基于乐理的蛇形机器人控制方法研究

根据生物蛇和蛇形机器人的结构及运动特点,提出了基于乐理的蛇形机器人控制方法,定义了乐理的符号、规则与蛇形机器人控制过程的对应关系,编写了蜿蜒运动步态谱.“勘查者—I”蛇形机器人上实现了蜿蜒运动的控制. 给出了今后的研究方向．     

基于循环抑制CPG模型控制的蛇形机器人蜿蜒运动

根据生物蛇和蛇形机器人的结构及运动特点，应用循环抑制CPG建模理论构建了蛇形机器人神经网络模型；利用蛇形机器人模型，仿真验证了CPG模型对蜿蜒运动控制的有效性；提出并仿真验证了实现有目的转弯控制的CPG参数调节方法。最后，给出了今后的研究方向。     

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.     

蛇形机器人蜿蜒运动控制分析

针对蛇形机器人的蜿蜒运动控制,首先分析了关节角度约束对运动控制函数参数取值的限制,确定了满足机械结构的运动控制参数范围;之后在Adams仿真环境下,建立蛇形机器人的三维虚拟运动模型,进行蜿蜒运动仿真,通过分析幅值控制参数对蛇形机器人弯曲度、运动速度和运动轨迹偏移的影响,提出了调整幅值参数的方法;实验结果表明,调整方法的有效性,从而实现蛇形机器人蜿蜒运动控制的优化。     

新型蛇形机器人蜿蜒运动的动力学分析

为提高蛇形机器人执行各种运动的能力,研制了新型蛇形机器人系统．重点研究了该蛇形机器人的动力学．建立了机器人的运动学模型,并根据运动学模型提出了控制蛇形机器人蜿蜒运动的复合运动控制方法．用拉格朗日方法建立动力学模型,对不同参数下蛇形机器人的关节力矩特性和摩擦力特性进行了分析比较,为蛇形机器人的有效运动提供了理论依据．     

基于形态学的蛇形机器人运动步态算法研究

基于蛇形机器人运动形态学,利用扩展Frenet-Serret分析了一种蛇形机器人运动的几何模型,并根据这种几何模型研究了一种确定蛇形机器人的运动步态规律的算法,称之为EFSA(extended frenet-serret algorithm)算法.用这种算法规划了无轮蛇形机器人的基本运动步态,而且重要的是实现了蛇形机器...     

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...     

蛇形机器人在缆索检测中螺旋滚动步态的研究

提出了一种检测桥梁缆索的方式,利用蛇形机器人在缆索上螺旋滚动步态的优点,检测缆索表面和内部损伤,克服传统的桥梁缆索检测方法的不足。研究了蛇形机器在缆索上螺旋滚动步态的实现,确定了螺旋滚动曲线的参数与蛇形机器人螺旋滚动姿态的关系。通过参数的调整和优化,使蛇形机器人既不会抱得过紧而损伤缆索,而降低蛇形机器人的运行速度和消耗蛇形机器人更多能量,又不会抱得太松而使蛇形机器人从缆索上滑落,而降低蛇形机器人在缆索上运动的安全性。最后通过Webots仿真软件的模拟真实环境,表明了蛇形机器人可以在桥梁缆索上实现螺旋运动,且螺旋运动可以适应不同直径的缆索,通过改变参数,可优化和调整蛇形机器人的螺旋形状,使蛇形机器人模块选择灵活、运动的安全和高效。     

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。     

基于双层级CPG的3维蛇形机器人运动控制方法

为实现3维蛇形机器人多模式运动控制,提出了一种基于双层级中枢模式发生器(CPG)的运动控制方法.该双层级CPG网络包含节律层和模式层,节律层的CPG神经元用于控制3维蛇形机器人的俯仰关节组和偏转关节组的相位关系,模式层的CPG神经元用于控制3维蛇形机器人关节组内各个关节的相位差及关节轨迹.首先,利用Kuramoto振荡器对CPG神经元进行建模,并确定CPG网络的层级结构和耦合拓扑;然后,基于蛇形约束曲线计算3维蛇形机器人侧滚运动、侧移运动、滑行运动及转向运动4种典型运动步态的控制参数;最后,通过联合仿真和实验验证该双层级CPG网络的控制性能.由实验结果可知,3维蛇形机器人的侧滚运动、侧移运动、滑行运动以及转向运动的实际速度分别能够达到3.9 cm/s、9.0 cm/s、2.1 cm/s和10.8°/s.因此,该方法能够有效地、灵活地控制3维蛇形机器人的多模式运动.     

一种具有三维运动能力的蛇形机器人的研究

分析了生物蛇的3种典型运动模式，介绍了研制出的具有三维运动能力的蛇形机器人，实现了生物蛇的3种典型运动模式．     

AmphiBot I: an amphibious snake-like robot

This article presents a project that aims at constructing a biologically inspired amphibious snake-like robot. The robot is designed to be capable of anguilliform swimming like sea-snakes and lampreys in water and lateral undulatory locomotion like a snake on ground. Both the structure and the controller of the robot are inspired by elongate vertebrates. In particular, the locomotion of the robot is controlled by a central pattern generator (a system of coupled oscillators) that produces travelling waves of oscillations as limit cycle behavior. We present the design considerations behind the robot and its controller. Experiments are carried out to identify the types of travelling waves that optimize speed during lateral undulatory locomotion on ground. In particular, the optimal frequency, amplitude and wavelength are thus identified when the robot is crawling on a particular surface.     

SnakeSIM: a ROS-based control and simulation framework for perception-driven obstacle-aided locomotion of snake robots

Biological snakes are capable of exploiting roughness in the terrain for locomotion. This feature allows them to adapt to different types of environments. Snake robots that can mimic this behaviour could be fitted with sensors and used for transporting tools to hazardous or confined areas that other robots and humans are unable to access. Snake robot locomotion in a cluttered environment where the snake robot utilises a sensory–perceptual system to perceive the surrounding operational environment for means of propulsion can be defined as perception-driven obstacle-aided locomotion (POAL). The initial testing of new control methods for POAL in a physical environment using a real snake robot imposes challenging requirements on both the robot and the test environment in terms of robustness and predictability. This paper introduces SnakeSIM, a virtual rapid-prototyping framework that allows researchers for the design and simulation of POAL more safely, rapidly and efficiently. SnakeSIM is based on the robot operating system (ROS) and it allows for simulating the snake robot model in a virtual environment cluttered with obstacles. The simulated robot can be equipped with different sensors. Tactile perception can be achieved using contact sensors to retrieve forces, torques, contact positions and contact normals. A depth camera can be attached to the snake robot head for visual perception purposes. Furthermore, SnakeSIM allows for exploiting the large variety of robotics sensors that are supported by ROS. The framework can be transparently integrated with a real robot. To demonstrate the potential of SnakeSIM, a possible control approach for POAL is considered as a case study.     

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.     

Snake Robot Obstacle-Aided Locomotion: Modeling, Simulations, and Experiments

Snakes utilize irregularities in the terrain, such as rocks and vegetation, for faster and more efficient locomotion. This motivates the development of snake robots that actively use the terrain for locomotion, i.e., obstacle-aided locomotion. In order to accurately model and understand this phenomenon, this paper presents a novel nonsmooth (hybrid) mathematical model for wheel-less snake robots, which allows the snake robot to push against external obstacles apart from a flat ground. The framework of nonsmooth dynamics and convex analysis allows us to systematically and accurately incorporate both unilateral contact forces (from the obstacles) and isotropic friction forces based on Coulomb's law using set-valued force laws. The mathematical model is verified through experiments. In particular, a back-to-back comparison between numerical simulations and experimental results is presented. It is, furthermore, shown that the snake robot is able to move forward faster and more robustly by exploiting obstacles.     

Dynamics and Motion Planning of Trident Snake Robot

The trident snake robot is a mechanical device that serves as a demanding testbed for motion planning and control algorithms of constrained non-holonomic systems. This paper provides the equations of motion and addresses the motion planning problem of the trident snake with dynamics, equipped with either active joints (undulatory locomotion) or active wheels (wheeled locomotion). Thanks to a partial feedback linearization of the dynamics model, the motion planning problem basically reduces to a constrained kinematic motion planning. Two kinds of constraints have been taken into account, ensuring the regularity of the feedback and the collision avoidance between the robot’s arms and body. Following the guidelines of the endogenous configuration space approach, two Jacobian motion planning algorithms have been designed: the singularity robust Jacobian algorithm and the imbalanced Jacobian algorithm. Performance of these algorithms have been illustrated by computer simulations.     

Obstacle avoidance of snake robot by switching control constraint

In this paper, we propose an obstacle avoidance method for autonomous locomotion control of a snake robot. The snake robot consists of rigid links, active joints and passive wheels, and can move only by varying its shape. The pass planning for the obstacle avoidance is a complicated problem because the snake robot has many states, control inputs and the under-actuated property. In our proposed method, the snake motion is restricted to a periodic undulate curve (called a serpenoid curve) by an additional control constraint and the undulate curve is tuned by switching the control constraint in order that the snake robot avoids the obstacle. Therefore, the path planning is simplified and the snake robot will achieve the obstacle avoidance with an efficient path. In this paper, we denote the details of our method and investigate the effectiveness of our strategy by numerical simulations.     

A review on modelling, implementation, and control of snake robots

This paper provides an overview of previous literature on snake robot locomotion. In particular, the paper considers previous research efforts related to modelling of snake robots, physical development of these mechanisms, and finally control design efforts for snake locomotion. The review shows that the majority of literature on snake robots so far has focused on locomotion over flat surfaces, but that there is a growing trend towards locomotion in environments that are more challenging, i.e. environments that are more in line with realistic applications of these mechanisms.     

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．     

A 'sidewinding' locomotion gait for hyper-redundant robots

This paper considers a novel form of hyper-redundant mobile robot locomotion which is analogous to the 'sidewinding' locomotion gait employed by several species of snake. It is shown that this gait can be generated by a repetitive traveling wave of mechanism deformation. This paper considers primarily the kinematics of the sidewinding gait. The kinematic analysis is based on a continuous 'backbone curve' model which captures the robot's important macroscopic features. Using this continuous model, we first develop algorithms which enable travel in a uniform direction. We subsequently extend this basic gait pattern to enable changes in the direction of travel.