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Integrated Sliding Mode Velocity Control of Linear Permanent Magnet Synchronous Motor with Thrust Ripple Compensation
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作者 Cong Bai Zhonggang Yin +2 位作者 Jing Liu Yanqing Zhang Xiangdong Sun 《CES Transactions on Electrical Machines and Systems》 CSCD 2023年第1期100-109,共10页
In this paper,a compound sliding mode velocity control scheme with a new exponential reaching law(NERL)with thrust ripple observation strategy is proposed to obtain a high performance velocity loop of the linear perma... In this paper,a compound sliding mode velocity control scheme with a new exponential reaching law(NERL)with thrust ripple observation strategy is proposed to obtain a high performance velocity loop of the linear permanent magnet synchronous motor(LPMSM)control system.A sliding mode velocity controller based on NERL is firstly discussed to restrain chattering of the conventional exponential reaching law(CERL).Furthermore,the unavoidable thrust ripple caused by the special structure of linear motor will bring about velocity fluctuation and reduced control performance.Thus,a thrust ripple compensation strategy on the basis of extend Kalman filter(EKF)theory is proposed.The estimated thrust ripple will be introduced into the sliding mode velocity controller to optimize the control accuracy and robustness.The effectiveness of the proposal is validated with experimental results. 展开更多
关键词 Linear permanent magnet synchronous motor(LPMSM) sliding mode velocity control New exponential reaching law Thrust ripple compensation
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Effects of sliding velocity and normal load on tribological behavior of aged Al-Sn-Cu alloy
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作者 章升程 潘清林 +1 位作者 严杰 黄星 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第7期1809-1819,共11页
The tribological behavior of aged Al-Sn-Cu alloy rubbed in the presence of lubricant over a range of sliding velocities and normal loads was investigated. The results showed that peak-aged (PA) alloy had a better tr... The tribological behavior of aged Al-Sn-Cu alloy rubbed in the presence of lubricant over a range of sliding velocities and normal loads was investigated. The results showed that peak-aged (PA) alloy had a better tribological behavior than under-aged (UA) and over-aged (OA) alloys, which could be attributed to the optimized strength-ductility matching and a better hardness under PA condition. Wear rate and friction coefficient showed great sensitivity to applied sliding velocity and normal load. The wear rate and friction coefficient of the alloy exhibited a reduction trend with the increase in sliding velocity. The low wear rate and friction coefficient of alloy at high velocities were due to the effectively protected film and homogeneous Sn on surface. However, an increase in normal load led to an obvious increment in wear rate. The friction coefficient exhibited a fluctuant trend with the increase of normal loads. The seriously destroyed film and abraded Sn resulted in poor tribological behavior at high normal loads. The Sn particles and lubricant film which includes low shear interfacial lubricating layer and oxide tribolayer are the key to the tribological behavior of Al-Sn-Cu alloy. 展开更多
关键词 Al-Sn-Cu alloy tribological behavior sliding velocity normal load AGING
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Structure and sliding wear behavior of 321 stainless steel/Al composite coating deposited by high velocity arc spraying technique 被引量:11
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作者 陈永雄 徐滨士 +2 位作者 刘燕 梁秀兵 许一 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第3期603-609,共7页
A typical 321 stainless steel/aluminum composite coating (321/Al coating) was prepared by high velocity arc spraying technique (HVAS) with 321 stainless steel wire as the anode and aluminum wire as the cathode. The tr... A typical 321 stainless steel/aluminum composite coating (321/Al coating) was prepared by high velocity arc spraying technique (HVAS) with 321 stainless steel wire as the anode and aluminum wire as the cathode. The traditional 321 stainless steel coating was also prepared for comparison. Tribological properties of the coatings were evaluated with the ring-block wear tester under different conditions. The structure and worn surface of the coatings were analyzed by scanning electron microscopy(SEM), X-ray diffractometry(XRD) and energy dispersion spectroscopy(EDS). The results show that, except for aluminum phase addition in the 321/Al coating, no other phases are created compared with the 321 coating. However, due to the addition of aluminum, the 321/Al coating forms a type of "ductile/hard phases inter-deposited" structure and performs quite different tribological behavior. Under the dry sliding condition, the anti-wear property of 321/Al coating is about 42% lower than that of 321 coating. But under the oil lubricated conditions with or without 32 h oil-dipping pretreatment, the anti-wear property of 321/Al coating is about 9% and 5% higher than that of 321 coating, respectively. The anti-wear mechanism of the composite coating is mainly relevant to the decrease of oxide impurities and the strengthening action resulted from the "ductile/hard phases inter-deposited" coating structure. 展开更多
关键词 HVAS 合成材料 奥氏体不锈钢 滑动磨损
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Reliability analysis of in-situ stress measurement using circumferential velocity anisotropy
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作者 Jiandong Liu1, 2, Luhe Shen1, 2, Juan Jin1, 2 1 Key Laboratory of Oil and Gas Reservoirs, China National Petroleum Corporation, Beijing, 100083, China 2 PetroChina Research Institute of Petroleum Exploration and Development, Beijing, 100083, China 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2011年第S1期457-460,共4页
In-situ stress measurement for deep reservoir formation is difficult in terms of security, reliability and technique. Acoustic velocity anisotropy test is a basic method for stress measurement of rock cores, which is ... In-situ stress measurement for deep reservoir formation is difficult in terms of security, reliability and technique. Acoustic velocity anisotropy test is a basic method for stress measurement of rock cores, which is based on the distribution of acoustic velocity in different directions around rock cores. The heterogeneity of core samples, such as fractures and gravel contained, can also lead to wave velocity anisotropy. Therefore, the corresponding reliability evaluation method is established to exclude some other anisotropy factors caused by non-tectonic stresses. In this paper, the reliability of testing results is evaluated from three aspects, i.e. phase difference, anisotropy index and waveform, to remove the factors caused by non-tectonic stresses. 展开更多
关键词 acoustic velocity measurement wave velocity anisotropy in-situ stress measurement
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Laboratory study of fluid viscosity induced ultrasonic velocity dispersion in reservoir sandstones 被引量:5
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作者 何涛 邹长春 +3 位作者 裴发根 任科英 孔繁达 史謌 《Applied Geophysics》 SCIE CSCD 2010年第2期114-126,193,共14页
Ultrasonic velocities of a set of saturated sandstone samples were measured at simulated in-situ pressures in the laboratory.The samples were obtained from the W formation of the WXS Depression and covered low to near... Ultrasonic velocities of a set of saturated sandstone samples were measured at simulated in-situ pressures in the laboratory.The samples were obtained from the W formation of the WXS Depression and covered low to nearly high porosity and permeability ranges.The brine and four different density oils were used as pore fluids,which provided a good chance to investigate fluid viscosity-induced velocity dispersion.The analysis of experimental observations of velocity dispersion indicates that(1)the Biot model can explain most of the small discrepancy(about 2–3%)between ultrasonic measurements and zero frequency Gassmann predictions for high porosity and permeability samples saturated by all the fluids used in this experiment and is also valid for medium porosity and permeability samples saturated with low viscosity fluids(less than approximately 3 mP·S)and(2)the squirt flow mechanism dominates the low to medium porosity and permeability samples when fluid viscosity increases and produces large velocity dispersions as high as about 8%. The microfracture aspect ratios were also estimated for the reservoir sandstones and applied to calculate the characteristic frequency of the squirt flow model,above which the Gassmann’ s assumptions are violated and the measured high frequency velocities cannot be directly used for Gassmann’s fluid replacement at the exploration seismic frequency band for W formation sandstones. 展开更多
关键词 ULTRASONIC velocity dispersion fluid viscosity reservoir sandstones in-situ conditions
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Study on Velocity Structure Models of the Sub-Sediments in Zhapu and Jintang near the Hangzhou Bay
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作者 Xianming Deng~(1,2),Chunhui Tao~1,Chunyan Sun~2,Jianping Zhou~1,Chunhua Gu~1 1.Key Laboratory of Submarine Geosciences,The Second Institute of Oceanography,SOA,Hangzhou 310012,China. 2.China University of Geosciences(Beijing),Beijing 100083,China 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期227-227,共1页
Marine sediment velocity structural models have strong regional characteristics.Hamilton made two shallow continental shelf sediment velocity structure models,Lu Bo gave a model in accordance with the characteristics ... Marine sediment velocity structural models have strong regional characteristics.Hamilton made two shallow continental shelf sediment velocity structure models,Lu Bo gave a model in accordance with the characteristics of the continental shelf of China.However,no model can contain all geological situations.We got the in-situ velocity data at Zhapu and Jintang near the Hangzhou Bay by using the MFI GeoA(Multi-Frequency In-situ Geoacoustic Measurement),and used these data to make the velocity structure models.Finally,we got two different models.One is Zhapu velocity structural model that we can describe as Lower velocity-Higher velocity -Lower velocity-Higher velocity model simply。 展开更多
关键词 sub-sediments velocity structure models in-situ measurement Zhapu and Jintang
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考虑强度速率衰减效应的地震滑坡SPH-FEM模拟
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作者 魏星 程世涛 +1 位作者 谢相焱 陈睿 《岩土工程学报》 EI CAS CSCD 北大核心 2024年第8期1753-1761,共9页
基于SPH和FEM耦合的数值计算方法,引入滑动面摩擦强度的速率衰减模型,提出了一种能够模拟地震诱发滑坡破坏过程的数值模拟方法。基于所提数值方法模拟了唐家山地震滑坡,模拟结果与现场勘查结果及室内试验现象较为一致。基于模拟的滑动... 基于SPH和FEM耦合的数值计算方法,引入滑动面摩擦强度的速率衰减模型,提出了一种能够模拟地震诱发滑坡破坏过程的数值模拟方法。基于所提数值方法模拟了唐家山地震滑坡,模拟结果与现场勘查结果及室内试验现象较为一致。基于模拟的滑动面上摩擦系数的演化过程,将唐家山滑坡的发生分为4个阶段:启动阶段、摩擦衰减阶段、低摩擦滑移阶段和逐步稳定阶段。模拟结果表明速度增加和摩擦强度衰减的相互促进,是触发滑体的高速运动的根本原因。提出采用滑体上作用的动摩擦力fd和动下滑力Td的比值R作为判别指标用于判断大型滑坡的启动,当首次出现R小于1时认为滑动面发生整体贯通并出现失稳启动。基于滑动面不同位置摩擦系数的演化,揭示了滑坡启动中滑动面摩擦强度衰减和滑动面的渐进贯通过程,解释了地震作用与滑动面摩擦参数速率衰减效应共同作用触发大型滑坡发生破坏的内在机理。 展开更多
关键词 大型滑坡 滑动面 摩擦强度 速度衰减效应 SPH-FEM耦合方法
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融冰沿气槽结构超疏水斜面下滑的解析数值分析
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作者 王昊利 《力学学报》 EI CAS CSCD 北大核心 2024年第6期1595-1605,共11页
文章提出了融冰沿气槽结构超疏水表面顺向下滑过程的物理几何模型.对融冰层液膜微剪切流进行分析,利用超疏水壁面“黏-滑”边界条件建立了微剪切流场的双Fourier级数方程,求得解析数值解,在此基础上研究了融冰层液膜微剪切流的速度分布... 文章提出了融冰沿气槽结构超疏水表面顺向下滑过程的物理几何模型.对融冰层液膜微剪切流进行分析,利用超疏水壁面“黏-滑”边界条件建立了微剪切流场的双Fourier级数方程,求得解析数值解,在此基础上研究了融冰层液膜微剪切流的速度分布及冰层下滑速度与超疏水表面气槽占比(a)、斜面倾角(α)以及融冰层液膜厚度(δ)之间的定量规律.研究结果表明,融冰层越薄或空气槽占比越大,融冰层微剪切流场偏离平板剪切流越显著;三相接触线处滑移速度梯度发生突变并达到峰值;a,α与δ的增大均会导致冰层超滑速度非线性增加,融冰层厚度增大到1之后超滑速度趋于渐近解析解函数.基于所取的参数值,a=0.95,δ=0.2以及a=0.9,δ=0.1时,由超疏水壁面结构导致的冰层下滑速度增量相对于总下滑速度的占比超过60%,此时冰层下滑速度主要来自超滑速度的贡献.文章的研究为当前超疏水除冰应用中的相关流体物理过程提供了参考. 展开更多
关键词 融冰 超疏水斜面 气槽 顺向下滑 超滑速度
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陀螺角速度控制下的单辙两轮车自平衡研究
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作者 陈宝 李志勇 +1 位作者 秦智明 马维忍 《内燃机与配件》 2024年第13期113-116,共4页
针对单辙两轮车的不稳定的系统,提出通过控制两个单框架控制力矩陀螺(SGCMG)来研究单辙两轮车的自平衡问题,设计了一个基于滑模控制(SMC)的陀螺角速度控制器,控制SGCMG产生进动力矩,并采用一个奇异回避算法避免陀螺发生奇异现象,以实现... 针对单辙两轮车的不稳定的系统,提出通过控制两个单框架控制力矩陀螺(SGCMG)来研究单辙两轮车的自平衡问题,设计了一个基于滑模控制(SMC)的陀螺角速度控制器,控制SGCMG产生进动力矩,并采用一个奇异回避算法避免陀螺发生奇异现象,以实现整车在静止和动态下的自平衡,并通过仿真验证验证在越障和跨壕沟路况时的自平衡能力。仿真结果表明,所采用的控制方法能够以较小的框架角度使整车快速平衡到直立状态,并且在行驶过过程中很好的抵抗外部干扰,以一个距平衡角度2°范围内的侧倾角度行驶,仿真结果对单辙两轮车的平衡行驶有显著意义。 展开更多
关键词 单辙两轮车 控制力矩陀螺 角速度控制器 滑模控制 奇异回避算法
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环形异向流浅层流场油滴流动及分离特性研究
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作者 艾星宇 邢宇涵 +4 位作者 蔡小垒 陈家庆 丁国栋 安申法 王秀军 《石油机械》 北大核心 2024年第5期98-106,共9页
目前关于环形多层异向流浅层流道内液滴流动和油水分离特性的研究尚不够深入。为此,借助流体动力学方法,对环形异向流浅层流道内分散油滴运移分离特性和多层浅层流道速度分布特性进行分析。研究结果表明:环形异向流浅层流道内油滴浮升... 目前关于环形多层异向流浅层流道内液滴流动和油水分离特性的研究尚不够深入。为此,借助流体动力学方法,对环形异向流浅层流道内分散油滴运移分离特性和多层浅层流道速度分布特性进行分析。研究结果表明:环形异向流浅层流道内油滴浮升至斜板表面所需板长为96 mm,小于理论计算所需板长122 mm;浅层通道内层间速度分布对分离效率影响较大,下层流道入口速度峰值为0.00805 m/s,环形多层浅层通道内油相浮升过程中会遇到交叉流,显著影响浅层通道分离效率;滑移距离是影响浅层通道间分离效率的重要因素,当板长为350 mm、油滴粒径为50μm时,滑移距离占板长38.35%。所得结论可为基于浅层沉降强化分离理论的紧凑型采出水处理设备结构创新优化设计提供理论支撑。 展开更多
关键词 采出水处理 环形异向流 浅层沉降分离 数值模拟 流道速度 分离效率 滑移距离
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催化裂化装置待生滑阀阀杆脱扣原因分析与处理
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作者 丘学东 《炼油技术与工程》 CAS 2024年第8期28-32,共5页
介绍了某催化裂化装置沉降器料位由41%开始突升并在调整过程中产生波动的原因及解决措施。分析原因:待生滑阀控制失灵造成沉降器料位波动。通过现场拆除待生滑阀阀杆和控制机构连接块、旋转和抽拉阀杆等调整措施,确认阀板和阀杆脱扣。... 介绍了某催化裂化装置沉降器料位由41%开始突升并在调整过程中产生波动的原因及解决措施。分析原因:待生滑阀控制失灵造成沉降器料位波动。通过现场拆除待生滑阀阀杆和控制机构连接块、旋转和抽拉阀杆等调整措施,确认阀板和阀杆脱扣。根据对阀杆连接结构的分析,采取调整旋转和抽拉阀杆等措施恢复了装置生产,并在阀杆180°方向带压开孔安装了一套临时的顶杆与原阀杆共同控制待生滑阀,保证了装置长周期运行。为明确故障原因,采用了流场模拟的方法对滑阀内压力云分布、流体速度分布、催化剂颗粒分布及吹扫蒸汽的控制进行了相关计算,得出吹扫蒸汽的流量控制对阀杆连接处的冲蚀具有较大影响。该结论在检修中得到了较好的验证。 展开更多
关键词 催化裂化装置 待生滑阀 阀杆脱扣 涡流 磨损 流速 冲蚀 仿真
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Probing the intriguing frictional behavior of hydrogels during alternative sliding velocity cycles 被引量:1
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作者 Yiming ZHAO Gang YI +6 位作者 Jiuyu CUI Ziqian ZHAO Yonggan YAN Luxing WEI Jinlong SHAO Hongbo ZENG Jun HUANG 《Friction》 SCIE EI CAS CSCD 2023年第12期2329-2341,共13页
Understanding the friction behavior of hydrogels is critical for the long-term stability of hydrogelrelated bioengineering applications.Instead of maintaining a constant sliding velocity,the actual motion of bio-compo... Understanding the friction behavior of hydrogels is critical for the long-term stability of hydrogelrelated bioengineering applications.Instead of maintaining a constant sliding velocity,the actual motion of bio-components(e.g.,articular cartilage and cornea)often changes abruptly.Therefore,it is important to study the frictional properties of hydrogels serving under various sliding velocities.In this work,an unexpected low friction regime(friction coefficientμ<10^(-4) at 1.05×10^(-3) rad/s)was observed when the polyacrylamide hydrogel was rotated against a glass substrate under alternative sliding velocity cycles.Interestingly,compared with the friction coefficients under constant sliding velocities,the measuredμdecreased significantly when the sliding velocity changed abruptly from high speeds(e.g.,105 rad/s)to low speeds(e.g.,1.05×10^(-3) rad/s).In addition,μexhibited a downswing trend at low speeds after experiencing more alternative sliding velocity cycles:the measuredμat 1.05 rad/s decreased from 2×10^(-2) to 3×10^(-3) after 10 friction cycles.It is found that the combined effect of hydration film and polymer network deformation determines the lubrication and drag reduction of hydrogels when the sliding velocity changes abruptly.The observed extremely low friction during alternative sliding velocity cycles can be applied to reduce friction at contacted interfaces.This work provides new insights into the fundamental understanding of the lubrication behaviors and mechanisms of hydrogels,with useful implications for the hydration lubrication related engineering applications such as artificial cartilage. 展开更多
关键词 hydrogel friction alternative sliding velocity ultra-low friction coefficient drag reduction
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连续组合现浇预应力连桥施工技术
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作者 关志文 蔡文浩 +1 位作者 孙佳佛 李敏子 《建筑技术开发》 2024年第11期124-127,共4页
龙华区观湖街道观城第一期城市更新单元项目共有9个地块,01~09地块围绕背夫山分部,各地块裙房二层通过背夫山生态云谷公园云环连桥连接,各座连桥首尾连续连接相通,且连桥下方道路的净高不小于5 m,其可保证市政道路的通行要求。研究依托... 龙华区观湖街道观城第一期城市更新单元项目共有9个地块,01~09地块围绕背夫山分部,各地块裙房二层通过背夫山生态云谷公园云环连桥连接,各座连桥首尾连续连接相通,且连桥下方道路的净高不小于5 m,其可保证市政道路的通行要求。研究依托观城08地块项目云环组合连桥施工技术进行分析,因裙房标高及市政道路净高限制,连桥最大板厚为1.5 m,最大跨度为39.8 m,连桥结构板里含有暗梁,暗梁均为预应力梁。预应力梁采用后张法进行施工,连桥结构混凝土强度等级为C50(自密实),要求混凝土强度达到90%以上方可张拉,张拉控制应力取σ_(con)=0.75f_(ptk),Φ_(s)15为低松弛钢绞线,f_(ptk)=1860 MPa,外径d=15.20 m。 展开更多
关键词 风载荷 角速度 滑道不平顺
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基于微动勘探技术的断裂带堆积层滑坡滑动面提取分析
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作者 郭维维 曾润强 +2 位作者 孟祥沛 尹海龙 孟兴民 《兰州大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第2期222-228,共7页
选择舟曲县东山镇牙豁口滑坡作为研究对象,采集滑坡体的微动信号进行后期处理,通过与钻孔数据对比发现,单点反演获得的S波速度结构与视S波速度剖面均能清晰显示滑动面位置.微动探测结果显示新滑坡的滑动面埋深在10~35 m,平均埋深为9.1 m... 选择舟曲县东山镇牙豁口滑坡作为研究对象,采集滑坡体的微动信号进行后期处理,通过与钻孔数据对比发现,单点反演获得的S波速度结构与视S波速度剖面均能清晰显示滑动面位置.微动探测结果显示新滑坡的滑动面埋深在10~35 m,平均埋深为9.1 m,钻孔揭露新滑动面平均埋深为10 m;微动探测结果显示老滑坡滑动面埋深在15~52 m,平均埋深为19.6 m,钻孔揭露新滑动面平均埋深为20 m.测试不同的采集时间、不同频率的检波器对探测深度和精度的影响,发现对该类滑坡应选取三重圆台阵, 4.5 Hz检波器, 90 min的采集时长.表明微动勘探方法是探测断层破碎带堆积层滑坡滑动面的一种有效方法,对于白龙江流域广泛分布的断层破碎带堆积层滑坡滑动面的探测,具有很好的技术优势以及应用前景. 展开更多
关键词 微动勘探 S波速度 滑动面 断层破碎带堆积层滑坡 白龙江流域
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飞行速度可调导弹三维制导律研究
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作者 戚人元 《计算机测量与控制》 2024年第5期156-162,共7页
为获得更好的制导性能,针对一类采用流量可调发动机的导弹,利用其所增加的飞行速度控制自由度,提出一种三维空间下比例导引+飞行速度控制的双重控制滑模制导律;以比例导引作为基础,在对二维、三维零控脱靶量分析的基础上,以零控脱靶量... 为获得更好的制导性能,针对一类采用流量可调发动机的导弹,利用其所增加的飞行速度控制自由度,提出一种三维空间下比例导引+飞行速度控制的双重控制滑模制导律;以比例导引作为基础,在对二维、三维零控脱靶量分析的基础上,以零控脱靶量为跟踪目标选取合适的滑模面,并进一步使用辅助滑模面和有限时间超螺旋干扰观测器对滑模面中的不确定项进行估计,推导了减少脱靶量的速度控制制导律;仿真结果表明,相比于经典的比例导引,在考虑空气阻力的场景下,所设计的制导律脱靶量更小,弹道更平滑,滑模面收敛情况理想,实现了导弹飞行速度的主动控制。 展开更多
关键词 导弹 制导律 滑模控制 超螺旋算法 飞行速度控制
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基于海底沉积物重力柱状取样器的新型原位声学一体化系统研制
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作者 叶玲婕 周建平 +1 位作者 王东 陶春辉 《海洋技术学报》 2024年第4期63-74,共12页
本文介绍了一种基于海底沉积物重力柱状取样器的新型原位声学一体化系统,名为海底沉积物原位声学与取样一体化系统(Sediment Acoustics and Sampling Integrated System,SASIS),该系统可以为海底区域地声模型研究和海洋工程地质评价等... 本文介绍了一种基于海底沉积物重力柱状取样器的新型原位声学一体化系统,名为海底沉积物原位声学与取样一体化系统(Sediment Acoustics and Sampling Integrated System,SASIS),该系统可以为海底区域地声模型研究和海洋工程地质评价等提供重要数据和样品。SASIS水下结构主要包括声学测量单元和重力柱取样单元,其发射换能器、接收换能器与重力柱状取样器实现一体化集成。系统利用振动滑行纵波方式测量沉积物的声速和声衰减,声波主频为12 k Hz、28 kHz可选,采用1发4收测量模式,在原位声学测量时可同步采集同一深度位置的沉积物样品。依托自然资源部第二海洋研究所-上海交通大学联合基金2023年度共享航次,SASIS在浙江舟山附近东海海域成功地进行了5站试验,试验站位水深约12.0 m,SASIS系统高效地同步采集了原位测量数据和沉积物样品。本文对沉积物声速和声衰减进行了初步数据分析,与前人测量数据、样品实验室声学测量结果对比表明,SASIS系统的原位声学数据可靠且有效。 展开更多
关键词 海底沉积物 原位声学测量 振动滑行波测量 声速 声衰减
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主动前轮转向控制特性研究
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作者 康瀚文 张磊 姚阳 《南方农机》 2024年第8期146-148,152,共4页
【目的】对主动前轮转向控制系统展开研究,改善汽车的转向性能及安全性能。【方法】使用Simulink建立车辆理想二自由度模型,基于滑模控制理论搭建主动前轮转向系统,并通过Simulink与Carsim的联合仿真环境进行车速分别为40 km/h、80 km/h... 【目的】对主动前轮转向控制系统展开研究,改善汽车的转向性能及安全性能。【方法】使用Simulink建立车辆理想二自由度模型,基于滑模控制理论搭建主动前轮转向系统,并通过Simulink与Carsim的联合仿真环境进行车速分别为40 km/h、80 km/h、120 km/h,地面附着系数为0.8的控制器效果仿真实验。【结果】主动前轮转向控制器提供的附加前轮转角可使实际横摆角速度紧密跟随理想横摆角速度,且无明显抖振。【结论】主动前轮转向控制器对于提升车辆稳定性有重要意义,可为AFSS控制器的开发提供一定的理论指导。 展开更多
关键词 横摆角速度 主动前轮转角 滑模控制 联合仿真
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Development of in-situ Marine Sediment Geo-Acoustic Measurement System with Real-Time and Multi Frequencies (the Second Generation) 被引量:7
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作者 陶春辉 邓显明 +6 位作者 李红星 周建平 金肖兵 傅顺声 Wlkens R. H 顾春华 何拥华 《China Ocean Engineering》 SCIE EI 2009年第4期769-778,共10页
Compared with the laboratory acoustic measurement of sediment samples, the in-situ acoustic measurement in marine sediment is considered more accurate and rehable, because it covers all of the surrounding environment ... Compared with the laboratory acoustic measurement of sediment samples, the in-situ acoustic measurement in marine sediment is considered more accurate and rehable, because it covers all of the surrounding environment factors and avoids the disturbance during the course of sampling and transporting of sediment samples. A new multi-frequency in-situ geoacoustic measurement system (MFIS^AMS) has been developed. The system can provide acoustic vdocity (compressional wave) and attenuation profiles of the uppermost 4 - 8 m sediment in the seafloor. It consists of 8 channels with 12 frequencies (multi-frequencies) and 0.5 - 2 MHz sampling rates. The data collected can be transmiuted in real-time. Associated with inclinometer and altimeter, it can provide the data for depth emendation. Acoustic velocity and attenuation data have been obtained from two in-situ experiments conducted in the Hangzhou Bay. 展开更多
关键词 marine sediment in-situ acoustic measurement acoustic velocity and attenuation
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Adaptive Sliding Mode Control for Re-entry Attitude of Near Space Hypersonic Vehicle Based on Backstepping Design 被引量:30
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作者 Jingmei Zhang Changyin Sun +1 位作者 Ruimin Zhang Chengshan Qian 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI 2015年第1期94-101,共8页
Combining sliding mode control method with radial basis function neural network (RBFNN), this paper proposes a robust adaptive control scheme based on backstepping design for re-entry attitude tracking control of near... Combining sliding mode control method with radial basis function neural network (RBFNN), this paper proposes a robust adaptive control scheme based on backstepping design for re-entry attitude tracking control of near space hypersonic vehicle (NSHV) in the presence of parameter variations and external disturbances. In the attitude angle loop, a robust adaptive virtual control law is designed by using the adaptive method to estimate the unknown upper bound of the compound uncertainties. In the angular velocity loop, an adaptive sliding mode control law is designed to suppress the effect of parameter variations and external disturbances. The main benefit of the sliding mode control is robustness to parameter variations and external disturbances. To further improve the control performance, RBFNNs are introduced to approximate the compound uncertainties in the attitude angle loop and angular velocity loop, respectively. Based on Lyapunov stability theory, the tracking errors are shown to be asymptotically stable. Simulation results show that the proposed control system attains a satisfied control performance and is robust against parameter variations and external disturbances. © 2014 Chinese Association of Automation. 展开更多
关键词 AIRSHIPS Angular velocity Attitude control BACKSTEPPING Control theory Design Functions Hypersonic aerodynamics Hypersonic vehicles Navigation Radial basis function networks sliding mode control Uncertainty analysis Vehicles
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Tests of new in-situ seabed acoustic measurement system in Qingdao 被引量:1
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作者 侯正瑜 郭常升 +2 位作者 王景强 李会银 李铁刚 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2014年第5期1172-1178,共7页
A new in-situ seabed acoustic measurement system is developed for direct in-situ measurement of sediment geoacoustic properties (compressional wave velocity and attenuation). The new in-situ system consists of two p... A new in-situ seabed acoustic measurement system is developed for direct in-situ measurement of sediment geoacoustic properties (compressional wave velocity and attenuation). The new in-situ system consists of two parts: the deck control unit and the underwater measurement unit. The underwater measurement unit emits sonic waves that propagate through the seafloor sediment, receives the returning signals, and transmits them to the deck control unit for waveform display and analysis. The entire operation is controlled and monitored in real time by the deck control unit on the research vessel and can provide recording of full waveforms to determine the sound velocity and attenuation. This paper outlines the design of the system, the measurement process, and demonstrates its application in tests carded out on seabed sediment off the Qingdao coast, China. The test results show that the system performed well and rapidly provided accurate in-situ acoustic velocity and attenuation estimates of the seafloor sediment. 展开更多
关键词 seafloor sediment in-situ measurement sound velocity and attenuation.
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