Pub Date : 2024-11-11DOI: 10.1109/LRA.2024.3495453
Farhad Aghili
This paper introduces an innovative guidance and control method for simultaneously capturing and stabilizing a target satellite using a spinning-base servicing satellite equipped with a robotic manipulator, joint locks, and reaction wheels (RWs). We assume the target satellite reaches a state of minimum kinetic energy due to the slow dissipation of energy caused by internal friction, resulting in a pure major axis spin. The method involves controlling the RWs of the servicing satellite to replicate the spinning motion of the target satellite while locking the manipulator's joints to achieve spin-matching. This maneuver makes the target stationary with respect to the rotating frame of the servicing satellite located at its center-of-mass (CoM), simplifying the robot capture trajectory planning and eliminating post-capture trajectory planning entirely. In the next phase, the joints are unlocked, and a coordination controller drives the robotic manipulator to capture the target satellite while maintaining zero relative rotation between the servicing and target satellites. The spin stabilization phase begins after completing the capture phase, where the joints are locked to form a single tumbling rigid body consisting of the rigidly connected servicing and target satellites. An optimal controller applies negative control torques to the RWs to dampen out the tumbling motion of the interconnected satellites as quickly as possible, subject to the actuation torque limit of the RWs and the maximum torque and force exerted by the manipulator's end-effector.
{"title":"Spinning-Base Space Robot for Seamless Capture and Stabilization of Rotating Objects","authors":"Farhad Aghili","doi":"10.1109/LRA.2024.3495453","DOIUrl":"https://doi.org/10.1109/LRA.2024.3495453","url":null,"abstract":"This paper introduces an innovative guidance and control method for simultaneously capturing and stabilizing a target satellite using a spinning-base servicing satellite equipped with a robotic manipulator, joint locks, and reaction wheels (RWs). We assume the target satellite reaches a state of minimum kinetic energy due to the slow dissipation of energy caused by internal friction, resulting in a pure major axis spin. The method involves controlling the RWs of the servicing satellite to replicate the spinning motion of the target satellite while locking the manipulator's joints to achieve spin-matching. This maneuver makes the target stationary with respect to the rotating frame of the servicing satellite located at its center-of-mass (CoM), simplifying the robot capture trajectory planning and eliminating post-capture trajectory planning entirely. In the next phase, the joints are unlocked, and a coordination controller drives the robotic manipulator to capture the target satellite while maintaining zero relative rotation between the servicing and target satellites. The spin stabilization phase begins after completing the capture phase, where the joints are locked to form a single tumbling rigid body consisting of the rigidly connected servicing and target satellites. An optimal controller applies negative control torques to the RWs to dampen out the tumbling motion of the interconnected satellites as quickly as possible, subject to the actuation torque limit of the RWs and the maximum torque and force exerted by the manipulator's end-effector.","PeriodicalId":13241,"journal":{"name":"IEEE Robotics and Automation Letters","volume":"9 12","pages":"11593-11600"},"PeriodicalIF":4.6,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142672204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-11DOI: 10.1109/LRA.2024.3495372
Bang-Shien Chen;Yu-Kai Lin;Jian-Yu Chen;Chih-Wei Huang;Jann-Long Chern;Ching-Cherng Sun
Robust estimation is essential in computer vision, robotics, and navigation, aiming to minimize the impact of outlier measurements for improved accuracy. We present a fast algorithm for Geman-McClure robust estimation, FracGM, leveraging fractional programming techniques. This solver reformulates the original non-convex fractional problem to a convex dual problem and a linear equation system, iteratively solving them in an alternating optimization pattern. Compared to graduated non-convexity approaches, this strategy exhibits a faster convergence rate and better outlier rejection capability. In addition, the global optimality of the proposed solver can be guaranteed under given conditions. We demonstrate the proposed FracGM solver with Wahba's rotation problem and 3-D point-cloud registration along with relaxation pre-processing and projection post-processing. Compared to state-of-the-art algorithms, when the outlier rates increase from 20% to 80%, FracGM shows 53% and 88% lower rotation and translation increases. In real-world scenarios, FracGM achieves better results in 13 out of 18 outcomes, while having a 19.43% improvement in the computation time.
{"title":"FracGM: A Fast Fractional Programming Technique for Geman-McClure Robust Estimator","authors":"Bang-Shien Chen;Yu-Kai Lin;Jian-Yu Chen;Chih-Wei Huang;Jann-Long Chern;Ching-Cherng Sun","doi":"10.1109/LRA.2024.3495372","DOIUrl":"https://doi.org/10.1109/LRA.2024.3495372","url":null,"abstract":"Robust estimation is essential in computer vision, robotics, and navigation, aiming to minimize the impact of outlier measurements for improved accuracy. We present a fast algorithm for Geman-McClure robust estimation, FracGM, leveraging fractional programming techniques. This solver reformulates the original non-convex fractional problem to a convex dual problem and a linear equation system, iteratively solving them in an alternating optimization pattern. Compared to graduated non-convexity approaches, this strategy exhibits a faster convergence rate and better outlier rejection capability. In addition, the global optimality of the proposed solver can be guaranteed under given conditions. We demonstrate the proposed FracGM solver with Wahba's rotation problem and 3-D point-cloud registration along with relaxation pre-processing and projection post-processing. Compared to state-of-the-art algorithms, when the outlier rates increase from 20% to 80%, FracGM shows 53% and 88% lower rotation and translation increases. In real-world scenarios, FracGM achieves better results in 13 out of 18 outcomes, while having a 19.43% improvement in the computation time.","PeriodicalId":13241,"journal":{"name":"IEEE Robotics and Automation Letters","volume":"9 12","pages":"11666-11673"},"PeriodicalIF":4.6,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142679352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-11DOI: 10.1109/LRA.2024.3495455
Neng Wang;Xieyuanli Chen;Chenghao Shi;Zhiqiang Zheng;Hongshan Yu;Huimin Lu
Loop closing is a crucial component in SLAM that helps eliminate accumulated errors through two main steps: loop detection and loop pose correction. The first step determines whether loop closing should be performed, while the second estimates the 6-DoF pose to correct odometry drift. Current methods mostly focus on developing robust descriptors for loop closure detection, often neglecting loop pose estimation. A few methods that do include pose estimation either suffer from low accuracy or incur high computational costs. To tackle this problem, we introduce SGLC, a real-time semantic graph-guided full loop closing method, with robust loop closure detection and 6-DoF pose estimation capabilities. SGLC takes into account the distinct characteristics of foreground and background points. For foreground instances, it builds a semantic graph that not only abstracts point cloud representation for fast descriptor generation and matching but also guides the subsequent loop verification and initial pose estimation. Background points, meanwhile, are exploited to provide more geometric features for scan-wise descriptor construction and stable planar information for further pose refinement. Loop pose estimation employs a coarse-fine-refine registration scheme that considers the alignment of both instance points and background points, offering high efficiency and accuracy. Extensive experiments on multiple publicly available datasets demonstrate its superiority over state-of-the-art methods. Additionally, we integrate SGLC into a SLAM system, eliminating accumulated errors and improving overall SLAM performance.
闭环是 SLAM 的一个重要组成部分,它通过两个主要步骤帮助消除累积误差:环路检测和环路姿态校正。第一步是确定是否应执行闭环,第二步是估计 6-DoF 姿态以纠正里程漂移。目前的方法大多侧重于开发用于环路闭合检测的鲁棒描述符,往往忽略了环路姿态估计。少数包含姿态估计的方法要么精度低,要么计算成本高。为了解决这个问题,我们引入了 SGLC,这是一种实时语义图引导的全闭环方法,具有鲁棒闭环检测和 6-DoF 姿势估计功能。SGLC 考虑了前景点和背景点的不同特征。对于前景实例,它建立了一个语义图,不仅抽象了点云表示,以便快速生成描述符和进行匹配,还能指导后续的环路验证和初始姿态估计。同时,背景点还能为扫描描述符的构建提供更多几何特征,并为进一步的姿态改进提供稳定的平面信息。环路姿态估计采用了一种粗-细-精配准方案,该方案同时考虑了实例点和背景点的配准,具有高效率和高精度的特点。在多个公开数据集上进行的广泛实验证明,它优于最先进的方法。此外,我们还将 SGLC 集成到 SLAM 系统中,消除了累积误差,提高了 SLAM 的整体性能。
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Pub Date : 2024-11-11DOI: 10.1109/LRA.2024.3495574
Jennifer A. Shum;Perrin E. Schiebel;Alyssa M. Hernandez;Robert J. Wood
While previous studies have explored electroadhesive climbing using the insect-scale Harvard Ambulatory Microrobot platform, the robot's ability to climb reliably over irregular terrain has remained limited. To evaluate potential solutions, we conducted an investigation of the electroadhesive pad design space and characterized the shear force climbing capabilities of the robot with different pad designs. We find that on smooth, flat terrains, a large simple circular footpad structure exhibited the greatest shear forces. However, on rougher inclined surfaces, pads which adjusted the width, length, and number of spoke-like features provide greater compliance and achieve more consistent shear adhesion forces. Such compliant spoke pad designs on rough surfaces performed with 84 % stick reliability and 1.02 kPa average adhesion forces compared to 45 % stick reliability and 0.81 kPa average adhesion forces for a comparable circular pad. We demonstrate the improved climbing capability of the 4.5 cm robot on terrain with 75 $mu$