High Synchronization Accuracy Research Articles

Precision time synchronization control method for smart grid based on wolf colony algorithm

Abstract In order to satisfy the high accuracy and high security requirements of time synchronization in smart grid, this paper has conducted a research on high-precision time synchronization control algorithm based on IEEE 1588 protocol. A slave clock model is built considering both phase offset and frequency drift. A novel approach using proportional–integral–derivative (PID) controller in cooperation with the wolf colony algorithm (WCA) is proposed to eliminate the offset of the slave clock with respect to the master clock. As a new swarm-intelligence algorithm, WCA is introduced for self-tuning the optimal parameters of the PID controller, which simulates the intelligent predatory behaviors and prey distribution rule of the wolf colony. The WCA-based PID control approach is compared with the method based on standard Particle Swarm Optimization (PSO) and Back-Propagation (BP) neural network. The experimental results show that the proposed WCA-based PID control approach in time synchronization for smart grid has higher precision, can adaptively adjust compensation and keep the master–slave clock synchronization effectively.

双马达旁路补偿同步控制行走系统的研究

为了提高静液驱动主动式铲运机行走控制系统的响应速度和直驶稳定性，针对大功率马达速度同步控制系统的同步精度低、响应速度慢的特点，结合交叉耦合控制与大功率阀泵并联调速系统提出了旁路补偿同步控制方案，即将子通道状态差值反馈信号直接作用于旁路设置的比例阀，以此来调节马达进油流量，达到同步误差补偿作用。建立了旁路补偿容积调速同步系统的数学模型，在Matlab/Simulink环境中进行仿真并对比相同控制条件下的容积调速同步控制方案。结果表明：该方案在承受稳定偏载及动态负载情况下的同步误差大幅减少，调节时间减少1/2；马达同步运动所需流量主要由变量泵提供，利用旁路比例阀对容积调速的同步误差进行补偿，这样较好的结合了节流调速和容积调速各自的优点，达到同步精度高、响应速度快、节能高效的目的。 In order to improve the response speed of control system and the stability on straight driving of hydrostatic drive self-propelled scooptram, in view of the low synchronous control precision and slow response of high power motor speed synchronization system, the synchronization control system with bypass compensation combined cross-coupling control and valve-pump combined high power hydraulic speed regulation was proposed. The status difference feedback signal of the sub channel is directly acting on the bypass proportional valve, so as to adjust the inlet flow of motors, and achieve a compensation for synchronization error. A mathematical model of the speed synchronization system with bypass compensation was established; the new control scheme was evaluated within Matlab/Simulink compared with a volume speed-modulating synchronization control scheme under the same conditions of control. Results show that: Synchronization error of the system proposed in this paper is reduced significantly under partial load and step load conditions, and the settling time is reduced by half; The flow for synchronized movement is mainly provided by the variable displacement pump, and the bypass proportional valve only compensates the synchronization error, so as to make a good used of each advantage of the throttle speed-modulating and the volume speed-modulating and achieves the purposes of fast response, high synchronization accuracy and energy efficiency.

Dynamic Logging with Dylog in Networked Embedded Systems

Event logging is an important technique for networked embedded systems like wireless sensor networks. It can greatly help developers to understand complex system behaviors and diagnose program bugs. Existing logging facilities do not well satisfy three practical requirements: flexibility , efficiency , and high synchronization accuracy . To simultaneously satisfy these requirements, we present Dylog, a dynamic logging facility for networked embedded systems. Dylog employs several techniques. First, Dylog uses binary instrumentation for dynamically inserting or removing logging statements, enabling flexible and interactive debugging at runtime. Second, Dylog incorporates an efficient storage system and log collection protocol for recording and transferring the logging messages. Third, Dylog employs a lightweight data-driven approach for reconstructing the synchronized time of the logging messages. Dylog uses MAC-layer timestamping and drift compensation to achieve high synchronization accuracy . We implement Dylog on the TinyOS 2.1.1/TelosB platform. Results show the following: (1) Dylog incurs a small overhead. Indirections in Dylog incur an additional execution overhead of less than 1%. Dylog reduces the logging storage size by approximately 50% compared with the standard TinyOS radio printf library. Dylog reduces the patch size by more than 90%, compared with incremental reprogramming. (2) Dylog reduces the synchronization overhead by 78% in terms of transmission cost, compared with a traditional time synchronization protocol, FTSP, and it can achieve a high time synchronization accuracy of 5.4μs. (3) Dylog can help diagnose system problems effectively at the source-code level for three real-world scenarios.

Continuous Reference Broadcast Synchronization with Packet Loss Tolerance

Among synchronization protocols applied in wireless sensor network, reference broadcast synchronization (RBS) is one prominent protocol achieving very high accuracy of synchronization given that the broadcasting medium is available. However, that the protocol lacks packet loss tolerance brings about degraded performance in severe conditions of wireless channel. Also, the instantaneous synchronization used in this protocol results in time discontinuity, which might cause serious faults in the distributed system. In this study, we propose a packet loss tolerance and continuous synchronization mechanism for RBS. Then we verified the result through simulations.

A Low Complexity Asynchronous UWB TDOA Localization Method

Impulse-radio ultrawideband (IR-UWB) is a promising technique for indoor localization due to its high accuracy and robustness against multipath interferences. In this paper, to deal with the synchronization challenges among anchors in traditional time-difference-of-arrival (TDOA) localization systems, we propose an asynchronous TDOA (ATDOA) localization method. Based on the ranging error model, we derive the theoretical lower bounds as the performance metrics of localization accuracy. Compared with the ideal TDOA method, ATDOA degrades on localization accuracy for eliminating the high accuracy synchronization requirements, which is pretty much attractive in energy and complexity limited scenarios. Based on the performance analysis, we show that there exists optimal anchor deployment in ATDOA that minimizes the localization errors. We also formulate the relationship between this optimal deployment and the size of the covered area, which is meaningful in both theoretical analysis and practical system designs.

A Multi-Source Dynamic Determination Algorithm for Digital Synchronization Equipment

In order to improve the security and reliability of digital synchronization network, digital synchronized equipment mostly uses reference source design and ensure the output performance in abnormal situation by redundancy back-up of multiple reference sources. The paper not only describes the concept of time-frequency equipment reference source and its judgment index, but also details a multi-source dynamic determination algorithm for digital synchronization equipment. A multi-component weighted average approach is designed the multi-source dynamic source selected processes by the study of several time sources of anomaly detection to improve the accuracy of the synchronization signal. The algorithm with simple structure can help keeping the high synchronization accuracy of multi-source time synchronization system.

An electro-hydraulic servo control system research for CFETR blanket RH

Based on the technical design requirements of China Fusion Engineering Test Reactor (CFETR) blanket remote handling (RH) maintenance, this paper focus on the control method of achieving high synchronization accuracy of electro-hydraulic servo system. Based on fuzzy control theory and practical experience, a fuzzy adaptive proportional-derivative (PD) controller was designed. Then a more precise co-simulation model was established with AMESim/Simulink. Through the analysis of simulation results, a fuzzy adaptive PD control algorithm was designed as the core strategy of electro-hydraulic servo control system.

RBS 성능향상을 위한 연속 클럭 동기화 및 패킷 손실 보상 기법

Reference Broadcast Synchronization (RBS)는 무선 센서 네트워크 동기화에 가장 널리 사용되는 프로토콜이다. 공통의 브로드케스트 채널이 존재할 경우 RBS는 상당히 높은 동기화 성능을 보인다. 그러나 RBS는 순간 클럭 동기화 (Instantaneous Clock Synchronization) 방식을 사용기 때문에 동기화 시간에 순간적인 시간 간격이 발생하여 시스템의 불안정을 초래할 수 있다. 또한 RBS는 패킷 손실 보상 기능이 없어 무선 채널 환경이 열악한 경우 동기화 성능의 현저한 저하를 초래할 수 있다. 본 논문에서는 RBS의 순간 클럭 동기화에 의한 문제점과 패킷 손실이 BRS 동기화에 미치는 영향에 대해서 분석한다. 이러한 문제점을 해결하기 위하여 RBS를 위한 연속 클럭 동기화 방식과 패킷 손실 보상 방식을 제안하고, 모의실험을 통하여 제안 방식의 성능향상에 대해 검증하고자 한다. Reference Broadcast Synchronization (RBS) is one of the most prominent synchronization protocols in wireless sensor nework. Given that the broadcasting medium is available, RBS can give very high accuracy of synchronization. However, RBS uses instantaneous synchronization and results in time discontinuity, which might cause serious faults in the distributed system. Also, RBS lacks packet loss tolerance, which brings about degraded performance in severe conditions of wireless channel. In this paper, the problem of time discontinuity in RBS is pointed out and the effect of packet loss on the performance of RBS is examined. Then, a continuous synchronization and a packet loss tolerance mechanism for RBS are proposed, and the result is verified through simulations.

Energy-Efficient Sleep/Wake Scheduling for Acoustic Localization Wireless Sensor Network Node

Both energy-saving and synchronization issues are the paramount concern in wireless sensor networks (WSNs). In this paper we propose a simple and efficient WSN node design based on acoustic positioning applications and present an on-demand sleep/wake scheduling synchronization protocol. Three aspects are already considered in the design: (a) power controllable; (b) energy efficient; (c) high synchronization accuracy. Our primary goal is to maximize energy saving and to control power supplying according to environments and demands. We establish a model of energy consumption and improve it by the ways of power control and on-demand synchronization. The on-demand synchronization protocols are implemented in sensor nodes and evaluated in a testbed. Analysis and simulation were performed that the proposed protocol has significantly reduced the energy consumption. It is also demonstrated by experiments that the platform is accurate and effective.

An LC Generator Based on Accurate Synchronization Controlling of Multisecondary Windings Saturable Pulse Transformer

High synchronization accuracy can be obtained when saturable pulse transformer (SPT) with multisecondary windings is employed in the technology of multipulses synchronization. LC generator based on multisecondary windings SPT is presented in this paper. The operation principle of the proposed LC generator is introduced. Three important requirements for voltage multiplication are analyzed and simulated. Experimental studies are carried out, and the results show that: when the primary energy storage capacitor is charged to 335 V, the output voltage of the system can reach up to 48.2 kV. The voltage multiplication ratio is 2.9. It means that the output voltage is 2.9 times larger than the charging voltage on single main energy storage capacitor. The step up ratio of the whole generator is 143.9. The voltage multiplication ratio increases with the increase of the charging voltage. The generator is suitable to operate at high voltage situation.

New Hydraulic Synchronization System Based on Fuzzy PID Control Strategy

Proposition of a high-speed switching valve pilot control of two-cylinder two-way electro-hydraulic synchronous drive system, the establishment of a mathematical model of the system, and using fuzzy PID control strategy designed controller, at the same time building a electro-hydraulic synchronization system simulation model based on fuzzy PID controller . Simulation results show that ,when using the fuzzy PID control strategy, slave cylinder of the synchronization system follow the initiative cylinder movement well, the peak-to-average speed of the slave cylinder is 20.3mm / s. Fuzzy PID control process according to the operating conditions change error and error change, by which it has automatic adjustment of PID parameters of the synchronization system. Therefore, fuzzy PID control has better adaptive ability, and the synchronization error is 0.04 mm, achieving high synchronization accuracy. Verifying that high-speed switching valve pilot control of the synchronous drive system and its control strategy is feasible.

New-Style Dielectric Loss of Transformer Bushing On-line Monitoring Apparatus

Abstract Transformer bushing dielectric loss factor (tanδ) is the reaction of the important parameters of the capacitor-type bushing insulation condition, the online monitoring is an effective means to determine the insulation condition. A new-style on-line monitoring apparatus of dielectric loss is designed. An approach using IRIG-B code to implement high-accuracy synchronization sampling in different places, combined with Harmonic analysis method. RS485-bus is used to implement communication between monitoring apparatus and bushing IED is presented .The sampling control of ADS8505 is realized by EP1C6Q240I7 that embedded soft-core processors Nios II Field Programmable Gate Array devices. The Fast Fourier Transform (FFT) processing of the signals is realized by Digital signal processing (DSP) device TMS320F28335. The digital information is transmitted by RS485-bus from monitoring terminal to bushing IED. Testing results show that the monitoring apparatus can improve the measurement of dielectric loss greatly with regard to accuracy and stability compared with conventional equipment. It is very useful and worth to promoting.

The perception of prototypical motion: Synchronization is enhanced with quantitatively morphed gestures of musical conductors.

Aesthetic theories have long suggested perceptual advantages for prototypical exemplars of a given class of objects or events. Empirical evidence confirmed that morphed (quantitatively averaged) human faces, musical interpretations, and human voices are preferred over most individual ones. In this study, biological human motion was morphed and tested for prototype effects in task-specific actions, perceptual judgments, and kinematic characteristics. A motion capture system recorded the movements of six novice and six expert orchestral conductors while they performed typical beat patterns in time with a metronome. Point-light representations of individual conductors and morphs of experts, novices, and a grand average morph were generated. In a repeated-measures sensorimotor synchronization paradigm, participants tapped a finger in time with the conducting and provided evaluations of the gestures' characteristics. Quantitatively averaged conducting motion resulted in reduced jerk (i.e., smoother motion) as well as higher synchronization accuracy and tapping consistency. Perceived beat clarity and quality of the gestures correlated with the timing of vertical acceleration in the conductors' movements. While gestures of individual conductors were perceived to be more expressive, morphs appeared more conventional. Thus, due to smoother spatiotemporal profiles of morphs, perception and action advantages were observed for prototypes that are presumably based both on motor resonance mechanisms and cognitive representations.

Nanosecond-range multi-pulses synchronization based on magnetic switch and saturable pulse transformer

Magnetic switch has been widely used in the field of pulsed power system for its advantages of solid state, high repetition rate, and long lifetime. In this paper, the synchronization of ns-range multi-pulses based on magnetic switch is studied and two kinds of technical methods are proposed. One of which is based on magnetic switches on a communal magnetic core. It was proved that the synchronization accuracy of 3 pulses is about 2 ns. Another proposed method is ns-range multi-pulse synchronization based on saturable pulse transformer and the experimental result showed that the synchronization accuracy of 2 pulses could achieve 2.5 ns. In contrast to other multi-pulse synchronization methods controlled by high-voltage pulse trigger or laser trigger, the synchronization based on magnetic switch and saturable pulse transformer has the advantages of high synchronization accuracy, long lifetime, and exemption from external trigger signals.

Lightweight Data Synchronization Scheme in Heterogeneous Sensor Networks

Data synchronization is critical for many sensor network operations including collaborative sensing, sensor scheduling and data fusion. Currently, large number of synchronization schemes have been proposed for the sensor network under the assumption that sensors work with the same network structure, network protocol and radio module. These techniques cannot survive in the heterogeneous sensor networks with the development of internet of things. In this paper, we propose a lightweight data synchronization scheme with low power which consists of two phases: first, we propose a heterogeneous clock synchronization algorithm based on the gateway which can synchronize the multi-hop sensor network with the TCP/IP network immediately without introducing amount of communication overhead; then, we also propose a synchronization control scheme in the gateway and we can balance the synchronization requirements through the adaptive buffer management. We implement the proposed scheme in real heterogeneous sensor network platform, and the experiment results show that our scheme can achieve high synchronization accuracy.

A CNC system based on real-time Ethernet and Windows NT

Modern manufacturing industry requires computer numerical control (CNC) systems to be more open, extendable, and networked. Real-time Ethernet is introduced and its use in CNC is discussed in this paper. Compared to traditional fieldbus, a real-time Ethernet which modifies the Ethernet data link layer to achieve fast delivery time and high synchronization accuracy is discussed. The method of synchronizing distributing clocks to reduce cumulative jitter of transmission for a synchronization frame is proposed. Some special considerations of this real-time Ethernet are discussed, e.g., incorporation with Windows NT and making feedback returned faster. A CNC system based on such a real-time Ethernet and Windows NT has been developed and presented. The system involves the service-oriented Windows Communication Foundation as an up-layer interface to the Internet, and a real-time Ethernet for connecting to hardware components of a machine tool. The non-real-time aspect of Windows NT is accounted for; for example, a driver rewriting the interrupt descriptor table is introduced and packets to be sent are buffered. Design and implementation of this system, such as main classes and services in the NC kernel, main modules (e.g., data link layer) in salve nodes, are also discussed. At last, experimental results are presented to illustrate the Windows NT’s performance and the real-time accuracy of the synchronization method.

Tracking Low-Precision Clocks With Time-Varying Drifts Using Kalman Filtering

Clock synchronization is essential for a large number of applications ranging from performance measurements in wired networks to data fusion in sensor networks. Existing techniques are either limited to undesirable accuracy or rely on specific hardware characteristics that may not be available in certain applications. In this paper, we examine the clock synchronization problem in networks where nodes lack the high-accuracy oscillators or programmable network interfaces some previous protocols depend on. This paper derives a general model for clock offset and skew and demonstrates its application to real clock oscillators. We design an efficient algorithm based on this model to achieve high synchronization accuracy. This algorithm applies the Kalman filter to track the clock offset and skew. We demonstrate the performance advantages of our schemes through extensive simulations and real clock oscillator measurements.

Clapping and Broadcasting Synchronization in Wireless Sensor Networks

The Clapping and Broadcasting Synchronization (CBS) algorithm, which is specifically designed for large-scale sensor networks with low communication overhead and high synchronization accuracy, is introduced. The CBS protocol uses broadcasting rather than pairwise communication to accomplish synchronization. In the CBS scheme, the initial offset of local clocks can be successfully eliminated by the operation of clapping nodes, which leads to significant improvement in synchronization accuracy. The CBS protocol was implemented on the TelosB platform and its performance was evaluated in a variety of experiments. The results demonstrate that the CBS protocol outperforms the current state-of-the-art approach, the Flooding Time Synchronization Protocol (FTSP), in both single-hop and multi-hop scenarios in terms of synchronous precision and energy consumption. In multi-hop scenarios, the CBS algorithm keeps about 50% of its synchronization errors within 1 ms. In comparison, the FTSP keeps less than 7% of its synchronization errors within this range. In both single-hop and multi-hop scenarios, the CBS protocol is over 3.2 times more energy-efficient than the FTSP.

Study on the Multi-Axis Motion System Based on EtherCAT

To obtain a faster response speed and higher synchronization accuracy, the paper firstly discusses the difficulties and disadvantages of organizing servo motion network with traditional fieldbus. Then, a novel method for constructing multi-axis motion system based on EtherCAT is presented. With DSP and an improved PID control algorithm, the hardware and software design is introduced in details. The system has realized high-speed remote data transmission and high-precision velocity control for Multi-axis which the traditional fieldbus can’t achieve.

Synchronization Motion of Four Supports Hydraulic Platform with Unbalanced Loading and Uncertainties

Radar leveling system is the key equipment for improving radar high mobility and survival capability. In this paper, an integrated hybrid controller, comprising of a sets of fuzzy cylinder controllers and one synchronous neural controller, is proposed for a antenna trailer of radar with four points supporting, which is driven by one hydraulic oil supply, to achieve synchronization motion under he various conditions of system uncertainties and disturbances. A new control strategy for better synchronization performance is proposed and a self-adaptive learning algorithm to adjust the weights of the neural network, is also derived. To verify the effectiveness and potential of the proposed controller, a series of experiments were made. Experimental results have demonstrated its high accuracy synchronization performance and fast dynamic response as well as stability of the leveling servo system. The hybrid controller can drive the radar truck leveling platform accurately, quickly and stably.