二次拟合：一种提高软件可靠性模型精度的新方法

针对软件可靠性模型精度不高的问题,提出了"一次建模 + 二次拟合"的方法,通过误差补偿机制来提高模型精度,并将该方法应用于航天软件失效数据集.实践结果表明,提出的方法对于提高软件可靠性模型精度是有效的.     

批量精确套印毕业证的简便方法

打印毕业证时,在纸上已印好一些文字,留有一些空白,需在空白处打印上有关的数据,这就是套印。套印时最头疼的事是模板制作,很难与原始纸上的文字对齐。本文将为大家详细介绍一种方便而精确的制作模板,进行邮件合并批量套印毕业证方法。     

红外成像制导导弹飞行仿真研究

为了实现红外成像制导导弹更加逼真和更加有效的仿真从而验证优化红外成像制导导弹的制导效果,研究了红外成像制导导弹飞行仿真技术;讨论了导弹飞行仿真的基本要求和红外成像制导仿真系统设计的基本原理和设计方案,提出了导弹飞行效果的一些评价指标,并利用虚拟现实仿真技术实现了一个导弹飞行可视化仿真系统;分析了仿真实验结果,实验结果表明仿真系统基本满足红外成像制导导弹飞行仿真要求,在红外成像制导导弹的科学研究中有一定价值.     

以就业为导向的实训改革

本文通过在职业教育中引入"教学设计"理念和"以学生为主体、能力培养为本位"的教学思想,努力探索全方位培养学生的专业能力、社会能力、方法能力和道德情操的教学模式,特别是实训考核评价方法的创新,具有普适性和推广价值。     

Vision-guidance of agricultural vehicles

A vision guidance system has been designed, built and commissioned which steers a tractor relative to the rows of a crop such as cotton. It was required to be insensitive to additional visual noise from weeds, while tolerating the fading out of one or more rows in a barren patch of the field. The system integrates data from several crop rows, testing for image quality. At the same time, the data processing requirements have been limited by the use of frame-sequential strategies to reduce the image space which must be processed. The design has been developed to the stage where six evaluation prototypes have been installed to test farmer-acceptance. The present prototypes employ a 486 PC motherboard embedded in a custom housing, together with a 68HC11 microcomputer to which the task of closing the steering servo loop is delegated. The system shows great promise for cost effective commercial exploitation.Experimental results are reported and further sensing systems are outlined for performing related guidance tasks when vision is inappropriate.     

Three Potential Elements of Developing Nerve Guidance Conduit for Peripheral Nerve Regeneration

Autograft replaced by a nerve guidance conduit (NGC) is challenging in peripheral nerve injury because current NGC is still limited by precise conductivity and excellent biocompatibility in vivo, which influences the peripheral nerve repair even for a long lesion gap repair. Several particular elements have the potential function for nerve conductivity acceleration based on the traditional three factors of neural tissue engineering. The review aims to address three questions: 1) What is the superior factor for nerve conduction in the application? 2) How can a more conductive regenerative scaffold be constructed in vivo? 3) What is the next step in nerve regeneration for NGC? The bibliometrics analysis of NGC-related references is adopted to acquire that the conductive material, manufacturing technology of neural scaffold, and electrical stimulation (ES) play essential roles in the acceleration of nerve conduction. This review visually analyses the research status and summarizes the main types of conductive materials, the manufacturing technologies of neural scaffolds, and the characteristics of ES. The viewpoints and outlook of developing NGC are also discussed in this review. The proposed three elements are expected to improve the nerve conduction of NGC in vivo and even address the dilemma of long-distance peripheral nerve injury.     

Event-triggered-based finite-time cooperative path following control for underactuated multiple marine surface vehicles

This paper develops an event-triggered-based finite-time cooperative path following (CPF) control scheme for underactuated marine surface vehicles (MSVs) with model parameter uncertainties and unknown ocean disturbances. First, a finite-time extended state observer (FTESO) is proposed, in which the FTESO can estimate the velocities and compound disturbances in finite time. Then, the finite-time LOS guidance law based on velocity estimation values is designed to obtain the desired surge velocity and the desired yaw rate. In order to realize the cooperative control of multiple paths in finite time, the cooperative control law for the path variable is designed. In addition, the relative threshold event-triggered control (ETC) mechanism is incorporated into the formation control algorithm, and an event-triggered-based finite-time CPF controller is designed, which not only effectively reduces the update frequency of controller and the mechanical loss of actuator but also improves the control performance of system. Furthermore, by using homogeneous method, Lyapunov theory, and finite-time stability theory, it is proved that under the proposed finite-time CPF control scheme, the formation errors can converge to a small neighborhood around origin in finite time. Finally, numerical simulation results illustrate the effectiveness of the proposed control scheme.     

Utilizing Iron's Attractive Chemical and Magnetic Properties in Microrocket Design,Extended Motion,and Unique Performance

All‐in‐one material for microrocket propulsion featuring acid‐based bubble generation and magnetic guidance is presented. Electrochemically deposited iron serves as both a propellant, toward highly efficient self‐propulsion in acidic environments, and as a magnetic component enabling complete motion control. The new microrockets display longer lifetime and higher propulsion efficiency compared to previously reported active metal zinc‐based microrockets due to the chemical properties of iron and the unique structure of the microrockets. These iron‐based microrockets also demonstrate unique and attractive cargo towing and autonomous release capabilities. The latter is realized upon loss of the magnetic properties due to acid‐driven iron dissolution. More interestingly, these bubble‐propelled microrockets assemble via magnetic interactions into a variety of complex configurations and train structures, which enrich the behavior of micromachines. Modeling of the magnetic forces during the microrocket assembly and cargo capture confirms these unique experimentally observed assembly and cargo‐towing behaviors. These findings provide a new concept of blending propellant and magnetic components into one, toward simplifying the design and fabrication of artificial micro/nanomachines, realizing new functions and capabilities for a variety of future applications.     

基于输送带及视觉跟踪的机器人分拣包装工作站仿真

目的 提高分拣包装工作站的生产效率和柔性,并探索在早期设计阶段利用虚拟仿真技术进行验证。方法 以某食品公司巧克力饼干产品的生产为例,提出结合输送带跟踪和视觉识别技术搭建分拣包装仿真工作站。在ABB公司离线编程与仿真软件Robotstudio开发环境下,首先对相关设备进行了三维建模,并根据任务要求完成工作站的空间布局。其次,需要完成输送带创建、动态Smart组件设计、工作站逻辑连接、输送带跟踪功能启用、相机数据记录和机器人控制程序编写。最后,分析工作站结构得到生产节拍的参数设定公式。结果 仿真工作站实现了对持续移动输送带上杂乱摆放物料的动态跟踪分拣装盒,能依据理论计算方式调节参数满足生产节拍的需求。结论 工作站达到了预期功能目标,可以为各行各业里以机器人为中心的分拣包装系统高效、柔性生产研究提供参考与借鉴。     

砂轮平衡精度的最小二乘测试计算法

提出一种测算砂轮不平衡精度的最小二乘新方法 ,给出基本原理和具体算法 .该方法能有效抑制测量误差的影响 ,大大提高测试精度 ;并能同时测出残余不平衡量的大小和相位 .可用于各类平衡器的精度测定