标题: | 智慧型自动导引车于动态环境中之自主式导航 Autonomous Navigation of an Intelligeot Mobile Robot in Dynamic Environments |
作者: | 张智超 Chang, Charles!C. 宋开泰 Kai-Tai Song 电控工程研究所 |
关键字: | 自动导引车;反应式导航;动态环境;环境模型建立;学习法则;自我定位;mobile robot;reactive navigation;dynamic environment;world modeling;learning algorithm;self-localization |
公开日期: | 1996 |
摘要: | 智慧型自动导引车必须能在动态、非结构化的环境中自主导航。在动态环 境中,能正确 估测障碍物的运动资讯对导航控制非常重要。由于现今的 车上感测器要即时地获取显式 (Explicit)的运动资讯有所困难,因此 我们提出使用环境预测器来取得内隐式(Implicit)的障碍物运动资讯。 这个预测器是由类神经网路所构成,并以本文所发展出的相对误差倒传( Relative Error Back-propagation ) 法所训练。藉由车上多个超音波感 测器与 CCD摄影机,它可以有效预测出动态障碍物的未来动向,提供导航 控制做预防的措施。为了达成同时应付多个动态障碍物,本文以虚拟力的 概念发展出对应前述环境预测器之导航法则。在路径规画部份,本文发展 出基于双向距离转换法(Bidirectional Distance Transform) 的路径规 画器。使用这个快速规画方法可使路径能在线上修改,所以在遇到非预期 情况时自动导引车也能显出平顺的运动。本文所发展之格子地图(Grid- map) 式的环境模型以多种感测 穈T资讯融合而建构,使得自动导引车拥 有学习能力。关于室内环境中的自我定位是融合了来自编码器、陀螺仪、 CCD 摄影机、和多个超音波感测器的资讯来达成。对于所发展的导航方法 ,论文 中提出了模拟和实验的结果。 An intelligent mobile robot should be able to navigate itself in dynamic and unstructured environments. In such circumstances, the motion of moving obstacles need to be estimated. Due to the difficulties for present-day on-board sensor system to get explicit motion information in real time, we propose to construct an environment predictor to obtain implicit motion information. Multiple sensors including ultrasonic rangefinders and a CCD camera are used to obtain motion prediction. The predictor is constructed by artificial neural networks, which are trained by a relative-error-backpropagation algorithm developed in this dissertation. To handle multiple moving obstacles, a reactive navigation method is developed to work with the predictor based on virtual force concept. Using the developed bidirectional distance-transform path planner, the planned path can be modified on-line based on a learned world model. A method is proposed for absolute position estimation in an indoor environment. Fused sensor data from encoders, gyroscope, CCD camera, and ultrasonic sensors are used to accomplish self-localization. Simulation and experimental results are presented to verify the proposed methods. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#NT850327066 http://hdl.handle.net/11536/61725 |
显示于类别: | Thesis |