In this paper, an efficient motion planning approach with grid-based generalized Voronoi diagrams (G2VD) is newly proposed for mobile robots. Different from existing approaches, the novelty of this work is twofold: 1)...
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In this paper, an efficient motion planning approach with grid-based generalized Voronoi diagrams (G2VD) is newly proposed for mobile robots. Different from existing approaches, the novelty of this work is twofold: 1) a new state lattice-based path searching approach is proposed, in which the search space is reduced to a novel Voronoi corridor to further improve the search efficiency; 2) an efficient quadratic programming-based path smoothing approach is presented, wherein the clearance to obstacles is considered to improve the path clearance of hard-constrained path smoothing approaches. We validate the efficiency and smoothness of our approach in various challenging simulation scenarios and outdoor environments. It is shown that the computational efficiency is improved by 17.1% in the path searching stage, and path smoothing with the proposed approach is 6.6 times faster than an advanced sparse-banded structure-based path smoothing approach and 53.3 times faster than the popular timed-elastic-band planner. A video showing outdoor navigation on our campus is available at https://***/iMXGthgvp58 . Note to Practitioners—This paper is motivated by the challenges of motion planning problems of mobile robots. An efficient motion planning approach called G2VD planner is proposed by combining path searching, path smoothing, and time-optimal velocity planning. Extensive simulation and experimental results show the effectiveness of the proposed motion planning approach. However, the prediction information of dynamic obstacles is not incorporated in the proposed motion planner, thus the motion planner may be a bit sluggish in response to dynamic obstacles. Furthermore, we plan to integrate the intention/trajectory prediction of pedestrians/vehicles into the proposed framework to enhance the foreseeability of the motion planner.
Neural architecture search (NAS) has shown great promise in automatically designing lightweight models. However, conventional approaches are insufficient in training the supernet and pay little attention to actual rob...
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ISBN:
(数字)9798350377705
ISBN:
(纸本)9798350377712
Neural architecture search (NAS) has shown great promise in automatically designing lightweight models. However, conventional approaches are insufficient in training the supernet and pay little attention to actual robot hardware resources. To meet such challenges, we propose RAM-NAS, a resource-aware multi-objective NAS method that focuses on improving the supernet pretrain and resource-awareness on robot hardware devices. We introduce the concept of subnets mutual distillation, which refers to mutually distilling all subnets sampled by the sandwich rule. Additionally, we utilize the Decoupled Knowledge Distillation (DKD) loss to enhance logits distillation performance. To expedite the search process with consideration for hardware resources, we used data from three types of robotic edge hardware to train Latency Surrogate predictors. These predictors facilitated the estimation of hardware inference latency during the search phase, enabling a unified multi-objective evolutionary search to balance model accuracy and latency trade-offs. Our discovered model family, RAM-NAS models, can achieve top-1 accuracy ranging from 76.7% to 81.4% on ImageNet. In addition, the resource-aware multi-objective NAS we employ significantly reduces the model’s inference latency on edge hardware for robots. We conducted experiments on downstream tasks to verify the scalability of our methods. The inference time for detection and segmentation is reduced on all three hardware types compared to MobileNetv3-based methods. Our work fills the gap in NAS for robot hardware resource-aware.
Stroke often leads to foot inversion, seriously affecting the patients' walking ability. In this paper, a lightweight, soft exosuit, JHT-EXO, is proposed for correcting foot inversion to help patients' gait re...
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ISBN:
(数字)9798331509644
ISBN:
(纸本)9798331509651
Stroke often leads to foot inversion, seriously affecting the patients' walking ability. In this paper, a lightweight, soft exosuit, JHT-EXO, is proposed for correcting foot inversion to help patients' gait rehabilitation. JHT-EXO mainly consists of two cable driving modules, two foot feedback modules, and a control module, with a total weight of no more than 2.5 kg. The cable driving module can pre-tighten the cable with a designed constant torque spring to prevent the cable from falling off. When the motor is not energized, it can still assist the person in stabilizing the walking gait and reducing power consumption. Customized foot pressure sensors recognize human gait, and IMUs on the feet measure the ankle angle used by the controller to change the output force of the exosuit. The constant torque spring was calibrated and tested, and the experimental results showed that the average output force of the constant torque spring was 20.0 N, with a maximum error of 5.6% compared to the theoretically calculated results. The ground walking test of the exosuit was performed by three subjects in three conditions: wearing the exosuit powered up, wearing the exosuit unpowered, and not wearing the exosuit. The test results showed that JHT-EXO could effectively reduce the ankle inversion angle by $22.11^\circ$ compared to not wearing the exosuit. JHT-EXO is feasible in preventing foot drop and stabilizing flip, and its high mobility and portability show potential for gait rehabilitation of foot inversion patients.
Fiber Bragg Gratings (FBG) are used widely for that it is small and sensitive. It is suitable to insert a sensor based on FBGs to some narrow cavities. At the same time, a slender continuum structure requires tiny sen...
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ISBN:
(数字)9798350394245
ISBN:
(纸本)9798350394252
Fiber Bragg Gratings (FBG) are used widely for that it is small and sensitive. It is suitable to insert a sensor based on FBGs to some narrow cavities. At the same time, a slender continuum structure requires tiny sensors inside it. A multi-node differential curvature measurement sensor of FBG fiber is designed in this paper to realize temperature compensation. Considering the friction among FBG, driving wires, and niti tube and external forces applied on the end, a mechanical model about the FBG sensor and the continuum manipulator is proposed. At last, a linear interpolation method is used in the curvature estimation. Under the condition that there is no end resistance and only the bending moment and friction along the outer surface of the continuum generated by the steel wire driven by the motor the absolute measurement error of the position of the end of the continuum is 1.9mm.
Water jet–guided laser processing technology (WJGL) has gradually entered the field of high precision manufacturing due to its excellent processing quality. In this study, the pressure signals of plasma shock waves d...
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Aiming at the demand for intelligent operation and maintenance of large-scale oil-immersed power transformers with high reliability tasks, the research on risk-driven design methods for power transformer internal insp...
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In this paper, a novel loss function for key point detection, named Helium Loss is proposed. All our experiments are based on Ultralytics' YOLOv8n-pose architecture. Initially, this paper analyze various existing ...
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ISBN:
(数字)9798350350302
ISBN:
(纸本)9798350350319
In this paper, a novel loss function for key point detection, named Helium Loss is proposed. All our experiments are based on Ultralytics' YOLOv8n-pose architecture. Initially, this paper analyze various existing loss functions, including L1 loss, L2 loss, and smooth L1 loss. There is a problem that current loss functions do not account for issues related to the quality of dataset annotations and unclear boundaries of targets. To address this challenge, this paper introduce a loss function that incorporates partial trust in annotated key points and utilizes Gaussian distribution to mitigate the impact of manual annotations.
In this paper we proposed a brachytherapy robotic system. The system uses a 7-Dof robotic arm and a set of tools to complete puncture and seeds implantation. We designed end tools for puncture and seed implantation se...
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ISBN:
(数字)9798350372694
ISBN:
(纸本)9798350372700
In this paper we proposed a brachytherapy robotic system. The system uses a 7-Dof robotic arm and a set of tools to complete puncture and seeds implantation. We designed end tools for puncture and seed implantation separately. A workflow based on this system has also been proposed. Finally, we used this system to conduct six animal experiments. The experimental results showed that the average error of seed implantation was 2.48mm, the minimum error is only 0.5mm, the maximum error reached 5.2mm.
The steam generator tube sheet quadruped maintenance robot is a novel mobile robot designed for the inspection of steam generator heat transfer tubes. This paper presents a motion planning method for this type of robo...
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ISBN:
(数字)9798350388077
ISBN:
(纸本)9798350388084
The steam generator tube sheet quadruped maintenance robot is a novel mobile robot designed for the inspection of steam generator heat transfer tubes. This paper presents a motion planning method for this type of robot. The trajectory of the robot's base is planned through kinematic solutions search. Additionally, a foothold motion evaluation system is established using the Technique for Order of Preference by Similarity to Ideal Solution algorithm to plan the movement of foothold points. For a given motion path, our proposed method divides the path into multiple straight-line segments, and then performs separate planning for turning foothold points and straight-line foothold points. The experiments demonstrate that the proposed algorithm is adaptable to steam generator tube sheets and performs well in environments with obstacles since the algorithm proposed has a planning success rate of 100% for the tube sheet robot. The experiments validate the effectiveness and feasibility of the proposed method.
Analyzing and forecasting trajectories of agents like pedestrians plays a pivotal role for embodied intelligent applications. The inherent indeterminacy of human behavior and complex social interaction among a rich va...
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