共查询到20条相似文献,搜索用时 187 毫秒
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针对汽车防盗,该文开发了一种密码控制的油路阀防盗系统,油路控制阀安装在汽车点火器处,密码控制器则安装在驾驶室内的操作台上.利用该控制系统,任何人进入车辆后,都必须输入正确的密码才能打开安装在油泵与汽车点火系统之间的油路控制阀,接通油路后,才能启动汽车发动机.在密码控制器中,设计了报警模块,当输入密码错误超过规定的次数后,控制器启动报警系统并同时锁定键盘.为了避免汽车意外熄火油路阀关闭切断油路以及密码控制器掉电而需要重新输入密码的麻烦,控制器的存储单元能记忆步进电机的当前位置并保持阀芯的当前开口,便于驾驶员快速重启发动机.最后利用摩托车发动机进行了实验研究,实验结果表明该密码控制油路阀系统具有很好的防盗作用. 相似文献
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利用磁流变阻尼器特性试验数据,通过曲线拟合等手段建立了双sigmoid力学模型。该模型的参数是控制电流和振动频率、振幅的函数,能准确描述不同激励条件下阻尼力-速度滞回特性。建立了双层隔振系统模型,分析了阻尼比对传递函数的影响。提出了一种模糊半主动振动控制算法。仿真结果表明,该控制算法在宽频范围上能取得很好的隔振效果。 相似文献
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高压静止无功补偿器用晶闸管阀均压/阻尼电路参数的优化 总被引:2,自引:0,他引:2
静目无功补偿器(SVC)在提高电力系统供电质量和运行稳定性等方面发挥,重要作用。本文详细分析TSVC用晶闸管阀的均压/阻尼电路参数对系统电压和电流的影响,通过仿真计算,分析提出了优化品闸管阀均压/阻尼电路参数的指导原则。试验比较结果表明:采用优化电路参数,关断时刻晶闸管阀产生的电压冲击小、无电压振荡,对系统的影响小。 相似文献
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针对电力系统中SVC装置的应用特点,提出了一种将模糊逻辑算法应用到SVC控制算法中,然后通过实验对比三种控制算法,从而得出了一种模糊逻辑算法与PI算法相结合的新型改进算法。该算法初步解决了SVC装置补偿过程中在某些系统工况下出现改善电压质量与提高功率因数相矛盾的问题。 相似文献
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针对传输控制协议(TCP, transmission control protocol)的拥塞控制算法未能满足视频传输质量要求的问题,提出了一种基于半马尔科夫决策过程的视频传输拥塞控制算法。首先, 为克服目前基于峰值信噪比的视频质量评估方法实时性低的缺点,设计了一种可在线运行的无参考视频质量评估方法。其次,根据接收端视频质量的反馈,采用半马尔科夫决策过程对拥塞控制进行建模,并通过求解此模型得到拥塞控制参数的调整策略。仿真实验结果表明,与目前典型的拥塞控制算法相比,该算法不但具备更好的TCP友好性,而且有效地提高了解码后视频序列的主观和客观质量。 相似文献
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《Mechatronics》2022
This paper presents a systematic study of the design optimization, development, vibration analysis and flight testing of a single power plant variable pitch quadrotor Unmanned Aerial System (UAS) for industrial applications. The use of variable pitch rotors enables the use of a two-stroke internal combustion engine for powering the four rotors through a mechanical transmission. The proposed methodology is described by carrying out the design of a quadrotor UAS with 2–3 kg payload capacity and have endurance in excess of one hour. The study is conducted in a systematic manner. First, the design of rotors is optimized for minimum power consumption during hover as well as forward flight condition using physics based simulation developed and validated for this purpose. From the rotor optimization, an untwisted rotor blade with taper ratio of 0.6 and aspect ratio of 10 appeared to be an optimal choice for the current design. Next, the powerplant selection is carried out based on the optimized rotor designed earlier. Next, two different approaches for mechanical power transmission design is considered: torque tube-bevel gear and belt–pulley system based designs. The transmission system designed using belt and pulley was nearly 14% lighter and showed greater tolerance to manufacturing imperfections. Next, two prototypes are designed and its static and dynamic analysis is carried out to ensure its airworthiness. A Proportional Integral Derivative (PID) based attitude controller is developed using quarternions for attitude stabilization and trajectory tracking to test the flight in simulation and then subsequently on the actual vehicle by implementing it on PixHawk autopilot board. Finally, system integration is carried out to build two prototypes of engine powered quadrotor UAS. Then, vibration data is recorded using the sensors onboard to conduct the vibration analysis and design an efficient vibration isolator. Performance analysis is also, carried out to estimate the speed for best endurance (11 m/s) and best range (27 m/s) for the variable pitch quadrotor designed. The estimated best endurance achieved is 2.2 h and estimated best range is more than 150 km. This design revisits and solves the challenge of developing an agile helicopter without cyclic pitch control which was first explored nearly a century ago. 相似文献
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高压隔膜泵是矿浆管道输送系统的动力源,随着无人值守泵站的投入运行,如何远程监测高压隔膜泵的运行状态就成为亟需解决的问题。文中设计了一种基于STM32的高压隔膜泵运行状态远程监测系统。该系统实时采集单向阀振动信号,将采集到的振动信号数据通过以太网传输到远程服务器中,在服务器中采用固有时间尺度分解方法(ITD),对高压隔膜泵单向阀振动信号进行分析,从而实现对高压隔膜泵运行状态的远程监测。实验结果表明,该系统采集信息准确,传输速度快速且稳定,可以在工业行业推广使用。 相似文献
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对高速列车司机室内的噪声和振动进行了测试,分析车内的噪声与振动水平、噪声传递路径及声源特性,探寻造成司机室噪声水平过大的原因,提出通过车轮鏇修解决司机室噪声过大问题的建议,并对车轮鏇修前后的司机室噪声与振动水平进行了对比测试分析,并由此开展了高速列车司机室噪声控制措施的研究.结果表明,车轮第20阶多边形是使车内噪声和振动过大,并形成588 Hz显著频率的主要原因.车辆结构在580 Hz附近存在局部模态区,当外界激振频率落在这一区域时,会激发车辆结构的共振.通过车轮鏇修,改善车轮多边形,可以在一定程度上缓解车内噪声问题.但是,优化车辆结构,使车辆模态避开车内噪声显著频率范围,才能从根本上解决包括司机室噪声过大在内的一系列由于共振引发的车内噪声问题.另外,结构振动声辐射对司机室显著声源具有一定贡献,针对司机室噪声控制,还需要采取一定的减振措施. 相似文献
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Vehicular ad-hoc network (VANET) is an essential component of the intelligent transportation system, that facilitates the road transportation by giving a prior alert on traffic condition, collision detection warning, automatic parking and cruise control using vehicle to vehicle (V2V) and vehicle to roadside unit (V2R) communication. The accuracy of location prediction of the vehicle is a prime concern in VANET which enhances the application performance such as automatic parking, cooperative driving, routing etc. to give some examples. Generally, in a developed country, vehicle speed varies between 0 and 60 km/h in a city due to traffic rules, driving skills and traffic density. Likewise, the movement of the vehicle with steady speed is highly impractical. Subsequently, the relationship between time and speed to reach the destination is nonlinear. With reference to the previous work on location prediction in VANET, nonlinear movement of the vehicle was not considered. Thus, a location prediction algorithm should be designed by considering nonlinear movement. This paper proposes a location prediction algorithm for a nonlinear vehicular movement using extended Kalman filter (EKF). EKF is more appropriate contrasted with the Kalman filter (KF), as it is designed to work with the nonlinear system. The proposed prediction algorithm performance is measured with the real and model based mobility traces for the city and highway scenarios. Also, EKF based prediction performance is compared with KF based prediction on average Euclidean distance error (AEDE), distance error (DE), root mean square error (RMSE) and velocity error (VE). 相似文献
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《Mechatronics》2020
Hydro viscous clutch (HVC) is a power transmission unit which relies on shear stress of fluid to transmit driving torque. The conventional pressure control system suffers from high minimum operating pressure problem. This makes the HVC has a large drag torque and greatly limits the usage flexibility. In this article, a valve-and-pump compounded pressure control (VCPC) system is proposed for the hydro viscous clutch (HVC) to enlarge the working pressure range in the low pressure direction. The pressure of the control cylinder is adjusted by the rotary speed of pump or the electro-proportional relief valve (ERV) when the VCPC system works on different pressure stage. The adaptive robust control (ARC) algorithm and the feedforward PID algorithm are introduced into the VCPC system for the purpose of obtaining better pressure tracking performance. The effectiveness of the proposed VCPC system is validated through the compared experiments. Electromagnetic interference is considered and experiment results are carefully analyzed. It can be concluded that the pressure control range is increased by 38% with the proposed VCPC system. And compared with conventional control algorithms, the ARC algorithm has a better pressure tracking performance and relatively smooth input signal on low pressure stage. 相似文献
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Jianfeng Sun Lingjun Zhang Xindan Hui Yingzhou Huang Jie Chen Chenguo Hu Hengyu Guo Song Qi Zhong Lin Wang 《Advanced functional materials》2023,33(9):2212248
Mechanical system with adjustable stiffness and damping (ASAD) shows great potential in vibration suppression of aircraft, vehicle, precise instrument, etc. However, current ASAD systems consist of power, sensing, and controlling components, which bring huge challenges of system reliability and integrability, and critically limit its application diversity. Herein, we proposed the first strategy for regulating ASAD system that is system simplification, self-powered and no-delay by deeply coupling triboelectric nanogenerator (TENG) and electrorheological fluid (ERF). Under the time-varying mechanical triggering, the local and time correlated output of TENG instantaneously applied on the ERF regulates the entire mechanical system dynamically and “in-phase”. As an illustration, the resonance of a cantilever system is effectively suppressed naturally without complicated controlling strategy, and the vibration isolating efficiency reaches up to 85.2%. Finally, a mechanical transmission system is demonstrated utilizing a rotary TENG and ERF, excellent soft-start performance is enabled by this self-regulating ASAD strategy. This work may provide the opening arsenal of methodologies used in self-powered and self-regulating mechanical systems. 相似文献
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This paper focuses on vehicle to roadside (V2R) communications in vehicular networks based on the IEEE 802.11 DCF MAC protocol.
In vehicular networks, roadside units (RSUs) are typically spaced apart along the road and each vehicle can be connected to
an RSU only when the vehicle is within its transmission range. Due to the high relative speed between a moving vehicle and
a stationary RSU, the residence time of the vehicle within the coverage of each RSU is very short. Thus it is hard for the
system to reach a steady state. With multi-hop forwarding, in which a vehicle may be connected to an RSU through relaying
over other vehicles, the connection time of each V2R access may be extended. But this is at the expense of introducing wireless
interference among vehicles, which may dramatically degrade the system performance. To tackle these challenges, we propose
a new mechanism called Proxy-based Vehicle to RSU access (PVR) for V2R communications. This protocol is designed to exploit
cooperative and opportunistic forwarding between any two distant RSUs and to emulate back-to-back transmissions within the
coverage of an RSU. As a result, it can shorten the access delay by taking advantage of opportunistic forwarding and mitigate
the interference problem during the short residence time within the coverage of an RSU. The simulation results show that PVR
achieves excellent performance and outperforms all existing solutions for V2R communications in vehicular networks. 相似文献
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《Vehicular Technology, IEEE Transactions on》2009,58(5):2150-2159
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This paper proposes a new robust speed control to suppress vibration caused by angular transmission error of planetary gears. For this purpose, this paper first constructs a new numerical simulation model of angular transmission error of planetary gear, which is confirmed by experimental data from a robot arm. Next, in order to suppress the vibration caused by angular transmission error, we propose a robust speed control system based on disturbance observer and coprime factorization. Numerical simulation results show that the proposed system regulates the angular speed of motor satisfactorily, and it suppresses the vibration caused by angular transmission error 相似文献