Modelling of thrust generated by oscillation caudal fin of underwater bionic robot

A simplified model of the thrust force is proposed based on a caudal fin oscillation of an underwater bionic robot. The caudal fin oscillation is generalized by cen- tral pattern generators （CPGs）. In this model, the drag coefficient and lift coefficient are the two critical parameters which are obtained by the digital particle image velocimetry （DPIV） and the force transducer experiment. Numerical simulation and physical experi- ments have been performed to verify this dynamic model.

Stability margin of the quadruped bionic robot with spinning gait

Spinning gait is valuable for quadruped robot,which can be used to avoid obstacles quickly for robot walking in unstructured environment. A kind of bionic flexible body is presented for quadruped robot to perform the spinning gait. The spinning gait can be achieved by coordinated movement of body laterally bending and legs swing,which can improve the mobility of robot walking in the unstructured environments. The coordinated movement relationship between the body and the leg mechanism is presented. The stability of quadruped robot with spinning gait is analyzed based on the center of gravity( COG) projection method. The effect of different body bending angle on the stability of quadruped robot with spinning gait is mainly studied. For the quadruped robot walking with spinning gait,during one spinning gait cycle,the supporting polygon and the trajectory of COG projection point under different body bending angle are calculated. Finally,the stability margin of quadruped robot with spinning gait under different body bending angle is determined,which can be used to evaluate reasonableness of spinning gait parameters.

Optimal Variable Stiffness Control and Its Applications in Bionic Robotic Joints:A Review

Variable Stiffness Actuation(VSA)is an efficient,safe,and robust actuation technology for bionic robotic joints that have emerged in recent decades.By introducing a variable stiffness elastomer in the actuation system,the mechanical-electric energy conversion between the motor and the load could be adjusted on-demand,thereby improving the performance of the actuator,such as the peak power reduction,energy saving,bionic actuation,etc.At present,the VSA technology has achieved fruitful research results in designing the actuator mechanism and the stiffness adjustment servo,which has been widely applied in articulated robots,exoskeletons,prostheses,etc.However,how to optimally control the stiffness of VSAs in different application scenarios for better actuator performance is still challenging,where there is still a lack of unified cognition and viewpoints.Therefore,from the perspective of optimal VSA performance,this paper first introduces some typical structural design and servo control techniques of common VSAs and then explains the methods and applications of the Optimal Variable Stiffness Control(OVSC)approaches by theoretically introducing different types of OVSC mathematical models and summarizing OVSC methods with varying optimization goals and application scenarios or cases.In addition,the current research challenges of OVSC methods and possible innovative insights are also presented and discussed in-depth to facilitate the future development of VSA control.

Motion Control and Motion Coordination of Bionic Robotic Fish： A Review

Fish＇s outstanding motion and coordination performance make it an excellent source of inspiration for scientists and engineers aiming to design and control next-generation autonomous underwater vehicles within the framework of bionics. This paper offers a general review of the current status of bionic robotic fish, with particular emphasis on the hydrodynamic modeling and testing, kinematic modeling and control, learning and optimization, as well as motion coordination control. Among these aspects, representative studies based on ideas and concepts inspired from fish motion and coordination are discussed. At last, the major challenges and the future research directions are addressed in the context of integration of various research streams from ichthyologic, hydrodynamic, mechanical, electronic, control, and artificial intelligence. Further development of bionic robotic fish can be utilized to execute some specific missions in complex underwater environments, where operations are unsafe or impractical for divers or conventional underwater vehicles.

Ionic Electroactive Polymers Used in Bionic Robots： A Review

Ionic electroactive polymers （IEAPs） are a category of intelligent soft materials exhibiting large displacement under electric excitation, based on inner ion or solvent transport. Due to their unique advantages such as flexibility, low driving voltage, large bending displacement and aquatic-environment adaptability, IEAPs have been documented as very promising actuators for the applications in bionic robots. This review presents an analysis to the current research status of IEAPs exploited in bionic robots. According to the specific bionic parts, those robots are divided into four classes： imitation of fins, limbs, joints and trunks. Their dimension, weight, voltage amplitude, frequency and maximum speed were summarized to show the optimum design range. The results show that the approach velocity of the current robots were higher （〉 35 mm· s-1） when the robot weighted 60 g - 180 g and the body was 90 mm - 130 mm long. For voltage from 1 V - 3 V and frequencies from 0.7 Hz - 1.2 Hz, the speed was relatively higher （〉 35 mm·s-1）.To some extent, the maximum speed decreases when the area of the IEAP material used in bionic robot increases. For underwater circumstances, IEAP materials are most suitable for designing bionic robots swimming with Body and/or Caudal Fin （BCF）. This review provides important guidance for the design of lEAP bionic robots.

Three-dimensional path following control system for net cage inspection using bionic robotic fish

With the increasing impacts of overfishing and environmental pollution,the deep-sea cage culture of marine fishes has become an important direction of mariculture.In this paper,a tuna-like robotic fish with a three-dimensional helix path-following control system is designed for deep-sea net cage inspection.To mimic the flexibility of the fish’s movement,the kinematic model of the robotic fish adopts a tuna-like double-joint design with an addi-tional thruster device at the tail.Since the descending interval control plays a critical role in deep-sea net cage inspection,the control system utilizes the proportion integration differ-entiation(PID)based fuzzy logic control method to control the descending interval and yaw angle during the helix path movement.A polar coordinate path definition method is also proposed to simplify the reference path definition during net cage inspection.The experi-mental results demonstrates that the proposed three-dimensional path-following model can conduct net inspection task in an interferential environment and move along prede-fined reference path.

Dynamic Bending of Bionic Flexible Body Driven by Pneumatic Artificial Muscles(PAMs) for Spinning Gait of Quadruped Robot

The body of quadruped robot is generally developed with the rigid structure. The mobility of quadruped robot depcnds on the mechanical properties of the body mechanism, It is difficult for quadruped robot with rigid structure to achieve better mobility walking or running in the unstructured environment. A kind of bionic flexible body mechanism for quadruped robot is proposed, which is composed of one bionic spine and four pneumatic artificial muscles（PAMs）. This kind of body imitates the four-legged creatures＇ kinematical structure and physical properties, which has the characteristic of changeable stiff＇hess, lightweight, flexible and better bionics. The kinematics of body bending is derived, and the coordinated movement between the flexible body and legs is analyzed. The relationship between the body bending angle and the PAM length is obtained. The dynamics of the body bending is derived by the floating coordinate method and Lagrangian method, and the driving tbrce of PAM is determined. The experiment of body bending is conductcd, and the dynamic bending characteristic of bionic flexible body is evaluated. Experimental results show that the bending angle of the bionic flexible body can reach 18. An innovation body mechanism for quadruped robot is proposed, which has the characteristic of flexibility and achieve bending by changing gas pressure of PAMs. The coordinated movement of the body and legs can achieve spinning gait in order to improve the mobility of quadruped robot.

Bionic Mechanism and Kinematics Analysis of Hopping Robot Inspired by Locust Jumping

A flexible-rigid hopping mechanism which is inspired by the locust jumping was proposed, and its kinematic characteris- tics were analyzed. A series of experiments were conducted to observe locust morphology and jumping process. According to classic mechanics, the jumping process analysis was conducted to build the relationship of the locust jumping parameters. The take-offphase was divided into four stages in detail. Based on the biological observation and kinematics analysis, a mechanical model was proposed to simulate locust jumping. The forces of the flexible-rigid hopping mechanism at each stage were ana- lyzed. The kinematic analysis using pseudo-rigid-body model was described by D-H method. It is confirmed that the proposed bionic mechanism has the similar performance as the locust hind leg in hopping. Moreover, the jumping angle which decides the jumping process was discussed, and its relation with other parameters was established. A calculation case analysis corroborated the method. The results of this paper show that the proposed bionic mechanism which is inspired by the locust hind limb has an excellent kinematics performance, which can provide a foundation for design and motion planning of the hopping robot.

Motor Driving Leg Design for Bionic Crab-like Robot

The paper presents the design of walking leg for bionics crab-like robot, which is driven with micro servo motor. The kinematic characteristics of the bionics machine are analysed for optimized structure parameters, which has been used in the robot design. A three closed loop motor control system structure for joint driver is also given, as well as the multi-joint driving system for walking robot leg.

Planning on Bionic Walking Gait of Quadruped Robot over Rough Terrain

A quadruped robot is more adjustable to a complex terrain than a wheeled or caterpillar robot to realize the continuous adjustable motions characterized by submissiveness and low energy consumption in basic control of the quadruped robot over rough terrain. This paper presents a static walking mode of ＂altitude hold＂, which means to keep absolute altitude by controlling limbs adjustably on the basis of which biokinetics studies have shown that quadrupeds can move with almost the same body altitude over rough terrains characterized by a nearly horizontal relief. The gait design specifies several characteristic states of stance phase and swing phase for a quadruped robot and controls the phase sequence and phase of four legs through change of characteristic states. Furthermore, we design a robot control system to generate adjustable gaits and control the coordinative movement of robot joints. This planning method is tested through ADAMS and MATLAB interactive co-simulation; the quadruped robot which has 8 degrees of freedom （8-DOF） is used to simulate the motion over a terrain character- ized by randomly arranged humps. The results show that this method can make the quadruped robot capable to walk over certain rough terrain.

四足机器人腾空跳跃的轨迹优化与控制方法

针对四足机器人难以跨越大尺寸障碍物的问题,提出了一种仿生腾空跳跃的轨迹优化控制方法 .首先,对马里努阿犬的越障运动进行测试和仿生学分析,得到腾空跳跃的参考轨迹.其次,根据摩擦锥、轨迹平滑、运动学和动力学等约束条件,基于轨迹优化的方法对仿生参考轨迹进行离线优化,生成四足机器人的期望跳跃轨迹,得到跳跃所需的足端位置、关节力矩和关节角度序列.再次,设计分阶段的跳跃控制器,采用关节和质心PD(Proportional Derivative)的组合控制策略,实现对期望跳跃轨迹的跟踪,采用变刚度虚拟模型控制实现对落地姿态的调整和足底力的缓冲.最后,在Webots仿真环境中完成了1 m高度的自由落地和跳跃0.75 m高度桌子的仿真实验.研究结果表明:仿生轨迹优化与控制算法能够使四足机器人跳跃大尺寸障碍物并且具有平稳落地的效果,对于提高四足机器人的高性能运动能力以及拓展其应用环境具有参考价值.

仿生六足折纸机器人结构设计与运动分析

针对现有折纸机器人组成结构单一,运动不够灵活的问题,将折纸结构与多足机器人设计相结合,耦合三浦折纸和六折痕折纸,提出新型的仿螃蟹六足折纸机器人设计方案,扩展了折纸机器人的运动构型,提升了折纸机器人的运动灵活性.在面对称假设下,该机器人单足具有2个自由度,此时将机器人腿部顶点等效为关节,轴线折痕等效为连杆,建立机器人腿部的平面连杆等效模型,并以折面夹角为运动变量,通过仿真计算得出机器人足端的理论运动范围.利用楔形面板技术对折面增厚并避免相邻折面发生物理干涉,建模得到折纸仿螃蟹六足机器人的三维模型.基于平面连杆的等效模型,分析折面夹角与足端运动之间的联系,设计确定机器人的足端运动轨迹与运动步态.利用3D打印技术设计并制作折纸仿生六足机器人试验样机,基于STM32单片机控制实现了机器人三横向角步态运动.结果表明,该折纸仿生机器人可以实现平面构型到仿螃蟹构型的转换,在6条腿的协同运动下,机器人可以平稳地左右横向移动.

受海龟爬行与山羊行走启发的四足仿生移动机器人多步态规划及动力学分析

为解决救援机器人运动速度慢、环境适应性差和步态单一等问题,参照海龟与山羊的生理结构,设计了一种四足仿生移动机器人。首先,根据海龟能在松软地面上爬行以及山羊运动能力强的特点,为机器人规划了仿海龟爬行和仿山羊行走两种步态以适应不同环境,提高了机器人的运动性能。然后,对机器人支腿进行了动力学分析,通过建立动力学模型来获取机器人关节扭矩与运动性能参数之间的定量关系。最后,通过仿真和样机实验来验证机器人步态的可行性以及机器人的环境适应能力。结果表明,所设计的机器人结构稳定,步态规划合理,可适应不同的复杂地形。研究结果可为仿生机器人的设计与开发提供重要参考。

机器人灵巧手研究综述

机器人灵巧手可以模仿人类动作,完成复杂场景下的多种任务。机器人灵巧手的研究是开发智能人形机器人的关键技术之一。以机器人灵巧手的研究历程为核心,阐述了多指灵巧手的研究现状,分析了灵巧手的演化过程和研究进展。从自由度数目、驱动方式、机械传动方式和传感技术等方面探讨了灵巧手分类和特征,展望了灵巧手未来的发展趋势。

基于CPG控制的双髻鲨仿生机器人设计与实验研究

随着人类对自然的探索越来越深入,新型水下航行器的需求与日俱增,仿生机器人因其特殊的推进方式和高效的推进效率而受到越来越多的关注,而传统的仿生鱼类仅模拟了流线型外壳,少有提及仿生对象本身结构对于仿生性能的影响,本文提出了一种基于中央模式发生器(CPG)的类双髻鲨仿生机器人.以鱼类基本运动形态为基础,将鱼身抽象为关节连杆结构,建立了三关节四连杆的仿生机器鱼模型并进行了仿真计算.根据步态规律预估了其运动性能,随后通过实验验证了可行性.本仿生鱼旨在以简单的机械结构和较低的控制成本,实现对双髻鲨的最大限度模拟,得益于良好的仿生结构,中央模式发生器的引入,以及柔性硅胶材料在鱼身的应用,此机器人拥有体型小,控制简单,地形适应能力强,能量利用率高等特点,与传统水下推进器相比噪音更小,环境适应能力更强,在科研、农业等行业均具有广泛的应用前景,如野外勘测,水下救援,水域巡逻等.

轨迹可控的微型水母机器人研制

为解决微型机器人在较小机身尺寸下实现高效轨迹控制的难题,设计并研制了微型仿水母机器人JRT,其由气室、重心调整机构和仿水母推进器三部分组成,尺寸仅为6.8 cm×5.3 cm,可通过重心调整机构和仿水母推进器协同控制有效实现水下轨迹可控.水下实验验证了机器人JRT沿竖直方向游泳和悬停、水平定向游泳以及水平弹射功能,并通过对机器人JRT沿竖直方向和水平方向游泳过程中的力平衡关系和运动状态数据分析提出了轨迹控制方案,测得水平定向游泳的速度可达到1.7 cm/s,轨迹偏差为0~3.4 cm,展现了微型仿水母机器人JRT较好的轨迹控制能力,可见其在水下资源勘查、环境监测等领域的应用潜力.

蝴蝶飞行机理及仿蝴蝶扑翼飞行器研究进展综述

仿生扑翼飞行器具有高机动性、高隐蔽性以及高效率等突出优势,在军事侦查、探险搜救等领域具有较好的应用前景,而其应用的基础是对生物飞行机理的深入探究.随着先进运动观测和实验技术的引入,对昆虫飞行行为的记录和分析更为便捷和准确.研究表明常见的昆虫拍打频率较高,在25~400 Hz之间,而蝴蝶较为特殊,其扑打频率较低,大约为10 Hz,对于蝴蝶的许多独特的飞行技能尚缺少足够的认识.蝴蝶前翼和后翼的翼面积都较大,身体同侧的前后翼几乎为同步拍打,且扑打幅度较大,甚至接近180°.蝴蝶飞行中身体有较大幅度的上下和俯仰震荡,翼和身体运动高度耦合.即便如此,蝴蝶仍具有敏捷的飞行能力,可以达到点对点的飞行目标,甚至上千公里的长途迁徙,是优秀的仿生学研究对象.因此,蝴蝶启发的仿生扑翼飞行器也得到了全世界研究人员的关注.蝴蝶的飞行机制相对于其他昆虫更加特殊,飞行行为和气动特性更为复杂,这使得仿蝴蝶扑翼飞行器的研制更加困难.目前对于仿蝴蝶飞行器的研制大多数对蝴蝶翼–身耦合的机理进行了简化,很少能实现受控的稳定飞行.最后,本文梳理了真实蝴蝶的飞行行为特点和飞行机理,指出了仿蝴蝶扑翼飞行器研制的关键技术,总结了该类飞行器未来的发展方向和应用前景.

Design and Kinematic Analysis of a Novel Humanoid Robot Eye Using Pneumatic Artificial Muscles

This paper proposed a novel humanoid robot eye, which is driven by six Pneumatic Artificial Muscles （PAMs） and rotates with 3 Degree of Freedom （DOF）. The design of the mechanism and motion type of the robot eye are inspired by that of human eyes. The model of humanoid robot eye is established as a parallel mechanism, and the inverse-kinematic problem of this flexible tendons driving parallel system is solved by the analytical geometry method. As an extension, the simulation result for saccadic movement is presented under three conditions. The design and kinematic analysis of the prototype could be a sig- nificant step towards the goal of building an autonomous humanoid robot eye with the movement and especially the visual functions similar to that of human.

仿人表情机器人的下颌机构设计与运动

针对目前仿人表情机器人口部运动模式单一的问题,基于人类下颌的解剖学运动机理,设计了一种新颖的多自由度仿生下颌机构.建立了仿生下颌机构的逆向运动学模型,分析了其运动模式,实现了仿生下颌机构在空间中的多自由度运动.对多自由度仿生下颌机构进行了多刚体仿真,并通过实验验证了其可行性.仿真和实验结果表明,基于逆向运动学模型,该机构可以模拟人类下颌的张合、前推、偏移3种基本运动模式,以及咀嚼、咬唇等口部复杂运动模式,弥补了现有仿人表情机器人口部运动模式受限的问题.

水陆两栖仿生机器人水下步态生成研究

设计一种拥有弧形腿与桨鳍结合的水陆两栖仿生机器人,提出一种水陆两栖机器人的水下步态映射函数,以期望机器人获得与海龟类似的推进方式。依据海龟的形态结构和运动形态,以Hopf振荡器为基本神经元建立六条腿全耦合式拓扑结构的中枢模式发生器(Central pattern generator,CPG)神经网络。对CPG输出信号以及机器人水下步态映射函数进行分析、优化实现参数的可调性及各步态间转换的平稳性。最后通过仿真与实验验证并生成水下步态生成的转换图,证明了优化后的步态CPG输出信号以及机器人水下步态映射函数的可行性。