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arXiv 2020年

作者： Gonzalez, Daniel J. Harry Asada, H. Robotics Research Center Department of Electrical Engineering and Computer Science United States Military Academy West PointNY10996 United States d’Arbeloff Laboratory for Information Systems and Technology Department of Mechanical Engineering Massachusetts Institute of Technology CambridgeMA02139 United States

The Extra Robotic Legs (XRL) system is a robotic augmentation worn by a human operator consisting of two articulated robot legs that walk with the operator and help bear a heavy backpack payload. It is desirable for the Human-XRL quadruped system to walk with the rear legs lead the front by 25% of the gait period, minimizing the energy lost from foot impacts while maximizing balance stability. Unlike quadrupedal robots, the XRL cannot command the human’s limbs to coordinate quadrupedal locomotion. Using a pair of Rimless Wheel models, it is shown that the systems coupled with a spring and damper converge to the desired 25% phase difference. A Poincaré return map was generated using numerical simulation to examine the convergence properties to different coupler design parameters, and initial conditions. The Dynamically Coupled Double Rimless Wheel system was physically realized with a spring and dashpot chosen from the theoretical results, and initial experiments indicate that the desired synchronization properties may be achieved within several steps using this set of passive components alone. Copyright © 2020, The Authors. All rights reserved.

关键词： Exoskeleton (robotics)

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Dynamic Balance and Trajectory Tracking Control of Quadruped Robots Based on Virtual Model Control

Dynamic Balance and Trajectory Tracking Control of Quadruped...

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第三十九届中国控制会议

作者： Guangrong Chen Bowen Hou Sheng Guo Junzheng Wang Robotics Research Center Beijing Jiaotong University Beijing Engineering and Technology Research Center of Rail Transit Line Safety and Disaster Prevention State Key Laboratory of Intelligent Control and Decision of Complex Systems School of Automation Beijing Institute of Technology

As for a motion control framework of robots, virtual model control（VMC） can use virtual components to create virtual forces/torques. Actually, the virtual forces/torques are generated by joint actuators when the virtual components interact between robots and environments. In this paper, a virtual model control is proposed to do the dynamic balance control of quadruped robots in trot gait. In each leg, virtual model control includes swing phase control of robots and stance phase counterparts. In whole body, based on the forces/torques distribution method between two stance legs, virtual model control is mainly about the attitude control containing roll, pitch and yaw. Then, an intuitive approach of velocity control is employed for the locomotion of quadruped robots. Based on the velocity planning and control, a trajectory tracking control approach is investigated by considering four factors: terrain complexity index, curvature radius of given trajectory, distance to terminal, and maximum velocity of quadruped robots. Finally, the effectiveness of proposed controllers is validated by co-simulations.

关键词： Virtual model control Dynamic balance control Trajectory tracking control Quadruped robots

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Continuity scaling: A rigorous framework for detecting and quantifying causality accurately

arXiv

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arXiv 2022年

作者： Ying, Xiong Leng, Si-Yang Ma, Huan-Fei Nie, Qing Lai, Ying-Cheng Lin, Wei School of Mathematical Sciences SCMS SCAM Fudan University Shanghai200433 China Research Institute for Intelligent Complex Systems CCSB LCNBI Fudan University Shanghai200433 China State Key Laboratory of Medical Neurobiology MOE Frontiers Center for Brain Science Institutes of Brain Science Fudan University Shanghai200032 China Institute of AI and Robotics Academy for Engineering and Technology Fudan University Shanghai200433 China School of Mathematical Sciences Soochow University Suzhou215006 China Department of Mathematics Department of Developmental and Cell Biology NSF-Simons Center for Multiscale Cell Fate Research University of California IrvineCA92697-3875 United States School of Electrical Computer and Energy Engineering Arizona State University TempeAZ85287-5706 United States Shanghai Artificial Intelligence Laboratory Shanghai200232 China

Data based detection and quantification of causation in complex, nonlinear dynamical systems is of paramount importance to science, engineering and beyond. Inspired by the widely used methodology in recent years, the cross-map-based techniques, we develop a general framework to advance towards a comprehensive understanding of dynamical causal mechanisms, which is consistent with the natural interpretation of causality. In particular, instead of measuring the smoothness of the cross map as conventionally implemented, we define causation through measuring the scaling law for the continuity of the investigated dynamical system directly. The uncovered scaling law enables accurate, reliable, and efficient detection of causation and assessment of its strength in general complex dynamical systems, outperforming those existing representative methods. The continuity scaling based framework is rigorously established and demonstrated using datasets from model complex systems and the real world. Copyright © 2022, The Authors. All rights reserved.

关键词： Dynamical systems

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Magnetically Actuated Pick-and-place Operations of Cellular Micro-rings for High-speed Assembly of Micro-scale Biological Tube

Magnetically Actuated Pick-and-place Operations of Cellular ...

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2020 IEEE/RSJ International Conference on Intelligent Robots and systems (IROS)

作者： Yang Wu Tao Sun Qing Shi Huaping Wang Qiang Huang Toshio Fukuda Intelligent Robotics Institute Key Laboratory of Biomimetic Robots and system Ministry of Education School of Mechatronical Engineering Beijing Institute of Technology Beijing China Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of Technology Beijing China

ISBN: (数字)9781728162126

ISBN: (纸本)9781728162133

Tissue engineering is trying to use modular tissue micro-rings to construct artificial biological microtubes as substitute of autologous tissue tubes to alleviate the shortage of donor sources. However, because of the lack of effective assembly strategies, it is still challenging to achieve high-speed fabrication of biological microtubes with high cell density. In this paper, we proposed a robotic-based magnetic assembly strategy to handle this challenge. We first encapsulated magnetic alginate microfibers into micro-rings formed by cell self-assembly to enhance the controllability. Afterwards, a 3D long-stroke manipulator with visual servoing system was designed to achieve magnetic pick-and-place operations of micro-rings for 3D assembly. Moreover, we developed a mathematical model of the motion of micro-ring in solution environments. Based on visual feedback, we analyzed the feasibility of automatic assembly and following response of micro-rings with the moving magnets, which shows our proposed method has great potential to achieve high-speed bio-assembly. Finally, we successfully assembled multi-micro-rings into a biological microtube with high cell density.

关键词： Robotic assembly Fabrication Three-dimensional displays Visual servoing Magnetic analysis Electron tubes Mathematical model

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A Guide for Human Walking Model and Control——Insights from Mechanical Property Analysis of Human Walking

A Guide for Human Walking Model and Control——Insights from...

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第32届中国控制与决策会议

This paper aims to establish the simplest human walking model and provide a guide for controlling biped ***,a human motion capture system was utilized to sample the motion data of human walking and a representative subject was ***,one of the simplest human walking model was set *** mechanical property analysis of human walking was done based on the established walking model via ***,the feasibility and effectiveness of proposed walking model were validated by numerical ***,the intrinsical relationships among human walking,biped walking model and control were discussed to provide a guide and insight for controlling biped robots.

关键词： Human Walking Model Biped Robots Leg Stiffness Legged Locomotion Model and Control

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Optimal reaction control for the flexible base redundant manipulator system

Optimal reaction control for the flexible base redundant man...

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2019 IEEE International Conference on robotics and Biomimetics, ROBIO 2019

作者： Zhang, Yaowen Liu, Yechao Xie, Zongwu Moallem, Mehrdad Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin Heilongjiang Province150006 China School of Mechatronic Systems Engineering Simon Fraser University VancouverBCV3T 0A3 Canada

ISBN: (纸本)9781728163215

The null space of the Jacobian for the redundant manipulators can be utilized to reach dual control goals and optimal effects. For the flexible base redundant manipulator system, the reaction force from the motion of the manipulator should be carefully handled while the end effector is tracking a desired trajectory. Different optimal goals are discussed, including the minimization of base deflection force/torque and base energy dissipation path. Considering the base reaction dynamic, the reaction force/torque is treated as the input of the base and the deflection energy is treated as the output, an integrated optimal goal is built and solved based on the LQR control to get an optimal feedback for the closed-loop dynamics. We discuss the different optimal goals and implement trough the redefined acceleration. We test the different control laws on the three- link manipulators which mounted on a three-DoF flexible base. Simulation results demonstrate that optimal goal in LQR form can be advantageous in terms of flexible base manipulator. © 2019 IEEE.

关键词： Redundant manipulators

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A 350 C piezoresistive n-type 4H-SiC pressure sensor for hydraulic and pneumatic pressure tests

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Journal of Micromechanics and Microengineering 2020年第5期30卷

作者： Fang, Xudong Wu, Chen Zhao, Yulong Jiang, Zhuangde Rong, Weibing Feng, Zhihong Lv, Yuanjie State Key Laboratory for Manufacturing Systems Engineering International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies Collaborative Innovation Center of Suzhou Nano Science and Technology Xi'an Jiaotong University Xi'an710049 China School of Mechanical Engineering Xi'an Jiaotong University Xi'an710049 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150080 China National Key Laboratory of Application Specific Integrated Circuit Hebei Semiconductor Research Institute Shijiazhuang050051 China

It has been a challenge to develop pressure sensors that can work in harsh environments. In this work, a piezoresistive n-type 4H-SiC pressure sensor is demonstrated, capable of working at 350 C under hydraulic and pneumatic pressure. The pressure measuring range of this sensor is 7 MPa and the chip dimension is 2.5 mm 2.5 mm 0.23 mm. A reliable Ti/TaSi2/Pt metal ohmic contact is used in the sensor and experimental results show that the metal combination can withstand a wide temperature range of 30 C-350 C. In order to avoid thermal stress induced by the mismatch of thermal expansion coefficients of different packaging materials when increasing temperature, a double-layer bonding scheme of cement glue and epoxy is proposed. The inner layer of the chip and the kovar alloy base are directly bonded with the epoxy, while the outer layer is wrapped with the high-temperature cement glue. Experiments confirm that this method can achieve reliable packaging with temperatures up to 350 C for 5 h. Based on the above key technologies, the sensitivity of this sensor can reach 13.2 mV V-1 kPa-1 and the test data exhibit high linearity and repeatability. Static tests prove that the sensor has good media compatibility which can operate under a hydraulic pressure load at 220 C and a barometric pressure load under 350 C. The sensor in this work can provide a reference for pressure measurements at high temperature and in complex media environments. © 2020 IOP Publishing Ltd.

关键词： Pressure sensors

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A Reverse CAD Approach for Estimating Geometric and Mechanical Behavior of FDM Printed Parts

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Procedia Manufacturing 2019年 34卷 535-544页

作者： Baltej Singh Rupal Khaled G. Mostafa Yeping Wang Ahmed Jawad Qureshi Additive Design and Manufacturing Systems Laboratory (ADaMS Lab) Department of Mechanical Engineering University of Alberta Edmonton Canada Laboratory for Computational Sensing and Robotics Johns Hopkins University Baltimore USA

Fused Deposition Modeling (FDM) printed parts are widely used in various applications. To avoid material and time wastage, it is necessary to assess the geometric and mechanical behavior of the part beforehand. The geometric and mechanical behavior of FDM printed parts is analyzed by various virtual and experimental approaches. The virtual approaches are based on analytical models, which take solid computer-aided design (CAD) models or STL files as input for the analysis. However, in reality, the input CAD model is converted to a combination of slices (toolpath) before it is sent to print. The difference between the CAD and the toolpath model creates a research gap for estimating the properties accurately. The reason being that the printed part is not the replica of the original CAD model but of the sliced model which is dependent on various slicing parameters. This paper presents a novel algorithm, which is capable of converting the sliced file back to a CAD model (called the Reverse CAD model). The Reverse CAD model is capable of providing an accurate assessment of the geometric and mechanical behavior of the printed part as it also incorporates the effect of slicing parameters. In order to validate the algorithm, primitive geometries are printed, and their geometric deviation and mass properties are compared to the Reverse CAD model. Standardized tensile test specimens are also printed with two different materials to compare the experimental mechanical behavior with the finite element analysis of the Reverse CAD model. Comparative studies validate the Reverse CAD model as a better and more accurate estimator of the FDM printed part properties.

关键词： Additive Manufacturing Fused Deposition Modeling Geometric Quality Mechanical Properties Reverse engineering

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Characterization and Evaluation of A Cable-Actuated Flexible Hand Exoskeleton*

Characterization and Evaluation of A Cable-Actuated Flexible...

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International Conference on Ubiquitous Robots and Ambient Intelligence (URAI)

作者： Hu Huang Aibin Zhu Jiyuan Song Yao Tu Xiaojun Shi Zhifu Guo Institute of Robotics & Intelligent Systems Xi'an Jiaotong University Shaanxi Key Laboratory of Intelligent Robots Xi'an China Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi’an China Taiyuan Institute Co.Ltd. of China Coal Technology and Engineering Group Taiyuan China

ISBN: (数字)9781728157153

ISBN: (纸本)9781728157160

Flexible hand exoskeleton robots are more and more used in medical rehabilitation. This is due to the fact that these exoskeletons have strong compatibility with hands, can realize continuous deformation, and can apply force according to the motion trajectory. This paper proposes a cable-actuated flexible hand exoskeleton. Firstly, a motion model of one finger is established. Then a hand exoskeleton for rehabilitation is designed and constructed based on it. The exoskeleton is remotely actuated by motor and the force is transmitted through cables to achieve the bidirectional drive of the fingers. In addition, a tensioning mechanism of pulley block is designed to pre-tension the wire slack in the process of wire transmission. Finally, the experiment results show that the exoskeleton can bend the three joints of the index finger (DIP, PIP, and MCP) to 57 degrees, 35 degrees, and 31 degrees respectively. Under the load of 2.5N per finger, the exoskeleton can still drive the fingers to flex. The experimental results verify that the exoskeleton is a feasible solution that can meet the requirements of hand rehabilitation and can enable patients to recover and improve finger function in daily activities.

关键词： Thumb Exoskeletons Force Joints Robots Wires

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Multi-agent Gaussian Process Motion Planning via Probabilistic Inference

Multi-agent Gaussian Process Motion Planning via Probabilist...

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作者： Petrović, Luka Marković, Ivan Seder, Marija University of Zagreb Faculty of Electrical Engineering and Computing Laboratory for Autonomous Systems and Mobile Robotics Croatia

This paper deals with motion planning for multiple agents by representing the problem as a simultaneous optimization of every agent's trajectory. Each trajectory is considered as a sample from a one-dimensional continuous-time Gaussian process (GP) generated by a linear time-varying stochastic differential equation driven by white noise. By formulating the planning problem as probabilistic inference on a factor graph, the structure of the pertaining GP can be exploited to find the solution efficiently using numerical optimization. In contrast to planning each agent's trajectory individually, where only the current poses of other agents are taken into account, we propose simultaneous planning of multiple trajectories that works in a predictive manner. It takes into account the information about each agent's whereabouts at every future time instant, since full trajectories of each agent are found jointly during a single optimization procedure. We compare the proposed method to an individual trajectory planning approach, demonstrating significant improvement in both success rate and computational efficiency. © 2018

关键词： Trajectories

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