Behavior and dynamics of gecko＇s locomotion： The effects of moving directions on a vertical surface

The study of the movement behavior of geckos on a vertical surface, including the measurement and recording of the reaction forces as they move in different directions, plays an important role in understanding the mechanics of the animals’ locomotion. This study provides inspiration for the design of a control system for a bionics robot. The three-dimensional reaction forces of vertical surface-climbing geckos (Gekko gecko) were measured using a three-dimensional force-sensors-array. The behavior of gecko as it moved on a vertical surface was recorded with a high speed camera at 215 fps and the function of each foot of a gecko are discussed in this paper. The results showed that the gecko increased its velocity of movement mainly by increasing the stride frequency in the upward, downward and leftward direction and that the speed had no significant relationship to the attachment and detachment times. The feet above the center-of-mass play a key role in supporting the body, driving locomotion and balancing overturning etc. The movement behavior and foot function of geckos change correspondingly for different conditions, which results in safe and effective free vertical locomotion. This research will be helpful in designing gecko-like robots including the selection of gait planning and its control.     

仿壁虎机器人足端三维力采集系统研究

在微重力环境下仿壁虎机器人在"着陆"到目标航天器表面时,将会受到较大的碰撞力,影响机器人稳定着陆粘附。针对以上问题,仿生设计了机器人的足端结构,在机器人足端装载三维力传感器;该力采集系统基于STM32和AD620芯片,设计了三维力采集系统硬件和软件;并对三维力传感器进行静态标定和解耦。实验开展了机器人脚掌的碰撞粘附力测试,达到了预期效果,能为实现微重力下仿壁虎机器人稳定粘附着陆,提供力反馈控制的硬件保障。     

Progress on gecko-inspired micro/nano-adhesion arrays

Gecko’s excellent adhesion ability is thought to derive from van der Waals force generated between the millions of keratinous hairs/setae and the contact surface. Fabricating highly gecko-inspired foot-hair becomes one of the key technologies to realize the three-dimensional-obstacle-free motion of robot. Researchers have fabricated various gecko-like foot-hair arrays which have leaning, large end, and hierarchical structures. Those significant works are summarized and suggestions for future work are proposed in this paper.     

基于虚拟模型的四足机器人控制策略

为提高四足机器人在对角小跑(Trot)步态下的行走稳定性,并减小控制策略的复杂程度,提出了一种基于虚拟模型的四足机器人控制策略;将四足机器人控制策略分为支撑相及机身运动控制、摆动腿相运动控制及足端轨迹规划三部分;在Trot步态下行走时支撑相中存在的前后对角支撑足,在分析四足机器人支撑足受力情况后,并添加相关的约束条件,实现了四足机器人足端力及力矩可控;并通过在四足机器人机身的质心位置添加相应的虚拟弹簧阻尼组件,实现了四足机器人姿态和高度控制;通过在摆动腿足端实际位置与环境之间添加虚拟的弹簧阻尼组件并结合足端轨迹规划实现了四足机器人柔顺行走以及足端轨迹跟踪精确性;通过Matlab和CoppeliaSim建立联合对比仿真验证了控制策略的有效性和优越性。     

Angular observation of joints of geckos moving on horizontal and vertical surfaces

Because of their outstanding climbing and motor coordination ability, geckos have provided the basis for a peculiar bionic model leading to the development of a geckorobot. A three-dimensional locomotion observation system was constructed to measure angular orientations of joints while geckos trotted (337.1 mm/s) and walked (66.7 mm/s) on horizontal surfaces, and trotted (241.5mm/s) and walked (30.6mm/s) on vertical surfaces. Moving over horizontal surfaces, the joints rotated more quickly the greater the s...     

小型爬壁机器人系统设计与应用

针对一种小型的双足爬壁机器人,设计开发了基于DSP2812处理芯片的控制系统.该机器人系统采用双足真空吸盘式结构和用3个电机驱动5个关节的欠驱动结构.双足真空吸盘式结构使其可以在光滑的墙面和天棚行走,又能够在交接面之间完成跨步行走.而欠驱动结构减少了电机的数目,从而减小了机器人的尺寸和降低了机器人的质量和能量消耗,但它也给机器人的控制和运动规划带来了新的挑战.已完成的系统设计包括运动模式设计、关节控制、通信模块设计和吸盘足控制等.实验结果证明了所提出方案的可行性.     

一种蛇形机器人蜿蜒运动的实现及环境适应性研究

生物蛇数量众多的脊椎骨以及无足的身体结构,使其形成了特殊的蜿蜒式前进步态,能够广泛适应于草地、沙漠和湖泊等起伏地形,这种节律性的运动方式被证明是由中枢模式发生器(CPG)控制的.利用Hopf振荡器的稳态特性建立了能够实现蛇形机器人蜿蜒步态的CPG步态控制网络,依据蛇形机器人的模型仿真器得到了控制蜿蜒运动的CPG网络参数,并利用该网络的输出蛇形机器人成功实现了前进.根据Hopf振荡器对控制参数突然变化的良好适应性,通过在线调整得到了新的输出.讨论了面对复杂环境时蛇形机器人转弯运动的实现以及改变蛇形机器人身体S波构形来提高其环境适应性的方法.在蛇形机器人样机上的实验证明了基于CPG的运动控制方法在蛇形机器人蜿蜒运动上的有效性.     

空间三弹簧系统的力逆解

对并联机器人机构，若其动平台与固定平台由三弹簧联接，则组成并联机器人空间三弹簧系统。其力逆解即给定作用于上平台上某点的外力，求系统处于静力平衡时的所有构形。建立了力逆解方程组，用连续法求出了全部解，得到了系统处于静力平衡时的全部构形。     

An in-pipe micro robot actuated by piezoelectric bimorphs

A novel in-pipe micro robot providing stable and accurate locomotion inside a tubular structure with diameters ranging from 16 mm to 18 mm is presented in this paper. Driven by impulsive voltages, deflections of the piezoelectric bimorphs are generated and then converted into translational locomotion by the principle of the Impact Drive Mechanism （IDM）. Theoretical analysis of the proposed system is performed based on a simplified mechanical model. Then dynamic simulations of the dynamic behavior are performed. Finally, an experiment is conducted to investigate the moving ability of this device. The results demonstrate that a maximum translational velocity of 3.5 mm/s can be obtained under an im- pulsive driving voltage with peak value at 50 V and frequency of 1100 Hz. Both theoretical analysis and experimental trials prove that the principle of IDM actuated by piezoelectric bimorphs is feasible and robust for achieving accurate locomotion of the micro robot in pipes with diameters of less than 20 mm.     

轮腿式机器人多运动模式运动学分析与建模

轮腿式移动机器人具有轮式、履带式和腿式等多种运动模式,对不同运动模式下的运动特性进行了分析,建立了轮式运动模式下的运动学方程,对履带运动模式下的转向运动学进行了运动学建模;通过对机器人在腿式模式的姿态描述,建立其运动学模型。为对轮腿式机器人进行综合运动分析,实现机器人控制提供了理论基础。     

小型地面移动机器人特殊运行姿态动力学建模与分析

该文以六履带移动机器人为研究目标，以适应越野路面及特殊功能需要，如爬越障碍、自身撑起、翻身等特殊动作。文中给出了系统构成、传动原理及系统设计方案，对运动姿态进行了描述，重点对自身撑起、爬越障碍、翻身3个特殊运动姿态进行了动力学建模，并结合动力驱动能力进行参数对比分析，得出了受力与驱动关系模型及状态临界条件：通过分析为小型地面机器人在复杂地理环境下顺利运行，提高机器人适应性提供了理论设计依据。     

基于无源观测器的机器人笛卡尔空间力/阻抗控制方法研究

许多由机器人完成的任务都需要机器人与外部环境接触。在如抛光、去毛刺和装配作业中都需要执行精确的力控制。由于环境模型的不准确在力控制过程中当机器人与环境脱离接触时可能与周围环境发生激烈碰撞。针对此问题提出了基于无源观测器的力控算法。通过分析系统无源性, 研究了笛卡尔空间力/阻抗控制的稳定条件。发现只有力控制器的输出会破坏系统的无源性,根据系统无源性的分析结果设计了使用无源性观测器的力/阻抗控制器。在MATLAB仿真环境中对力/阻抗控制控制算法和基于无源性观测器的力/阻抗控制进行仿真验证。仿真结果表明基于无源性观测器的力/阻抗控制器在机器人末端工具与环境脱离接触时能够有效降低机械臂移动速度,减小对周围环境的冲击力。     

A stereotaxic method and apparatus for the Gekko gecko

To study the modulation mechanism of the middle brain of the Gekko to the locomotion, we introduced a stereotaxic method first in literature and developed an apparatus suitable for Gekko gecko, the big-gest wall and ceiling climber in nature. We defined the bregma and nasal points as reference points, selected the bilateral infraorbital margin and top point of the maxillary tooth for locating and fixing, and set up the line passing through the bregma and paralleling to a line connecting the bilateral infraorbital margin as x axis. Then, we defined a horizontal plane in the stereotaxic instrument, passing through x axis and the certain point which is 4.8 mm exactly above the nasal point, as the XOY plane; the sagittal plane, i.e. the YOZ plane, is the plane which is perpendicular to x axis and passes through the bregma; the plane, i.e. the XOZ plane, which passes through x axis and is perpendicular to the horizontal plane is the coronal plane. We designed a set of head holder which includes three parts: bilateral infraorbital margin clamps, a gecko adaptor holding the rostral side of the upper jaw. The allocation and operation of the head holder is accurate and simple, and the device is low in cost and compatible with standard stereotaxic instrument.     

Role of locust <Emphasis Type="Italic">Locusta migratoria manilensis</Emphasis> claws and pads in attaching to substrates

The present study attempts to investigate the role of rigid claws and smooth adhesive pads in the locust Locusta migratoria manilensis,when attaching to various substrates.We measured the attachment forces on sandpaper and silicate glass plate of locusts with intact attachment system,and those with either the pretarsal claws or the tarsal pads having been entirely destroyed,to explore the role of pads and claws when a locust is walking on various substrates.To obtain information about morphological characteristics and material properties of the claws,we examined the intact and fractured claws by scanning electron microscopy,and tested the fractural force in a fracture experiment.We proposed a mechanical model for locust climbing on a slanting surface to analyze the conduction and final result of the attachment forces generated by the attachment organs on the fore-,mid-and hindlegs.Attachment forces generated by locusts with destroyed pads were similar to those generated by locusts with intact attachment system on both substrates,which presumably indicated that the claws have a significantly important role when attaching to various substrates.The result of the fracture experiment demonstrated that the claws are made of relatively stiff material,and their shear strength ranged between 39-45 MPa.Mechanical analysis of locust climbing on slanting surface showed that the force generated by the hindlegs suspended the whole body of locust up from the surface and pushed the body forward,while the midlegs steadily suspended the centre of gravity and the forelegs pulled the suspended body forward.The results obtained contribute to the further interpretation of the interaction mechanisms between insect attachment system and substrates,and supply information for designing and manufacturing slippery plates for trapping plague locusts.     

一种壁面牵引移动式玻璃幕墙清洗机器人

提出了一种新颖的平面玻璃幕墙清洗机器人结构设计原则,据此设计了2个自身无行走机构并依靠壁面牵引移动的清洗机器人系统.机器人吸附在壁面上,在楼顶卷扬机的牵引作用下依靠自身重力沿壁面下滑,同时完成清洗作业,并通过双负压吸盘的交替吸附跨越突起的水平窗框障碍.为提高机器人的工作能力,进行了作业安全分析,并研究了吸盘吸附力的调整控制方法.现场试验表明机器人能有效完成幕墙清洗任务,具有机构简单、效率高、成本低、清洗效果好的特点.     

Locomotor kinematics of the gecko （Tokay gecko） upon challenge with various inclines

Tokay geckos are skillful climbers and are able to negotiate difficult terrain such as steep slopes and overhanging inclines without losing their foothold. Here, we present data on the changes in locomotor kinematics when geckos are challenged to walk on various inclined surfaces. We trained individual geckos to move along a platform which can be tilted to simulate different slopes. The animals were filmed using a high-speed video camera. The results showed that their speed decreased with increasing slope angle, and their speed on the steep and inverted slopes （sloped angle 〉60~） decreased at a faster rate than on the shallow slopes （sloped angle 〈60~）. The geckos＇ stride length was much greater on the shallow slopes compared to the inverted slopes. The influence of stride length and stride frequency on speed was different when the geckos moved across different slopes. There are significant differences duty factor, which varied from 0.54 when wall climbing （90° slope） to 0.84 when walking on the ceiling （180° slope）. The mechanisms revealed this study will improve our understanding of control strategies in kinematics and inspire the design of robots with greater mobility.     

消除惯性力对机器人腕力传感器输出的影响

由于惯性力的影响，机器人腕力传感器输出的六维信号不能准确反映机械手夹持器与外界环境接触力的大小．理论分析表明，为了消除惯性力对输出的影响，必须知道机械手工作时的加速度．介绍了用以消除惯性力对腕力传感器输出的影响的方法，并详细叙述了腕力传感器中加速度计的设计．     

双臂巡检机器人沿输电线路行走特性研究

传统双臂巡检机器人沿大跨度输电线路行走过程中存在行走轮受力不均、易脱线等问题.针对这些问题,分别建立了传统双臂巡检机器人和带柔索双臂巡检机器人行走轮受力模型,对比分析表明:与传统双臂巡检机器人相比,随着线路倾斜角度增大,带柔索双臂巡检机器人两臂行走轮受力较均匀,不会出现脱线现象.在相同质量参数和结构参数条件下,采用虚拟样机技术分析了2种类型机器人沿输电线路行走时行走轮受力情况,仿真结果表明,传统双臂巡检机器人在线路倾斜角度达到28°时,出现单臂挂线现象;而带柔索双臂巡检机器人在线路倾斜角度达到37°时,仍能保持稳定地双臂挂线.综合分析表明,带柔索双臂巡检机器人的结构设计在线路行走方面具有明显优势,对于倾斜角较大的大跨度输电线路具有更强的适应能力,行走稳定性更好.      

机器人力控制系统仿真分析

本文对由Movemaster-EX机器人和HUST-FS6腕力传感器组成的力控制系统进行了分析,讨论了接触物体和腕力传感器刚度、力反馈矩阵、库仑摩擦以及间隙非线性对整个力控制系统稳定性的影响;引入力的微分反馈有助于增强力控系统的稳定性,用单关节机器人模型进行了仿真研究.结果表明,接触物体综合刚度、力反馈矩阵、库仑摩擦和间隙非线性对力控系统影响很大;引入力微分反馈能改善系统性能.     

随五轴加工轨迹变抛光力的控制策略与方法

设计了以PWM信号高速开关控制为核心的气动抛光力加载控制系统,采用滑动平均滤波PID算法调节,通过Simulink仿真和实验调整PID参数,提高系统动态性能,保证变抛光力的控制要求.借助五轴混联机器人动平台,搭建五轴变抛光力试验系统,进行跟随轨迹的变抛光力加载实验.实验结果表明,设计的滑动平均滤波PID控制能够在力控制要求改变时快速响应,使抛光力跟踪至设定值,力实测值误差在±1N以内,波动范围小,具有足够的稳定性和准确性,满足变抛光力的控制要求,实现了跟随五轴加工轨迹的变抛光力控制.