Robot Learning

ISSN: 2960-1436 (Print)

ISSN: 2960-1444 (Online)

CODEN: RLABAV

About This Journal
Special Issues
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Human-in-the-Loop Robot Learning in the Era of Foundation Models: Challenges and Opportunities
Special Issue Editor:   Jianzhuang Zhao, Xing Liu, Marta Lagomarsino, Francesco Tassi, Shufei Li, Chao Zeng, Chenguang Yang, Wansoo Kim
Submission Deadline:  01 October 2026
Human-Robot Interaction and Human-Centered Robotics
Special Issue Editor:   Anqing Duan, Shuo Ding, Junling Fu, Elisa Iovene, Sipu Ruan, Peng Zhou, Chenguang Yang
Submission Deadline:  31 December 2026
Intelligent Vision-Driven Robotics
Special Issue Editor:   Peng Zhou, David Navarro-Alarcon
Submission Deadline:  31 December 2026
Learning-Based Motion Planning and Control for Contact-Rich Legged Robots
Special Issue Editor:   Jiatao Ding, Peng Xu, Dongliang Zheng, Zhenyu Lu, Ning Wang, Yanlong Huang
Submission Deadline:  30 September 2026
Latest Articles
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Smooth LiDAR–Inertial–Joint Odometry for perception-driven legged locomotion
Bingquan Li,Jia Pan,Tianwei Zhang
Article10 Aug 2026OPEN ACCESS

Light Detection and Ranging (LiDAR)–Inertial Odometry (LIO), which tightly fuses complementary data from LiDAR and Inertial Measurement Units (IMUs), is a key technology for high-precision state estimation in legged robot navigation. However, conventional Iterative Closest Point (ICP)-based LIO  frameworks provide only pose constraints. Their position estimates often exhibit centimetre-level jitter due to LiDAR measurement noise, especially when the robot is stationary or moving slowly. This temporal inconsistency degrades the performance of downstream perception-driven motion planning and control.  In this paper, we propose LiDAR–Inertial–Joint Odometry (LIJO), a novel state estimation framework for quadruped robots that integrates LiDAR, IMU, and joint encoder measurements within a manifold extended Kalman filter (EKF). The torso velocity is first estimated from joint angles and angular velocities via forward kinematics and is then used as a proprioceptive velocity factor in the EKF prediction step.  To cope with foot slippage and aggressive motions, we further design a dynamic weighting scheme that adaptively adjusts the confidence of the joint-based velocity factor according to the current motion speed,  while treating IMU measurements as filter observations rather than inputs. The resulting system maintains the localization accuracy of state-of-the-art LIO methods and significantly suppresses high-frequency jitter in the estimated trajectory. Extensive experiments on a real quadruped robot in challenging outdoor scenarios, including steep staircases and large-scale loop trajectories, show that LIJO produces smoother and more stable odometry than existing LIO and kinematic-inertial baselines, while preserving real-time performance. The proposed approach thus provides more reliable state inputs for perception and control modules in all-terrain legged locomotion.

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Impact-aware compliant foot placement for quiet humanoid locomotion via reinforcement learning
Kai Jian,Shaojie Zhang,Dong Zhu,Xiangyu Shao
Article27 Jul 2026OPEN ACCESS

Recent advances in legged robots have substantially improved their locomotion capabilities over outdoor and complex terrains. However, quiet locomotion for humanoid robots in noise-sensitive indoor environments remains underexplored, despite its growing importance in human-centered applications.  While encouraging progress has been made in quadrupedal robots, transferring the quiet locomotion ability to humanoid robots remains nontrivial due to their fundamentally different foot-ground contact patterns. This paper proposes a control method for reducing foot–ground contact noise during humanoid walking, achieving compliant contact and continuous regulation of locomotion noise by establishing a foot corner contact model along with a virtual compliance parameter. The experimental results show that the average sound pressure level is reduced by 4.88 dB.

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Design of a soft gripper with a changeable adapter for enhanced grasping and manipulation
Chengqi Song,Jingxiang Wang,Qinglei Bu,Jie Sun,Qinyao Liu
Article21 Jul 2026OPEN ACCESS

Soft grippers utilize compliant materials to achieve adaptable grasping, yet they often face challenges in accommodating objects with widely varying dimensions due to their fixed kinematic structures. This paper presents the design, fabrication, modeling, and control of a novel soft gripper featuring a rigid-flexible coupled variable range adapter. By integrating a motorized crank-slider mechanism with soft pneumatic fingers, the gripper achieves a dynamic volumetric workspace capable of manipulating objects ranging from compact to large geometries. Theoretical modeling and experimental characterization reveal that the adapter serves a dual purpose: it not only expands the effective workspace but also functions as a mechanical force amplifier, capable of exponentially boosting the contact force through kinematic reconfiguration. Furthermore, an intuitive Human-in-the-Loop (HITL) teleoperation strategy is established using wearable flex sensors. This control framework maps human gestures to robotic actuation, leveraging human visual feedback as a high-level perception loop to validate the open-loop response of the soft actuators. Experimental results demonstrate that this integrated system significantly improves adaptability and payload stability for diverse object geometries compared to fixed-base counterparts.

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Review on path planning for obstacle avoidance oriented to micro-/nanorobots
Tongzhou Ye,Tianhao Peng,Lidong Yang
Review14 Nov 2024OPEN ACCESS
Path planning algorithms are indispensable for controlling micro-/nanorobots through complex and unknown environments in the biomedical and medical fields. With the tasks performed becoming more complex, higher-quality paths are required to avoid obstacles for ensuring the safe and efficient movement of micro-/nanorobots. A comparative analysis of path planning algorithms is conducted to elucidate the algorithm’s application and optimization for different environments. According to the environment modeling approach, existing path planning algorithms are classified into searching, sampling, and dynamic aspects. Searching path planning algorithms directly retrieve the global path possessing minimum cost from the modeled static waypoints. Sampling path planning algorithms employ randomly sampled waypoints within the target space, which eliminates the necessity for environmental modeling. Dynamic path planning algorithms utilize local paths to regulate the motion of micro-/nanorobots in real time. Deep learning networks based on big data will become an important research direction for the control and navigation of micro-/nanorobots. The advantages and limitations of path planning algorithms in varied spatial contexts are elucidated through detailed examples and descriptions, providing a comprehensive understanding of performance and applicability. This review underscores recent advancements in this emerging domain and stands as a testament to the dynamic landscape of micro-/nanorobotics and the continual pursuit of superior motion control solutions.
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Survey on heterogeneous aquatic robot systems: communication, perception, navigation, control, decision-making and energy management
Ruonan Liu,Xiuzhong Hu,Zihan Jiang,Junzhi Wang,Weidong Zhang
Survey30 May 2025OPEN ACCESS
Heterogeneous aquatic robot systems, consisting of ROVs, AUVs, ASVs, and UAVs, are vital for environmental exploration, monitoring, and task execution. This paper presents advancements in critical technologies within these systems, focusing on communication (underwater acoustic, radio, and optical), multi-sensor fusion, and collaborative navigation techniques. It reviews control strategies like deep reinforcement learning, end-to-end control, and large model-based methods, addressing autonomous decision-making and adaptability in complex environments. The paper also discusses energy management strategies for efficient storage, utilization, and recovery. Furthermore, it explores the ethical and environmental impacts of deploying such systems, emphasizing sustainability and minimizing ecological disruptions. Finally, case studies and applications in ocean exploration and environmental monitoring are highlighted, showcasing the real-world utility and future potential of heterogeneous aquatic robot systems. This work provides valuable insights into the technological, ethical, and practical considerations for developing these systems.
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Optimizing scene flow with neural rigidity prior
Zhiheng Feng,Jiuming Liu,Hesheng Wang
Article28 Nov 2024OPEN ACCESS
Scene flow estimation provides the 3D low-level motion understanding in dynamic scenes. In this paper, we propose an optimization-based scene flow estimation method with neural rigidity prior for the autonomous driving environment. Specifically, we utilize the rigidity prior of dynamic scenes to partition the point clouds into pillars of different resolutions. Then, the flow vector of a point is represented as the average of local rigid transformations associated with the different pillars to which it belongs. To model local rigidity, we employ the neural implicit representation for encoding the intrinsic constraints of pillars. Our method achieves state-of-the-art accuracy on three commonly-used autonomous driving datasets: Argoverse, Waymo, and nuScenes, and even surpasses previous supervised learning-based methods. Experiment results demonstrate the effectiveness of our method, particularly on sparse points in the autonomous driving scene.
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