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IEEE-RAS International Conference on Humanoid Robots

作者： Andrew SaLoutos Elijah Stanger-Joncs Yanran Ding Matthew Chignoli Sangbae Kim Biomimetic Robotics Laboratory at the Department of Mechanical Engineering Massachusetts Institute of Technology (MIT) Cambridge MA USA

Enabling humanoid robots to achieve human-level athletic feats, such as running and jumping, is at the frontier of robotics research. To execute these behaviors, a robot platform must have high power density and robust mechanical and electrical systems. In this paper, we present the MIT Humanoid, a robust research platform that is designed to meet these requirements and be able to perform highly dynamic, parkour-style motions. The robot is just over 1 m tall and weighs approximately 24 kg, with 18 actuated degrees of freedom, each of which has a custom high-torque proprioceptive motor module. We also present initial hardware results from our new platform, demonstrating model-based controllers for pose control, walking, and jumping. The robot's high control bandwidth allows us to achieve stable pose control and walking, and the high power density allows the robot to achieve vertical jumps of roughly 30 cm, as measured by torso displacement.

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Telemanipulators with Sensor/Actuator Asymmetries Fail the Robustness Criterion

Telemanipulators with Sensor/Actuator Asymmetries Fail the R...

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International Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (HAPTICS)

作者： Lawton N. Verner Allison M. Okamura Department of Mechanical Engineering Laboratory for Computational Sensing and Robotics Johns Hopkins University Baltimore MD USA

Force reflection in telemanipulators can be challenging and costly, often prohibitively so. By reducing the number of sensors and actuators used in the telemanipulator and providing the user only partial force feedback, cost and performance concerns can be optimized. While partial force feedback is beneficial practically, it creates a sensor/actuator asymmetry in the device. Robust stability for systems with sensor/actuator asymmetries has not been examined previously. We show that telemanipulators with sensor/actuator asymmetries are not passive and do not satisfy the robustness stability criterion. Thus, they are potentially unstable. Further, we motivate the need for additional stability criterion for telemanipulators that are not passivity-based.

关键词： Actuators Robustness Force feedback Force sensors Robust stability Master-slave mechanical sensors Robot sensing systems Reflection Stability criteria

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Implementation of OpenMP and MPI hybrid parallelization to Monte Carlo dose simulation for particle therapy

Implementation of OpenMP and MPI hybrid parallelization to M...

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World Congress on Medical Physics and Biomedical engineering

作者： Furuta, T. Ishikawa, K.L. Fukunishi, N. Noda, S. Takagi, S. Maeyama, T. Fukasaku, K. Himeno, R. RIKEN Computational Science Research Program Wako Japan University of Tokyo Department of Nuclear Engineering and Management Graduate School of Engineering Tokyo Japan RIKEN Nishina Center for Accelerator-Based Science Wako Japan RIKEN Advanced Center for Computing and Communication Wako Japan University of Tokyo Department of Mechanical Engineering Tokyo Japan Himon'ya Hospital Department of Neurosurgery Tokyo Japan

ISBN: (纸本)9783642293047

We report a successful implementation of the sharedmemory parallelization using OpenMP to the dose calculation by the Monte Carlo particle and heavy-ion transport code PHITS. The OpenMP shared-memory parallelization is better suited than the MPI distributed-memory parallelization which is originally implemented in the PHITS code in the case of human voxel data which requires a large memory space. We have confirmed that the same results can be obtained with and without the shared-memory parallelization by the modified PHITS code. Sufficiently high OpenMP parallelization efficiency (92.4% with 8 parallelized cores within a single node) is achieved even when the special treatment for accessing memory to avoid memory contentions is taken into account. We implement the OpenMP parallelization on top of the MPI parallelization originally included in PHITS so that the modified code works in a hybrid way such that the distributed-memory parallelization for different nodes by MPI and the shared-memory parallelization among the cores in a single node by OpenMP. The performance has been checked on supercomputers: RICC and K computer. © 2013 Springer-Verlag.

关键词： Supercomputers

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Adjustment of Intention to Start a Motion of Lower Limbs Based on Cerebral Hemoglobin Information

Adjustment of Intention to Start a Motion of Lower Limbs Bas...

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International Conference on Intelligent Human-Machine Systems and Cybernetics, IHMSC

作者： Chunguang Li Juan Li Haiyan Hu Weida Li Ziwu Ren Wei Qu School of Mechanical and Electric Engineering Soochow University Project Management Department ECOVACS Robotics Suzhou China

ISBN: (纸本)9781479986477

To increase intelligence of walking-assisted devices, it is important to provide a start command of action based on the motion intention of subjects. In this paper, a method for identifying motion intention was proposed based on cerebral hemoglobin information. Spontaneous movements (upstairs, downstairs, upslope, down-slope, sit-down, squat, and the corresponding standup) without an advanced imagination or external stimuli were performed on two subjects. During the experiment, cerebral hemoglobin information was recorded by applying near-infrared spectroscopic technology. Multiple analyses of variance on different features of the variation of total hemoglobin were combined and a series of significant levels were set. The corresponding precision rate was up to 74.8%, and the sensitivity was up to 79.2%. Since the proposed identification method is realized based on the brain information recorded in a real movement environment, it is helpful and practical to enhance intelligence of walking-assisted devices.

关键词： Legged locomotion Detectors Acceleration Analysis of variance Probes

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Application of UPFC to improve the LVRT capability of wind turbine generator

Application of UPFC to improve the LVRT capability of wind t...

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2012 22nd Australasian Universities Power engineering Conference: "Green Smart Grid Systems", AUPEC 2012

作者： Alharbi, Yasser M. Yunus, A. M. Shiddiq Siada, A. Abu Electrical and Computer Engineering Department Curtin University Perth Australia Mechanical Eng. Dept. Energy Conv. Study Program State Polytechnic of Ujung Pandang Makassar Indonesia

ISBN: (纸本)9789791884723

Variable speed wind turbine generators installation has been significantly increased worldwide in the last few years. Voltage sag at the grid side may call for the disconnection of the wind turbine from the grid as under such faults it may not comply with the recent developed grid codes for wind energy conversion systems (WECS). In this paper, a Unified Power Flow Controller (UPFC) is applied to improve the low voltage ride through (LVRT) capability of doubly fed induction generator (DFIG)-based WECS during voltage sag at the grid side. Simulation is carried out using MATLAB/Simulink software. Results show that UPFC can significantly improve the LVRT capability of DFIG-based WECS and hence maintaining wind turbine connection to the grid during certain levels of voltage sag at the grid side. © 2012 Institut Teknologi Sepulul.

关键词： Wind Turbine Generators

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CWave: High-performance single-source any-angle path planning on a grid

CWave: High-performance single-source any-angle path plannin...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Dmitry A. Sinyukov Taşkin Padir Robotics Engineering Program Worcester Polytechnic Institute Worcester MA USA Department of Electrical and Computer Engineering Northeastern University Boston MA

Path planning on a 2D-grid is a well-studied problem in robotics. It usually involves searching for a shortest path between two vertices on a grid. Single-source path planning is a modified problem which asks to find distances from a given point to all other points on the map. A high-performance algorithm for single-source any-angle path planning on a grid that we named CWave is proposed in this work. “Any-angle” attribute of a path planning algorithm implies that such algorithm can find paths which may include any angle segments, as opposed to standard A* on an 8-connected graph, the path can turn with 45°-increments only. The key idea of the presented algorithm is that it does not represent the grid as a graph and uses discrete geometric primitives to define the wave front. In its purest form, CWave requires for computation only integer arithmetics and multiplication by two, but can accumulate the distance error at turning points. A modified version of CWave with minimal usage of floating-point calculations is also developed. It allows to eliminate any accumulative errors which is proven mathematically and experimentally on several maps. The performance of the algorithm on three maps is demonstrated to be significantly faster than that of Theta*, Lazy Theta* and Field A* adapted for single-source planning. The limitations of the current implementations of the algorithm as well as potential improvements are discussed.

关键词： Path planning Algorithm design and analysis Two dimensional displays Navigation Planning Mobile robots

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Distributed Modal Identification and Vibration Control of Continua: Theory and Applications

Distributed Modal Identification and Vibration Control of Co...

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American Control Conference (ACC)

作者： H. S. Tzou Department of Mechanical Engineering Center for Robotics and Manufacturing Systems University of Kentucky Lexington Kentucky 40506-0046

Conventional transducers and actuators are "discrete" in nature, i.e., they usually measure and control spatially discrete locations. These discrete devices become useless when they are placed at modal nodes or lines. In this paper, a generic "distributed" modal identification and vibration control theory for sensing and control of continua, e.g., shells, plates, cylinders, beams, etc., is proposed. The generic theory is derived for a thin shell coupled with two electroded piezoelectric layers. One piezoelectric layer serves as a distributed sensor and the other a distributed actuator. The sensor output, or a reference signal, is processed, amplified, and fed back into the distributed actuator. Due to the converse effect, the injected high voltage induces in-plane strains which result in counteracting moments used to suppress the shell oscillation. System dynamic equations and state equations are also derived. The theory shows that the distributed sensor can identify all vibration modes and the distributed actuators also control all modes. Simplification of the generic theory to other geometries is also demonstrated.

关键词： Vibration control Equations Distributed control Control systems Geometry Distributed parameter systems Orbital robotics Piezoelectric actuators mechanical engineering Robots

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Safe and compliant guidance in robot-assisted gait rehabilitation using Proxy-based Sliding Mode Control

Safe and compliant guidance in robot-assisted gait rehabilit...

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IEEE International Conference on Rehabilitation robotics (ICORR)

作者： P. Beyl M. Van Damme P. Cherelle D. Lefeber Robotics & Multibody Mechanics Research Group Department of Mechanical Engineering Vrije Universiteit Brussel Brussels Belgium

Research in robot-assisted gait rehabilitation has seen significant improvements in human-robot interaction, thanks to high performance actuator technologies and dedicated control strategies. In this context we propose a combination of lightweight, intrinsically compliant, high power actuators (pleated pneumatic artificial muscles, PPAMs) with safe and adaptable guidance along a trajectory by means of proxy-based sliding mode control (PSMC). Treadmill walking experiments performed by a healthy subject wearing a powered knee exoskeleton indicate two main challenges: synchronizing the compliant device and the subject, and tuning the control parameters in view of safe guidance. The exoskeleton is able to compliantly guide the test person's knee along various target trajectories, while ensuring a smooth response to large perturbations.

关键词： Rehabilitation robotics Sliding mode control Knee Exoskeletons Human robot interaction Pneumatic actuators Muscles Legged locomotion Testing Trajectory

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Highly Thermally Stable, Highly Electrolyte-Wettable Hydroxyapatite/Cellulose Nanofiber Hybrid Separators for Lithium-Ion Batteries

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ACS Applied Energy Materials 2023年第7期6卷 3862-3871页

作者： Liu, Yi Li, Chunxing Li, Chao Liang, Zhenye Hu, Xueshan Liu, Hao Zhang, Ze Cui, Meng Chen, Gang Wan, Jiayu Zhang, Xiangwu Tao, Jinsong State Key Lab of Pulp and Paper Engineering South China University of Technology Guangzhou510640 China SUSTech Energy Institute for Carbon Neutrality Southern University of Science and Technology Shenzhen518055 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China Fiber and Polymer Science Program Department of Textile Engineering Chemistry and Science Wilson College of Textiles North Carolina State University RaleighNC27695-8301 United States

Separators have an important influence on the safety and performance of lithium-ion batteries (LIBs). However, traditional polyolefin-based separators suffer from poor thermal stability and weak electrolyte wettability. Here, by using hydroxyapatite (HAP) and cellulose nanofibers (CNFs) as raw materials, we fabricated a unique HAP/CNF hybrid separator. The separators exhibit excellent thermal properties, with high thermal stability (up to 250 °C) and outstanding flame retardancy. The separators also demonstrate excellent electrolyte wettability. Compared to polypropylene (PP) separators, the HAP/CNF separators show a smaller contact angle with electrolytes, 17.2° for HAP/CNF and 45.5° for PP. Meanwhile, the HAP/CNF separators illustrate an excellent smoothness of 68.0 nm. In addition, the batteries assembled with the hybrid separators display a better performance compared with the batteries assembled with commercial PP separators. The raw materials are green, and the fabrication processes are free of organic solvents. We envision that the HAP/CNF hybrid separator could be a promising separator candidate for next-generation high-safety and high-performance LIBs. © 2023 American Chemical Society.

关键词： Thermodynamic stability

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Maximum velocity analysis of parallel manipulators

Maximum velocity analysis of parallel manipulators

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IEEE International Conference on robotics and Automation (ICRA)

作者： P. Huynh T. Arai Autonomous Machinery Division Department of Robotics Mechanical Engineering Laboratory AIST MITI Tsukuba Ibaraki Japan

In order to analyse the maximum velocity of parallel manipulators in operational space, a graphical method based on the analysis of the algebraic inequalities describing the constraints on the kinematics model is presented. We consider a general 6 d.o.f parallel manipulator and assume that all articular velocities are bounded by the same limit. The method is then applied to the conventional Stewart platform chosen as a reference and a new parallel manipulator for their performance comparisons. For these two parallel manipulators, respective formula of Jacobian matrix is also given.

关键词： Manipulators Jacobian matrices Parallel robots Electronic mail mechanical engineering Laboratories Kinematics Equations Machinery Orbital robotics

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