基于简化虚拟受力模型的群机器人多目标搜索协调控制

针对未知凸和非凸障碍物以及动态障碍物环境下群机器人多目标搜索问题,提出了一种基于简化虚拟受力分析模型的循障和避碰方法(SRSMT-SVF).对复杂环境下群机器人多目标搜索行为进行了分解并抽象出简化虚拟受力分析模型.基于此受力模型,设计了个体机器人协同搜索和漫游状态下的运动控制策略,使得机器人在搜索目标的同时能够实时避碰.通过对不同群体规模系统的仿真实验表明,本文控制方法能够使个体机器人在整个搜索过程中保持良好的避碰性能,有效地减少系统与环境之间和系统内部个体之间的碰撞冲突.相比于扩展粒子群算法(EPSO),本文方法使得搜索耗时和系统能耗至少减少了13.78%、11.96%,数值仿真结果验证了本文方法的有效性.     

基于改进蚁群算法的机器人路径规划

本文主要结合蚁群算法对机器人路径规划进行了系统的研究。针对蚂蚁在搜索路径过程中落入障碍物陷阱而造成算法停滞的现象,提出了蚂蚁系统回退策略。为了检验改进型算法的性能,基于MATLAB软件设计了仿真程序。仿真结果表明：对基本蚁群算法的改进,提高了算法的有效性和鲁棒性,增强了蚁群算法在机器人路径规划中的适应能力。     

基于随机行走的群机器人二维地图构建

机器人在未知环境自主探索时,需要快速准确地获取环境地图信息。针对高效探索和未知环境的地图构建问题,将随机行走算法应用于群机器人的探索中,机器人模拟布朗运动,对搜索区域建图。然后,改进了布朗运动算法,通过设置机器人随机行走时的最大旋转角度,来避免机器人重复性地搜索一个区域,使机器人在相同时间内探索更多的区域,提高机器人的搜索效率。最后,通过搭载激光雷达的多个移动机器人进行了仿真实验,实验分析了最大转角增量、机器人数量以及机器人运动步数对搜索区域的影响。     

未知环境下基于VFH＊的机器人避障

机器人避障问题一直是机器人应用中的热点和难点问题。为此采用了路径跟踪和VFH*相结合的方法实现机器人沿着预定路径前进中的避障问题。路径跟踪算法follow the carrot用来选取局部目标点。对于VFH*算法中存在的由于超声传感器的方向误差及对障碍物的扩展导致某些可行路径被忽略的情况进行了改进,在障碍物进行扩展时根据障碍物与机器人中心点的距离大小进行不同程度的扩展。另外,在障碍物比较稀的区域,VFH*算法对每个valley最多只选取三个候选方向,导致一些更好的方向丢失,根据valley的大小及机器人当前选定方向来增加一个新的候选方向。并用仿真验证了所做的改进是有效的。     

多移动机器人区域分割优化覆盖算法研究

针对多机器人协作的全覆盖路径规划优化问题,提出了一种区域分割优化覆盖算法,完成多机器人对未知区域的快速、高效的覆盖任务.在移动机器人全覆盖路径规划研究中,将机器人的能量、速度、任务完成时间等作为限制条件,对所需机器人的数目、机器人分成的组数及机器人工作的起始位置进行规划,以实现利用最少数目的机器人完成给定区域的优化分割和覆盖.对比仿真实验,结果表明本方法在给定机器人数量的情况下,完成了最大区域的覆盖.该方法可以有效完成多机器人对未知区域的快速高效的搜索覆盖任务.     

基于强化学习算法的多机器人系统的冲突消解策略

多机器人系统中，随着机器人数目的增加．系统中的冲突呈指数级增加．甚至出现死锁．本文提出了基于过程奖赏和优先扫除的强化学习算法作为多机器人系统的冲突消解策略．针对典型的多机器人可识别群体觅食任务．以计算机仿真为手段，以收集的目标物数量为系统性能指标，以算法收敛时学习次数为学习速度指标，进行仿真研究，并与基于全局奖赏和Q学习算法等其他9种算法进行比较．结果表明所提出的基于过程奖赏和优先扫除的强化学习算法能显著减少冲突．避免死锁．提高系统整体性能．     

穿越稠密障碍物的自适应动态窗口法

针对应用广泛的局部避障算法-----动态窗口法(DWA)穿越稠密障碍物时存在路径不合理、速度和安全性不能兼顾等问题,提出参数自适应的DWA算法,根据机器人与障碍物距离和障碍物的密集度自动调整目标函数中的权值,以自适应环境的动态变化,从而获得移动机器人的最佳运行速度和合理路径.该方法可明显改善机器人穿越稠密障碍物区域时的性能;同时,该方法还可避免机器人从密集障碍物区域外绕行以及轨迹不平滑现象.仿真实验表明:改进的DWA算法在复杂环境中通过逐步优化可使运行轨迹更加合理,能够同时兼顾路径平滑性和安全性;机器人在离稠密障碍物较远处保持高速,通过狭窄通道或者稠密障碍物区域时速度适当降低,安全性更高,实验中总迭代次数和运行时间可缩短20%以上.     

栅格地图中多机器人协作搜索目标

目标搜索是多机器人领域的一个挑战.本文针对栅格地图中多机器人目标搜索算法进行研究.首先,利用Dempster-Shafer证据理论将声纳传感器获取的环境信息进行融合,构建搜索环境的栅格地图.然后,基于栅格地图建立生物启发神经网络用于表示动态的环境.在生物启发神经网络中,目标通过神经元的活性值全局的吸引机器人.同时,障碍物通过神经元活性值局部的排斥机器人,避免与其相撞.最后,机器人根据梯度递减原则自动的规划出搜索路径.仿真和实验结果显示本文提及的算法能够实现栅格地图中静态目标和动态目标的搜索.与其他搜索算法比较,本文所提及的目标搜索算法有更高的效率和适用性.     

未知环境下群机器人多目标搜索协同控制

未知环境下,群机器人无法预先获取多目标搜索的环境信息,仅可局部感知与局部通信.本文针对避障效率与搜索效率的缺陷提出边界扫描的避障策略和目标位置估计的粒子群算法,边界扫描的避障策略(BSOA)将障碍物简化成连续障碍物与非连续障碍物两种情况,并根据情况向特定边界运动;目标位置估计的粒子群算法(TPEPSO)则利用获取的目标信号估计目标位置,结合粒子群算法到达目标附近,从而实现目标搜索.提出的方法与基于简化虚拟受力分析模型的循障避碰方法(SVF)及扩展粒子群算法(EPSO)、自适应机器人蝙蝠算法(ARBA)仿真比较,搜索效率提高5.72%～21.58%,总能耗减少4.30%～19.11%.     

救援机器人搜索目标路径环境快速建模仿真

为了使救援机器人在灾害发生救援过程中更好地了解环境空间信息,规划出一条最优搜索目标路径,提出救援机器人搜索目标路径环境快速建模方法.采用贝叶斯滤波器计算栅格占用率,获得静态、动态地图逆向传感器,使用URG-04LX暗光条件激光雷达,得到不同方向上障碍物位置信息构成的扇形平面,并利用拓扑方法处理地图,准确体现出障碍物位置关系信息,依据基于主动生长的栅格Voronoi图生成现场环境模型.仿真结果表明,利用所提方法设计的实验机器人在行驶的过程中没有碰到任何障碍物,说明上述环境模型对环境区域描述精准度比较高.     

考虑障碍环境下的多机器人编队控制研究

编队和避障控制是机器人路径规划设计中的典型问题,文中提出了将leader—following法和人工势场法相结合的方法,来更好地完成多机器人在未知环境下的编队和避障控制。之前的研究只将leader—following算法用于多机器人的编队控制,而文中提出此方法也可以用于多机器人系统的避障控制。基于leader—following法,多机器人能自动编队并保持队形;而结合人工势场法,多机器人可以保持队形行进,在遇到障碍物的情况下变换队形避障,在避障后恢复原队形,最终到达目标。通过仿真实验证明,该算法实现了多机器人在未知环境下的自动编队和避障,从而证明了leader—following算法可以用于机器人的避障控制。     

Control of leader–follower formation and path planning of mobile robots using Asexual Reproduction Optimization (ARO)

This paper presents the optimal path of nonholonomic multi robots with coherent formation in a leader–follower structure in the presence of obstacles using Asexual Reproduction Optimization (ARO). The robots path planning based on potential field method are accomplished and a novel formation controller for mobile robots based on potential field method is proposed. The efficiency of the proposed method is verified through simulation and experimental studies by applying them to control the formation of four e-Pucks robots (low-cost mobile robot platform). Also the proposed method is compared with Simulated Annealing, Improved Harmony Search and Cuckoo Optimization Algorithm methods and the experimental results, higher performance and fast convergence time to the best solution of the ARO demonstrated that this optimization method is appropriate for real time control application.     

Navigation of Mobile Robots Using a Fuzzy Logic Controller

This paper describes a mobile robot navigation control system based on fuzzy logic. Fuzzy rules embedded in the controller of a mobile robot enable it to avoid obstacles in a cluttered environment that includes other mobile robots. So that the robots do not collide against one another, each robot also incorporates a set of collision prevention rules implemented as a Petri Net model within its controller. The navigation control system has been tested in simulation and on actual mobile robots. The paper presents the results of the tests to demonstrate that the system enables multiple robots to roam freely searching for and successfully finding targets in an unknown environment containing obstacles without hitting the obstacles or one another.     

Path planning of humanoids based on artificial potential field method in unknown environments

In this paper, an artificial potential field based navigational controller has been developed for motion planning of humanoid robots. Here, NAO robots are used as the humanoid platform using the underlying principles of potential field based method. The movement of the robot is considered to be under a negative gradient scheme by the combined effect of attractive and repulsive forces generated due to target and obstacles, respectively. The working of the controller is tested in a V‐REP simulation platform, and the simulation results are validated through a real‐time experimental set‐up developed under laboratory conditions. Here, the navigation of both single and multiple humanoids has been attempted. For avoiding intercollision among multiple humanoids during their navigation in a common platform, a Petri‐Net control scheme has been proposed. The results obtained from both the simulation and experimental platforms are compared against each other with a good agreement between them having minimal percentage of deviations. Finally, the proposed controller is also evaluated against another existing navigational model, and a significant performance improvement has been observed.     

复杂环境下基于势场原理的路径规划方法

针对势场原理所固有的几个缺陷:在相近障碍物间不能发现路径;在狭窄通道中摆动;在障碍物前振荡;存在陷阱区域;当目标附近有障碍物时无法达到目标点,提出了改进办法.改进后的势场法适用于未知复杂环境下移动机器人的路径规划,并具备一定的学习能力.仿真实验验证了该方法的有效性.     

An algorithm for safe navigation of mobile robots by a sensor network in dynamic cluttered industrial environments

Mobile robots have been widely implemented in industrial automation and smart factories. Different types of mobile robots work cooperatively in the workspace to complete some complicated tasks. Therefore, the main requirement for multi-robot systems is collision-free navigation in dynamic environments. In this paper, we propose a sensor network based navigation system for ground mobile robots in dynamic industrial cluttered environments. A range finder sensor network is deployed on factory floor to detect any obstacles in the field of view and perform a global navigation for any robots simultaneously travelling in the factory. The obstacle detection and robot navigation are integrated into the sensor network and the robot is only required for a low-level path tracker. The novelty of this paper is to propose a sensor network based navigation system with a novel artificial potential field (APF) based navigation algorithm. Computer simulations and experiments confirm the performance of the proposed method.     

Efficient collision-free path-planning of multiple mobile robots system using efficient artificial bee colony algorithm

This paper aims to propose a novel design approach for on-line path planning of the multiple mobile robots system with free collision. Based on the artificial bee colony (ABC) algorithm, we propose an efficient artificial bee colony (EABC) algorithm for solving the on-line path planning of multiple mobile robots by choosing the proper objective function for target, obstacles, and robots collision avoidance. The proposed EABC algorithm enhances the performance by using elite individuals for preserving good evolution, the solution sharing provides a proper direction for searching, the instant update strategy provides the newest information of solution. By the proposed approach, the next positions of each robot are designed. Thus, the mobiles robots can travel to the designed targets without collision. Finally, simulation results of illustration examples are introduced to show the effectiveness and performance of the proposed approach.     

Navigation strategy of multiple mobile robot systems based on the null-space projection method

This paper deals with a navigation algorithm for swarm robot systems in which multiple mobile robots work together. The motion of each mobile robot is modeled in such a way to have more inputs than the number of outputs. The null-space projection method of this model is employed to resolve the motion of the swarm robot system while avoiding obstacles. The feasibility of the proposed navigation algorithm is verified through a simulation study using several swarm robot models.     

Multi-robot collaboration for robust exploration

This paper presents a new sensing modality for multirobot exploration. The approach is based on using a pair of robots that observe each other, and act in concert to reduce odometry errors. We assume the robots can both directly sense nearby obstacles and see each other. The proposed approach improves the quality of the map by reducing the inaccuracies that occur over time from dead reckoning errors. Furthermore, by exploiting the ability of the robots to see each other, we can detect opaque obstacles in the environment independently of their surface reflectance properties. Two different algorithms, based on the size of the environment, are introduced, with a complexity analysis, and experimental results in simulation and with real robots. This revised version was published online in August 2006 with corrections to the Cover Date.