关于AGV稳定性的探究

制丝车间成品库主要通过AGV小车将成品烟丝运送到指定站台,以达到不间断的对卷包车间提供成品烟丝的目的。AGV装备有电磁或光学等自动导引装置,能够沿规定的导引路径行驶。AGV运行的稳定性直接关系到成品库与卷包车间的衔接,激光导引和障碍物探测器是整个AGV最为关键的装置。经过长时间的使用,AGV会出现在一些区域无法准确定位,并且不能明确区分障碍物的情况。对激光导引的位置修正,对障碍物探测器的校准势在必行。本文主要介绍激光导引和障碍物探测的工作原理,以及校准方法。     

红外反射式传感器在自主式寻迹小车导航中的应用

本文介绍了利用红外反射式传感器实现小车自动寻迹导航的设计与实现。自动寻迹是基于自动导引小车(AGV—auto guidedvehicle)机器人系统 ,用以实现小车自动识别路线 ,判断并自动规避障碍 ,以及选择正确的路线。实验中采用与地面颜色有较大差别的线条作引导 ,使用反射式红外传感器感知导引线和判断障碍物。系统控制核心采用AT89C2 0 5 1单片机 ,系统驱动采用控制方式为单向PWM的直流电机。该技术可以应用于无人驾驶机动车 ,无人工厂、仓库、服务机器人等领域。     

AGV混合导引系统的研究与实现

AGV混合导引系统结合了电磁导引与射频识别(Radio Frequency Identification,RFID),并使用3种不同的路径选择方法实现了系统的导航功能。该系统对AGV硬件电路及导航信号源进行了精密设计,同时实现了包括无线通信的软件控制系统及四级保护的安全开发系统。测试结果显示,系统的测量与控制信号具有较高的精度和稳定性,AGV混合导引系统解决了国内电磁导航技术不能适应复杂路径的局限性,在导航、定位和路径规划上实现了技术突破,提高了AGV的生产效率。     

考虑冲突避免的多AGV路径规划研究

目的 提高物流企业“货到人”拣选系统在实际生产中的工作效率，避免自动导引小车(AGV)间的冲突死锁，研究大规模多AGV的无冲突路径规划和协同避障问题。方法 首先考虑AGV空载、负载情况和路径扩展成本，改进A^*算法，动态调整代价函数，优化路径扩展方式。其次，提出冲突检测及避免算法，对可能产生局部冲突的路径交叉点进行避障调度，通过预约锁格，实现局部冲突的检测，制定优先级避障策略，解决AGV动态行驶路径上产生的局部冲突和死锁，进而实现全局无冲突路径规划。结果 对多组不同任务量和不同AGV规模的场景进行仿真，实验结果表明，考虑冲突避免的改进A^*算法能有效实现100个任务、90个货架单位和7个拣选站场景下的多AGV动态路径规划，相较于传统A^*算法，其平均拣选时长缩短了52.61%。结论 该方法可实现大规模场景下的多AGV动态路径规划，在付出较小转弯代价的同时有效避免局部动态冲突，该方法可为相关企业实现多AGV协同调度提供新的思路和理论依据。     

二维码导引系统的研究与实现

为了对用户在场馆中提供快捷有效的导引服务,区别于传统导引标牌,提出一种二维码导引系统,使用户可以通过手机拍摄的方式获取导引信息。与传统导引方式相比,本文系统有更人性化的交互方式,提供更丰富的信息,维护更方便,部署也更简单。实验结果证明了该系统的可行性和实用性。     

浅谈AGV行驶地面要求

近年来,国内外各工业企业多在建造物流系统中引进AGV（即无人导引自动小车）,为了适应AGV自身性能的要求以及为了使之能更好地运行以降低设备故障率,本文介绍了一种适合AGV行驶的地面设计要求。     

重载AGV在机车检修行业中的应用

本文通过分析物流运输和机车检修的现状和发展趋势,提出了一种应用于高级检修车间的重载AGV,介绍了其主要系统架构。本类重载AGV的硬件结构以可编程控制器为核心,接受处理信息并发送指令;通过地面磁条和磁传感器实现精准导引,PC端上位机实时接收位置信息,监控AGV运行状态,具有高灵活性、高准确性和高承载力等特点,可有效提高机车检修效率,优化检修系统结构。     

喷流导引系统的实际应用

主要介绍了喷流导引系统在地下车库通风工程设计中的应用，并着重介绍了该系统的原理优点及设计要点。     

磁带导引AGV的自抗扰循迹控制方法

本文研究了磁带导引自动导引小车(AGV)的循迹控制问题,设计了一种线性自抗扰控制器,以达到AGV精准循迹、抗干扰能力强的控制要求。首先,建立了磁带导引AGV循迹误差系统的数学模型,将循迹控制系统的不确定动态描述为系统的加性总和干扰,通过设计扩张状态观测器对这些干扰量进行实时估计,进一步,设计线性自抗扰控制器对这些干扰进行动态线性化补偿,从而降低AGV循迹模型的不确定性及循迹过程中外部随机干扰对循迹控制性能的影响。最后,搭建了磁带导引AGV实验平台,并在该平台上验证了所提出方法的有效性和优越性。     

基于贝塞尔轨迹的视觉导引AGV路径跟踪研究

为提高视觉导引自动导引车(automatic guided vehicle,AGV)路径跟踪精度,提出一种基于贝塞尔轨迹的精确路径跟踪算法。该算法首先将采集的多种路径特征图像进行预处理得到形状信息,训练SVM多层路径形状特征分类器;然后根据命令,改变AGV采集到的分支路径图像的权重,迭代计算所选择路径的若干最小内接圆;最后,利用最小二乘规则,将最小内接圆的圆心拟合成贝塞尔轨迹,实现AGV的精确路径跟踪。将该算法应用于视觉引导AGV中,并进行路径特征的在线识别和轨迹跟踪实验。结果表明:路径特征的识别准确率为99.7%以上,识别时间约为22 ms,弯道轨迹跟踪准确度为20 mm和20°;与传统方法相比,该方法显著提高路径特征识别和轨迹跟踪的准确率,更能满足工业现场需求。     

基于IGPS和麦克纳姆轮的AGV导航控制系统设计

目前常规使用的舵轮和差速轮自动导引车（automated guided vehicle,AGV）的精度和灵活性低,无法满足在大型高端产品装配过程中精确定位和导航的要求。为了进一步提高AGV的导航精度和柔性,提出了一种基于IGPS （indoor global positioning system,室内全球定位系统）和麦克纳姆轮的AGV高精度导航控制系统。首先通过IGPS高精度定位和坐标计算获取IGPS接收器的位置坐标,其次采用车体中心提取算法和坐标转换矩阵实现接收器坐标位置到车体中心坐标的转换,最后通过对全向移动AGV的建模,采用模糊PI控制方法对AGV的路径偏差进行纠正,实现AGV的精确定位和循迹导航。利用Simulink对模糊PI控制和传统PI控制进行仿真分析,结果表明,相对于传统PI控制,模糊PI控制响应速度快,调整曲线更平滑。同时,在基于IGPS的AGV试验平台进行试验,采用激光跟踪仪对AGV重复定位位置进行测量,结果显示定位精度达到±0.2 mm。研究结果对提高AGV的高精度定位能力具有借鉴意义,也为后续可移动机器人加工模式的研究提供参考。     

Deadlock prediction and avoidance based on Petri nets for zone-control automated guided vehicle systems

Deadlock problems of zone-control uni-directional automated guided vehicle (AGV) systems are discussed in this paper. Deadlocks of two types in such AGV systems are first classified from the perspective of shared resources, i.e. guide-path zones and buffers. A special class of Petri nets, attributed Petri nets (APN), is defined and used to represent the current state and to generate future states of zone-control AGV systems. We propose an algorithmic procedure to predict in real time and to avoid deadlocks that are caused by sharing guide-path zones in zone-control AGV systems. The proposed algorithm utilizes the current system state and future predicted states to avoid deadlocks. These states are obtained and generated from the obtained APN. A modular approach is employed to facilitate the construction of APN models of zone-control AGV systems.     

Performance evaluation of tandem and conventional AGV systems using generalized stochastic Petri nets

This paper investigates the different policies and concepts followed in the traffic management of automated guided vehicle (AGV) systems, and develops the controls for automatically eliminating potential vehicle conflicts in an AGV system. The planning of the AGV system is performed in such a way that there are no conflicts or deadlocks for the vehicles using stochastic Petri nets (SPNs). The major effort is devoted to determining the benefits of the tandem AGV control in comparison with the conventional AGV control method. SPNs have been used to model the different designs of flexible manufacturing systems (FMSs) and with different policies for the movement of material, vehicle path control, inventory planning and tool control. The SPN model is solved and the performance of the system can be evaluated. In this study, the effort is directed to model an FMS with two different types of AGV traffic management methods, namely the conventional and tandem AGV control. A SPN program is used which takes the FMS Petri net model as the input and evaluates the different properties of the Petri net. Finally the performance measures are obtained, which helps in evaluating and comparing the two different AGV traffic management methods.     

Conflict resolution in AGV systems

Currently, conflict-free routing in AGV systems is established by means of one of the following three approaches: (i) the problem elimination through the adoption of a segmented path flow or tandem queue configuration; (ii) the identification of imminent collisions through forward sensing and their aversion through vehicle backtracking and/or rerouting; or (iii) the imposition of zone control and extensive route pre-planning, typically based on deterministic timing of the vehicle traveling and docking stages. Among these three approaches, the segmented path flow-based approach presents the highest robustness to the system stochas-ticities/randomness, but at the cost of restricted vehicle routings and the need for complicated handling operations. This paper proposes an alternative conflict resolution strategy that will ensure robust AGV conflict resolution, while maintaining the operational flexibility provided by free vehicle travel on arbitrarily structured guidepath networks. Specifically, the approach advocated in this paper also employs zone control, but it determines vehicle routes incrementally, one zone at a time. Routing decisions are the result of a sequence of safety and performance considerations, with the former being primarily based on structural/logical rather than timing aspects of the system behavior. The resulting control problem is characterized as the AGV structural control. After defining the notion of AGV structural control, the paper proceeds to the formal characterization and analysis of the problem, and to the development of a structural control policy appropriate for the class of AGV resource allocation systems. The paper concludes with some discussion on the accommodation of emerging AGV operational features in the proposed modeling and analysis framework, and the integration of AGV structural control with the broader control of material-flow among the shop-floor workstations.     

A neural algorithm for finding the shortest flow path for an automated guided vehicle system

The automated guided vehicle (AGV)system is emerging as the dominant technology to maximize the flexibility of material handling, while increasing the overall productivity of manufacturing operations. This paper presents a new way of finding the shortest flow path for an AGV system on a specific routing structure. An optimal solution of the system is determined by using an approach based on the Hopfield neural network with the simulated annealing (SA) procedure. In other words, the proposed approach reduces the total cost of an AGV delivery path from one workstation to another on the shop floor. By changing the temperature of the two-stage SA, a solution can be found that avoids potential collisions between AGVs. Both the flow path and the potential collision, which are major problems in AGV systems, may be solved simultaneously by the proposed neural network approach. Other advantages offered by the proposed method are its simplicity compared with operations research (OR)methods and a decreased number of needed AGVs. The performance of the approach is also investigated.     

Tandem Configurations for Automated Guided Vehicle Systems and the Analysis of Single Vehicle Loops

Automated Guided Vehicle (AGV) systems continue to play a significant role in many low to medium flow manufacturing operations, including Flexible Manufacturing Systems (FMS) and other applications. The relatively inexpensive guidepath, coupled with the high degree of flexibility and control offered in vehicle routing, has made AGV systems a proven and viable handling technology for the 90's.

Traditionally, AGV systems have been implemented and analyzed assuming that every vehicle is allowed to visit any pick up/deposit point in the system. We introduce a conceptually simple and intuitive approach where the system is decomposed into non-overlapping, single-vehicle loops operating in tandem. In this paper, we also develop an analytical model to study the throughput performance of a single vehicle loop. The resulting expressions are the first closed form analytical expressions that have been obtained to determine the throughput capacity of a single vehicle operating under a specific dispatching rule in a non-deterministic environment.     

自动导引车模型设计

 自动导引车(AGV)的实现是智能移动机器人研究的重要内容之一． 阐述了自动导引车系统(AGVS)的构
成及工作原理，在此基础上对试验型AGV 模型的功能结构与硬件配置进行了详细的设计，并从软件上得以实现．
通过测试，表明该AGV模型达到了预期效果，为工业应用AGVS的开发提供了参考．     

Deadlock avoidance in an automated guidance vehicle system using a coloured Petri net model

This paper addresses the problem of deadlock control in automated guided vehicle (AGV) systems for automated manufacturing systems with unidirectinal guided paths. First, a Petri net (PN) model was developed for the problem. Then, by using the PN model developed, the condition for deadlock-free operation in AGV system and a control law are presented. To avoid deadlocks in AGV systems by this law, one needs only to observe the state of the system and check the number of free spaces available in some of the circuits. It is estimated that the proposed control law is simple enough to be used in the real-time control of contemporary system configuration. Three examples are used to show the application and efficiency of the proposed control law.     

一种用于自动导引车(AGV)的超声波导航系统

设计了一种用于自动导引车（AGV）的超声波导航系统，介绍了系统的工作原理及结构，并进行了各项导航功能的样车实验，实验数据表明：系统可适应AGV的工作特点，可用于CIMS中固定及自由路径模式的AGV。     

Conflict detection of automated guided vehicles: a Petri net approach

This research project investigates and develops techniques for automatically detecting potential vehicle conflicts in an automated guided vehicle (AGV) system. Three activities are involved: (1) construction of a set of formal definitions of Petri nets for modelling AGV systems; (2) development of procedures for detection of vehicle routeing conflicts; (3) development of a simulation program of the procedure. In this paper the first two activities are discussed in detail, and examples are provided.