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Sliding mode control (SMC) is emerged as a powerful robust controller for the process control application. However, it does not posses robustness properties during reaching phase and suffers from chattering, which is undesirable. In this paper, a chatter free discrete sliding mode controller (DSMC) with reaching phase elimination is proposed. The issue of existence of reaching phase due to physical constraints such as saturation of actuating devices is also addressed. The two-input–two-output (TITO) system is decoupled into two single-input–single-output (SISO) systems using ideal decoupler. The DSMCs are separately designed for two decoupled SISO systems. The stability is ensured via Lyapunov approach. Simulation study and experimentation on real life interacting two tank liquid level system are included to demonstrate effectiveness and applicability of the proposed controller. 相似文献
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干线埋地管道均为强制电流+外防腐层联合保护方式,这就要求被保护管道有良好的绝缘性能。阀室内管道与电气之间采用绝缘卡套进行绝缘,放空管与阀室内管道间也存在绝缘接头。基于电气安全考虑,阀室电气设备均有接地,如果管道与接地网搭接或绝缘失效,将会造成阀室管道电位偏正,阴保处于欠保护状态。因此针对运行的阀室,做好绝缘排查,消除阴保电流流失,确保阀室埋地管道处于良好的阴极保护状态尤为重要。本文通过对某输油线某阀室阴保漏电进行原因排查并采用了固态去耦合器解决了阀室阴极保护漏电,对解决阀室阴极保护漏电提供了一种全新的思路和方法。 相似文献
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具有单向离合解耦器的发动机前端附件驱动系统的旋转振动建模及参数优化设计 总被引:1,自引:0,他引:1
建立了具有单向离合解耦器(Overrunning Alternator Decoupler,OAD)的八轮-多楔带发动机前端附件驱动系统的非线性旋转振动数学模型.采用Gear数值算法求解从动轮和张紧臂的角度波动.计算结果表明,有OAD装置时从动轮和张紧臂的角度波动、各带段的动态张力和带-轮间的滑移率等系统动态特性均明显减小.计算和研究了OAD弹簧刚度的大小、电机转子与电机轮惯量比的大小以及电机负载转矩的大小对系统动态特性的影响.以张紧臂角度波动、OAD弹簧转矩和带-电机轮间的滑移率最小为优化目标,建立了OAD弹簧刚度和电机转子转动惯量两参数的优化设计数学模型.结果表明,采用优化后的系统参数,该系统的动态特性均得到一定程度的改善. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(5):352-358
With a view to enhancing the thermal-neutron intensity obtained from a pulsed neutron source, an experimental study has been made to determine the optimum size of a rectangular shaped light water moderator provided with fast neutron reflector of beryllium oxide or graphite, and decoupled thermal-neutronically by means of Cd sheet. The optimum dimensions for the moderator are derived for the neutron emission surface and the thickness, for the cases in which the neutron-producing target is placed beneath the moderator (“wing geometry”) or immediately behind the moderator (“slab geometry”). The major conclusions drawn from the experimental results are as follows. The presence of the Cd decoupler inserted between the moderator and reflector prevent the enhancement of thermal-neutron emission time gained by the provision of reflector. with a graphite reflector about 14 cm thick, (a) the optimum area of emission surface would be 25x25 cm2 for wing geometry and still larger for slab geometry, and (b) the optimum moderator thickness would be 5.5 cm for slab geometry and 8.5 cm for wing geometry. It is thus concluded that a higher neutron emission intensity can be obtained with slab than with wing geometry provided that a large emission surface can be adopted for the moderator. 相似文献
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进行了带有调整系统的远铰解耦挂架抑制机翼/外挂颤振的低速风洞试验研究.试验是在大展弦比机翼颤振模型上进行的.试验结果表明:当外挂俯仰频率落在柔性区范围时,机翼/远铰解耦挂架/外挂的颤振速度比机翼/常规挂架/外挂的颤振速度有显著提高;且其颤振速度对外挂惯性特性的变化不敏感.试验结果还表明;调整系统可将外挂与机翼的相对静偏移修正到很小的设计角度内.文中还进行了单铰和远铰两种解耦挂架方案颤振抑制效果的比较,试验结果表明:远铰方案中外挂俯仰振动加速度响应比单铰时明显减小;且调整电机启动频率也比单铰时为低.文中还讨论了远铰挂架四连杆机构参数对外挂俯仰频率的影响. 相似文献
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Li-jun Yang Zhi-ren Yin Ming He Run-ze Duan Fang-yan Li 《Combustion and Flame》2013,160(12):2866-2878
A nonlinear pulse combustor model with an exhaust decoupler and vent pipe was solved using the Poincaré–Lindstedt perturbation analysis method. The solutions included expressions for the pressure in the combustion chamber and the exhaust decoupler respectively. Experiments were made to validate the theoretical analysis; results showed that an exhaust decoupler and a vent pipe can affect the frequency of the pulse combustor and the pressure in the exhaust decoupler (both amplitude and phase). There are five main dimensionless parameters: dimensionless exhaust decoupler volume v, dimensionless vent pipe length l, dimensionless vent pipe area s and dimensionless enthalpy ht0, hd0. Following the values of these five parameters, the working domain of the pulse combustor was divided into three parts: the inphase zone, critical interval and antiphase zone. In the critical interval domain, the pulse combustor cannot work stable. To make a pulse combustor work at the antiphase zone (recommended in engineering applications), a large exhaust decoupler volume, and fairly long vent pipe with a proper cross-section area are required. 相似文献
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The effect of a multi‐tailpipe structure on a pulse combustor with an exhaust decoupler and a vent pipe is investigated. A nonlinear theoretical model is established, and corresponding experiments are made to verify the theoretical model. The results show that the multi‐tailpipe structure has two effects: It enhances the exhaust gas resistance and decreases exhaust gas velocity in the tailpipe; it also expands the tailpipe heat dissipation area and increases the heat loss. The amplitude of pressure fluctuations in the combustion chamber and exhaust decoupler is determined by competition between the strengthening effect of tailpipe resistance and the weakening effect of heat loss from the tailpipe. Frequency and pressure characteristics are dominated by tailpipe resistance and tailpipe heat loss. The working region is divided into three parts for different structure parameters: low frequency inphase zone, unstable zone, and high‐frequency antiphase zone. Tailpipe resistance only affects the unstable zone, and the necessary value of tailpipe friction exists to minimize the unstable zone. Heat loss from the tailpipe can reduce the unstable zone and cause it to squeeze the inphase zone, resulting in shrinkage of the inphase zone. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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王健健 《石油化工腐蚀与防护》2012,29(3):52-55
杭嘉主干线管道沿线有多处高电压等级(500 kV)的输电线路,虽然管道与高压线的敷设满足标准GB/T 21447允许的最小水平安全距离,但现场测试及评估发现磁感应干扰电压总体较高,交流干扰电压最高为70.29 V,从而对管道造成了较为严重的交流干扰腐蚀,导致强制电流阴极保护系统运行异常。针对杭嘉线存在的高压输电线路交流干扰的问题,通过分析对比,并结合管道的实际特点,采取隔直排流法,以固态去耦合器作为排流装置、以锌带和棒状锌合金牺牲阳极为联合接地体对管道的交流干扰进行了排流防治设计。介绍了杭嘉线受干扰的严重程度、排流方法和排流点的选择以及排流防治措施。 相似文献