检索结果-内蒙古大学图书馆

Experiments on the relationship between the structural parameters of contraposition transducers and the acoustic levitation transportation trajectory

Experiments on the relationship between the structural param...

引用

2019 International Congress on Ultrasonics, ICU 2019

作者： Dong, Huijuan Sui, Mingyang Mao, Chuncheng Mu, Guanyu Zhao, Jie School of Mechatronics Engineering Harbin Institute of Technology Hei Longjiang Harbin150001 China State Key Laboratory of Robotics and System Harbin Institute of Technology Heilongjiang Harbin150001 China

ISBN: (纸本)9781665407090

Standing wave acoustic levitation transportation technique has been widely used in many research areas. In this work, two Langevin-type piezoelectric transducers' central lines are mounted at a certain angle which is named a contraposition transducer array. The levitator developed in this work is constructed using the array and a reflector. Accordingly, a standing wave acoustic field is formed to levitate and transport particles by optimizing the angle between central lines of the two transducers, the distance between the two transducers' output and their reflectors, the exciting phase differential on the two transducers. In this standing wave acoustic field, the trapped objects can be levitated and transported by modulating the exciting phase difference of the two transducers. In this work, the locations of the levitated particles are acquired by a high speed video camera and are clarified using the Hough Circle algorithm. The experiments carried out by the authors have demonstrated the effects of the levitator's structure parameters (including the angle between central lines of the two transducers, the distance between the two transducers' output and the reflector) on the transportation trajectory. © 2020 Acoustical Society of America.

关键词： Video cameras

来源：评论

学校读者我要写书评

暂无评论

Design of a series elastic actuator with double-layer parallel spring for lower limb exoskeletons

Design of a series elastic actuator with double-layer parall...

引用

2019 IEEE International Conference on robotics and Biomimetics, ROBIO 2019

作者： Chen, Chaofeng Wu, Dongmei Dong, Wei Du, Zhijiang He, Long Huang, Linxiang Wang, Jiaqi Shi, Yongjun Xu, Guoqiang Si, Fang Xiao, Tiantian Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin Heilongjiang Province China China South Industries Group Corporation Weapon Equipment Research Institute Beijing China

ISBN: (纸本)9781728163215

This paper presents a novel Series Elastic Actuator (SEA) with double-layer parallel spring for lower limb exoskeletons (LLE). The SEA can improve the human-robot interaction comfort and have the ability to absorb shock and vibration. In order to make the assembly process simple and convenient, the series elastic unit adopt split structure, which includes an inner ring structure, an outer ring structure and rectangular springs as elastic element. At the same time, in order to meet the requirements of the stiffness and dimensions of the SEA, a double-layer parallel spring arrangement is adopted. The stiffness of SEA is 312Nm/rad, which is obtained by the stiffness calibration experiment. In the experiments, the SEA is used in the knee joint of LLE and an impedance controller is designed to achieve knee joint tracking motion. Finally, the experiments results show the position tracking performance of the LLE, which illustrates the effectiveness of the SEA. © 2019 IEEE.

关键词： Human robot interaction

来源：评论

学校读者我要写书评

暂无评论

Design of dielectric-elastomer actuated XY stages with millimeter range and submicrometer resolution

Design of dielectric-elastomer actuated XY stages with milli...

引用

International Conference on Manipulation, Automation and robotics at Small Scales (MARSS)

作者： Ningyuan Ding Jiang Zou Guoying Gu Robotics Institute School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai China

ISBN: (数字)9781728193496

ISBN: (纸本)9781728193502

In this paper, we present the development and performance evaluation of dielectric-elastomer actuated XY (DEA-XY) stages with a millimeter range and submicrometer resolution. The design of the DEA-XY stage is based on a circular dielectric-elastomer actuator with two vertically distributed electrodes that can generate a two degree-of-freedom motion. To optimize their performances, various DEAXY stages with different dimensions and pre-stretches are firstly fabricated. Then, both static and dynamic performances of the DEA-XY stages are investigated by experiments, which demonstrate that: i) the workspace of the DEA-XY stage can reach 2.5 mm × 2.5 mm; ii) the cross-coupling effect is less than 6.5%; iii) the dynamic responses of the DEA-XY stage show both viscoelastic creep and hysteresis nonlinearities. To demonstrate the resolution of the DEA-XY stage, we implement a feedback controller to remove the creep effect. By tracking step trajectories, the results show that the DEA-XY stage can achieve the positioning resolution of 100 nm. This work demonstrates the potential application of the DEA-XY stage in the field of microscale manipulators.

关键词： Electrodes Creep Actuators Micromanipulators High-voltage techniques Hysteresis Fabrication

来源：评论

学校读者我要写书评

暂无评论

A Bipolar Myoelectric Sensor-Enabled Human-Machine Interface Based On Spinal Module Activations

A Bipolar Myoelectric Sensor-Enabled Human-Machine Interface...

引用

IEEE International Conference on robotics and Automation (ICRA)

作者： Chunzhi Yi Feng Jiang Guangming Lu Chifu Yang Zhen Ding Jianfei Zhu Jie Liu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang China School of Computer Science and Technology Harbin Institute of Technology Harbin Heilongjiang China Pengcheng Laboratory Shenzhen Guangdong China Nanjing Jinling Hospital Clinical School Medical College Nanjing University Nanjing Jiangsu China AI Research Institute Harbin Institute of Technology Shenzhen Guangdong China

The surface electromyography (sEMG) signal-based human-machine interface (HMI) has been widely used for various scenarios of physical human-robot interaction. However, current HMIs based on bipolar myoelectric sensors are hindered by the limitations of global sEMG features, which are prone to variability and delay. In this letter, we define a HMI that takes advantage of the underlying neural information of spinal module activations from bipolar sEMG signals, inspired by recent findings of neural codes. Firstly, the spinal module activations are identified by the spiking trains of the muscle synergies extracted from bipolar sEMG signals. Secondly, we extract the information encoded in both firing rates and spike timings of the spinal module activation in a population coding manner, which follows the information encoding principle of neurons. Thirdly, we map the series of spinal module activations into gait phases, locomotion modes, joint moment and human identity in order to experimentally reveal the physiological information contained in the spinal module activations. The contained information and the benefit of our design are demonstrated and experimentally explained by the presented results and comparisons with the traditionally used global sEMG features. The proposed bipolar myoelectric sensor-enabled human-machine interface could contribute to various scenarios of physical human-robot interaction.

关键词： Sociology Neurons Human-robot interaction Sensor phenomena and characterization Muscles Robot sensing systems Encoding

来源：评论

学校读者我要写书评

暂无评论

Using rgb image as visual input for mapless robot navigation

arXiv

引用

arXiv 2019年

作者： Ma, Liulong Liu, Yanjie Chen, Jiao State Key Laboratory of Robotics and System Harbin Institute of Technology China

Robot navigation in mapless environment is one of the essential problems and challenges in mobile robots. Deep reinforcement learning is a promising technique to tackle the task of mapless navigation. Since reinforcement learning requires a lot of explorations, it is usually necessary to train the agent in the simulator and then migrate to the real environment. The big reality gap makes RGB image, the most common visual format, rarely used. In this paper we present a learning-based mapless motion planner taking RGB image as visual input. In the end-to-end navigation network many of the parameters are used to extract visual features. The proposed motion palnner decoupled visual features extracted module from the reinforcement learning network to improve the sample efficiency. Variational Autoencoder (VAE) is used to encode the image, and the obtained latent vector is input as low-dimensional visual features into the network together with the target and motion information. We built and released a set of simulation environments for algorithm comparison. In the test environment, the proposed method was compared with the end-to-end network, which proved its effectiveness and efficiency. The source code is available: Https://***/marooncn/navbot. Copyright © 2019, The Authors. All rights reserved.

关键词： Deep learning

来源：评论

学校读者我要写书评

暂无评论

Using spanwise flexibility of caudal fin to improve swimming performance for small fishlike robots

引用

Journal of Hydrodynamics 2018年第5期30卷 859-871页

作者： Dan Xia Wei-shan Chen Jun-kao Liu Xiang Luo School of Mechanical Engineering Southeast UniversityNanjing 211189China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

This paper examines the beneficial effects of the spanwise flexibility of the caudal fin for the improvement of the swimming performance for small fishlike robots. A virtual swimmer is adopted for controlled numerical experiments by varying the spanwise flexible trajectories and the spanwise flexible size of the caudal fin while keeping the body kinematics fixed. 3-D Navier-Stokes equations are used to compute the viscous flow over the robot. Elliptical, parabolic and hyperbola trajectories are chosen to describe the spanwise flexible profile of the caudal fin. According to the sign（positive or negative） of the phase difference of the swinging motion, the spanwise flexibility can be divided into the fin surface of ＂bow＂ and the fin surface of ＂scoop＂. It is observed that for both the fin surface of ＂bow＂ and the fin surface of ＂scoop＂, the spanwise elliptical trajectory has the optimal swimming velocity, thrust, lateral force, and efficiency. With comparisons, using the flexible caudal fin with the fin surface of ＂bow＂, the lateral force and the power consumption can be reduced effectively and the swimming stability can be increased while reducing little the swimming velocity and thrust. Meanwhile, using the flexible caudal fin with the fin surface of ＂scoop＂ can greatly improve the swimming velocity, thrust, and efficiency while increasing part of the lateral force and the power consumption. Three-dimensional flow structures clearly indicate the evolution process around the swimming robot. It is suggested that the fish, the dolphin, and other aquatic animals may benefit their hydrodynamic performance by the spanwise flexibility of the caudal fin.

关键词： Spanwise flexibility caudal fin fishlike robot swimming performance flow structures

来源：评论

学校读者我要写书评

暂无评论

Understanding the friction behavior and surface characteristic in multiple ball-end milling passes of soft-brittle KH 2 PO 4 optics

引用

Tribology International 2025年 211卷

作者： Hongqin Lei Qiang Zhao Jian Cheng Linjie Zhao Mingjun Chen Qi Liu Dinghuai Yang Guang Chen State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 China School of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China Zhengzhou Research Institute Harbin Institute of Technology Zhengzhou 450000 China Department of Mechanical Engineering University of Bath Bath BA2 7AY United Kingdom

The utilization of a ball-end cutter to fabricate multi-layer microstructures is the preferred technique for eliminating surface defects in soft-brittle KH 2 PO 4 (KDP) optics. However, the previous milling pass would inevitably affect the tool-workpiece friction behavior and surface characteristics in the next milling process, which poses a great challenge to obtaining a defect-free microstructure surface. In this study, the effect of the multiple ball-end milling (MBEM) passes on material removal mode is explored according to tensile stress, residual stress and cutting force, which is verified from the perspectives of surface characteristics and roughness. The spindle speed, feed rate and milling depth of each-pass machining process are 50,000 r/min, 3 mm/s and 2 μm. The evaluation models of tool-workpiece friction behavior during the MBEM passes are developed, and the influence of soft-brittle materials on tool wear is analyzed. The results show that with when the number of milling passes ( i ) rises, the normalized plowing friction coefficient, tool-chip contact length and area increase, indicating that the tool-workpiece friction becomes severe. Meanwhile, with the rise in the i , the stress concentration area and surface roughness increase, which is attributed to the intensified tool-workpiece friction leading to an increase in cutting forces, thereby elevating the tensile stress exerted on the brittle KDP materials. When the i reaches 4, the brittle-plastic transition behavior occurs and edge chippings appear on the down-cut side. Furthermore, after the MBEM passes (the length of the milling path reaches 330 mm), there is no crack at the grain boundary, single grain spalling or even tool fracture on the CBN tool surface. Nevertheless, the low hardness of the KDP materials (2.18 GPa), coupled with the thermal softening effect, results in many chips adhering to the tool surface. The chemical composition of the built-up edge (BUE) consists of K, P and O. In part

关键词： Surface defects

来源：评论

学校读者我要写书评

暂无评论

Design of A Close-range Radiotherapy Particle Implantation Device*

Design of A Close-range Radiotherapy Particle Implantation D...

引用

IEEE International Conference on robotics and Biomimetics

作者： Guang Ban Changle Li Xuehe Zhang Gangfeng Liu Yubin Liu Jie Zhao Leifeng Zhang Yilun Fan State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

The validity of brachytherapy has been proved in clinical tumor treatment, and robotic surgery system has been used in recent years to ensure surgical consistency. In our work, a new automatic radioactive particle implantation device with two degrees of freedom was proposed to apply in the brachytherapy robotic surgery system as an end effector. Furthermore, physical assembling and simple function verifying experiments were accomplished. This device can help simplify the operating steps during surgery, and improve the stability of the surgical system, and enhances the surgical efficiency.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Real-time Dynamic Grasping Force Optimization of Multi-fingered Dextrous Hand *

Real-time Dynamic Grasping Force Optimization of Multi-finge...

引用

IEEE International Conference on robotics and Biomimetics

作者： Ziqi Liu Li Jiang Bin Yang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

A technique for real-time dynamic grasping force optimization is presented in this article. The force optimization is divided into online and offline two parts. The improved linear constrained gradient flow algorithm reduces the dimension of the description matrix based on the traditional gradient flow, and the non-negative linear combination method is introduced to optimize the initial force of the algorithm. Relatively optimal initial grasping force and dimensionality reduction gradient flow algorithm improve the calculating efficiency online. The corresponding illustrative examples are made to verify that the proposed method to obtain both optimal grasping force and faster convergence rate in the dynamic grasp process is feasible.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A Vector Control Method of PMSM Using Single Phase Current Sensor

A Vector Control Method of PMSM Using Single Phase Current S...

引用

IEEE International Conference on robotics and Biomimetics

作者： Chuangqiang Guo Chunya Wu Fenglei Ni Hong Liu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

This paper presents a new method of realizing vector control for the surface mounted permanent magnet synchronous machine (PMSM) using single phase current sensor. A simplified estimating method of phase current, which only requires the information from single phase current sensor and motor position sensor, has been proposed in this paper. Compared with the classical approaches, based on the reference current in synchronous rotor frame, the proposed method can get better accuracy, especially when there is a sudden change of the reference current. Furthermore, the method not relays on the model and parameters of PMSM and the control performance of current close-loop and also not sensitive to working conditions. The extensively experimental results under different work conditions, based on MATLAB/SIMULINK, have validated the feasibility and robustness of the proposed vector control method.

关键词：

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：