Author name cluster

Luyang Li

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6 papers

2 author rows

IROS Conference 2025 Conference Paper

Heterogeneous Graph Network-Based UWB Localization for Complex Indoor Environments

Bo Yang
Luyang Li
Sizhen He
Weinan Chen
Hong Zhang

Accurate indoor location-based services are important for mobile robots, especially in complex indoor environments. In this paper, we propose a heterogeneous graph network-based ultra-wide band (UWB) localization method to provide accurate and robust localization results for mobile robots in complex indoor scenarios. The core of our approach lies in constructing the anchors, ranging measurements and tags into a heterogeneous graph structure according to the topological structure of the UWB localization system, and then design a spatial-temporal heterogeneous graph attention neural network to extract high-level features and estimate the tag locations from the graph. Therefore, the geometric relationships contained in the UWB localization system are comprehensively established, while the spatial and temporal information contained in the ranging measurements can also be extracted. We validate the proposed method through real-world experiments. The results demonstrate that, compared to existing deep learning-based methods, the constructed heterogeneous graph better represents the geometric structure of the UWB localization system, and the designed heterogeneous graph neural network effectively extracts the spatial-temporal and geometric features. Consequently, the accuracy and robustness of UWB localization are significantly improved.

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TCS Journal 2024 Journal Article

Further construction of even-variable balanced rotation symmetric Boolean functions with optimal algebraic immunity

Qinglan Zhao
Pan Li
Dong Zheng
Luyang Li
Baodong Qin

The field of cryptography has given a lot of attention to rotation symmetric Boolean functions (RSBFs) because they possess special structures and include many functions with good cryptographic properties. It is difficult to construct even-variable balanced RSBFs with optimal algebraic immunity in the study on RSBFs. Recently, Mesnager et al. proposed the first and only construction of balanced RSBFs with optimal algebraic immunity for arbitrary even variables (Des. Codes Cryptogr. 89 (1) (2021) 1-17). The nonlinearity of their functions is not high. In this paper, we develop further research based on their construction and present a fresh design of n-variable balanced RSBFs with optimal algebraic immunity for arbitrary even n. Our functions have higher nonlinearity compared to their functions. Furthermore, the algebraic degree and fast algebraic immunity of our functions are not less than n − 2 for n not bigger than 16.

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IROS Conference 2016 Conference Paper

Pose graph optimization with hierarchical conditionally independent graph partitioning

Hengbo Tang
Yun-Hui Liu 0001
Luyang Li

In this paper, we propose a hierarchical pose graph optimization algorithm, which hierarchically divides a large pose graph into subgraphs and solves the optimization problem for each subgraph independently. Applying a modified graph partitioning algorithm, normalized cut, the original graph could be partitioned into subgraphs, which are conditionally independent on a set of key nodes. A modified normalized cut algorithm is applied to automatically partition a pose graph into several subgraphs, which are independent on each other when conditioned on a small number of keynodes. Preserving keynodes only, a simplified upper level graph is generated by a pose graph sparsification algorithm. Given the optimization results of all keynodes, which are obtained by solving the upper level graph, each subgraph in the lower level can be solved efficiently without concerning other subgraphs. The scale of each optimization is limited during graph partitioning. Therefore, the efficiency of the optimization is improved. Experiments with both public standard datasets and a dataset collected by an autonomous guided vehicle (AGV) system are conducted to test our algorithm.

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ICRA Conference 2015 Conference Paper

Design and control of a novel multi-state compliant safe joint for robotic surgery

Zerui Wang
Peng Li 0019
David Navarro-Alarcon
Hiu Man Yip
Yun-Hui Liu 0001
Weiyang Lin
Luyang Li

In this paper, we propose a novel design of compliant safe joint, which has flexibility when the work load exceeds a predefined threshold. The compliance is generated by a spring. We design a special transmission mechanism to convert axial motion into circumferential motion such that the linear compliance can be converted into circular one. When the end-effector of a surgical robot actuated by the compliant safe joints collides with patient's body, the compliance of the joints will protect the patient by absorbing part of the collision energy. Because of the system's special mechanical structure, the control methods should be different when it works under different states. We propose a simple algorithm to choose control methods so that the system can work both under rigid and flexible states with different controllers. We have built a prototype to validate the design and the controller.

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IROS Conference 2014 Conference Paper

Visual servoing based trajectory tracking of underactuated water surface robots without direct position measurement

Kai Wang
Yun-Hui Liu 0001
Luyang Li

The trajectory tracking of underactuated water surface robots (or boats, surface vessels, etc.) has been an attractive topic over the past decade, and a lot of controllers are proposed for this challenging problem. However, most of the existing trajectory tracking controllers of the underactuated water surface robots assume the global positions of the robots can be accurately measured. In the working environments of the robots, the global position measurements are sometimes unstable or even unavailable. To avoid the direct position measurement, a new controller is proposed in this paper for the trajectory tracking of underactuated water surface robots by adopting the monocular visual feedback. This controller works on the basis of a novel adaptive algorithm for estimating global position of the robot online using visual feature tracking from a monocular camera, and its orientation and velocity measured by the AHRS (Attitude and Heading Reference System) sensor and visual odometry. It is proved by Lyapunov theory that the proposed adaptive visual servo controller gives rise to the asymptotic trajectory tracking and convergence of the position estimation to the actual position. An experiment is conducted to validate the effectiveness and robust performance of the proposed controller.

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ICRA Conference 2013 Conference Paper

Vision-based tracking control of nonholonomic mobile robots without position measurement

Kai Wang
Yun-Hui Liu 0001
Luyang Li

Localization is one of the most crucial and difficult problems for motion control of mobile robots despite of tremendous research efforts made for years. This paper presents a new vision-based controller for controlling a nonholonomic mobile robot to track a desired trajectory without directly measuring its position. A novel adaptive estimator is embedded into this new controller to estimate global position of the mobile robot online using natural visual features measured by a vision system, and its orientation and velocity measured by odometry/inertia/magnetic sensors. It is proved by Lyapunov theory that the proposed controller gives rise to asymptotic tracking of a desired trajectory and convergence of the position estimation to the actual position. The experiment is conducted to validate the proposed controller.

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