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On-line Access: 2026-01-12

Received: 2025-04-23

Revision Accepted: 2025-07-29

Crosschecked: 2026-01-12

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Citations:  Bibtex RefMan EndNote GB/T7714

 ORCID:

Jun-hui Zhang

https://orcid.org/0000-0002-2603-2065

Bing Xu

https://orcid.org/0000-0003-0236-7896

Pengyuan JI

https://orcid.org/0009-0006-3435-5776

Lizhou FANG

https://orcid.org/0009-0009-4467-7236

Jinyuan LIU

https://orcid.org/0009-0003-1613-5823

Dandan WANG

https://orcid.org/0009-0007-6925-6273

Jikun AI

https://orcid.org/0000-0002-3416-1764

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Journal of Zhejiang University SCIENCE A 2025 Vol.26 No.12 P.1163-1178

http://doi.org/10.1631/jzus.A2500142


Stable and continuous vertical jumping control of hydraulic legged robots through reinforcement learning


Author(s):  Junhui ZHANG, Pengyuan JI, Lizhou FANG, Jinyuan LIU, Dandan WANG, Jikun AI, Huaizhi ZONG, Bing XU

Affiliation(s):  State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310058, China

Corresponding email(s):   hzzong@zju.edu.cn

Key Words:  Legged robot, Deep reinforcement learning, Quasi-realistic modelling, Hydraulic system, Jumping control


Junhui ZHANG, Pengyuan JI, Lizhou FANG, Jinyuan LIU, Dandan WANG, Jikun AI, Huaizhi ZONG, Bing XU. Stable and continuous vertical jumping control of hydraulic legged robots through reinforcement learning[J]. Journal of Zhejiang University Science A, 2025, 26(12): 1163-1178.

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author="Junhui ZHANG, Pengyuan JI, Lizhou FANG, Jinyuan LIU, Dandan WANG, Jikun AI, Huaizhi ZONG, Bing XU",
journal="Journal of Zhejiang University Science A",
volume="26",
number="12",
pages="1163-1178",
year="2025",
publisher="Zhejiang University Press & Springer",
doi="10.1631/jzus.A2500142"
}

%0 Journal Article
%T Stable and continuous vertical jumping control of hydraulic legged robots through reinforcement learning
%A Junhui ZHANG
%A Pengyuan JI
%A Lizhou FANG
%A Jinyuan LIU
%A Dandan WANG
%A Jikun AI
%A Huaizhi ZONG
%A Bing XU
%J Journal of Zhejiang University SCIENCE A
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%N 12
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%@ 1673-565X
%D 2025
%I Zhejiang University Press & Springer
%DOI 10.1631/jzus.A2500142

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A1 - Junhui ZHANG
A1 - Pengyuan JI
A1 - Lizhou FANG
A1 - Jinyuan LIU
A1 - Dandan WANG
A1 - Jikun AI
A1 - Huaizhi ZONG
A1 - Bing XU
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DOI - 10.1631/jzus.A2500142


Abstract: 
Hydraulic legged robots have potential for high-dynamic motion due to their large power-to-weight ratios. However, it is challenging to ensure both stability and continuity in the motion of such robots. In this study, we propose a jumping motion control framework based on deep reinforcement learning that enables hydraulic limb leg units to perform stable and continuous jumping motions. First, to accurately represent the performance of a physical prototype, a quasi-realistic model incorporating physical feasibility constraints is constructed. This model is informed by analysis of the relevant fluid dynamics, and incorporates a trajectory generator and a motion tracking controller. To achieve stable and continuous jumping performance, a deep reinforcement learning algorithm is developed, which jointly optimizes the trajectory generator and the motion tracking controller. Through validation on the physical prototype, we demonstrate that the proposed method reduces the maximum deviation and the average deviation by over 47% and 60%, respectively, and improves landing compliance by up to 7.7% compared to a baseline optimization algorithm, the non-dominated sorting genetic algorithm (NSGA-II). The proposed control framework may serve as a reference for high-dynamic motion control of legged robots and multi-objective optimization across several decision variables.

基于强化学习的液压足式机器人稳定连续的垂直跳跃控制方法

作者:张军辉,姬鹏远,方李舟,刘津源,王丹丹,艾吉昆,纵怀志,徐兵
机构:浙江大学,流体动力基础件与机电系统全国重点实验室,中国杭州,310058
目的:液压式足式机器人由于具有较高的功率质量比,在实现高动态运动方面具有巨大潜力。然而,如何同时保证其运动的稳定性与连续性仍面临挑战。本文旨在提出针对液压足式机器人动态跳跃运动的控制方法,在解决控制器优化过程中参数耦合问题的同时实现运动性能的多方面提升。
创新点:1.建立准真实仿真模型,准确反映液压肢腿单元的动态特性;2.提出基于强化学习的液压足式机器人运动控制框架;3.在样机上实现强化学习策略的部署与验证。
方法:1.基于液压驱动系统的动力学分析,结合物理可行性约束,构建液压肢腿单元的准真实模型;2.运用近端策略优化(PPO)强化学习算法,同时优化轨迹生成器与运动跟踪控制器的参数,并在仿真环境中训练控制策略;3.将训练后的策略部署于样机,在竖直跳跃和前向跳跃的不同工况下验证控制策略的性能。
结论:1.所提出的准真实模型能够准确反映物理样机的性能;2.运用强化学习控制框架的液压肢腿单元能够在仿真中实现连续且稳定的跳跃;3.训练后的策略成功部署于物理样机并在高度跟踪和落地柔顺性方面取得显著提升。

关键词:足式机器人;深度强化学习;准真实模型;液压系统;跳跃控制

Darkslateblue:Affiliate; Royal Blue:Author; Turquoise:Article

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