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  • 1
    Online Resource
    Online Resource
    Path Planning Using a Tangent Graph for Mobile Robots Among Polygonal and Curved Obstacles : Communication
    SAGE Publications ; 1992
    In:  The International Journal of Robotics Research Vol. 11, No. 4 ( 1992-08), p. 376-382
    Details
    In: The International Journal of Robotics Research, SAGE Publications, Vol. 11, No. 4 ( 1992-08), p. 376-382
    Abstract: This article proposes a tangent graph for path planning of mobile robots among obstacles with a general boundary. The tangent graph is defined on the basis of the locally shortest path. It has the same data structure as the visibility graph, but its nodes represent common tangent points on obstacle boundaries, and its edges correspond to collision-free common tangents between the boundaries and convex boundary seg ments between the tangent points. The tangent graph requires O( K 2 ) memory, where K denotes the total number of convex segments of the obstacle boundaries. The tangent graph in cludes all locally shortest paths and is capable of coping with path planning not only among polygonal obstacles but also among curved obstacles.
    Type of Medium: Online Resource
    ISSN: 0278-3649 , 1741-3176
    URL: Article
    DOI: 10.1177/027836499201100409
    Language: English
    Publisher: SAGE Publications
    Publication Date: 1992
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  • 2
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    Decentralized Adaptive and Nonadaptive Position/Force Controllers for Redundant Manipulators in Cooperations
    SAGE Publications ; 1998
    In:  The International Journal of Robotics Research Vol. 17, No. 3 ( 1998-03), p. 232-247
    Details
    In: The International Journal of Robotics Research, SAGE Publications, Vol. 17, No. 3 ( 1998-03), p. 232-247
    Abstract: This paper addresses the problem of controlling positions and forces of multiple redundant manipulators cooperatively handling an ob ject in a decentralized manner while optimizing a performance in dex. The authors propose one adaptive and two nonadaptive de centralized controllers. The adaptive controller is able to cope with unknown or uncertain physical parameters of the system. The Lya punov approach proves that this controller not only yields asymp totic convergence of the position and force errors but also opti mizes the specified performance index. To improve the transition performance, besides the nonadaptive version of the controller, an implicit decentralized force controller with exponential stability is developed. The controllers realize the force and position controls simultaneously by using coupled force and position signals. The coupled signals distinguish these methods from traditional hybrid controllers in which decoupling of the signals is a must. The de centralized architectures of all the controllers must be emphasized. In detail, the joint input for each robot is designed in its own state space; thus, no coordinator exists, and the computation cost is less expensive than that of centralized controllers designed in the state space of the whole system.
    Type of Medium: Online Resource
    ISSN: 0278-3649 , 1741-3176
    URL: Article
    DOI: 10.1177/027836499801700302
    Language: English
    Publisher: SAGE Publications
    Publication Date: 1998
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  • 3
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    Online Resource
    Modal-graph 3D shape servoing of deformable objects with raw point clouds
    SAGE Publications ; 2023
    In:  The International Journal of Robotics Research
    Details
    In: The International Journal of Robotics Research, SAGE Publications
    Abstract: Deformable object manipulation (DOM) with point clouds has great potential as nonrigid 3D shapes can be measured without detecting and tracking image features. However, robotic shape control of deformable objects with point clouds is challenging due to: the unknown point correspondences and the noisy partial observability of raw point clouds; the modeling difficulties of the relationship between point clouds and robot motions. To tackle these challenges, this paper introduces a novel modal-graph framework for the model-free shape servoing of deformable objects with raw point clouds. Unlike the existing works studying the object’s geometry structure, we propose a modal graph to describe the low-frequency deformation structure of the DOM system, which is robust to the measurement irregularities. The modal graph enables us to directly extract low-dimensional deformation features from raw point clouds without extra processing of registrations, refinements, and occlusion removal. It also preserves the spatial structure of the DOM system to inverse the feature changes into robot motions. Moreover, as the framework is built with unknown physical and geometric object models, we design an adaptive robust controller to deform the object toward the desired shape while tackling the modeling uncertainties, noises, and disturbances online. The system is proved to be input-to-state stable (ISS) using Lyapunov-based methods. Extensive experiments are conducted to validate our method using linear, planar, tubular, and volumetric objects under different settings.
    Type of Medium: Online Resource
    ISSN: 0278-3649 , 1741-3176
    URL: Article
    DOI: 10.1177/02783649231198900
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
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  • 4
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    Integrated planning and control of robotic surgical instruments for task autonomy
    SAGE Publications ; 2023
    In:  The International Journal of Robotics Research Vol. 42, No. 7 ( 2023-06), p. 504-536
    Details
    In: The International Journal of Robotics Research, SAGE Publications, Vol. 42, No. 7 ( 2023-06), p. 504-536
    Abstract: Agile maneuvers are essential for robot-enabled complex tasks such as surgical procedures. Prior explorations on surgery autonomy are limited to feasibility study of completing a single task without systematically addressing generic manipulation safety across different tasks. We present an integrated planning and control framework for 6-DoF robotic instruments for pipeline automation of surgical tasks. We leverage the geometry of a robotic instrument and propose the nodal state space to represent the robot state in SE (3) space. Each elementary robot motion could be encoded by regulation of the state parameters via a dynamical system. This theoretically ensures that every in-process trajectory is globally feasible and stably reached to an admissible target, and the controller is of closed-form without computing 6-DoF inverse kinematics. Then, to plan the motion steps reliably, we propose an interactive (instant) goal state of the robot that transforms manipulation planning through desired path constraints into a goal-varying manipulation (GVM) problem. We detail how GVM could adaptively and smoothly plan the procedure (could proceed or rewind the process as needed) based on on-the-fly situations under dynamic or disturbed environment. Finally, we extend the above policy to characterize complete pipelines of various surgical tasks. Simulations show that our framework could smoothly solve twisted maneuvers while avoiding collisions. Physical experiments using the da Vinci Research Kit validates the capability of automating individual tasks including tissue debridement, dissection, and wound suturing. The results confirm good task-level consistency and reliability compared to state-of-the-art automation algorithms.
    Type of Medium: Online Resource
    ISSN: 0278-3649 , 1741-3176
    URL: Article
    DOI: 10.1177/02783649231179753
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
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  • 5
    Online Resource
    Online Resource
    Computing n-Finger Form-Closure Grasps on Polygonal Objects
    SAGE Publications ; 2000
    In:  The International Journal of Robotics Research Vol. 19, No. 2 ( 2000-02), p. 149-158
    Details
    In: The International Journal of Robotics Research, SAGE Publications, Vol. 19, No. 2 ( 2000-02), p. 149-158
    Abstract: This paper presents an efficient algorithm for computing all n-finger form-closure grasps on a polygonal object based on a new sufficient and necessary condition for form-closure. With this new condition, it is possible to transfer the problem of computing the form-closure grasp in R 3 to one in R 1 . We demonstrate that the non-form-closure grasps consist of two convex polytopes in the space of n parameters representing grasp points on sides of the polygon. The proposed algorithm works efficiently for n ≤ 3 and takes O(n 3n/2 ) time for n 〉 3, where n denotes the number of the fingers. The algorithm has been implemented and its efficiency has been confirmed with two examples.
    Type of Medium: Online Resource
    ISSN: 0278-3649 , 1741-3176
    URL: Article
    DOI: 10.1177/02783640022066798
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2000
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  • 6
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    On the visual deformation servoing of compliant objects: Uncalibrated control methods and experiments
    SAGE Publications ; 2014
    In:  The International Journal of Robotics Research Vol. 33, No. 11 ( 2014-09), p. 1462-1480
    Details
    In: The International Journal of Robotics Research, SAGE Publications, Vol. 33, No. 11 ( 2014-09), p. 1462-1480
    Abstract: In this paper, we address the active deformation control of compliant objects by robot manipulators. The control of deformations is needed to automate several important tasks, for example, the manipulation of soft tissues, shaping of food materials, or needle insertion. Note that in many of these applications, the object’s deformation properties are not known. To cope with this issue, in this paper we present two new visual servoing approaches to explicitly servo-control elastic deformations. The novelty of our kinematic controllers lies in its uncalibrated behavior; our adaptive methods do not require the prior identification of the object’s deformation model and the camera’s intrinsic/extrinsic parameters. This feature provides a way to automatically control deformations in a model-free manner. The experimental results that we report validate the feasibility of our controllers.
    Type of Medium: Online Resource
    ISSN: 0278-3649 , 1741-3176
    URL: Article
    DOI: 10.1177/0278364914529355
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2014
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  • 7
    Online Resource
    Online Resource
    Application of a Proportional Feedback Controller for Active Control of a Vibration Isolator
    SAGE Publications ; 2005
    In:  Journal of Low Frequency Noise, Vibration and Active Control Vol. 24, No. 3 ( 2005-09), p. 181-190
    Details
    In: Journal of Low Frequency Noise, Vibration and Active Control, SAGE Publications, Vol. 24, No. 3 ( 2005-09), p. 181-190
    Abstract: This paper proposes the application of a proportional controller to active vibration control incorporated with a passive vibration isolator to suppress its resonant oscillation at its natural frequency. Vibration acceleration acquired from an accelerometer is fed to the controller as a feedback signal. The processed signal from the controller is transmitted to the voice coil actuator in order to control the vibration. Firstly, based on the theoretical equations which govern the vibrational system, the physical mechanism of active control in the total system is studied. Then, vibration on a stiff foundation and passive isolator is measured in order to understand the efficiency of the traditional vibration control method. Finally, an experiment on active vibration control is performed to study the suppression efficiency of the oscillation of the passive vibration isolator. The experiment results show that 99% of the vibration energy can be cancelled by active control.
    Type of Medium: Online Resource
    ISSN: 1461-3484 , 2048-4046
    URL: Article
    DOI: 10.1260/026309205775374442
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2005
    detail.hit.zdb_id: 2025887-2
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  • 8
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    Online Resource
    The Design and Implementation of Proportional Feedback Controller for the Distortion Improvement of Vibrator in Low Frequency Motion
    SAGE Publications ; 2003
    In:  Journal of Low Frequency Noise, Vibration and Active Control Vol. 22, No. 3 ( 2003-09), p. 173-181
    Details
    In: Journal of Low Frequency Noise, Vibration and Active Control, SAGE Publications, Vol. 22, No. 3 ( 2003-09), p. 173-181
    Abstract: The Total Harmonic Distortion (T.H.D.) of acceleration involved in the vibrator power amplifier combination of the low-frequency primary vibration calibration system at CMS/ITRI is higher than 2% at frequencies below 2 Hz before control. This is outside the requirement of ISO 16063–11. A waveform comparison feedback control method to reduce the T.H.D. of the vibrator is proposed. This paper describes a method of distortion reduction on a low frequency vibration standard, where a laser interferometer is used, with feedback loop control software on the calibration scheme. The vibrator signal is measured by an accelerometer located on a moving platform that is driven by the vibrator, and compared with a pure sine signal to obtain an error signal. Through multiplication of the error signal by a factor k, it is combined with the original input signal of the vibrator to reduce the T.H.D. This paper shows the experimental results at 0.8 Hz and 1 Hz. The measured T.H.D. results are both below 2%. At the same time we also evaluate the typed A standard uncertainty for accelerometer voltage sensitivity. The standard uncertainty before and after improvement is 0.154% and 0.068%, respectively.
    Type of Medium: Online Resource
    ISSN: 1461-3484 , 2048-4046
    URL: Article
    DOI: 10.1260/026309203322986645
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2003
    detail.hit.zdb_id: 2025887-2
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  • 9
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    Molecular Cloning of the Genes Encoding the PR55/Bβ/δ Regulatory Subunits for PP-2A and Analysis of Their Functions in Regulating Development of Goldfish, Carassius auratus
    SAGE Publications ; 2010
    In:  Gene Regulation and Systems Biology Vol. 4 ( 2010-01), p. GRSB.S6065-
    Details
    In: Gene Regulation and Systems Biology, SAGE Publications, Vol. 4 ( 2010-01), p. GRSB.S6065-
    Abstract: The protein phosphatase-2A (PP-2A), one of the major phosphatases in eukaryotes, is a heterotrimer, consisting of a scaffold A subunit, a catalytic C subunit and a regulatory B subunit. Previous studies have shown that besides regulating specific PP-2A activity, various B subunits encoded by more than 16 different genes, may have other functions. To explore the possible roles of the regulatory subunits of PP-2A in vertebrate development, we have cloned the PR55/B family regulatory subunits: β and δ, analyzed their tissue specific and developmental expression patterns in Goldfish ( Carassius auratus). Our results revealed that the full-length cDNA for PR55/Bβ consists of 1940 bp with an open reading frame of 1332 nucleotides coding for a deduced protein of 443 amino acids. The full length PR55/Bδ cDNA is 2163 bp containing an open reading frame of 1347 nucleotides encoding a deduced protein of 448 amino acids. The two isoforms of PR55/B display high levels of sequence identity with their counterparts in other species. The PR55/Bβ mRNA and protein are detected in brain and heart. In contrast, the PR55/Bδ is expressed in all 9 tissues examined at both mRNA and protein levels. During development of goldfish, the mRNAs for PR55/Bβ and PR55/Bδ show distinct patterns. At the protein level, PR55/Bδ is expressed at all developmental stages examined, suggesting its important role in regulating goldfish development. Expression of the PR55/Bδ anti-sense RNA leads to significant downregulation of PR55/Bδ proteins and caused severe abnormality in goldfish trunk and eye development. Together, our results suggested that PR55/Bδ plays an important role in governing normal trunk and eye formation during goldfish development.
    Type of Medium: Online Resource
    ISSN: 1177-6250 , 1177-6250
    URL: Article
    DOI: 10.4137/GRSB.S6065
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2010
    detail.hit.zdb_id: 2383407-9
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  • 10
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    Amelioration of paraquat-induced pulmonary fibrosis in mice by regulating miR-140-5p expression with the fibrogenic inhibitor Xuebijing
    SAGE Publications ; 2020
    In:  International Journal of Immunopathology and Pharmacology Vol. 34 ( 2020-01), p. 205873842092391-
    Details
    In: International Journal of Immunopathology and Pharmacology, SAGE Publications, Vol. 34 ( 2020-01), p. 205873842092391-
    Abstract: Intravenous Xuebijing (XBJ) therapy suppresses paraquat (PQ)-induced pulmonary fibrosis. However, the mechanism underlying this suppression remains unknown. This work aimed to analyze the miR-140-5p-induced effects of XBJ injection on PQ-induced pulmonary fibrosis in mice. The mice were arbitrarily assigned to four groups. The model group was administered with PQ only. The PQ treatment group was administered with PQ and XBJ. The control group was administered with saline only. The control treatment group was administered with XBJ only. The miR-140-5p and miR-140-5p knockout animal models were overexpressed. The gene expression levels of miR-140-5p, transglutaminase-2 (TG2), β-catenin, Wnt-1, connective tissue growth factor (CTGF), mothers against decapentaplegic homolog (Smad), and transforming growth factor-β1 (TGF-β1) in the lungs were assayed with quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot analysis. The levels of TGF-β1, CTGF, and matrix metalloproteinase-9 (MMP-9) in the bronchoalveolar lavage fluid were assessed by enzyme-linked immunosorbent assay (ELISA). Hydroxyproline (Hyp) levels and pulmonary fibrosis were also scored. After 14 days of PQ induction of pulmonary fibrosis, AdCMV-miR-140-5p, and XBJ upregulated miR-140-5p expression; blocked the expressions of TG2, Wnt-1, and β-catenin; and decreased p-Smad2, p-Smad3, CTGF, MMP-9, and TGF-β1 expressions. In addition, Hyp and pulmonary fibrosis scores in XBJ-treated mice decreased. Histological results confirmed that PQ-induced pulmonary fibrosis in XBJ-treated lungs was attenuated. TG2 expression and the Wnt-1/β-catenin signaling pathway were suppressed by the elevated levels of miR-140-5p expression. This inhibition was pivotal in the protective effect of XBJ against PQ-induced pulmonary fibrosis. Thus, XBJ efficiently alleviated PQ-induced pulmonary fibrosis in mice.
    Type of Medium: Online Resource
    ISSN: 2058-7384 , 2058-7384
    URL: Article
    DOI: 10.1177/2058738420923911
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2020
    detail.hit.zdb_id: 2505963-4
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