Design of a Novel Robotic Fish Structure Utilizing PVC Gel Actuators

In this research work, it has been designed a bionic robot fish structure, can swim underwater. The active compact body is powered by eight sets of symmetric PVC gel actuators with a caudal fin. The robot’s 200 mm-long, fish structure design incorporates a 55.52 angle to optimize the fish dynamics movement. It’s a fast and smooth operation and can swim. The robot can swim fast and quietly by using the right positions and the appropriate actuators on PVC gel actuators. This design entails a unique architecture that enables the robot to move safely and unobtrusively at the same time, which makes it suitable equipment for different exploration and surveillance missions in the water with speed and silent operation as the foremost concern.

Flexible Bio-tensegrity Manipulator with Multi-degree of Freedom and Variable Structure

Conventional manipulators with rigid structures and sti ness actuators have poor flexibility,limited obstacle avoidance capability,and constrained workspace.Some developed flexible or soft manipulators in recent years have the characteristics of infinite degrees of freedom,high flexibility,environmental adaptability,and extended manipulation capability.However,these existing manipulators still cannot achieve the shrinking motion and independent control of specified segments like the animals,which hinders their applications.In this paper,a flexible bio-tensegrity manipulator,inspired by the longitudinal and transversal muscles of octopus tentacles,was proposed to mimic the shrinking behavior and achieve the variable motion patterns of each segment.Such proposed manipulator uses the elastic spring as the backbone,which is driven by four cables and has one variable structure mechanism in each segment to achieve the independent control of each segment.The variable structure mechanism innovatively contains seven lock-release states to independently control the bending and shrinking motion of each segment.After the kinematic modeling and analysis,one prototype of such bionic flexible manipulator was built and the open-loop control method was proposed.Some proof-of-concept experiments,including the shrinking motion,bending motion,and variable structure motion,were carried out by controlling the length of four cables and changing the lock-release states of the variable structure mechanism,which validate the feasibility and validity of our proposed prototype.Meanwhile,the experimental results show the flexible manipulator can accomplish the bending and shrinking motion with the relative error less than 6.8%through the simple independent control of each segment using the variable structure mechanism.This proposed manipulator has the features of controllable degree-of-freedom in each segment,which extend their environmental adaptability,and manipulation capability.

Bioinspired MXene-Based Soft Actuators Exhibiting Angle-Independent Structural Color

In nature,many living organisms exhibiting unique structural coloration and soft-bodied actuation have inspired scientists to develop advanced structural colored soft actuators toward biomimetic soft robots.However,it is challenging to simultaneously biomimic the angle-independent structural color and shape-morphing capabilities found in the plum-throated cotinga flying bird.Herein,we report biomimetic MXene-based soft actuators with angle-independent structural color that are fabricated through controlled self-assembly of colloidal SiO_(2) nanoparticles onto highly aligned MXene films followed by vacuum-assisted infiltration of polyvinylidene fluoride into the interstices.The resulting soft actuators are found to exhibit brilliant,angle-independent structural color,as well as ultrafast actuation and recovery speeds(a maximum curvature of 0.52 mm−1 can be achieved within 1.16 s,and a recovery time of~0.24 s)in response to acetone vapor.As proof-of-concept illustrations,structural colored soft actuators are applied to demonstrate a blue gripper-like bird’s claw that can capture the target,artificial green tendrils that can twine around tree branches,and an artificial multicolored butterfly that can flutter its wings upon cyclic exposure to acetone vapor.The strategy is expected to offer new insights into the development of biomimetic multifunctional soft actuators for somatosensory soft robotics and next-generation intelligent machines.

Biomimetic flexible plate actuators are faster and more efficient with a passive attachment

Using three-dimensional computer simulations, we probe biomimetic free swimming of an internally actuated flexible plate in the regime near the first natural frequency. The plate is driven by an oscillating internal moment approximating the actuation mechanism of a piezoelectric macro fiber composite (MFC) bimorph. We show in our simulations that the addition of a passive attachment increases both swimming velocity and efficiency. Specifically, if the active and passive sections are of similar size, the overall performance is the best. We determine that this optimum is a result of two competing factors. If the passive section is too large, then the actuated portion is unable to generate substantial deflection to create sufficient thrust. On the other hand, a large actuated section leads to a bending pattern that is inefficient at generating thrust especially at higher frequencies.

Augmented Virtual Stiffness Rendering of a Cable-driven SEA for Human-Robot Interaction

Human-robot interaction(HRI) is fundamental for human-centered robotics, and has been attracting intensive research for more than a decade. The series elastic actuator(SEA) provides inherent compliance, safety and further benefits for HRI, but the introduced elastic element also brings control difficulties. In this paper, we address the stiffness rendering problem for a cable-driven SEA system, to achieve either low stiffness for good transparency or high stiffness bigger than the physical spring constant, and to assess the rendering accuracy with quantified metrics. By taking a velocity-sourced model of the motor, a cascaded velocity-torque-impedance control structure is established. To achieve high fidelity torque control, the 2-DOF(degree of freedom) stabilizing control method together with a compensator has been used to handle the competing requirements on tracking performance, noise and disturbance rejection,and energy optimization in the cable-driven SEA system. The conventional passivity requirement for HRI usually leads to a conservative design of the impedance controller, and the rendered stiffness cannot go higher than the physical spring constant. By adding a phase-lead compensator into the impedance controller,the stiffness rendering capability was augmented with guaranteed relaxed passivity. Extensive simulations and experiments have been performed, and the virtual stiffness has been rendered in the extended range of 0.1 to 2.0 times of the physical spring constant with guaranteed relaxed passivity for physical humanrobot interaction below 5 Hz. Quantified metrics also verified good rendering accuracy.

The emerging technology of biohybrid micro-robots:a review

In the past few decades,robotics research has witnessed an increasingly high interest in miniaturized,intelligent,and integrated robots.The imperative component of a robot is the actuator that determines its performance.Although traditional rigid drives such as motors and gas engines have shown great prevalence in most macroscale circumstances,the reduction of these drives to the millimeter or even lower scale results in a significant increase in manufacturing difficulty accompanied by a remarkable performance decline.Biohybrid robots driven by living cells can be a potential solution to overcome these drawbacks by benefiting from the intrinsic microscale self-assembly of living tissues and high energy efficiency,which,among other unprecedented properties,also feature flexibility,self-repair,and even multiple degrees of freedom.This paper systematically reviews the development of biohybrid robots.First,the development of biological flexible drivers is introduced while emphasizing on their advantages over traditional drivers.Second,up-to-date works regarding biohybrid robots are reviewed in detail from three aspects:biological driving sources,actuator materials,and structures with associated control methodologies.Finally,the potential future applications and major challenges of biohybrid robots are explored.

A Micro Peristaltic Pump Using an Optically Controllable Bioactuator

Peristalsis is widely seen in nature, as this pumping action is important in digestive systems for conveying sustenance to every corner of the body. In this paper, we propose a muscle-powered tubular micro pump that provides peristaltic transport. We utilized Drosophila melanogaster larvae that express channelrhodopsin-2 (ChR2) on the cell membrane of skeletal muscles to obtain light-responsive muscle tissues. The larvae were forced to contract with blue light stimulation. While changing the speed of the propagating light stimulation, we observed displacement on the surface of the contractile muscle tissues. We obtained peristaltic pumps from the larvae by dissecting them into tubular structures. The average inner diameter of the tubular structures was about 400 lm and the average outer diameter was about 750 lm. Contractions of this tubular structure could be controlled with the same blue light stimulation. To make the inner flow visible, we placed microbeads into the peristaltic pump, and thus determined that the pump could transport microbeads at a speed of 120 lm-s1.

纺织基软体机器人结构设计与驱动性能研究

针对现有软体气动机器人制备成本高、设计灵活性差、功率密度低、控制技术复杂等问题,文章以鞘芯结构的涤纶∕氨纶弹性纱为基材编织针织罗纹组织,以涤纶纱为纬向衬垫纱间隔织入,形成力学各向异性的针织衬纬组织,并将该衬纬组织作为包覆层与气囊内胆装配,实现具有高致动应变、低能量耗散的高性能纺织基气动机器人开发。文章通过力学性能和驱动变形测试,表征分析了衬纬组织织物层的各向异性力学特征和针脚排列方式等因素对软体机器人驱动性能、变形特征、输出力和运动状态的影响规律。结果表明:纺织基软体机器人展现了优良的弯曲应变(弯曲曲率可达0.27 cm^(-1)),高的驱动力输出(13 N∕kg)。此外,开发的纺织基气动机器人具有低成本、设计灵活快捷、操控简单等优势,可通过编织结构设计和针脚方向的配置实现多模式的复杂变形,在可穿戴医疗康复训练设备和软体抓取器件等领域具有可观的应用前景。

六自由度3D打印机平台的设计与分析

近年来,机器人学的发展打破了传统3D打印机打印位置的局限。多自由度的运动模式有更灵活的打印轨迹和更丰富的机构设计。本研究以基于Stewart并联机构的3D打印机械结构为研究对象,确定了并联机构的具体尺寸,对3D打印机主体框架进行结构设计,利用Solidworks建立机构平台的三维模型,并分析其运动轨迹,将模型导入Matlab软件进行运动学仿真分析,运用Ansys进行静力学分析。本研究可以在材料承载端提供六自由度的运动,为后续开发多自由度的打印机提供参考。

自主式水下机器人滑模容错自动化控制方法

针对因水下机器人工作环境噪声影响较大、难以提取故障特征点,导致控制精准度较低的问题,该文提出一种滑模容错自动化控制方法。建立机器人五自由度空间方程以及故障执行器的动力学方程,计算机器人每个关键滑模点的不确定性因素变化矢量,推导得到机器人的离散故障状态方程。根据机器人在期望状态下的滑模特性,将故障状态参数代入后,识别定位到故障点,提取机器人线性反馈的控制规律,设定机器人在滑模容错控制函数中的双曲正切函数,计算产生滑模动态的控制输入值,实现自动化控制。实验结果证明,所提方法在第25 s处即发现故障,输出信号幅值稳定在-28 Hz~28 Hz之间,具有良好的自动化控制能力。

一种基于多自由度鱼尾的仿生机器鱼设计

针对传统的水下机器人运动效率低、水下作业时产生的噪声污染会影响鱼群生活环境、隐蔽性差容易被雷达探测识别,而大多数仿生鱼尾部摆动模式不够灵活、环境适应性差的问题,提出了一种基于多自由度鱼尾的仿生机器鱼的结构方案。该鱼尾能够产生横向和纵向两个方向的运动矢量,尾部能够进行更加灵活的摆动。对机器鱼尾部结构进行了实验,实验结果表明:在横向上驱动线变化量为50 mm时达到最大摆角116°,纵向上驱动线变化量在46 mm时达到纵向最大摆角61°。

苹果采摘机器人结构设计

苹果采摘机器人在提高采摘效率和降低劳动成本方面显示出巨大潜力。研究设计了一种高效智能的苹果采摘机器人,以解决传统人工采摘方式存在的效率低下和劳动强度大的问题。基于苹果采摘机器人机械臂的工作环境,制定了机械臂设计方案,包括总体结构、选型与设计、末端执行器、传输结构、分拣结构、动力系统及行走机构的详细设计。搭建了测试环境并进行了测试分析,结果验证了设计的有效性和实用性。

软体机器人气压驱动结构研究综述

气压驱动是最早的软体机器人驱动方式。本文综述了软体机器人气压驱动的主要结构形式和工作原理,包括形约束型驱动结构、纤维约束型驱动结构、织网约束型驱动结构、颗粒增强型驱动结构等,并进一步从结构设计创新、智能材料与驱动结构的深度融合、建模与仿真技术、制造技术等方面分析讨论了气压驱动软体机器人研究中存在的技术难题,指出了气压驱动结构在设计、智能材料、建模仿真、加工制造等方面需要亟待解决的关键问题和研发方向。气压驱动软体机器人是目前最广泛研究和最有可能率先得到应用的软体机器人形式,具有相对良好的相关技术基础,机器人、机械工程、材料科学、智能控制、计算机图形学等多学科交叉和深度合作将有助于促进该方向的快速发展。

面向飞机自动化装配的制孔末端执行器的设计

末端执行器是飞机装配的关键部件之一,其性能直接影响到制孔和铆接的质量,突破面向飞机自动化装配的末端执行器结构设计关键技术具有迫切的实际需求。首先,根据行业需求提出了末端执行器的总体结构,并分析了工作原理,在此基础上对末端执行器的主要功能部件进行了设计,最后研制出一套具备制孔、压紧和法向找正的试验样机,试验结果表明,该末端执行器的性能达到了飞机装配的要求。

欠驱动冗余度空间机器人优化控制

欠驱动控制是空间技术中容错技术的重要方面.本文研究了被动关节中有制动器的欠驱动冗余度空间机器人系统的运动优化控制问题.从系统动力学方程出发,分析了欠驱动冗余度空间机器人的优化能力和控制方法;给出了主、被动关节间的耦合度指标;提出了欠驱动冗余度空间机器人系统的“虚拟模型引导控制”方法,在这种方法中采用与欠驱动机器人机构等价的全驱动机器人作为模型来规划机器人的运动,使欠驱动系统在关节空间中逼近给出的规划轨迹,实现了机器人末端运动的连续轨迹运动优化控制;通过末关节为被动关节的平面三连杆机器人进行了仿真,仿真的结果证明了提出算法的有效性.

六自由度水下机械手臂的设计与研究

针对水下作业机械手环境恶劣,时变等难题,结合水下作业的具体要求,设计了一种六自由度水下机械手臂。肩部可水平摆动100°,大臂可绕肩关节上下摆动120°,前臂可绕肘关节上下摆动120°,前臂绕自身轴线旋转270°,腕部可绕肘关节上下摆动120°,腕部绕自身轴线旋转360°。利用MATLAB对机械手正向运动学模型进行分析,为下一步六自由度水下机械手的智能控制提供了设计参数。

箱型钢结构焊接机器人系统机构设计与研究

箱型钢结构在建筑、桥梁等领域的应用愈来愈广泛,针对安装现场迫切需要解决的自动化焊接问题,提出了一种箱型钢结构焊接机器人系统。在对其总体结构进行了功能分析和论证的基础上,进行了机械结构详细设计。在焊接机器人系统水平安装和垂直安装两种极限使用位置下,对所设计的轨道机械结构进行了力学有限元分析,结果表明:该机构设计合理,力学性能完全满足使用要求。该机器人系统具有使用灵活、可适用于不同尺寸的钢结构焊接、有助于获得良好的焊接质量和较高的焊接效率、适应条件恶劣的现场焊接工况等优点。

基于螺旋理论三自由度并联机器人型综合新方法

并联机器人的构型设计即型综合是并联机器人设计的首要环节,基于螺旋理论,从并联机构运动链分类的角度,提出用约束添加法对三自由度并联机构进行型综合,让主动链控制所需的自由度,而从动链约束不需要的自由度;提出了相应主动链和从动链各种类型,并对约束链作了较详细的分类,通过不同组合可得到不同性能的新构型.最后通过实例进一步阐明这一方法.该方法使型综合步骤更简洁,只要选择与自由度数相同个数的主动链,并合理选择约束链就可以组合出新的并联机器人.

高压输电线路螺栓紧固机器人结构设计与动力学分析

以高压输电线路耐张线夹引流板螺栓为作业对象,研究提出了一种可以沿高压输电线路行驶并由双作业臂携带螺栓紧固末端工具进行耐张线夹引流板螺栓紧固的带电作业机器人。研究提出了一种四臂移动作业的螺栓紧固作业机器人构型,即移动机器人的双臂、一个携带螺栓固定末端的机械手、一个携带螺栓拧紧末端的机械手,研究了带电作业机器人的机械结构,分析了作业末端的性能与携带螺栓拧紧末端的机械手动力学模型,研制了机器人样机。通过在实际线路上的带电作业试验,验证了提出的构型方案的正确性和有效性。

一种复杂曲面打磨机器人自适应贴合柔性机构研究

针对工程中复杂曲面打磨困难的问题,提出一种能迅速贴合工件表面的柔顺混联式自适应机构,对其工作空间、运动学和动力学工作特性进行了分析研究。利用基于方位特征集的拓扑结构理论求解自适应机构的自由度、耦合度。利用数学应用软件对机构的参数进行数值计算,获得了自适应机构在抛光打磨过程中的工作特性曲线和工作空间模拟图。建立自适应机构的样机模型并进行样机实验,分析了在对模拟的复杂工件曲表面加工时的运动学和动力学特性,实验得出本设计相对传统机型的优势。