Level Set方法求解机器人路径规划的探讨

移动机器人路径规划是机器人学的一个最基本也是最复杂的问题,路径规划的主要方法有势能方法、单元分解方法、神经网络(NN)等。水平集(level set)方法已经广泛应用于图像处理和计算机图形学领域,因为其具有能够处理拓扑改变、数值稳定性好和独立于参数化的优势。为了探讨Level set方法在求解机器人路径规划中的应用,在介绍水平集法的基本思想和相关技术,以及路径规划的求解方法等的基础上,引入路径规划问题的隐式主动轮廊模型,即水平集模型,并采用快速推进方法(FMM)求解此模型方程,进而给出了路径规划模型的计算结果及其可视化界面,并且与经典势能法的计算结果进行了比较。理论和计算结果证明,Level set方法求解机器人路径规划是可行和有效的,从而为机器人路径规划研究提供了新的思路和方法。     

一个基于全景视觉的移动机器人导航系统的设计与实现

针对移动机器人路径规划与导航的实际应用,设计了一个基于全景视觉的移动机器人路径规划导航系统．首先,对导航系统的体系结构和功能进行描述．然后,分别就如何采用全景视觉传感器进行环境探索与地图创建,基于回归神经网络的广度优先搜索法和Voronoi骨架图法两种路径规划算法原理,以及如何实现按规划路径实施导航这三个方面进行了详细阐述．最后,结合实际机器人进行导航实验,评估导航系统的性能和路径规划算法的有效性．     

Application of Heuristic Asymmetric Mapping for mobile robot navigation using ultrasonic sensors

In this paper, an experimental study of a navigation system that allows a mobile robot to travel in an environment about which it has no prior knowledge is described. Data from multiple ultrasonic range sensors are fused into a representation called Heuristic Asymmetric Mapping to deal with the problem of uncertainties in the raw sensory data caused mainly by the transducer's beam-opening angle and specular reflections. It features a fast data-refresh rate to handle a dynamic environment. Potential-field method is used for on-line path planning based on the constructed gridtype sonar map. The mobile robot can therefore learn to find a safe path according to its self-built sonar map. To solve the problem of local minima in conventional potential field method, a new type of potential function is formulated. This new method is simple and fast in execution using the concept from distance-transform path-finding algorithms. The developed navigation system has been tested on our experimental mobile robot to demonstrate its possible application in practical situations. Several interesting simulation and experimental results are presented.This work was supported partly by the National Science Council of Taiwan, ROC under the grant NSC-82-0422-E-009-321.     

移动机器人路径规划算法的研究综述

路径规划是移动机器人的热门研究之一,是实现机器人自主导航的关键技术。针对移动机器人路径规划的算法进行研究,以了解不同条件下路径规划算法的发展与应用,系统性地总结了路径规划的研究现状和发展。针对移动机器人路径规划的特点,将其划分为智能搜索算法、基于人工智能算法、基于几何模型算法和用于局部避障算法。基于上述分类,介绍了近年来具有代表性的研究成果,重点分析各类规划算法的优缺点,对移动机器人路径规划的未来发展趋势进行展望,为移动机器人路径规划研究提供一定的思路。     

A 3-level autonomous mobile robot navigation system designed by using reasoning/search approaches

This paper describes how soft computing methodologies such as fuzzy logic, genetic algorithms and the Dempster–Shafer theory of evidence can be applied in a mobile robot navigation system. The navigation system that is considered has three navigation subsystems. The lower-level subsystem deals with the control of linear and angular volocities using a multivariable PI controller described with a full matrix. The position control of the mobile robot is at a medium level and is nonlinear. The nonlinear control design is implemented by a backstepping algorithm whose parameters are adjusted by a genetic algorithm. We propose a new extension of the controller mentioned, in order to rapidly decrease the control torques needed to achieve the desired position and orientation of the mobile robot. The high-level subsystem uses fuzzy logic and the Dempster–Shafer evidence theory to design a fusion of sensor data, map building, and path planning tasks. The fuzzy/evidence navigation based on the building of a local map, represented as an occupancy grid, with the time update is proven to be suitable for real-time applications. The path planning algorithm is based on a modified potential field method. In this algorithm, the fuzzy rules for selecting the relevant obstacles for robot motion are introduced. Also, suitable steps are taken to pull the robot out of the local minima. Particular attention is paid to detection of the robot’s trapped state and its avoidance. One of the main issues in this paper is to reduce the complexity of planning algorithms and minimize the cost of the search. The performance of the proposed system is investigated using a dynamic model of a mobile robot. Simulation results show a good quality of position tracking capabilities and obstacle avoidance behavior of the mobile robot.     

移动机器人路径规划算法综述

路径规划算法是实现移动机器人自主导航的关键技术。针对移动机器人路径规划技术进行研究,分析各算法的实现机制与原理,并系统性的总结了主流路径规划算法研究现状。根据移动机器人路径规划算法的特点,将路径规划算法分为：传统规划算法、智能规划算法、基于采样的规划算法。基于以上分类,分述近年来的主要研究成果,重点分析各类算法的优缺点。针对移动机器人路径规划算法研究现状,对其未来研究方向进行展望,为移动机器人路径规划大发展提供一定的思路。     

动态环境下机器人多目标路径规划蚂蚁算法

研究了一种新颖的动态复杂不确定环境下的机器人多目标路径规划蚂蚁算法。该方法首先根据蚂蚁觅食行为对多个目标点的组合进行优化,规划出一条最优的全局导航路径。在此基础上,机器人按照规划好的目标点访问顺序根据多蚂蚁协作局部路径算法完成局部路径的搜索。机器人每前进一步都实时地进行动态障碍物运动轨迹预测以及碰撞预测,并重新进行避碰局部路径规划。仿真结果表明,即使在障碍物非常复杂的地理环境,用该算法也能使机器人沿一条全局优化的路径安全避碰的遍历各个目标点,效果十分令人满意。     

Using roadmaps to classify regions of space for autonomous robot navigation

The roadmap approach to robot path planning is one of the earliest methods. Since then, many different algorithms for building roadmaps have been proposed and widely implemented in mobile robots but their use has always been limited to planning in static, totally known environments. In this paper we combine the use of dynamic analogical representations of the environment with an efficient roadmap extraction method, to guide the robot navigation and to classify the different regions of space in which the robot moves. The paper presents the general reference architecture for the robotic system and then focuses on the algorithms for the construction of the roadmap, the classification of the regions of space and their use in robot navigation. Experimental results indicate the applicability and robustness of this approach in real situations.     

Hybrid approach to implement multi-robotic navigation system using neural network,fuzzy logic,and bio-inspired optimization methodologies

Mobile robots have been increasingly popular in a variety of industries in recent years due to their ability to move in variable situations and perform routine jobs effectively. Path planning, without a dispute, performs a crucial part in multi-robot navigation, making it one of the very foremost investigated issues in robotics. In recent times, meta-heuristic strategies have been intensively investigated to tackle path planning issues in the similar way that optimizing issues were handled, or to design the optimal path for such multi-robotics to travel from the initial point to such goal. The fundamental purpose of portable multi-robot guidance is to navigate a mobile robot across a crowded area from initial point to target position while maintaining a safe route and creating optimum length for the path. Various strategies for robot navigational path planning were investigated by scientists in this field. This work seeks to discuss bio-inspired methods that are exploited to optimize hybrid neuro-fuzzy analysis which is the combination of neural network and fuzzy logic is optimized using the particle swarm optimization technique in real-time scenarios. Several optimization approaches of bio-inspired techniques are explained briefly. Its simulation findings, which are displayed for two simulated scenarios reveal that hybridization increases multi-robot navigation accuracy in terms of navigation duration and length of the path.     

基于势场法的移动机器人避障路径规划

针对势场法所固有的几个缺陷,提出了一种基于势场法的移动机器人避障路径规划算法,并成功应用于未知复杂环境下移动机器人的路径规划中。仿真试验表明:提出的方法具有较强的路径规划能力,克服了传统势场法的缺点,具有较强的实用性。     

基于近似Voronoi图的移动机器人实时路径规划

运用Voronoi图理论及人工势场理论,研究了一种基于近似Voronoi图的移动机器人实时路径规划的方法,用来实现未知室内环境中移动机器人的自主导航。该方法朝向预先定义的目标点位置来探测室内环境,生成近似Voronoi图,同时利用人工势场法进行避障,生成一条能达到目标点的安全、光滑路径。仿真结果表明,该方法简单且易于实现,同时能够减少规划时间。     

基于路径预测的机器人足球路径规划

针对常用的机器人路径规划算法过于复杂并且在每个运动周期都计算路径的问题,提出了一种结合路径预测的路径最优算法.充分利用预测结果减少每周期的路径规划时间;用微量调整动态控制机器人左右轮速度,并充分利用折线路径的短距离优势,为避障机器人创建一条最短路径;以基于周期性预测在同个时间轴上的相交作为碰撞信号,来减少每个周期的重复性计算时间.实验结果表明,该方法能大大提高机器人路径规划的速度,降低不同周期上路径规划结果不一致导致的运动震荡.     

改进人工势场法的洗浴机器人擦洗路径规划

针对洗浴机器人末端执行器与人体直接接触擦洗的自主导航问题进行了研究,提出一种基于人体点云的改进人工势场法三维覆盖路径规划算法。首先,在传统人工势场法基础上增设障碍物引力势场,使机器人能够贴近障碍物表面向目标点移动,并且通过添加虚拟目标点的方法克服了凹陷区域产生的局部极小值问题。然后,将人体点云切段分割后投影至平面,结合改进的人工势场法完成对人体表面的覆盖路径规划。以人体模型点云为对象进行仿真实验及对比,结果表明提出算法可以快速有效地完成基于人体点云的三维覆盖擦洗路径规划。     

基于模糊人工势场法的智能全向车路径规划

针对于移动机器人在传统人工势场法路径规划中易于陷入局部最小点而无法抵达目标点的问题,同时考虑到实际环境中人工势场法相关参数的不确定性,提出了一种基于模糊人工势场法的动态路径规划方法。借助于专家经验进行模糊决策,调整移动机器人在各个时刻的合力大小和方向,进而解决斥力常数、引力方向偏角以及机器人行驶速度的不确定性问题。为了验证该方法的有效性,在智能全向车平台进行了应用,结果表明,智能全向车运动轨迹平滑,避免了实际应用中的震荡问题。     

A New Mobile Robot Toolbox for Matlab

In this study, a wheeled mobile robot navigation toolbox for Matlab is presented. The toolbox includes algorithms for 3D map design, static and dynamic path planning, point stabilization, localization, gap detection and collision avoidance. One can use the toolbox as a test platform for developing custom mobile robot navigation algorithms. The toolbox allows users to insert/remove obstacles to/from the robot’s workspace, upload/save a customized map and configure simulation parameters such as robot size, virtual sensor position, Kalman filter parameters for localization, speed controller and collision avoidance settings. It is possible to simulate data from a virtual laser imaging detection and ranging (LIDAR) sensor providing a map of the mobile robot’s immediate surroundings. Differential drive forward kinematic equations and extended Kalman filter (EKF) based localization scheme is used to determine where the robot will be located at each simulation step. The LIDAR data and the navigation process are visualized on the developed virtual reality interface. During the navigation of the robot, gap detection, dynamic path planning, collision avoidance and point stabilization procedures are implemented. Simulation results prove the efficacy of the algorithms implemented in the toolbox.     

越野环境建模与动态路径规划

针对越野环境下移动机器人的导航与控制问题，提出了一种越野环境下环境建模与动态路径规划方法。该方法能够针对地形的数字高程模型，在综合考虑机器人的性能约束和地形特征等因素的基础上有效地实现越野环境的建模；在此基础上的路径规划采用全局信息与局部信息、前期规划结果与当前规划相结合的方法，满足了越野环境下动态路径规划的要求。实验结果表明，该方法能够很好地适应各种复杂的越野环境。     

用势场法改进的极限环导航方法在移动机器人中的应用

结合人工势场法,提出一种新的极限环方法.它可以在诸如机器人足球赛等动态变化的环境中为自主移动机器人进行很好的实时路径规划.将障碍物的运动速度和一些不易直接表达的策略① 等转化成势场,然后把势场抽象成虚拟的障碍物,通过改变非线性方程的极限环半径,获得动态运动路径规划.这种方法能让机器人对高速运动的障碍物有很平滑的避障能力,并且能综合复杂的路径规划要求达到目标.仿真和试验都表明了这种方法在机 器人足球赛中的应用价值.􀁱 􀁽     

基于V距离势场的实时滚动路径规划

本文针对移动机器人作业环境中存在的大量未知障碍，而其传感器探测范围有限的特点，采用Ｖ距离势场，通过势场的局部增量修改，实现实时滚动路径规划，并通过仿真说明了其 有效性。     

Path planning with obstacle avoidance based on visibility binary tree algorithm

In this paper, a novel method for robot navigation in dynamic environments, referred to as visibility binary tree algorithm, is introduced. To plan the path of the robot, the algorithm relies on the construction of the set of all complete paths between robot and target taking into account inner and outer visible tangents between robot and circular obstacles. The paths are then used to create a visibility binary tree on top of which an algorithm for shortest path is run. The proposed algorithm is implemented on two simulation scenarios, one of them involving global knowledge of the environment, and the other based on local knowledge of the environment. The performance are compared with three different algorithms for path planning.     

New Potential Functions with Random Force Algorithms Using Potential Field Method

Autonomous mobile robot path planning is a common topic for robotics and computational geometry. Many important results have been found, but a lot of issues are still veiled. This paper first describes new problem of symmetrically aligned robot-obstacle-goal (SAROG) when using potential field methods for mobile robot path planning. In addition, we consider constant robot speed for practical use. The SAROG and the constant speed involve two potential risks: robot-obstacle collision and local minima trap. For dealing with the two potential risks, we analyze the conditions of the collision and the local minima trap, and propose new potential functions and random force based algorithms. For the algorithm verification, we use WiRobot X80 with three ultrasonic range sensor modules.