Real-time accurate hand path tracking and joint trajectory planning for industrial robots(Ⅱ)

Previously, researchers raised the accuracy for a robot′s hand to track a specified path in Cartesian space mainly through increasing the number of knots on the path and the segments of the path. But, this method resulted in the heavier on-line computational burden for the robot controller. In this paper, aiming at this drawback, the authors propose a new kind of real-time accurate hand path tracking and joint trajectory planning method for robots. Through selecting some extra knots on the specified hand path by a certain rule, which enables the number of knots on each segment to increase from two to four, and through introducing a sinusoidal function and a cosinoidal function to the joint displacement equation of each segment, this method can raise the path tracking accuracy of robot′s hand greatly but does not increase the computational burden of robot controller markedly.     

Real-time accurate hand path tracking and joint trajectory planning for industrial robots(Ⅰ)

Previously, researchers raised the accuracy for a robot′s hand to track a specified path in Car-tesian space mainly through increasing the number of knots on the path and the number of the path′s segments, which results in the heavier online computational burden for the robot controller. Aiming at overcoming this drawback, the authors propose a new kind of real-time accurate hand path tracking and joint trajectory planning method. Through selecting some extra knots on the specified hand path by a certain rule and introducing a sinusoidal function to the joint displacement equation of each segment, this method can greatly raise the path tracking accuracy of robot′s hand and does not change the number of the path′s segments. It also does not increase markedly the computational burden of robot controller. The result of simulation indicates that this method is very effective, and has important value in increasing the application of industrial robots.     

Global optimal path planning for mobile robot based on improved Dijkstra algorithm and ant system algorithm

A novel method of global optimal path planning for mobile robot was proposed based on the improved Dijkstra algorithm and ant system algorithm. This method includes three steps： the first step is adopting the MAK-LINK graph theory to establish the free space model of the mobile robot, the second step is adopting the improved Dijkstra algorithm to find out a sub-optimal collision-free path, and the third step is using the ant system algorithm to adjust and optimize the location of the sub-optimal path so as to generate the global optimal path for the mobile robot. The computer simulation experiment was carried out and the results show that this method is correct and effective. The comparison of the results confirms that the proposed method is better than the hybrid genetic algorithm in the global optimal path planning.     

Dynamic modeling and simulation for nonholonomic welding mobile robot

Based on the Newton-Euler method, the dynamic behaviors of the left and right driving wheels and the robot body for the welding mobile robot were derived. In order to realize the combination control of body turning and slider adjustment, the dynamic behaviors of sliders were also investigated. As a result, a systematic and complete dynamic model for the welding mobile robot was constructed. In order to verify the effectiveness of the above model, a sliding mode tracking control method was proposed and simulated, the lateral error stabilizes between ?0.2 mm and 0.2 mm, and the total distance of travel for the slider is consistently within ±2 mm. The simulation results verify the effectiveness of the established dynamic model and also show that the seam tracking controller based on the dynamic model has excellent performance in terms of stability and robustness. Furthermore, the model is found to be very suitable for practical applications of the welding mobile robot.     

Identification of abnormal movement state and avoidance strategy for mobile robots

1 INTRODUCTION Abnormality identification is crucial for dead-reckoning, locating and mapping, navigating and safety of mobile robots, especially when robots work in unknown environments such as planetary exploration. The abnormalities of mobile robots can be divided into two categories: faults of internal components (such as sensor, actuator, etc)[1?5] and abnormal movement states while interacting with environments (such as slipping of wheel)[6?7]. Those abnormal movement states include …     

Adaptive genetic algorithm for path planning of loosely coordinated multi-robot manipulators

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EMDS 3.0:A modeling framework for coping with complexity in environmental assessment and planning

The Ecosystem Management Decision Support (EMDS) system is an application framework for knowledge-based decision support of ecological assessments at any geographic scale. The system integrates state-of-the-art geographic information system (GIS) as well as knowledge-based reasoning and decision modeling technologies to provide decision support for a substantial portion of the adaptive management process of ecosystem management. EMDS 3.0 is implemented as an ArcMap extension and integrates the logic engine of NetWeaver to perform landscape evaluations, and the decision modeling engine of Criterium DecisionPlus for evaluating management priorities. Key features of the system's evaluation component include abilities to (1) reason about large, abstract, multi-faceted ecosystem management problems, (2) perform useful evaluations with incomplete information, (3) evaluate the influence of missing information, and (4) determine priorities for missing information. A key feature of the planning component is the ability to determine priorities for management activities, taking into account not only ecosystem condition, but also criteria that account for the feasibility and efficacy of potential management actions. Both components include powerful and intuitive diagnostic features that facilitate communicating the explanation of modeling results to a broad audience.     

Robust simultaneous tracking and stabilization of wheeled mobile robots not satisfying nonholonomic constraint

A robust unified controller was proposed for wheeled mobile robots that do not satisfy the ideal rolling without slipping constraint.Practical trajectory tracking and posture stabilization were achieved in a unified framework.The design procedure was based on the transverse function method and Lyapunov redesign technique.The Lie group was also introduced in the design.The left-invariance property of the nominal model was firstly explored with respect to the standard group operation of the Lie group SE(2).Then,a bounded transverse function was constructed,by which a corresponding smooth embedded submanifold was defined.With the aid of the group operation,a smooth control law was designed,which fulfills practical tracking/stabilization of the nominal system.An additional component was finally constructed to robustify the nominal control law with respect to the slipping disturbance by using the Lyapunov redesign technique.The design procedure can be easily extended to the robot system suffered from general unknown but bounded disturbances.Simulations were provided to demonstrate the effectiveness of the robust unified controller.     

基于遗传蚁群算法的机器人全局路径规划研究

蚁群算法是基于生物界群体启发行为的一种随机搜索寻优方法,它的正反馈性和协同性使其可用于分布式系统,隐含的并行性更使其具有极强的发展潜力,它在解决组合优化问题上有着良好的适应性。因此将其应用到智能机器人全局路径规划中,其目的是探索一种新的路径寻优算法.在基于栅格划分的环境中,研究了机器人路径规划问题中蚁群系统的"外激素"表示及更新方式,并将遗传算法的交叉操作结合到蚁群系统的路径寻优过程中,提高了蚁群系统的路径寻优能力,为蚁群算法的应用提供了一种新的探索.     

一种基于APGA的移动机器人路径规划算法

提出了基于自适应并行遗传算法的移动机器人路径规划算法,其基本思想是结合多种群并行进化及自适应调整控制参数,提高了搜索的范围和效率,缓解了传统遗传算法早熟收敛问题,从而克服了使用单种群遗传算法进行路径规划的不足．实验结果表明了该算法在移动机器人路径规划中的可行性和有效性．     

基于势场栅格法的机器人全局路径规划

综合势场法和栅格法的优点，提出了一个新的全局路径规划方法——势场栅格法、算法在避免局部最优点和降低计算量方面，有着良好的效果；并且可以自动确定栅格粒度．最后，文章分析了影响算法精度的因素，仿真试验表明此算法有良好的可行性和有效性．     

移动机器人路径动态规划有向D*算法

针对传统D*路径规划算法搜索效率低、成本较高的问题,提出有向D*算法. 该算法考虑目标点与障碍物信息,引入关键节点概念,逐级扩展确定可行路径,并且引入导向函数以控制单次搜索的节点搜索范围来提高搜索效率;在原欧几里得评价指标的基础上引入路径平滑度函数对偏移路径进行惩罚,避免机器人无效转弯而增加移动成本;通过路径平滑度函数中的“转弯因子”协调路径长度与平滑度之间的关系,给出路径平滑度函数的分段原理与转弯因子的确定方法,并对算法收敛性进行证明. 在不同环境下的仿真实验表明,该算法较传统算法能更好地兼顾局部搜索与全局最优性,尤其适用于障碍物较多的复杂环境.     

基于混沌遗传算法的移动机器人路径规划方法

结合遗传算法优化的反演性和混沌优化方法的遍历性,基于混沌遗传算法的移动机器人路径规划方法能够有效改善遗传算法的局部搜索能力和搜索精度,避免单纯使用遗传算法规划机器人路径时容易出现的早熟收敛现象．仿真试验表明,提出的路径规划方法在稀疏环境和密集环境下均能收敛到全局最优路径,具有更强的鲁棒性．     

基于改进蚁群算法的移动机器人路径规划

针对大多数路径规划方法所忽视的路径尖峰,以及传统蚁群算法(ACA)易出现的早熟、陷入局部最优等问题,提出一种改进ACA以用于路径规划.首先,在ACA中融入遗传算子,利用交叉与变异操作来扩大解的搜索空间,提升解的全局性.然后,引入简化与平滑操作优化算子,对所寻路径做进一步处理,消除路径中不必要的尖峰,提高其平滑性.栅格环境下的机器人路径规划仿真结果表明,与A*以及传统ACA相比,所提算法能够得到更为平滑的最短路径.     

基于可拓遗传算法的机器人路径规划

在遗传算法基础上,用扩展物元来表示机器人的位置信息,使计算机能够较容易读懂这种语言,加快了计算速度;用关联函数作为遗传算法的适应度函数,使算法更容易找到最优化路径;采用可拓工程方法中的三种可拓变换形式,丰富了遗传算法的变异方式．实验证明,可拓遗传算法的机器人路径规划能有效提高的机器人路径规划的速度和准确性．     

基于粗糙集移动机器人微种群路径规划算法

针对机器人的路径规划,提出了一种将粗糙集和微种群遗传算法相结合的路径规划算法.该算法采用栅格法划分机器人的工作空间,十进制路径编码方式.在粗糙集生成初始路径的基础上,通过运用微种群遗传算法对这些初始路径进行优化后,得到了一条最优或近似最优路径.在Matlab环境进行的机器人路径规划仿真实验中,笔者用到的微种群遗传算法与一般遗传算法相比,具有优化效果明显,环境适应性强等优点,能够有效地提高机器人路径规划速度,结果表明作者提出的方法是正确和有效的.     

移动机器人路径规划技术综述

针对Q学习算法在动态连续环境中应用时因状态连续、数量过多,导致Q值表出现存储空间不足和维数灾的问题,提出了一种新的Q值表设计方法,并设计了适用于连续环境的R值和动作.不同于以状态-动作为索引,将时间离散化为时刻,以时刻-动作为索引来建立Q值表.将在某状态应选择某一动作的问题转化为在某时刻应选择某一动作的问题,实现了Q学习算法在动态连续环境中的应用.采用了先利用遗传算法进行静态全局路径规划,然后利用Q学习算法进行动态避障.整个方法为一种先\     

基于超混沌同步控制的移动机器人全覆盖路径规划

针对移动机器人执行警戒、巡逻等特殊任务的随机性、遍历性等需求,提出一种基于超混沌同步控制的移动机器人全覆盖路径规划方法。以四维超混沌Lorenz系统为主驱动方程,利用单边耦合同步控制构造超混沌同步响应方程;将同步后的超混沌同步响应方程与移动机器人运动学方程相结合,构造混沌机器人路径规划器,产生满足特殊任务要求的全覆盖遍历轨迹;利用镜面映射方法对覆盖轨迹运行范围进行限制和对运行边界进行静态避障。对规划轨迹进行定性分析和定量计算发现,与同步以前的超混沌方程相比,利用超混沌同步方法构造后产生的全覆盖轨迹具有更好的遍历覆盖特性和随机特性,能够满足自主移动机器人执行警戒、巡逻等特殊任务的需求。