Not Only Rewards But Also Constraints: Applications on Legged Robot Locomotion

Fuente: arXiv
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Bibliographic Details
Main Authors: Kim, Yunho, Oh, Hyunsik, Lee, Jeonghyun, Choi, Jinhyeok, Ji, Gwanghyeon, Jung, Moonkyu, Youm, Donghoon, Hwangbo, Jemin
Format: Preprint
Published: 2023
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_version_ 1866914878248189952
author Kim, Yunho
Oh, Hyunsik
Lee, Jeonghyun
Choi, Jinhyeok
Ji, Gwanghyeon
Jung, Moonkyu
Youm, Donghoon
Hwangbo, Jemin
author_facet Kim, Yunho
Oh, Hyunsik
Lee, Jeonghyun
Choi, Jinhyeok
Ji, Gwanghyeon
Jung, Moonkyu
Youm, Donghoon
Hwangbo, Jemin
contents Several earlier studies have shown impressive control performance in complex robotic systems by designing the controller using a neural network and training it with model-free reinforcement learning. However, these outstanding controllers with natural motion style and high task performance are developed through extensive reward engineering, which is a highly laborious and time-consuming process of designing numerous reward terms and determining suitable reward coefficients. In this work, we propose a novel reinforcement learning framework for training neural network controllers for complex robotic systems consisting of both rewards and constraints. To let the engineers appropriately reflect their intent to constraints and handle them with minimal computation overhead, two constraint types and an efficient policy optimization algorithm are suggested. The learning framework is applied to train locomotion controllers for several legged robots with different morphology and physical attributes to traverse challenging terrains. Extensive simulation and real-world experiments demonstrate that performant controllers can be trained with significantly less reward engineering, by tuning only a single reward coefficient. Furthermore, a more straightforward and intuitive engineering process can be utilized, thanks to the interpretability and generalizability of constraints. The summary video is available at https://youtu.be/KAlm3yskhvM.
format Preprint
id arxiv_https___arxiv_org_abs_2308_12517
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Not Only Rewards But Also Constraints: Applications on Legged Robot Locomotion
Kim, Yunho
Oh, Hyunsik
Lee, Jeonghyun
Choi, Jinhyeok
Ji, Gwanghyeon
Jung, Moonkyu
Youm, Donghoon
Hwangbo, Jemin
Robotics
Artificial Intelligence
Machine Learning
Several earlier studies have shown impressive control performance in complex robotic systems by designing the controller using a neural network and training it with model-free reinforcement learning. However, these outstanding controllers with natural motion style and high task performance are developed through extensive reward engineering, which is a highly laborious and time-consuming process of designing numerous reward terms and determining suitable reward coefficients. In this work, we propose a novel reinforcement learning framework for training neural network controllers for complex robotic systems consisting of both rewards and constraints. To let the engineers appropriately reflect their intent to constraints and handle them with minimal computation overhead, two constraint types and an efficient policy optimization algorithm are suggested. The learning framework is applied to train locomotion controllers for several legged robots with different morphology and physical attributes to traverse challenging terrains. Extensive simulation and real-world experiments demonstrate that performant controllers can be trained with significantly less reward engineering, by tuning only a single reward coefficient. Furthermore, a more straightforward and intuitive engineering process can be utilized, thanks to the interpretability and generalizability of constraints. The summary video is available at https://youtu.be/KAlm3yskhvM.
title Not Only Rewards But Also Constraints: Applications on Legged Robot Locomotion
topic Robotics
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2308.12517