Revisiting the Parallel Strategy for DOACROSS Loops

Journal of Computer Science and Technology - DOACROSS loops are significant parts in many important scientific and engineering applications, which are generally exploited pipeline/wave-front...     

Fixed-time synchronization criteria for complex networks via quantized pinning control

In this paper, fixed-time (FDT) synchronization of complex networks (CNs) is considered via quantized pinning controllers (QPCs). New control schemes with logarithmic quantization are designed, which not only can reduce control cost but also can save channel resources. The QPC with sign function can be used more generally than the QPC without sign function, but the QPC without sign function can be utilized to overcome the chattering phenomenon in some existing results. Based on designed Lyapunov function and different control schemes, several FDT synchronization criteria expressed by linear matrix inequalities (LMIs) are presented. Moreover, a numerical example is presented to illustrate the theoretical results.     

F-OFDM仿真系统设计与时频同步算法

针对新一代5G波形的F-OFDM技术开展了研究,通过把一个宽带分为若干个子带,对每个子带进行滤波处理以实现更好的通信效能。基于Simulink平台进行了F-OFDM仿真系统的搭建,重点对F-OFDM符号同步方法和频偏估计方法进行了研究与仿真分析。实验结果表明,基于Chu序列相比采用PN序列可以获得更好的同步效果,基于导频的Classen频偏估计算法相比基于CP的CFO估计算法和基于训练序列的Moose估计方法可以获得更好的频偏估计效果。     

Robust distributed attitude synchronization of multiple three-DOF experimental helicopters

Multiple experimental three-degrees-of-freedom (three-DOF) helicopters that are equipped with active disturbance systems constitute an attractive platform to validate robust control strategies. In this paper, a distributed synchronization controller is developed for such a platform, where each helicopter is subjected to unknown model uncertainties and external disturbances, and the desired trajectories are generated online, communicated through a network and not accessible by all helicopters. The controller is composed of a continuous tracker and a continuous uncertainty and disturbance estimator (UDE). The tracker makes the nominal closed-loop system globally asymptotically stable, and the UDE output is used to reject total uncertainties. The conditions that ensure zero-error tracking for each helicopter are identified; for the case with nonzero error, explicit relationship inequalities between the involved design parameters and the ultimate bound of error are revealed. Experimental results of four cases demonstrate improved tracking and synchronization accuracy of using the UDE with small parameters.     

摇篮式五坐标加工中心C轴转台旋转故障原因分析与处理

针对HS664RT,摇篮式五坐标加工中心力矩电动机驱动的C轴转台故障,介绍了故障排查、处理方法和力矩电动机相位角同步设置步骤。     

多点驱动带式输送机功率平衡机制研究

针对多点驱动带式输送机功率不平衡降低输送效率及生产寿命问题,对多电机间的协调控制进行研究。对传统偏差耦合多电机协调控制结构进行了改进,增加了基于转速功率控制的同步误差补偿器,通过求取所有电机的平均转速和单台电机的转速差,利用PI控制器,同时结合每台电机的系统转速跟踪误差,反馈补偿到每台电机的控制回路进行多电机协调控制。仿真结果表明,系统可以在负载变化扰动的情况下有效降低各电机的同步误差,特别是对系统刚启动时负载不均衡导致的电机功率不平衡问题,改进结构可以有效实现多电机间的功率平衡分配。     

一种新型随钻轨迹仪的研制

针对现有随钻轨迹仪工作时间短、需人工同步、"数钻杆"记录钻孔深度不足等问题,采用深度实时测量技术、电源智能管理技术和数据自动同步与成图等关键技术,研制了新型随钻轨迹仪。该仪器由直线位移传感器、压力传感器、霍尔开关等组成,具有钻孔深度自动测量、电源智能管理、测量数据与深度自动匹配等功能。试验结果表明:新型钻孔轨迹仪工作稳定可靠、无需人工干预、工作时间长、生产效率高。     

Scalable Clock Synchronization Analysis: A Symmetric Noncooperative Output Feedback Tubes-MPC Approach

In the cyber-physical environment, the clock synchronization algorithm is required to have better expansion for network scale. In this paper, a new measurement model of observability under the equivalent transformation of minimum mean square error (MMSE) is constructed based on basic measurement unit (BMU), which can realize the scaled expansion of MMSE measurement. Based on the state updating equation of absolute clock and the decoupled measurement model of MMSE-like equivalence, which is proposed to calculate the positive definite invariant set by using the theoretical-practical Luenberger observer as the synthetical observer, the local noncooperative optimal control problem is built, and the clock synchronization system driven by the ideal state of local clock can reach the exponential convergence for synchronization performance. Different from the problem of general linear system regulators, the state estimation error and state control error are analyzed in the established affine system based on the set-theory-in-control to achieve the quantification of state deviation caused by noise interference. Based on the BMU for isomorphic state map, the synchronization performance of clock states between multiple sets of representative nodes is evaluated, and the scale of evaluated system can be still expanded. After the synchronization is completed, the state of perturbation system remains in the maximum range of measurement accuracy, and the state of nominal system can be stabilized at the ideal state for local clock and realizes the exponential convergence of the clock synchronization system.      

基于AMESim和Simulink的液压升降台同步控制仿真研究

采用AMESim和Simulink仿真软件对升降台液压系统同步协调控制进行了仿真比较分析.仿真结果表明采用主从式同步控制策略能够达到很好的同步效果,同步精度达到±1 mm,为实际升降台同步顶进提供了参考依据.     

刨煤机工作面加面探索与实践

对刨煤机工作面加面工艺进行了系统介绍,对合理的煤炭资源开采提供了更好的解决办法,并针对薄煤层开采设备特殊性作了细致的阐述。