Experimental Study on Hydrodynamic Characteristics of Hydrofoil of the Birds Embedded in Marine Seismic Streamers

Author(s):  
Xiaoqing Zhang ◽  
Weijing Zhang ◽  
Jun Chen

A “bird” is a device usually being used to control the depth and position of marine seismic streamers. Exact position of the streamers can effectively promote the precision, reduce the measured times and save the costs for marine seismic exploitation. So the “birds” have important significance to marine oil exploitation. A Hydrodynamic characters test concerning a new embedded bird has been introduced in this paper. And some useful hydrodynamic character-data of the hydrofoil are obtained, such as lift-attack angle diagram, resistance-attack angle diagram, torque-attack angle diagram. These data and diagrams are more helpful for studying on the embedded bird, including the control method and control strategy etc. Above all, the results of the test have significant reference value for the control of birds and marine seismic streamers.

2020 ◽  
Vol 10 (20) ◽  
pp. 7021
Author(s):  
Yan Li ◽  
Peng Xiang ◽  
Yandong Chen

This article proposes a topology of the secondary reconfigurable inverter and the corresponding fault-tolerant control strategy. When the secondary reconfigurable inverter is operating normally, its topology structure is the TPSS circuit. When the power semiconductor devices in the inverter are faulty, the inverter circuit needs to be reconfigured. After removing the faulty power semiconductor devices, the remaining power semiconductor devices and the DC side powers are reconstructed as the TPFS structure to keep the system running normally. This article also proposes a switch-pulse-resetting algorithm. This paper adopts the control strategy connecting the constant-voltage, constant-frequency control method with the switch pulse resetting algorithm. It need not change the control algorithm when the proposed reconfigurable inverter is transformed from the normal running state into the faulty running state. The inverter dependability is greatly improved. Finally, the feasibility and effectiveness of the proposed second reconfigurable inverter topology and control strategy are verified by simulation and experiment.


Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1058 ◽  
Author(s):  
Chuanxiang Ren ◽  
Jinbo Wang ◽  
Lingqiao Qin ◽  
Shen Li ◽  
Yang Cheng

Setting up an exclusive left-turn lane and corresponding signal phase for intersection traffic safety and efficiency will decrease the capacity of the intersection when there are less or no left-turn movements. This is especially true during rush hours because of the ineffective use of left-turn lane space and signal phase duration. With the advantages of vehicle-to-infrastructure (V2I) communication, a novel intersection signal control model is proposed which sets up variable lane direction arrow marking and turns the left-turn lane into a controllable shared lane for left-turn and through movements. The new intersection signal control model and its control strategy are presented and simulated using field data. After comparison with two other intersection control models and control strategies, the new model is validated to improve the intersection capacity in rush hours. Besides, variable lane lines and the corresponding control method are designed and combined with the left-turn waiting area to overcome the shortcomings of the proposed intersection signal control model and control strategy.


2013 ◽  
Vol 787 ◽  
pp. 886-890
Author(s):  
Lan Chun Zhang ◽  
You Jun Ma ◽  
Shao Yi Bel

In this paper,a novel CVT with electronic control and a motor as actuator (EM-CVT) is presented, whose speed ratio can be adjusted by driving the two movable discs of the primary and secondary pulley at the same time. Firstly, the EM-CVT transmission dynamics mode was established based on the analysis of EM-CVT working principle and ratio change characteristics. Secondly, the speed ratio control strategy and control method for EM-CVT was designed according to the EM-CVT features and functional requirements of the control system; Finally, the simulation was carried out to verify the validity of the control strategy and meth


2013 ◽  
Vol 401-403 ◽  
pp. 1822-1825
Author(s):  
De Qi Ren

Aimed at the puzzle that it is heavy in energy consumption and not better in water quality to water supply engineering resulted in inappropriate control strategy, the paper explored the energy saving strategy and control mechanism of water supply system. In the paper, it discussed the cybernetics characteristic of water supply process, proposed the intelligence-fusion based control strategy and the energy saving executing strategy, and analyzed the control model of water supply purifying process and the control algorithm of constant pressure control system. The comparative research of simulation demonstrated that the proposed strategy would be better than conventional PID control method. The simulation results show that the strategy combined intelligence-fusion based control with speed control by inverter has better application prospect.


2020 ◽  
Vol 13 (2) ◽  
pp. 156-170
Author(s):  
Bing Zhang ◽  
Saike Jiang ◽  
Ziliang Jiang ◽  
Jiandong Li ◽  
Kehong Zhou ◽  
...  

Background: The parallel mechanism is widely used in motion simulators, parallel machine tools, medical equipment and other fields. It has advantages of high rigidity, stable structure and high carrying capacity. However, the control strategy and control method are difficult to study because of the complexity of the parallel mechanism system. Objective: The purpose of this paper was to verify the dynamic model of a hydraulic driven 3-DOF parallel mechanism and propose a compound control strategy to broaden the bandwidth of the control system. Methods: The single rigid body dynamic model of the parallel mechanism was established by the Newton Euler method. The feed forward control strategy based on joint space control with inverse kinematic was designed to improve the bandwidth and control precision. The co-simulation method based on MATLAB / SIMULINK and ADAMS was adopted to verify the dynamics and control strategy. Results: The bandwidth of each degree of freedom in the 3-DOF parallel mechanism was used to expand about 10Hz and the amplitude error was controlled below 5%. Conclusion: Based on the designed dynamic model and composite control strategy, the controlled accuracy of the parallel mechanism is improved and the bandwidth of the control system is broadened. Furthermore, the improvements can be made in aspects of control accuracy and real-time performance to compose more patents on parallel mechanisms.


2012 ◽  
Vol 229-231 ◽  
pp. 2182-2187
Author(s):  
Jian Chen ◽  
Yu Xin Liu

At present in China control strategy and control plan of highway monitor system are realized by collecting traffic environmental information, analyzing and processing by computer technology, publishing induction or banned instructions automatically and uniting the overall coordination of the road network traffic operation. In recent years in some provinces monitor plans of the whole distance have been started and monitor strategies of the whole distance have been made completely in order to make highway transportation safer, more open and more comfortable. With the help of the engineering experience and the characteristics of control strategy and control plan of highway monitor system in some provinces and cities ,I study the control strategy and control plan of highway monitor system and in detail analyze four cases that are the traffic flow control plan, the traffic incident control plan, the meteorological environment control plan and the emergency phone alarm control plan by research on the control method, the control process, the facility linkage control and the control result.


2019 ◽  
Vol 9 (4) ◽  
pp. 727 ◽  
Author(s):  
Jingguo Rong ◽  
Xin Ai ◽  
Yunning Li ◽  
Dapeng Ren

Power electronic transformers (PETs), as the core devices of the energy internet, are the key to achieve both effective consumption for renewable energy and the safe and coordinated operation for AC/DC hybrid system. In order to overcome the shortcomings of the existing PETs, a novel PET with an improved structure that applicable for multi-voltage level AC/DC hybrid distribution network is proposed. The topology of the proposed PET is analyzed, and the corresponding control methods are suggested for different parts. The input stage utilizes the modular multilevel converter structure and applies the virtual synchronous machine control strategy to enhance the inertia and damping of the system. The power of the output stage is adjusted flexibly and that enables the PET to provide certain power support to the upper grid and participate in its primary frequency regulation. A combined connection of input-series output-series and input-series output-parallel is applied for the dual-active-bridge modules of the isolation stage to enable network interconnection and electrical isolation of AC/DC grids with significantly different voltage levels. A power coordinated control method is then proposed to meet the power demand of the distribution networks connected to the output stage and ensure stable operations of PET simultaneously. The reliability and efficiency of the proposed PET topology and control strategy for AC/DC hybrid distribution network are finally verified via PSCAD/EMTDC simulation.


2013 ◽  
Vol 734-737 ◽  
pp. 1450-1459
Author(s):  
Neng Qian Jiang ◽  
Ming Hua Zhu ◽  
Yi Feng Xie

The wide use of oil drilling rig brings nominated economic profits for oil drilling industry. However, it will bring about great quantities of harmonic current to the grid, lowering the power quality and reliability of the power grid. Meanwhile, harmonic currents will have a deteriorated influence to surrounding electrical equipment and grid. This paper studies the distribution characteristics of the harmonic current in the oil industry and puts forward a control strategy aiming for improving stability and reliability of the power supply system. This paper also proposes an algorithm for detecting harmonic current based on time domain transformation and control strategy based on two cascade (voltage and current) control loop. Experiment and simulation results validate the proposed control strategy.


Author(s):  
Dong-Hun Lee ◽  
Duc-Quan Tran ◽  
Young-Bok Kim

In this study, a motion control problem for the vessels towed by tugboats or towing ships on the sea is considered. The towed vessels including barge ships are need to have assistance of tugboats. Combining two vessels, some work purposes in the sea or harbor area can be completed. In this study, the authors give newly developed mathematical model and control system strategy. Especially, the system model fully presenting the physical characteristics of two vessels are derived. For controlling the system effectively, it is considered that the towed vessel has no power propulsion system but the rudder is activated to improve the maneuverability. Considering the strong nonlinearities included in the vessel dynamics, the modelled system is presented by nonlinear system without linearization of nonlinear parameters. Thus, the control system for the towed vessel is designed based on the nonlinear control scheme. Exactly, the back-stepping control method is applied to its motion control. Also, the PID control method is applied for comparing with the proposed control strategy.


2021 ◽  
Vol 2005 (1) ◽  
pp. 012204
Author(s):  
Hankun Shi ◽  
Xuelin Wang ◽  
Shenchao Zhu ◽  
Hongmao Zhou ◽  
Zhaolun Zhang

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