A3972在步进电机控制系统中的应用

介绍了步进电机工作原理,对步进电机驱动芯片A3972做了详述,以C8051F320单片机为控制器,基于A3972设计了一种步进电机控制系统,实现了软硬件相结合的控制方法,用软件代替脉冲分配器,从而达到对步进电机的最佳控制。     

步进电机驱动控制的应用研究

针对步进电机的控制以及研究，我们先了解步进电机的基本的构造、特性以及步进电机的基本工作原理。其实步进电机是一种用脉冲来完成机械的位移加工的一种机电设备，它能够实现良好的精确的定位，并且它利用控制在加工过程中并没有累积的误差。在各种用途当中，它的性价比都是比较高的，在各种行业里面都得到了广大应用。所以在针对它的应用要求，于是就开发了多款的驱动控制器，同时我们为了研究步进电机可以将单片机帮助实现芯片的自动化拍照。     

步进电机驱动控制的应用研究

针对步进电机的控制以及研究，我们先了解步进电机的基本的构造、特性以及步进电机的基本工作原理。其实步进电机是一种用脉冲来完成机械的位移加工的一种机电设备，它能够实现良好的精确的定位，并且它利用控制在加工过程中并没有累积的误差。在各种用途当中，它的性价比都是比较高的，在各种行业里面都得到了广大应用。所以在针对它的应用要求，于是就开发了多款的驱动控制器，同时我们为了研究步进电机可以将单片机帮助实现芯片的自动化拍照。     

步进电机闭环控制的研究与探讨

<正>引言步进电机作为一种数字式的执行元件, 在运动控制中得广泛应用。其电机本体、步进驱动器、步进控制器构成步进控制系统不可分割的三大部分。步进系统的主要优点之一是能在开环系统中工作,这种运行方式由于控制线路经济简单,不需反馈编码器和相应的电子线     

单片机在对步进电机的控制

本文利用80C51单片机的输出口向五相步进电动机传送控制信号,采用软件法对单片机的输出控制信号进行脉冲分配,从而驱动步进电动机转动,实现对步进电机的方向、速度的控制.     

基于PLC的步进电机调速和正反转控制系统

本文阐述三相步进电动机结构与步进过程原理,以及对步进电动机的调速和正反转研究,采用PLC基本逻辑指令和常用指令的方法对步进电动机的调速和正反转控制,经过对步进电机的通电方式和步距角的计算研究,用可编程控制器进行硬件和软件设计,可用于数控机床步进电机的调速控制。     

基于STM32步进电机控制器的设计研究

随着工业和科技的发展,嵌入式控制系统也越来越受到人们生产生活的青睐,其拥有强大的处理、控制的性能的同时还有着低功耗,体积小等特点。本设计选用基于ARM Cortex-M3内核的STM32芯片作为主控芯片,外围电路包括红外接收模块,电机驱动器;该系统的控制流程是通过红外遥控模块发送指令,STM32接收指令并向步进电机驱动模块发送相应的脉冲。驱动模块通过细分等操作驱动步进电机完成所需的动作特性;程序在MDK环境下进行编程,通过程序实现不断扫描红外遥控是否发出指令,发出什么指令,从而根据扫描的结果使步进电机产生相对应的动作如正转、反转、加速、加速等动作,再由测试软件算法估算出电机的速度。实验结果表明,该系统的稳定性和步进电机各项运动指标均满足要求。     

步进电机一体化控制系统的设计

作为一种数字伺服执行元件,步进电机具有结构简单、运行可靠、控制方便、控制性能好等优点,广泛应用在数控机床、机器人、自动化仪表等领域。为了实现步进电机的简易运动控制,一般以单片机作为控制系统的微处理器,通过步进电机专用驱动芯片实现步进电机的速度和位置定位控制。     

步进电机均匀细分驱动器的设计与实现探讨

在对步进电机细分驱动原理进行分析研究的基础上,提出一种基于FPGA控制的步进电机细分驱动器。利用FPGA中的嵌入式EAB构成LPM-ROM,存放步进电机各相细分电流所需的PWM控制波形数据表,并通过FPGA设计的数字比较器,同时产生多路PWM电流波形,实现对步进电机转角进行均匀细分控制。     

基于dsp f2812的能量回馈调速系统

节能调速系统是基于电机专用控制dsp控制器-tms320f2812设计的,主电路由三相不可控整流桥、智能功率模块ipm和有源逆变装置组成.采用电流转速双闭环矢量控制方式进行调速,对有源逆变装置采用电压和电流内环相结合的双闭环串级控制方式,对功率因数进行校正,实现能量回馈,节省能源.     

基于工艺改进的高效电机损耗降低研究

结合高效效率的检测,从降低电机总损耗的角度,分别针对定子铜耗、铁耗、转子铜耗、杂散耗、机械耗提出电机生产工艺的改进措施,经生产实践证明能有效降低高效电机的损耗,有效提高了电机的能效水平。     

Service Contract Negotiations in Marketing Channels:

This study investigates the factors that influence motor carriers perceptions of the success of negotiations with customers over contractual transportation service in marketing channels. The findings indicate that the motor carrier's perceived success of the negotiation is influenced directly by his/her trust of the customer, and indirectly by the customer's dependence on his/her organization. The results also suggest that though the nature of contract negotiation for motor carriage service has become more cooperative in the deregulated environment, a certain degree of opportunism still influences the negotiator's behaviors. From these findings, issues are presented which can aid the channel members in developing successful strategy for future negotiation with motor carriers.     

进口机动车智能服务平台的研究与应用

通过对现有模式存在问题的分析,提出了利用无线射频技术、物联网技术以及信息化技术构建智能化服务平台的解决方案。在全面整合进口机动车管理资源的基础上,创新进口机动车检验监管工作模式,研究并应用进口机动车智能服务平台,实现了宏观管控、规则管理、登检核销、检验操作、公众查询、售后维修、后续监管等功能,构建了进口机动车物流、检测及后续监管服务体系,形成了进口机动车全过程智能化的“一点通”服务模式。达到了改善通关环境,提高通关效率,促进贸易便利化的目标。     

一种改进的重置成本法在旧机动车价格评价体系中的应用

旧机动车属于固定资产机器设备的一类产品,对旧机动车的评估也是以资产评估理论为基础,评估中重置成本法具有更多的优点和更广阔的适用范围,因此本文选择重置成本法作为旧机动车评估的理论依据.将原有的重置成本法公式进行改进,对成新率的综合调整系数采用了英国运筹学家赛特(T.L.Saaty)提出的层次分析法进行确定.文章详细介绍了这一种改进的重置成本法,并通过实例进行了实际应用.     

A New Look at the Longitudinal Relationship Between Motor Carrier Financial Performance and Safety

Motor carrier safety impacts the well‐being of the traveling public and the economic well‐being of the shippers who entrust motor carriers with safely transporting freight. Shippers are affected by motor carrier safety due to accidents damaging their cargo and disrupting their customers’ operations. One characteristic frequently theorized to predict motor carrier safety is motor carriers financial performance. However, the literature offers mixed evidence linking motor carrier financial performance to safety. This does not help practitioners or policy makers and necessitates research to resolve these inconsistent findings, which we undertake in this research. We extend previous work by developing a theoretical framework based on strain theory to explain why both absolute (static) financial performance and year‐to‐year change in financial performance should uniquely affect carrier safety. We test our hypotheses by fitting mixed‐effects models to a repeated‐measure, longitudinal database of publically traded motor carrier financial performance and safety measures. Results indicate that financial performance measures uniquely affect carrier safety. These findings attempt to resolve the inconsistencies in the past literature and, carry important implications for researchers studying motor carrier safety, motor carrier managers, shippers, and policy makers.     

A Multivariate Time‐Series Examination of Motor Carrier Safety Behaviors

Motor carriers’ operational safety affects multiple stakeholders including truck drivers, motor carriers, insurance companies, shippers, and the general public. In this article, I devise and test theory regarding motor carriers’ longitudinal performance for three classes of safety behaviors linked to carriers’ accident rates—Unsafe Driving, Hours‐of‐Service Compliance, and Vehicle Maintenance—tracked by the Federal Motor Carrier Safety Administration as part of the Compliance, Safety, and Accountability (CSA) program. Specifically, I draw on core concepts from sociological agency theory and resource dependency theory to devise middle‐range theory that generates never‐before‐tested hypotheses regarding carriers’ longitudinal safety performance for these classes of safety behaviors after the start of the CSA program. The hypothesized predictions are tested by fitting a series of multivariate latent curve models to four years of panel data for a random sample of 484 large, for‐hire motor carriers operating in the United States. The empirical findings corroborate the theoretical predictions and remain after robustness testing. These findings have important implications for scholars, motor carrier managers, procurers of motor carrier transportation services, and public policy makers.     

电流法在天线传动系统故障及跟踪性能分析中的应用

分析了天线传动系统影响电机电流特性的因素。提出了天线正常跟踪卫星的电流特性 标准,电流在6 A以下属于正常范围。利用电机电流分析法,对测控天线传动系统的周期性 故 障、阻尼增大故障以及系统级故障进行定位判断,提出了产生故障的因素。同时,分析了上 述 三类故障对测控天线的跟踪性能的影响。结果表明,电机电流分析法可以对天线传动系统的 故障进行预判断,有效避免系统级故障的发生,确保天线运行在良好的跟踪状态。     

基于TMS320F2812的步进电机SVPWM细分驱动

利用数字信号处理器TMS320F2812的外设事件管理器实现硬件空间矢量脉宽调制(SVPWM)算法,并结合细分驱动技术,实现了对三相步进电机的驱动及起停、调速等功能的控制。实验结果表明,电机运行平稳顺畅。     

Cognitive motor coordination training and the improvement of visual‐spatial cognition in office work

It has been shown that motor coordination training can enhance performance in spatial cognition tasks. This was investigated in an applied setting. Twenty‐eight office workers attended either cognitive motor coordination training or core‐stability training for one hour every week for six weeks. Before and after training, mental rotation and spatial visualization as well as cognitive processing speed were measured. Results showed a significant improvement in both spatial tasks after the cognitive motor coordination training but not in the general cognitive measurement. Core‐stability training did not impact either of these dependent variables. It is concluded that motor coordination training can be a useful supplement for working environments where spatial cognition is essential, such as architecture or surgery.     

Developing and Testing a Dynamic Theory of Motor Carrier Safety

Developing an understanding of the longitudinal relationships between different measures of motor carrier safety is important to advance theory and practice regarding this significant supply chain management and public policy issue. In this article, we combine core principles from several theoretical traditions to propose a dynamic theory of motor carrier safety that specifies the longitudinal relationships between three core measures of safety publically reported by the Federal Motor Carrier Safety Administration: unsafe driving, hour‐of‐service compliance, and vehicle maintenance. We test this theory using four years of longitudinal data on motor carrier safety for a random sample of large, for‐hire motor carriers. Results from fitting a vector multivariate autoregressive moving average time‐series model are largely consistent with the theory we propose. We describe the implications of our research for supply chain management theory and practice, summarize limitations, and suggest directions for future research.