training. We leverage a physical simulator with a digital twin of our workstation, and optimize the relevant parameters with a black-box optimizer. We showcase the efficacy of our method with a 7-DOF KUKAiiwa manipulator in a task that includes obstacle avoidance and a contact-rich insertion (peg-in-hole), in which our method outperforms the baselines. (Less)
Please use this url to cite or link to this publication:
author
; ; ; and
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Reinforcement Learning, Robotics, Skills, Manipulators, Bayesian Optimization, Learning
host publication
2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
pages
7 pages
publisher
IEEE - Institute of Electrical and Electronics Engineers Inc.
conference name
IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 2021
conference location
Prague, Czech Republic
conference dates
2021-09-27 - 2021-10-01
external identifiers
  • scopus:85124333353
ISBN
978-1-6654-1714-3
978-1-6654-1715-0
DOI
10.1109/IROS51168.2021.9636292
project
RobotLab LTH
Efficient Learning of Robot Skills
Robotics and Semantic Systems
WASP Package: Bayesian optimization methods and their applications to real-world problems
WASP Professor Package: Cognitive Robots for Manufacturing
language
English
LU publication?
yes
id
091ae119-c2a1-4e1c-9d7c-e20c1ed351f5
date added to LUP
2022-01-14 13:58:50
date last changed
2024-04-18 05:14:13
@inproceedings{091ae119-c2a1-4e1c-9d7c-e20c1ed351f5,
  abstract     = {{Reinforcement Learning (RL) is a powerful mathematical framework that allows robots to learn complex skills by trial-and-error. Despite numerous successes in many applications, RL algorithms still require thousands of trials to converge to high-performing policies, can produce dangerous behaviors while learning, and the optimized policies (usually modeled as neural networks) give almost zero explanation when they fail to perform the task. For these reasons, the adoption of RL in industrial settings is not common. Behavior Trees (BTs), on the other hand, can provide a policy representation that a) supports modular and composable skills, b) allows for easy interpretation of the robot actions, and c) provides an advantageous low-dimensional parameter space. In this paper, we present a novel algorithm that can learn the parameters of a BT policy in simulation and then generalize to the physical robot without any additional training. We leverage a physical simulator with a digital twin of our workstation, and optimize the relevant parameters with a black-box optimizer. We showcase the efficacy of our method with a 7-DOF KUKAiiwa manipulator in a task that includes obstacle avoidance and a contact-rich insertion (peg-in-hole), in which our method outperforms the baselines.}},
  author       = {{Mayr, Matthias and Ahmad, Faseeh and Chatzilygeroudis, Konstantinos and Nardi, Luigi and Krueger, Volker}},
  booktitle    = {{2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)}},
  isbn         = {{978-1-6654-1714-3}},
  keywords     = {{Reinforcement Learning; Robotics; Skills; Manipulators; Bayesian Optimization; Learning}},
  language     = {{eng}},
  month        = {{12}},
  pages        = {{7572--7572}},
  publisher    = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
  title        = {{Learning of Parameters in Behavior Trees for Movement Skills}},
  url          = {{http://dx.doi.org/10.1109/IROS51168.2021.9636292}},
  doi          = {{10.1109/IROS51168.2021.9636292}},
  year         = {{2021}},
}