共查询到20条相似文献,搜索用时 187 毫秒
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自动导引车在柔性制造业、物流业和自动仓储中具有广泛的应用前景和价值.提出并设计了一种基于CCD摄像头、RFID传感器、编码器、陀螺仪、声纳等多种传感器的自动导引车系统.通过对多种传感器数据进行信息融合达到控制目的,在实验室中搭建了模拟环境,开发了原型系统并进行测试,实验结果证明该方法提高了自动导引车系统的实时性和导航精度. 相似文献
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在食品车间使用自动导引车进行物料运输可以节省人力,避免运输中产生交叉感染。基于食品车间环境,提出一种自动导引车测控系统的设计方案。该测控系统由不同的模块组成,通过各个模块间的相互作用实现自动导引车的正确行驶及站点停靠。由于食品车间环境比较特殊,系统采用磁导航传感器和光电传感器对路径进行识别。并且叙述了使用BangBang和PID相结合的控制算法在直流电机控制上的实现,以及模糊自适应PID算法在舵机控制上的应用。 相似文献
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一种解决构件连接死锁问题的方法 总被引:1,自引:0,他引:1
隐式硬编码的基于过程调用构件连接束缚构件集成的灵活性,且存在的死锁连接造成软件可靠性隐患问题.针对该问题,首先建立基于过程调用连接器形式语义模型,显式地将连接关系从构件中分离;然后给出并通过映射规则进行连接器到构件连接有向图的转换,并设计给出两阶段死锁检查算法和基于极大复用频率死锁连接消除算法,用于找到存在的所有死锁连接回路和消除所有死锁连接需要消除的最小数目连接的位置.最后应用及实验结果表明,该解决方法可行而且有效,可以用于增强软件可靠性,同时因其从语义上分离描述和存储构件连接方式,适合以此为基础进一步设计实现适应性连接器. 相似文献
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基于时戳的分布式数据库系统中的死锁预防策略 总被引:5,自引:0,他引:5
本文讨论了分布式数据库系统中基于时戳的死锁预防策略,分析了预防死锁问题的两种可行的动态优先级方案——等待一死亡方案和伤害一等待方案,提出了使用时戳的动态优先级死锁预防策略在解决分布式数据库系统并发控制的可行性和有效性,保证了产生死锁问题的条件不能发生,从而有效的预防了死锁,并给出了相应的实例。 相似文献
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针对自动导引车(AGV)轨迹跟踪问题,在确定其可行驶区域的基础上,考虑自动导引车的大小和形状,本文设计了一种基于模型预测控制理论的轨迹跟踪控制方法.首先,将车辆运动学模型进行线性化处理,得到车辆动力学线性模型;其次,运用模型预测控制方法,利用预测路径与期望路径之间的误差,通过优化得到使性能指标最优的控制序列;最后,在MATLAB软件上对轨迹跟踪控制器进行仿真.实验结果表明,AGV可以稳定地跟踪参考轨迹,且距离偏差和角度偏差都在给定的可行范围内,证明了提出的基于模型预测控制的轨迹跟踪算法具有良好的跟踪性能. 相似文献
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通过对自动制造系统的Pctri网模型的分析.可以揭示出被模拟系统的死锁跟其初始标识和其结构有关。要想消除自动制造系统的死锁异常,可以通过修改Petri网的初始标识或Pctri网的结构来解决。该文结合具体示例,给出了具体的可操作算法并设计出了控制自动制造系统死锁的Petri网模型,从而为自动制造系统的异常处理提供了一条有效途径。 相似文献
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针对AGVS中循环死锁搜索算法研究中存在的不能搜索全部的循环死锁的问题,利用任务-资源图提出一个改进算法.改进算法如下:首先,根据AGV的相对位置关系和执行任务的情况,利用任务-资源图(Task-Resource graph,T-R图)对AGVS进行建模,然后根据循环死锁的T-R图特征,在每一个状态时刻下的T-R图使用图的强连通分支理论搜索循环死锁.当访问完所有状态时刻下的T-R图,也就找到了AGVS中的所有循环死锁.算例验证与理论分析均说明改进算法可以搜索到全部类型的循环死锁,解决了原算法存在的不足.根据改进算法开发的控制规则,可以有效避免新循环死锁的产生.同时指出,对改进算法稍加修改,可以找到AGVS中所有的循环死锁和非循环死锁. 相似文献
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《Journal of Manufacturing Systems》1998,17(4):237-250
The paper presents a control-based Petri net (PN) modeling method that translates a high-level automated guided vehicle system (AGVS) flowpath net model into a low-level on/off control model systematically. The relation between a high-level AGVS flowpath net model and the equivalent low-level control net model is uniquely defined by introducing certain I/O control functions and station control macros into the net model. To ensure the uniqueness of the translation, the AGVS flowpath layout is first decomposed into constituent basic PN flowpath modules. By employing a modular concept, the wiring layout of each basic flowpath module is established. Proper I/O control functions and station control macros are introduced and incorporated into basic flowpath net modules to generate basic control net modules. The union of constituent basic control net modules systematically leads to a complete AGVS control PN model. A laboratory AGVS is used to verify the effectiveness of the proposed modeling method. The results indicate that the proposed method is capable of generating a control model directly from a given flowpath layout. Many by-products are generated by the method: wiring layout, minimum size and specification of the controller, scanning time of the control program, and so on. These features allow a designer to quickly conduct cost estimation and performance evaluation on any given flowpath layout. 相似文献
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This short communication revisits the leaderless consensus problem in directed networks. The network topology is described by a general directed graph which is only needed to contain at least a directed spanning tree, and is not necessarily strongly connected. A bounded and smooth control law using the hyperbolic tangent function is developed as the consensus protocol. Explicit stability analysis based on Lyapunov's second method and the concept of condensation graph is given. The proposed approach transforms the leaderless consensus problem into two subproblems: reaching leader-following consensus under a graph containing a directed spanning tree with the leader being the root node and reaching leaderless consensus under a strongly connected graph. Remarkably, a perturbed system is formulated as the bridge between these two subproblems which are solved by Lyapunov's second method. The global leaderless consensus is achieved based on the stability of the perturbed system. Finally, two numerical examples are presented to illustrate the effectiveness of the proposed approach. 相似文献
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In this paper, a new control method for a planar bipedal robot, which we call Graph-based Model Predictive Control, is proposed. This method makes use of a directed graph constructed on the state space of the robot. The vertices of the directed graph are called waypoints, and they serve as intermediate target states to compose complex motions of the robot. By simply tracing the directed edges of the graph, one can achieve Model Predictive Control over the waypoint set. Such a directed graph is pre-designed and stored into the controller’s memory to significantly reduce the computational effort required in real time. In addition, by constructing multiple directed graphs based on different objective functions, one can design multiple motions and switching trajectories among them in a uniform way. The proposed method is applied to variable-speed walking control of a bipedal walker on a two-dimensional plane, and its effectiveness is verified by numerical simulations. 相似文献
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基于图论的路网交通检测器之布点 总被引:1,自引:0,他引:1
为获取各路段的交通流量,将路网检测器布点问题转变成寻求有向图的流控制子图的问题.首先将任意路网抽象为有向图,定义弧的度表征路段的重要性,证明完全有向回路图(CCG)的若干结论后给出CCG最小流控制子图的获取算法,同时给出有向图非回路部分的流控制子图获取方法,进而提出能在任意路网上进行检测器优化布点的完整算法.算例选取广州火车东站附近的路网,结果验证了所提出的方法的有效性. 相似文献
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多智能体沿多条给定路径编队运动的有向协同控制 总被引:2,自引:1,他引:2
研究了在有向通信连接下二阶积分器描述的多智能体沿多条给定路径编队运动的控制器设计及其稳定性分析问题. 智能体的动态和指定路径都是在固定直角坐标系下描述的. 通过引入路径函数来设计路径跟踪控制, 根据路径函数与弧长的关系来设计编队控制律, 使得多智能体沿期望路径的位置和速度在规定队形下达到一致. 利用图论证明, 当通信拓扑对应的有向图具有全局可达点时, 设计的编队控制系统是渐近稳定的. 本文设计的有向协同控制律可以应用于区域的信息优化采集. 相似文献
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Distributed containment control for Lagrangian networks with parametric uncertainties under a directed graph 总被引:2,自引:0,他引:2
In this paper, we study the distributed containment control problem for networked Lagrangian systems with multiple dynamic leaders in the presence of parametric uncertainties under a directed graph that characterizes the interaction among the leaders and the followers. We propose a distributed adaptive control algorithm combined with distributed sliding-mode estimators. A necessary and sufficient condition on the directed graph is presented such that all followers converge to the dynamic convex hull spanned by the dynamic leaders asymptotically. As a byproduct, we show a necessary and sufficient condition on leaderless consensus for networked Lagrangian systems under a directed graph. Numerical simulation results are given to show the effectiveness of the proposed control algorithms. 相似文献
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