Double-level ball-riding robot balancing: From system design,modeling, controller synthesis,to performance evaluation

In this research, a new robot, double-level ball-riding robot, is introduced. The robot consists of an upper ball-riding subsystem and a lower ball-riding subsystem. The robot’s dynamics model can be considered separately in two identical planes. Euler–Lagrange equation of motion is applied in order to obtain the dynamics model. Motors are included in the robot’s model. The model is then linearized. The robot’s parameters are identified. The robot’s prototype is manufactured and assembled. Linear Quadratic Regulator with Integral (LQR + I) controller is proposed and applied in order to balance both levels of the robot. The complementary and orientation transformation are used to fuse sensors in order to obtain robot leaning angles. Balancing performance of the developed double-level ball-riding robot is evaluated by simulations and experiments. The results show efficient control performance of LQR + I controller.     

一种带新型自动门控电源的像增强器

针对第二代像增强器普遍存在的动态范围小,不能在强光下工作的缺点,设计了自动门控电源取代直流高压电源为第二代像增强器供电的全新方案,为提高第二代像增强器性能开辟了一条新途径。     

数据采集系统应用的高速并行A/D转换器

本文介绍了高速并行A/D转换器MAX1448在数据采集系统中的应用。     

8位液晶译码驱动MAX7232BF的原理及应用

介绍了美国MAXIM公司的液晶驱动芯片MAX7232BF．并详细论述了液晶驱动MAX7232的结构与原理。同时介绍了他的动态显示驱动时序、译码方式以及工作时序．最后给出了MAX7232BF与AT89C51的串行接口方式以及相应的程序。     

MAX3100在80C196串口扩展中的应用

介绍采用新型的UART器件MAX3100为Intel单片机80C196扩展串口，给出了硬件设计和软件编程，并对关键技术进行了说明。     

用MAXⅡ CPLD开发人体反应速度测试系统

以Ahear公司MAXⅡ器件系列中的EPM1270T144C5为核心,以QuaausⅡ7．2为软件开发平台,实现人体反映速度测试系统。该系统通过复杂可编程逻辑器件（CPLD）实时采集测试信号,由开发的软件平台分析和处理采集信号,计算反应时间,显示于LCD。通过仿真和实际测试表明,该系统最小时间误差为10^-6s,测量精度高,稳定可靠。     

The Digital Age of Mobile Cellular Network in Germany and China ：Policies,Technologies and Markets （Part Ⅰ）

The German Postal Reform I in 1989 introduced competition in the mobile cellular market. German cellular operators, DeTeMobil, Mannesmann, E-Plus and VIAG Interkom, built D1-, D2-, E1-and E2-Netze based on GSM standards made in Europe. China Unicom was created in 1994 and China Telecom was separated from MPT in 1995. China Telecom and China Unicom competed in a duopoly from the mid-1990s onwards and the cellular services provided by them also rely on GSM standards. China Telecom additionally deployed XLT technology (PHS) from the late 1990s onwards. While DeTeMobil and Mannesmann conquered approximately 80%-90% of the market throughout the 1990s and were the two dominant market players in Germany, China’s cellular market was mainly controlled by China Mobile. In Germany, prices related to cellular technology continued the downwards trend as a major result of the process of deregulation, liberalisation and competition. In China, price wars had led to significant price reductions in the cellular market. Although network operators in both countries strived to deliver differentiated cellular services, the two national markets in the 1990s were visibly shaped by product homogeneity.     

The Digital Age of Mobile Cellular Network in Germany and China：Policies,Technologies and Markets （Part Ⅱ）

The German Postal Reform I in 1989 introduced competition in the mobile cellular market. German cellular operators, DeTeMobil, Mannesmann, E-Plus and VIAG Interkom, built D1-, D2-, E1-and E2-Netze based on GSM standards made in Europe. China Unicom was created in 1994 and China Telecom was separated from MPT in 1995. China Telecom and China Unicom competed in a duopoly from the mid-1990s onwards and the cellular services provided by them also rely on GSM standards. China Telecom additionally deployed XLT technology (PHS) from the late 1990s onwards. While DeTeMobil and Mannesmann conquered approximately 80%-90% of the market throughout the 1990s and were the two dominant market players in Germany, China's cellular market was mainly controlled by China Mobile. In Germany, prices related to cellular technology continued the downwards trend as a major result of the process of deregulation, liberalisation and competition. In China, price wars had led to significant price reductions in the cellular market. Although network operators in both countries strived to deliver differentiated cellular services, the two national markets in the 1990s were visibly shaped by product homogeneity.     

基亏μC／OS-Ⅱ的高精度超声波测距系统设计

介绍一种以ARM处理器LPC2138为核心,采用超声波回波信号的A／D采样检测原理,实时测距,液晶屏显示的便携式系统。该系统利用ARM处理器处理速度快的优点,自行处理A／D采样速度。系统的测距范围在0．1-4．5m内,测量精度为1cm,实时性好,准确方便,有较高的推广价值。     

一种基于2.4GHz频段的宽带射频发射机的研制

在现代无线通信系统中,研制宽带无线发射机成为射频无线电的发展趋势。以采用ADI公司的ADF4115和MAXIM公司的MAX2750构成的锁相环路提供2880MHz的射频信号源,以ADI公司的AD9857将基带信号调制为70MHz的QPSK信号,再以MAXIM公司的MAX2671作为直接上变频器,从而可以设计出一款工作在2．4GHz频段的宽带射频发射机,从而满足红外图像信号等大信息量数据的无线传输。