Finite-Time Sideslip Differentiator-Based LOS Guidance for Robust Path Following of Snake Robots

This paper presents a finite-time sideslip differentiator-based line-of-sight(LOS)guidance method for robust path following of snake robots.Firstly,finite-time stable sideslip differentiator and adaptive LOS guidance method are proposed to counteract sideslip drift caused by cross-track velocity.The proposed differentiator can accurately observe the cross-track error and sideslip angle for snake robots to avoid errors caused by calculating sideslip angle approximately.In our method,the designed piecewise auxiliary function guarantees the finite-time stability of position errors.Secondly,for the case of external disturbances and state constraints,a Barrier Lyapunov functionbased backstepping adaptive path following controller is presented to improve the robot’s robustness.The uniform ultimate boundedness of the closed-loop system is proved by analyzing stability.Additionally,a gait frequency adjustment-based virtual velocity control input is derived to achieve the exponential convergence of the tangential velocity.At last,the availability and superiority of this work are shown through simulation and experiment results.

Position Errors and Interference Prediction-Based Trajectory Tracking for Snake Robots

This work presents a trajectory tracking control method for snake robots.This method eliminates the influence of time-varying interferences on the body and reduces the offset error of a robot with a predetermined trajectory.The optimized line-of-sight(LOS)guidance strategy drives the robot’s steering angle to maintain its anti-sideslip ability by predicting position errors and interferences.Then,the predictions of system parameters and viscous friction coefficients can compensate for the joint torque control input.The compensation is adopted to enhance the compatibility of a robot within ever-changing environments.Simulation and experimental outcomes show that our work can decrease the fluctuation peak of the tracking errors,reduce adjustment time,and improve accuracy.

Modeling and Control of Head of the Underwater Snake-like Robot Swimming

In order to solve oscillation of head of the underwater snake-like robot,the Central Pattern Generator( CPG)-based control scheme with head-controller was presented. The Kane dynamic model was constructed to be processed with a commercial package MotionGenesis Kane 5. 3,to which the proposed control scheme was applied. The relation between CPG parameters and orientation offset of head was investigated. The target orientation of head-controller was calculated through a convenient method. The advantage of this control scheme is that the head of the underwater snake-like robot remains in the forward direction during swimming. To prove the feasibility of the proposed methodology,two basic motion patterns,swimming along the straight line and swimming along the curved path,had been implemented in our simulation platform. The results showed that the simulation platform can imitate the swimming of the underwater snake-like robot and the head of the underwater snake-like robot remains in a fixed orientation directed towards the target. The oscillation of head's orientation is inhibited effectively.

Kinematic Control of Wheeled Snake-Like Mobile Robot

From a bionics viewpoint , this paper proposes a mechanical model of a wheeled snake like mobile mechanism. On the hypothesis of the existing non holonomic constraints on the robot kinematics, we set up the relationship among the kinetic control parameters in the snake like movement using Lie group and Lie algebra of the principle fiber bundle and provide some theoretical control methods to realize the snake like locomotion.

Locomotion of Bioinspired Underwater Snake Robots Using Metaheuristic Algorithm

Snake Robots(SR)have been successfully deployed and proved to attain bio-inspired solutions owing to its capability to move in harsh environments,a characteristic not found in other kinds of robots(like wheeled or legged robots).Underwater Snake Robots(USR)establish a bioinspired solution in the domain of underwater robotics.It is a key challenge to increase the motion efficiency in underwater robots,with respect to forwarding speed,by enhancing the locomotion method.At the same time,energy efficiency is also considered as a crucial issue for long-term automation of the systems.In this aspect,the current research paper concentrates on the design of effectual Locomotion of Bioinspired Underwater Snake Robots using Metaheuristic Algorithm(LBIUSR-MA).The proposed LBIUSR-MA technique derives a bi-objective optimization problem to maximize the ForwardVelocity(FV)and minimize the Average Power Consumption(APC).LBIUSR-MA technique involves the design ofManta Ray Foraging Optimization(MRFO)technique and derives two objective functions to resolve the optimization issue.In addition to these,effective weighted sum technique is also used for the integration of two objective functions.Moreover,the objective functions are required to be assessed for varying gait variables so as to inspect the performance of locomotion.A detailed set of simulation analyses was conducted and the experimental results demonstrate that the developed LBIUSR-MA method achieved a low Average Power Consumption(APC)value of 80.52W underδvalue of 50.The proposed model accomplished the minimum PAC and maximum FV of USR in an effective manner.

Knowledge presentation by the MNSM-based controller for swimming motion of a snake-like robot

A MNSM( mirror neuron system mechanism)-based controller is developed to present the swimming rhythm of a snake-like robot in Cartesian space. From engineering viewpoint,the proposed controller is composed of a neuron for rhythm angle and two neurons for motion knowledge in XY plane. The given knowledge is a rhythm curve for swimming motion of a snake-like robot. Experimental results show that the proposed controller can present the knowledge of swimming rhythm,which represents the corresponding control law to drive the snake-like robot to swim with different speeds and turning motion. This work provides a novel method to present the knowledge for swimming motion of snake-like robots.

Head Orientation Stability of Underwater Snake-Like Robot Swimming

In prior research,the orientation of head of the snake-like robot is changed according to the sinusoidal wave. To solve this problem,we propose Central Pattern Generator( CPG)-based control scheme with head-controller to stabilize the head of the underwater snake-like robot. The advantage of the CPG-based control scheme with head-controller is that the head of the underwater snake-like robot is direct to the target orientation during swimming. The relation between CPG parameters and orientation stability of head is discussed.The adaptation of the proposed method to environment changes is tested. The influences of CPG parameters and hydrodynamic forces on the orientation offset of head are investigated. The target orientation( the input of headcontroller) with an experimental optimization is calculated through a convenient method. To prove the feasibility of the proposed methodology,the different swimming modes have been implemented in our simulation platform.The results show that the oscillation of head's orientation is inhibited effectively,and the proposed method has strong adaptation to environment and CPG parameters changes.

Snake模型和遗传算法在特殊焊缝提取中的应用

针对CCD直接拍摄图像的弧焊机器人焊缝视觉检测问题,文中提出了一种精确提取带有较大的间断、尖锐的拐点、较多的干扰等特殊焊缝轨迹的算法.该算法先用小波变换进行焊缝边缘线的平滑,得到与最终焊缝距离很近的初始焊缝轨迹,再用基于Snake模型和遗传算法的进行特殊焊缝的精确匹配和提取.结果表明,该算法能进一步提高特殊焊缝轨迹识别的识别和检测精度,具有较强的适应性,也为弧焊机器人视觉检测的智能化的进一步提高提供一定的技术参考.

基于ISO-TW算法的多仓储机器人路径规划研究

针对当前智能仓库中多仓储机器人协同规划效率低下、动态性不足等问题,提出了一种融合改进蛇优化(Improved Snake Optimizer,ISO)算法和时间窗(Time Window,TW)模型的路径规划方法。首先,在静态规划阶段,利用考虑阻塞因素的改进蛇优化算法为多仓储机器人规划出全局最优路径,同时计算出各机器人的时间窗,从而提升仓储机器人的规划效率;其次,在动态规划阶段,通过建立的多仓储机器人时间窗模型并引入动态调节策略,以消解冲突提升算法的动态性能;最后,进行仿真及实验。仿真结果表明,ISO-TW算法相较其他算法在阻塞点数量上最多可减少27~43个,减少幅度达22.50%~31.62%(机器人规模为80个);重规划路径比重可降低39.82%~41.05%(机器人规模为40个);平均运行时长最多可缩短38~40 s,缩短幅度约为18.27%~19.05%(机器人规模为60个)。实验结果表明,ISO-TW算法较其他算法平均运行时长减少8.53%~9.23%,冲突次数减少11.63%~15.56%,能够在真实场景中实现多仓储机器人的高效协同规划。

水下蛇形机器人建模与运动控制

针对水下蛇形机器人在复杂水下环境自主游动难问题,设计了一种水下蛇形机器人机构。基于蛇类运动机理建立运动学模型,提出一种基于模糊控制和中枢模式生成(CPG)的运动控制方法,通过对单个Hopf振荡器模型中极限环的稳定性进行分析,搭建由多个Hopf振荡器构建形成的具有双耦合链条网拓结构的CPG模型,引入模糊控制器与CPG模型一起构成闭环控制网络。对水下蛇形机器人进行仿真和实验结果表明,样机可实现直线蜿蜒运动、左右转弯运动和U型运动实验,在3种运动模式中,水下蛇形机器人不仅拥有良好的稳定性,而且能够保持优越的灵活性与机动性。

模块化蛇形机器人运动控制系统研究

近年来,人工智能技术得到了广泛的应用和发展,其中机器人技术已经取得了长足进步。而蛇形机器人因其高度仿真的蛇形动态及运动特性而备受瞩目。以锥齿传动结构蛇形机器人为载体,以STM32为主控制器,采用开环控制和闭环控制相结合的方式控制其运动,通过位置式PID控制算法解算装置姿态,提出一种适用于蛇形机器人灵活运动的控制算法。

弯-扭型绳驱蛇形臂的结构设计与运动学分析

为了进一步提升蛇形机械臂的工作效率,建立一种具有扭转关节的多自由度绳驱蛇形机械臂,为其运动学建模奠定基础。所述蛇形臂(摆动+扭转)将传统蛇形臂(摆动+俯仰)的俯仰关节替换为扭转关节,在不同姿态变化中分析其末端执行器能够到达的空间范围,并研究达到目标姿态的连贯性。研究结果表明:文中所述蛇形臂末端执行器与传统蛇形臂具有相同的工作空间;在切换特殊位置时,利用特有的扭转自由度,替代了现有蛇形臂利用俯仰和摆动联动来解算绳索伸缩量,提高了机械臂的反应速度及工作效率。

基于CoppeliaSim的蛇形机器人建模与运动仿真

在进行蛇形机器人的结构设计及控制算法研究时,需要建立合理的仿真模型和良好的测试环境,便于研究人员有效评估。以课题组自主研发的蛇形机器人为例,基于CoppeliaSim和ROS设计了仿真模型及其运动控制系统,并进行了虚拟仿真,测试了蛇形机器人的蜿蜒运动和侧移运动。结果表明,仿真环境中模型的运动状态良好,机器人与环境交互正常,为蛇形机器人结构和控制算法的测试提供了理想的评估环境。

欠驱动蛇形机器人轨迹跟踪算法

蛇形机器人由于其狭长的机械臂和超冗余自由度,在复杂极端环境中具有优越的灵活性。本文在欠驱动蛇形臂机器人的结构基础上,提出了基于等效杆长和等效虚拟关节的两种轨迹跟踪算法,实现蛇形臂机器人对目标曲线的跟踪,满足蛇形臂机器人的运动控制需求。最后,设计了臂长1075 mm包含7关节单元的蛇形机器人样机,并进行了轨迹跟踪实验,结果表明蛇形机器人可轻松穿过直径90 mm以上的狭小管道。运动过程平稳、无振动,验证了轨迹控制算法的正确性和结构设计的合理性。

多蛇形机器人编队路径跟踪控制

为了实现多个蛇形机器人的编队控制,该文提出一种基于误差约束的抗干扰路径跟随方法。该方法使用高度耦合的动态频率补偿器来调整每个机器人的运动速度,以确保编队成员之间位置和速度的一致性。在动力学控制中,通过障碍函数的等效原则消除了虚拟变量的奇异现象,提高了路径跟随的稳定性。此外,该文设计了模型不确定性和外界干扰的预测值,以此来提前补偿机器人的关节偏移量和扭矩输入,从而进一步提高了跟随误差的收敛速度和稳态性能。最后,利用Lyapunov理论证明了该方法的一致最终有界性(UUB)。仿真数据表明,相对于其他经典方法,该文所提模型和控制策略具有更高的跟随精度。

复杂环境下仿蛇机器人的路径规划策略

为完成多障碍物复杂环境中的侦察任务,改善仿蛇机器人的路径搜索能力和提升自主决策能力,本文中提出了一种基于先验知识推理库强化学习的路径规划控制策略。首先,建立仿蛇机器人的运动模型和交互环境模型;其次,通过建立模糊逻辑先验知识推理库(FLIS)与Soft Actor-Critic(SAC)动作网络组成的动作分层选择模型,将输出动作空间进行离散化的方法来调整运动控制精度,提供奖惩机制指导机器人与环境模型进行交互,实现机器人运动自主决策的持续生成过程。仿真结果表明:在多障碍物环境中所提出的改进算法得到的运动控制策略收敛速度和鲁棒性明显提升,降低了训练探索次数,提高了机器人对复杂环境的适应性;试验验证了训练所生成的策略模型在真实环境中的可行性。

蛇形机器人研究综述及在核电中的应用展望

随着“双碳”目标的提出,核能行业迎来多用途利用的爆发期,同时核电安全也成为不容忽视的重点。智能机器人参与核环境作业能更好地提升核电安全水平,但传统机器人的灵巧性不够,且大多缺乏感知功能。蛇形机器人是新型仿生机器人,通过借鉴蛇的生物学特征及运动特征,使机器人在复杂环境中实现多步态运动,可用于核事故现场环境检测以及区域监测、清除放射性污染物、核管道检修等。从仿生学原理出发,综述了蛇形机器人实体及理论发展现状,包括其在核能领域的应用前景,将蛇形机器人实体分为刚性、刚-柔、柔性三大类型进行了研究和分析,对蛇形机器人建模方法、运动控制、导航定位等理论研究情况进行梳理分析。特别地,对蛇形机器人在核电领域的潜在应用进行展望,强调了其未来发展的一些关键问题。旨在为蛇形机器人的研究和应用提供参考,特别是在核技术领域的创新应用。

基于ROS的蛇形机器人控制系统设计

蛇形机器人具有超冗余度的躯干结构和多样化的移动步态。为验证其控制算法,需要一个稳定可靠且具备强扩展性的控制系统。设计开发了一种由正交关节单元组成的蛇形机器人,并提出基于ROS(Robot Operating System)的控制系统设计方案。该方案将控制系统分为应用层、决策层和运动控制层,各层之间分工明确且耦合性低,从而提高了系统的稳定性和扩展性。采用曲线离散法规划蛇形机器人的运动步态,并进行蜿蜒运动和侧移运动测试。实验结果表明,该运动控制策略对机器人有效且设计方案具有可行性和实用性。

蛇形管道机器人设计与轨迹跟踪算法实现

蛇形机器人模仿蛇的身体结构与运动机理,具有体积小、自由度多等特点,在复杂环境中表现出优秀的运动性能。设计一种适用于狭小管道环境的蛇形机器人,采用模块化的构型,机器人共拥有5个自由度。利用Denavit-Hartenberg方法对机器人进行运动学分析,基于从机器人尾部到头部的前向轨迹跟踪控制算法,建立机器人的轨迹跟踪运动控制方法;设计实验样机并开展运动控制实验和实际管道转弯实验,验证了机器人结构设计的合理性、逆运动学的正确性和运动控制方法的有效性。

Locomotion control of a rigid-soft coupled snake robot in multiple environments

The versatile motion capability of snake robots offers themselves robust adaptability in varieties of challenging environments where traditional robots may be incapacitated.This study reports a novel flexible snake robot featuring a rigid-flexible coupling structure and multiple motion gaits.To better understand the robot's behavior,a bending model for the soft actuator is established.Furthermore,a dynamic model is developed to map the relationship between the input air pressure and joint torque,which is the model base for controlling the robot effectively.Based on the wave motion generated by the joint coupling direction function in different planes,multiple motion gait planning methods of the snake-like robot are proposed.In order to evaluate the adaptability and maneuverability of the developed snake robot,extensive experiments were conducted in complex environments.The results demonstrate the robot's effectiveness in navigating through intricate settings,underscoring its potential for applications in various fields.