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Modeling of nonlinear dynamic characteristics and experimental study of piezoelectric energy harvesters with a panel type structure

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IOP Conference Series: Materials Science and Engineering 2019年第1期531卷

作者： Jinda Jia Xiaobiao Shan Yingxiang Liu Tao Xie State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 China

Panel flutter vibration is a typical aeroelastic phenomenon taking place in flying aircrafts as they move at high speed. The vibration has been a hot academic research aspect. The present paper focuses on converting this aerodynamic mechanical vibration into useful electricity by using piezoelectric patches. A mathematical Euler-Bernoulli distributed model of the piezoelectric energy harvesting system is established to investigate nonlinear dynamical behaviour of a piezoelectric cantilever plate. The dynamical responding ability of energy harvesting is numerically calculated. Influences of the length and the thickness of piezoelectric layer, the external resistance and wind velocity on the output performance are emphatically explored. A series of prototypes of piezoelectric energy harvesters with different physical dimensions were designed and manufactured. Wind tunnel experiments were setup and carried out at different wind velocities. The experimental results show that the harvesting power gets enhanced as increasing the wind velocity. The maximum power could be obtained at condition of a reasonable piezoelectric length and width. Maximum power is 2.0 mW at wind speed of 11.0 m/s. This work provides a strong theoretical and experimental basis for the study of aerodynamic energy harvesting from panel aircrafts.

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Time-varying keys for encryption in WSNs: IEEE CNS 17 poster

Time-varying keys for encryption in WSNs: IEEE CNS 17 poster

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2017 IEEE Conference on Communications and Network Security, CNS 2017

作者： Uchiteleva, Elena Shami, Abdallah Refaey, Ahmed State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

ISBN: (纸本)9781538606834

This work presents a novel scheme which reinforces strength of encryption keys in low-power and low-rate wireless sensor networks (WSNs). The proposed algorithm utilizes pseudo-random features of physical layer (PHY) of the communication stack to enable time-evolution of network keys increasing their complexity and reliability. This scalable and light-weight scheme is suitable for large networks of memory- A nd energy-restricted sensing devices and is aimed at enhancing security strength during broadcasting. Our preliminary results demonstrate that generated time-varying key sequences show no correlation or linear dependencies between instances and are resilient to intelligent brute-force attacks. © 2017 IEEE.

关键词： Cryptography

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Design of a Cable Driven Floating Robotic Arm with Continuum Joints

Design of a Cable Driven Floating Robotic Arm with Continuum...

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IEEE International Conference on Real-time Computing and robotics (RCAR)

作者： Zhonghao Wu Marco Cederle Elisa Rosalinda Giani Kai Xu RII Lab (Lab of Robotics Innovation and Intervention) UM-SJTU Joint Institute Shanghai Jiao Tong University Shanghai China Politecnico di Milano Milano Italy State Key Laboratory of Mechanical System and Vibration School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China

ISBN: (数字)9781728137261

ISBN: (纸本)9781728137278

Long-reach manipulator shows potentials in inspection, search and rescue. However, the reach of such a manipulator is often limited, due to fact that the distal structures become payloads of the proximal joints. This research hence focuses on a proof-of-concept study of a slim long-reach robotic arm designed with continuum joints and floating links. A float link and a continuum joint constitute a module that is weightless due to buoyancy. The reach hence becomes unlimited in theory. The actuation of each joint is decoupled via a transmission arrangement, providing a simple kinematic model no matter how many robotic modules are used. Each floating link is composed of a from-the-shelf helium-filled Mylar balloon that is caged by acrylic rings. Each of the two-degree-of-freedom continuum joints is made from a super-elastic nitinol (nickel-titanium alloy) rod and actuated by three cables pulled by three stepper motors. Preliminary experimental results on this constructed 3-meter prototype show that the floating robotic arm can move with acceptable accuracy in still air, validating the proposed concept.

关键词： Handheld computers Kinematics Conferences Real-time systems Robots Bending Calibration

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Online Calibration for Monocular Vision and Odometry Fusion

Online Calibration for Monocular Vision and Odometry Fusion

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2017 IEEE International Conference on Unmanned systems (ICUS)

作者： Xuefeng Wang Haoyao Chen Yanjie Li the School of Mechanical Engineering and Automation in Harbin Institute of Technology Shenzhen and the State Key Laboratory of Robotics and System

ISBN: (纸本)9781538631089;9781538631072

A novel calibration approach for mobile robot equipped with encoder and monocular camera has been proposed in this *** this work,we divide the calibration into four steps:1) a coarse calibration step is employed to estimate the transform between odometry and visual system and the scale of visual system;2) a nonlinear-optimization step is employed to optimize the transform between odometry and visual system;3) during the process of SLAM of mobile robot,the transform between odometry and visual system is optimized with the poses of mobile robot and positions of mappoints in a local map;4) the scale of visual system is optimized after a loop *** method uses only nature features in visual system without any artificial landmark or any prior *** experiment and compare have been performed to illustrate the effectiveness.

关键词： Sensor Fusion Calibration

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Development and Analysis of an Electrically Actuated Lower Extremity Assistive Exoskeleton

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Journal of Bionic Engineering 2017年第2期14卷 272-283页

作者： Yi Long Zhijiang Du Chaofeng Chen Weidong Wang Long He Xiwang Mao Guoqiang Xu Guangyu Zhao Xiaoqi Li Wei Dong State Key Laboratory of Robotics and System Harbin Institute of Technology (HIT) Harbin 150001 China Weapon Equipment Research Institute China South Industries Group Corporation Beijing 102202 China

An electrically actuated lower extremity exoskeleton is developed, in which only the knee joint is actuated actively while other joints linked by elastic elements are actuated passively. This paper describes the critical design criteria and presents the process of design and calculation of the actuation system. A flexible physical Human-Robot-Interaction （pHR1） measurement device is designed and applied to detect the human movement, which comprises two force sensors and two gasbags attached to the inner surface of the connection cuff. An online adaptive pHRI minimization control strategy is proposed and implemented to drive the robotic exoskelcton system to follow the motion trajectory of human limb. The measured pHRI information is fused by the Variance Weighted Average （VWA） method. The Mean Square Values （MSV） of pHRI and control torque are utilized to evaluate the performance of the exoskeleton. To improve the comfort level and reduce energy consumption, the gravity compensation is taken into consideration when the control law is designed. Finally, practical experiments are performed on healthy users. Experimental results show that the proposed system can assist people to walk and the outlined control strategy is valid and effective.

关键词： exoskeleton pHRI measurement data fusion pHRI minimization adaptive control

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Current detection based on GPR for grasping control of underac-tuated hands 49

Current detection based on GPR for grasping control of under...

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49th International Symposium on robotics, ISR 2017

作者： Cao, Wenwu Zhao, Siyu Wang, Weidong Du, Zhijiang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China

In the actual process of grasping, the unexpected movement of objects is the main contributing factor for the failure. In order to eliminate such phenomenon and improve the success rate of grasping, a novel controlling method of current detection based on Gaussian Process Regression (GPR) for underactuated hands grasping is proposed in this paper. Ac-cording to the practical requirements, the criterion for current detection is established firstly. Then based on multiple groups of learning samples, the reference model for controlling is acquired through GPR machine learning, and imple-mented in experiments of a 3-knuckles-2-fingeres underactuated hand compared with current detection method based on the theoretical model. The experimental results prove that the reference model can be used for the collision detection of a variety of objects, and then the unexpected movement of objects can be eliminated to achieve grasping successfully. © 49th International Symposium on robotics, ISR 2017. All rights reserved.

关键词： Object detection

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A novel actuation configuration of robotic hand and the mechanical implementation via postural synergies

A novel actuation configuration of robotic hand and the mech...

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2017 IEEE International Conference on robotics and Automation, ICRA 2017

作者： Liu, Yuan Jiang, Li Fan, Shaowei Yang, Dapeng Zhao, Jingdong Liu, Hong State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150080 China

ISBN: (纸本)9781509046331

How to design a robotic hand for reproducing the move characteristics of human hand joints is a big challenge in robotics. In this paper, we present an approach to determine the actuation configuration based on the statistical results of hand joint angle in different grasps. A relationship between the basic statistical metrics and actuation configuration strategies is built. In this case, a novel actuation configuration is proposed and the joints of four fingers are arranged into five actuation modules. For the mechanical implementation, the motion of human four finger joints is decomposed to proportion motion, differential motion and chain proportion motion, mechanically implemented by pulley, planetary gear differential module and gear transmission chain. Finally, the implemented mechanism is embedded in palm, and the mechanical implementation to the human hand move characteristics is verified by the measured joint angles of the robotic hand when actuators separately move along PC1 and PC2. Meanwhile, the robotic hand can grasp different objects with a versatile grasp function. © 2017 IEEE.

关键词： Mechanical actuators

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Design of a highly integrated underactuated finger towards prosthetic hand

Design of a highly integrated underactuated finger towards p...

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2017 IEEE International Conference on Advanced Intelligent Mechatronics, AIM 2017

作者： Cheng, Ming Jiang, Li Fenglei, Ni Fan, Shaowei Liu, Yuan Liu, Hong State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150080 China

ISBN: (纸本)9781509059980

This paper presents a highly integrated underactuated anthropomorphic finger with three joints and two DOFs using a novel coupled-Adaptive linkage mechanism. The finger has two main motion modes: coupled motion in free space and self-Adaptive motion when contacting with the object. Compared with conventional prosthetic finger, the combination of these two motion modes improves the anthropomorphic characteristics and grasping capacity remarkably. Besides, kinds of sensors embedded, force, position and tactile sensor in the finger not only intensify proactive perceptive ability, but also ameliorate the control ability. Moreover, according to a series of grasp experiments, the anthropomorphic finger can accomplish coupled motion and self-Adaptive motion stably. © 2017 IEEE.

关键词： Prosthetics

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A Novel Deployable Capture Mechanism Based on Bennett Networks for Active Debris Removal

A Novel Deployable Capture Mechanism Based on Bennett Networ...

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IEEE International Conference on robotics and Biomimetics

作者： XueAi Li Kui Sun Yuanfei Zhang Jingdong Zhao Hong Liu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Harbin Institute of Technology Harbin Heilongjiang CN

ISBN: (纸本)9781728103785;9781728103778

To stabilize the space debris problem, it's of great significance to perform Active Debris Removal (ADR) missions. The capturing phase plays a crucial role in the entire ADR mission. One of the greatest challenges is to capture the target in a simple manner. In this paper, a set of principal requirements are firstly established to guide the design of the capture mechanism. A malfunctioned satellite is chosen as the target due to increased collisions it may pose. Based on spatial overconstrained Bennett linkages that are linked by scissor elements, two types of 1-DOF linkage networks are built by tessellations. Both of the networks fold into bundles and deploy into "grippers", which also enables the deployment to be reversible with only one actuator. Without the need for latching devices, a novel concept of deployable capture mechanisms is proposed according to the networks. Besides, self-locking screw transmission and linkage mechanisms are compactly designed to drive the networks. Finally, simulations of the capturing operation are conducted to verify the compliance to the requirements, and the two types of mechanisms are compared to find their respective application occasions.

关键词： Couplings Grippers Actuators Satellites Fasteners Space vehicles Compaction

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Design of a pneumatic variable stiffness ankle joint

Design of a pneumatic variable stiffness ankle joint

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IEEE International Conference on Intelligence and Safety for robotics (ISR)

作者： Xizhe Zang Jiaqi Song Yixiang Liu Xinyu Zhou the State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Harbin Institute of Technology Harbin Heilongjiang CN

ISBN: (纸本)9781538655481

The foot-ground impact is a vital problem for biped robots walking stability. Various works have been done to reduce the impact and enhance the walking stability. This paper investigates the foot-ground impact using mathematic models and introduces the design of a pneumatic variable stiffness ankle joint. First, the torque and energy consumption of the ankle joint during double support phase are derived from a seven-link idealized model. Then, in order to find the optimal range of ankle stiffness, dynamic simulations are conducted on two virtual prototypes with variable stiffness ankle and rigid ankle respectively. After that, a pneumatic unit is designed based on the simulation results and a test is performed to measure its range of stiffness. Finally, combining the pneumatic unit with a parallelogram mechanism, an integrated variable stiffness ankle joint is developed.

关键词： Legged locomotion Foot Force Stability analysis Springs Torque

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