水下六足机器人及其运动规划研究现状

水下六足机器人具有丰富的步态样式和冗余的肢体结构,凭借其离散式的地面支撑和对水下障碍、礁坪等复杂特殊地形的极强适应性,具有广泛的应用前景。本文通过充分的文献调研和总结,对目前水下六足机器人平台发展现状进行了综述。针对水下六足机器人的海底爬行能力,分别从稳定性判据、路径规划与自适应行走方法 3项关键技术进行了分析和总结;在稳定性判据方面,分别针对水下六足机器人静态稳定性判据与动态稳定性判据进行阐述;在路径规划方面,在目前典型陆地六足机器人路径规划方法的基础上,结合水下六足机器人独有的运动特性进行阐述;针对水下六足机器人自适应行走方面,分别阐述传统自适应调整方法与目前基于深度强化学习的方法进行介绍;最后对这些关键技术的未来发展趋势进行了展望。     

四足机器人节律柔顺行走控制

针对节律运动突变碰撞力大和柔顺性低的问题,改进基于Hopf振荡器的中枢模式发生器模型,提出一种节律柔顺行走控制方法。分析Hopf振荡器输出信号与关节运动之间的关系,整合膝关节变量,改变神经元之间的作用关系,实现对称步态和非对称步态行走;分析节律运动碰撞力突变对四足机器人行走产生的负面影响,提出基于碰撞力大小和四足机器人身体姿态的柔顺性评估方法;通过连续调整碰撞阶段大腿的摆动幅度,增大摆动周期,减小碰撞阶段的关节运动速度,形成机器人本体与地面之间的缓冲,实现节律柔顺行走。四足机器人慢走步态和对角小跑步态仿真实验验证了该控制方法的有效性。     

小型两栖仿龟机器人多模式运动研究

针对浅滩环境和水下狭窄空间的科研考察、资源勘探等任务,提出一种“腿－多矢量喷水”复合驱动的小型两栖仿龟机器人。通过研究“腿－多矢量喷水”复合式驱动系统的运动机理,设计仿生爬行步态和旋转步态。根据“腿－多矢量喷水”复合驱动机构的变结构特性,提出“H”、“工”和“X”等多模式运动。通过机器人水中运动学建模,建立基于实时动态推力矢量分配优化机制的水中3维自主运动控制方法。最后搭建机器人原型机,陆地上的多地形运动实验验证了机器人在非结构化浅滩环境中的适应能力强,水中运动控制实验验证了两栖机器人多模式运动控制的灵活性和可行性。     

双足机器人HEUBR-1 样机研制与实验研究

模拟人的肌肉驱动方式,为双足机器人HEUBR-1 设计了二自由度的空间并联机构,并将其应用于双 足机器人HEUBR-1 下肢关节,实现了一种新的串并混联的仿人下肢结构．在HEUBR-1 的足部增加了足趾关节,使 机器人能够模拟人的行走方式,实现真正的拟人步态行走．阐述了双足机器人HEUBR-1 稳定拟人行走的关键性技 术,提出了综合稳定性判据,分析了拟人的多种步态．通过拟人行走步态实验分析,验证了双足机器人HEUBR-1 串 并混联的仿人结构的设计合理性及拟人步态分析的准确性．     

一种六足仿生巡检机器人的设计与实现

六足仿生机器人因其灵活度好、可靠性高、适应性强等特点而得到广泛应用;针对六足仿生巡检机器人,从结构设计、步态规划、系统仿真和实物构建等方面,探索一般意义上系统设计和实现方法;首先设计了六足仿生机器人的多关节机械结构,并给出了此类系统的量化建模方法;然后采用了重心随动的三角步态规划方法,对系统稳定性和典型步态规划进行了量化分析;在此基础上基于标准D-H参数法建立了机器人的运动学模型,并且通过仿真实现了六足机器人向前纵向行走和向右横向行走的直线平稳运动;最后通过六足仿生巡检机器人实物测试,验证了所设计的结构和步态规划方法的可行性和有效性。     

基于AT89S52的六足机器人运动控制器的设计

文章应用AT89S52内部的2个定时器,采用多舵机分时控制方法,设计了可驱动机器人足部12个舵机协调运动的控制器;按照六足机器人典型行走步态,实现了六足机器人按步态规划运动。测试结果验证了该设计方案的正确性和可靠性。     

仿蟹机器人步态分析与仿真

在仿蟹机器人的行走控制中,步态的选择对机器人的稳定快速行走具有至关重要的作用。本文对仿蟹八足机器人的基本步态进行了分类,并进一步对八足波形步态进行分析,得出八足步行机器人在采用双四足步态的行走方式时,既可以满足速度的要求,又可以保证机器人的稳定性。通过计算机软件ADAMS对所选步态进行全局仿真,结果验证了步态规划的合理性,同时得到了机器人相关物理量的变化曲线,为进一步选择电机,分析机器人系统的动态特性提供了依据。     

新型仿生球形两栖子母机器人系统设计

为解决传统两栖机器人的一些突出缺点,探寻机器人领域更多的可能性。本文设计了一种新型仿生球形两栖子母机器人系统,该系统中球形两栖母机器人在陆地采用仿生四足爬行方式运动,在水下采用矢量喷水电机进行喷水推进,无噪声,增加隐蔽性,并为微型子机器人提供控制信号和能源。微型子机器人陆地采用轮式驱动,设计了可以实现水陆两栖的桨叶轮。该子母机器人系统通过XBee通信模块实现无线通信。通过进行的子母机器人的陆地和水下运动试验,验证了设计的子母机器人系统的有效性。     

四足机器人步态生成算法研究与仿真

在四足机器人行走动态控制的研究中,为使四足机器人能在复杂地面状况下行走,提出了一种四足机器人在不平坦地面爬行时的平动步态生成算法.首先构建四足机器人步行机构模型,根据静态稳定性对角线原理的判定确定机器人腿的摆动顺序;以平动步态为例根据机器人前行方向、初始位姿、地面不平坦等因素计算一个步态周期后机器人的位姿从而实现平动直线行走的连续步态算法.考虑了机器人机构约束以及状态变化因素使机器人在每一个步态周期都能跨出尽可能大的步幅实现行走效率的最大化.通过仿真验证了算法的正确性.仿真结果对四足机器人步态稳定性的研究及实现具有实际的参考价值.     

六足救援机器人结构设计与步态分析

分析甲虫生物的原型特点和运动方式,对仿生甲虫六足救援机器人进行结构设计和样机设计,对甲虫生物原型设计了六足救援机器人。通过对仿生甲虫机器人三足运动步态,给出了直线行走时6条腿的末端位置矢量的表达式,结果证明仿生甲虫六足救援机器人的稳定性较强。     

Prior notice method of robotic arm motion for suppressing a threat to a human

The ability to develop a gait with one or more legs missing is an important issue for multi-legged robots used in demining applications. Accordingly, this paper presents a three-legged gait under the assumption that one leg of a quadruped walking robot is missing. After outlining a posture classification scheme for three-legged walking, the kick-and-swing gait is proposed as a basic and reasonable gait for three-legged walking and analyzed using a simple dynamic model. Minimum energy gait planning and an active shock-absorbing method are also investigated. The validity of the proposed gait is shown based on experiments using the quadruped walking robot TITAN VIII.     

Wave CPG model for autonomous decentralized multi-legged robot: Gait generation and walking speed control

In this paper, we propose a method to control gait generation and walking speed control for an autonomous decentralized multi-legged robot by using a wave Central Pattern Generator (CPG) model. The wave CPG model is a mathematical model of nonlinear oscillators and generates rhythmic movements of the legs. The gait generation and the walking speed control are achieved by controlling the virtual energy of the oscillators (Hamiltonian). A real robot experiment showed the relationship to the Hamiltonian, the actual energy consumption and the walking speed, and the effectiveness of the proposed method was verified.     

A roller-skating/walking mode-based amphibious robot

An amphibious spherical robot capable of motion on land as well as underwater is developed to implement the complicated underwater operations in our previous research. In order to improve the speed performance of the spherical robot on a slope or comparatively smooth terrains, we propose a new roller-skating mode for the robot by equipping a passive wheel on each leg to implement the roller-skating motion in this paper. A braking mechanism is designed to transform the state of each passive wheel between free rolling and braking states by compressing and releasing the spring, which is controlled by the vertical servo motor on each leg. Besides, in order to improve the walking stability of the wheeled robot in longitudinal direction, a closed-loop control method is presented to control the stability of the direction of movement while walking. Therefore, we conduct the experiments on smooth terrains and down a slope to evaluate the performance of the roller-skating motion, including gait stability and velocity. Finally, plenty of walking experiments are conducted to evaluate the ability of directional control.     

Crab walking of quadruped robots with a locked joint failure

Fault tolerance is an important aspect in the development of control systems for multi-legged robots since a failure in a leg may lead to a severe loss of static stability of a gait. In this paper, an algorithm for tolerating a locked joint failure is described in gait planning for a quadruped robot with crab walking. A locked joint failure is one for which a joint cannot move and is locked in place. If a failed joint is locked, the workspace of the resulting leg is constrained, but legged robots have fault tolerance capability to continue walking maintaining static stability. A strategy for fault-tolerant gaits is described and, especially, a periodic gait is presented for crab walking of a quadruped. The leg sequence and the formula of the stride length are analytically driven based on gait study and robot kinematics. The adjustment procedure from a normal gait to the proposed fault-tolerant crab gait is shown to demonstrate the applicability of the proposed scheme.     

Design of six-legged walking robot,Little Crabster for underwater walking and operation

This paper describes the development of a ground test robot platform to study a multi-legged walking robot capable of precise proximity exploration and operations under a shallow sea in the presence of a strong tidal current environment. For both underwater walking and complex operations, a six-legged robot that uses two legs as manipulators during underwater operations is proposed. The dimensions, joint structure, range of motion, and mass distribution of the robot are determined by considering biological data, and then suitable joint actuators are chosen through a simple force analysis. In addition, a main controller, a communication bus, motor controllers, sensors, and a battery are chosen to build the whole control system. The detailed design is performed using 2D/3D computer aided design (CAD) software, and the robot is finally built by machining the parts and assembling them. The degree of design completion is proved by basic walking experiments and future works are addressed.     

Effects of turning gait parameters on energy consumption and stability of a six-legged walking robot

Minimization of energy consumption plays a key role in the locomotion of a multi-legged robot used for various purposes. Turning gaits are the most general and important factors for omni-directional walking of a six-legged robot. This paper presents an analysis on energy consumption of a six-legged robot during its turning motion over a flat terrain. An energy consumption model is developed for statically stable wave gaits in order to minimize dissipating energy for optimal feet forces distributions. The effects of gait parameters, namely angular velocity, angular stroke and duty factors are studied on energy consumption, as the six-legged robot walks along a circular path of constant radius with wave gait. The variations of average power consumption and energy consumption per unit weight per unit traveled length with the angular velocity and angular stroke are compared for the turning gaits of a robot with four different duty factors. Computer simulations show that wave gait with a low duty factor is more energy-efficient compared to that with a high duty factor at the highest possible angular velocity. A stability analysis based on normalized energy stability margin is performed for turning motion of the robot with four duty factors for different angular strokes.     

多足步行机器人液压控制系统研究现状与发展趋势

针对多足步行机器人液压系统能量损失较大、结构相对单一及控制策略相对复杂等问题,从机器人液压系统和控制策略2个方面分析了多足步行机器人液压控制系统现状．将液压系统从泵源、液压执行器和液压控制结构3个方面分别阐述．从动力来源和油路结构介绍了泵源,从结构分类、一体化集成和特殊功能简述了不同液压执行器的应用,从阀控液压系统和泵控液压系统介绍了液压控制结构．从自由空间和约束空间两方面介绍了系统控制策略．多足步行机器人液压系统的发展方向包括小型化、轻量化、节能降耗、降低噪声和泄漏以及对控制策略的改进．     

CPG model for autonomous decentralized multi-legged robot system—generation and transition of oscillation patterns and dynamics of oscillators

A central pattern generator (CPG) model is proposed for the gait-pattern generation mechanism of an autonomous decentralized multi-legged robot system. The topological structure of the CPG is represented as a graph on which two time evolution systems, the Hamilton system and a gradient system, are introduced. The CPG model can generate oscillation patterns depending only on the network topology and can bifurcate different oscillation patterns according to the network energy, which means that the robot can generate gait patterns by connecting legs and transit gait patterns according to such parameters as the desired speed.     

仿人机器人斜坡行走的步态规划

为了解决双足机器人在复杂路面的行走问题,提出了一种具体的基于几何约束的机器人斜坡行走步态规划方法。通过对机器人行走的起步阶段,单脚支撑期中摆动腿对机器人身体稳定的影响,以及行走步态流程进行了详细的规划,以机器人Nao为研究对象,构建出了机器人的连杆模型,计算出机器人在前向和侧向运动中保证身体稳定的踝关节约束范围,分析了流程图中机器人各行走步态,并计算出各步态中关节角度变化,从而规划出了机器人Nao从起步到结束行走的过程。运用三次多项式插值的方法使得各关节运动平滑稳定,并根据规划中的各个步态运动利用MATIAB仿真,获得机器人在步行过程中X、Y、Z方向上的质心轨迹,并通过x、y方向的轨迹可以看出机器人行走过程重心稳定,从而证明此方法用于机器人斜坡行走的可行性。     

Synchronization of a class of cyclic discrete-event systems describing legged locomotion

It has been shown that max-plus linear systems are well suited for applications in synchronization and scheduling, such as the generation of train timetables, manufacturing, or traffic. In this paper we show that the same is true for multi-legged locomotion. In this framework, the max-plus eigenvalue of the system matrix represents the total cycle time, whereas the max-plus eigenvector dictates the steady-state behavior. Uniqueness of the eigenstructure also indicates uniqueness of the resulting behavior. For the particular case of legged locomotion, the movement of each leg is abstracted to two-state circuits: swing and stance (leg in flight and on the ground, respectively). The generation of a gait (a manner of walking) for a multi-legged robot is then achieved by synchronizing the multiple discrete-event cycles via the max-plus framework. By construction, different gaits and gait parameters can be safely interleaved by using different system matrices. In this paper we address both the transient and steady-state behavior for a class of gaits by presenting closed-form expressions for the max-plus eigenvalue and max-plus eigenvector of the system matrix and the coupling time. The significance of this result is in showing guaranteed stable gaits and gait switching, and also a systematic methodology for synthesizing controllers that allow for legged robots to change rhythms fast.