基于微分几何的蛇形机器人移动与操作统一动力学模型研究

蛇形机器人本体是一种多关节串联机构,可以在各种环境中运动,并且当一端固定时可以实现操作.本文提出一种蛇形机器人移动与操作的统一动力学建模方法,统一蛇形机器人移动状态及操作状态的动力学方程.机器人从移动状态到操作状态的转换意味着机构上的重构,即移动状态无固定基座,而操作状态有固定基座.应用虚设机构法在机构学上统一这两种状态(即构形空间中的嵌入关系),利用指数积公式描述这两种状态的运动学方程.在Riemann流形上建立起蛇形机器人移动和操作的动力学模型,并在对动力学模型中各项计算分析的基础上发现机器人操作动力学方程可直接由移动动力学方程退化得到,同时应用子流形的Gauss公式给出证明.由此在微分几何框架下建立蛇形机器人移动与操作的统一动力学模型.按照几何的观点将蛇形机器人移动与操作动力学模型的统一看作是子流形问题,并赋予几何意义.较单独针对蛇形机器人的一种状态(移动或操作)的动力学模型而言,这种统一的动力学模型能够更深刻地揭示蛇形机器人动力学的特征.     

形状记忆合金驱动的蛇形机器人运动仿真研究

基于Serpenoid 曲线建立了蛇形机器人行波运动和攀爬运动的运动学、动力学模型,根据模型提出一种具有万向节功能的pitch-roll 模块,利用形状记忆合金驱动器具有结构小和只受温度变化影响两大特点建立了蛇形机器人关节。应用MSC/ADAMS 虚拟样机软件对基于形状记忆合金驱动蛇形机器人进行行波运动和攀爬运动的动力学分析,并对仿真过程中遇到问题提供了解决办法。模型仿真效果非常理想,完全达到设计要求,为下一步研制物理样机提供了理论指导,也为其他仿生机器人的研究提供了参考。     

蛇形机器人侧向运动的研究

本文提出了一种新型蛇形机器人机构，建立了其空间运动学模型，实现了蛇形 机器人的两种侧向运动：侧向蜿蜒运动和侧向滚动，前者通过调节两个异相波的频率比，实 现了任意方向的侧向运动．后者通过控制运动波的幅值变化，实现了各种形式的纯侧向移动 ，当幅值足够大时，这种侧向滚动可以跨越障碍．     

柔性机器人水下运动的建模与仿真

本文以柔性机器人水下环境中的柔顺运动为研究对象,建立了柔性机器人水下运动的动力学模型。并运用VC 6.0和Matlab7.0进行仿真,结果显示了柔性机器人在水下环境中良好的运动学特性。     

一种基于空间连杆机构的蛇形机器人

提出了一种基于空间连杆机构的蛇形机器人模型．该蛇形机器人各骨节间通过万向铰链连接，每节安装两个微型伺服电机，电机带动曲柄转动，曲柄经两端为球铰的连杆驱动另一骨节运动．通过两个电机的耦合驱动，该蛇形机器人能实现蜿蜒爬行、转向、抬头等多种运动方式．文中给出了该空间连杆机构的运动学解，基于Serpenoid曲线计算得到了实际控制所需的关节转角和步数，并编程实现了上述运动方式．     

改进末端跟随运动的超冗余蛇形臂机器人运动学逆解

针对超冗余蛇形臂机器人运动学逆解中计算量大、超关节极限和位形偏移量大的问题,提出了一种改进末端跟随运动的逆解算法．在末端跟随法中引入蛇形臂弯曲角度的约束,调整关节位置的更新方式,使关节在蛇形臂轴线上运动．通过依次更新关节的空间位置,将超冗余多节蛇形臂的运动学逆解转化为2自由度单节蛇形臂的运动学逆解．仿真分析了蛇形臂机器人在基座移动和基座固定条件下的轨迹跟踪效果,对比了同一目标位置下不同方法的性能．结果表明,改进后的算法能保证蛇形臂的弯曲角度不超过给定范围,关节的运动量从末端到基座依次减小,机器人的运动更协调;与基于雅可比矩阵的数值法和现有启发式方法相比,该方法运算量降低,机器人整体位形偏移量减小,能用于蛇形臂机器人的实时控制．     

基于Hopf振荡器实现的蛇形机器人的步态控制

针对生物蛇不同步态的运动特点,提出了一种基于Hopf振荡器实现的蛇形机器人的中枢模式发生器(CPG)运动控制方法.首先,利用具有非线性极限环特性的耦合的Hopf振荡器构建出能够实现蜿蜒运动和侧向蜿蜒运动两种步态的链式网络模型.然后,根据动力学仿真软件建立机器人的虚拟样机,利用模型中振荡器的输出作为蛇形机器人分布式多冗余度关节的控制信号来驱动前进,成功实现了以上两种运动方式,并讨论了CPG的模型参数与机器人前进速度的关系.最后,在实物样机上的实验进一步验证了所提出的方法在实现蛇形机器人多种步态控制方面的有效性.     

基于ADAMS的弧焊机器人运动仿真

机器人三维运动仿真是当前机器人研究领域中重要的研究方向之一。采用CAD软件Pro/E和机械系统动力学仿真软件ADAMS,对德国CLOOS公司生产的76AW型弧焊机器人建立了三维运动仿真模型。采用Denavit-Hartenberg方法建立了连杆坐标系下的机器人运动学模型,并采用Matlab编写了运动学正、逆解的程序。详细阐述了模型的建立方法及具体过程,实现了在ADAMS环境下的机器人焊缝路径的运动仿真。为机器人动力学及离线编程技术的研究提供了基础。     

空间机器人目标捕获过程中碰撞运动分析

针对空间机器人目标捕获过程中的碰撞问题,提出了一种碰撞运动分析算法．基于空间机器人运动学 和动力学模型,利用碰撞过程中产生冲量的原理建立了碰撞动力学模型．针对具体的碰撞模型,利用空间解析几何 的方法进行了空间机器人与目标物之间的碰撞检测,设计了碰撞发生后机器人的运动分析算法．最后,通过仿真实 验验证了该算法的正确性和适用性．     

柔性机器人协调操作闭链负载机构的一般模型

本文利用闭链刚性负载内部运动参数之间的微分关系,在单柔性机器人有限元动力 学模型基础上,建立了系统的运动学和动力学协调约束条件,首次导出了基于负载运动任务 参数的柔性机器人协调操作闭链刚性负载的动力学方程,并给出了两3R柔性机器人协调操作 刚性四杆机构的仿真算例．     

Analysis of creeping locomotion of a snake-like robot

Snakes perform many kinds of movement adapted to the environment. Utilizing the snake (its forms and motion) as a model to develop a snake-like robot, that performs the snake's function, is important for generating a new type of locomotion and expanding the possible uses of robots. In this study, we developed a simulator to simulate the creeping locomotion of the snake-like robot, in which the robot dynamics is modeled and the interaction with the environment is considered through Coulomb friction. This simulator makes it possible to analyze creeping locomotion with normaldirection slip, adding to the glide along the tangential direction. Through the developed simulator, we investigate the snake-like robot creeping locomotion which is generated only by swinging each of the joints from side to side and discuss the optimal creeping locomotion of the snake-like robot that is adapted to the environment.     

Analysis of Creeping Locomotion of a Snake-like Robot on a Slope

The diverse locomotion modes and physiology of biological snakes make them supremely adapted for their environment. To model the noteworthy features of these snakes we have developed a snake-like robot that has no forward direction driving force. In order to enhance the ability of our robot to adapt to the environment, in this study we investigate the creeping locomotion of a snake-like robot on a slope. A computer simulator is presented for analysis of the creeping locomotion of the snake-like robot on a slope, and the environmentally-adaptable body shape for our robot is also derived through this simulator.     

Adaptive controller design for underwater snake robot with unmatched uncertainties

Because of hydrodynamic model error of the present dynamic model, there is a challenge in controller design for the underwater snake-like robot. To tackle this challenge, this paper proposes an adaptive control schemes based on dynamic model for a planar, underwater snake-like robot with model error and time-varying noise. The adaptive control schemes aim to achieve the adaptive control of joint angles tracking and the direction of locomotion control. First, through approximation and reducibility using Taylor expansion method, a simplified dynamics model of a planar amphibious snake-like robot is derived. Then, the L1 adaptive controller based on piecewise constant adaptive law is applied on the simplified planar, underwater snake-like robot, which can deal with both matched and unmatched nonlinear uncertainties. Finally, to control the direction of locomotion, an auxiliary bias signal is used as the control input to regulate the locomotion direction. Simulation results show that this L1 adaptive controller is valid to deal with different uncertainties and achieve the joint angles tracking and fast adaptive at the same time. The modified L1 adaptive controller, in which the auxiliary bias item is added, has the ability to change the direction of locomotion, that is, the orientation angle is periodic with arbitrarily given constant on average.     

基于Webots的蛇形机器人翻滚运动仿真及实现

针对蛇形机器人的侧向翻滚运动,给出一种建立正交关节蛇形机器人三维空间运动模型的方法,提出了一种更为简单的实现蛇形机器人侧向翻滚运动的舵机输入函数.通过选择不同的控制参数,可以实现蛇形机器人"U"字形和"V"字形侧向翻滚运动.在Webots移动机器人仿真软件上进行正交关节蛇形机器人翻滚运动仿真,并在蛇形机器人本体上进行试验,验证了所提控制规律的有效性.     

A unified dynamic model for locomotion and manipulation of a snake-like robot based on differential geometry

A snake-like robot, whose body is a seried-wound articulated mechanism, can move in various environments. In addition, when one end is fixed on a base, the robot can manipulate objects. A method of dynamic modeling for locomotion and manipulation of the snake-like robot is developed in order to unify the dynamic equations of two states. The transformation from locomotion to manipulation is a mechanism reconfiguration, that is, the robot in locomotion has not a fixed base, but it in manipulation ha...     

Gaits-transferable CPG controller for a snake-like robot

With slim and legless body, particular ball articulation, and rhythmic locomotion, a nature snake adapted itself to many terrains under the control of a neuron system. Based on analyzing the locomotion mechanism, the main functional features of the motor system in snakes are specified in detail. Furthermore, a bidirectional cyclic inhibitory （BCl） CPG model is applied for the first time to imitate the pattern generation for the locomotion control of the snake-like robot, and its characteristics are discussed, particularly for the generation of three kinds of rhythmic locomotion. Moreover, we introduce the neuron network organized by the BCI-CPGs connected in line with unilateral excitation to switch automatically locomotion pattern of a snake-like robot under different commands from the higher level control neuron and present a necessary condition for the CPG neuron network to sustain a rhythmic output. The validity for the generation of different kinds of rhythmic locomotion modes by the CPG network are verified by the dynamic simulations and experiments. This research provided a new method to model the generation mechanism of the rhythmic pattern of the snake.     

Adaptive creeping locomotion of a CPG-controlled snake-like robot to environment change

In this paper, we present a biomimetic approach which is based on Central Pattern Generator (CPG) to solve the difficulty in control of a snake-like robot with a large number of degrees of freedom. A new network with a feedback connection is proposed, which can generate uniform outputs without any additional adjustment. The relations between the CPG parameters and the characteristics of output are also investigated. A simulation platform is also established for the analysis of the CPG-based locomotion control of a snake-like robot. To figure out adaptive creeping locomotion of the robot to the environment with changed friction or the given slope, the relations of CPG parameters and locomotion efficiency by the proposed curvature adaptive principle have been discussed.     

基于路径积分强化学习方法的蛇形机器人目标导向运动

路径积分方法源于随机最优控制,是一种数值迭代方法,可求解连续非线性系统的最优控制问题,不依赖于系统模型,快速收敛.文中将基于路径积分强化学习的策略改善方法用于蛇形机器人的目标导向运动.使用路径积分强化学习方法学习蛇形机器人步态方程的参数,不仅可以在仿真环境下使蛇形机器人规避障碍到达目标点,利用仿真环境的先验知识也能在实际环境下快速完成相同的任务.实验结果验证方法的正确性.     

基于控制函数的蛇形机器人攀爬运动分析

为实现对正交关节蛇形机器人多种运动形式的简单、统一控制,从研究蛇形机器人控制函数出发,提出了一种简单的并可同时实现正交关节蛇形机器人蜿蜒运动、行波运动、侧向翻滚运动和螺旋攀爬运动等多种运动形式的控制函数.对蛇形机器人实现螺旋攀爬运动的控制参数进行了分析,并用粒子群优化算法(PSO)对控制参数进行了优化拟合,给出了控制参...