自适应半主动悬架系统机械硬件在环试验研究

车辆处于加速、制动或转向工况时,运动惯性会导致车身发生俯仰、侧倾运动,如果幅值过大将使乘员产生紧张、眩晕等不舒适感。为解决此问题,提出一种基于车身姿态补偿控制与天棚加速度控制相结合的算法,建立自适应阻尼控制系统,不仅可使车辆垂向运动的振动效果得到改善,还能兼顾车身俯仰、侧倾控制,使其控制效果更加接近主动悬架。另外,搭建一种新型的减振器机械硬件在环试验台,可以对车辆垂向、俯仰及侧倾运动进行控制算法有效性验证,能克服四分之一减振器台架仅能验证车辆垂向运动的局限性。试验结果表明,与被动悬架相比,该算法在不同车速工况下B级路面和C级路面质心加速度幅值平均降幅达21.16%和13.21%,不同减速度和加速度工况下俯仰角波动峰峰值平均降幅达25.50%和28.82%,蛇形工况下不同车速的侧倾角幅值也均有降低。     

基于改进型天棚阻尼控制算法的馈能式半主动油气悬架系统

为了在改善车辆平顺性的同时获得较好的馈能效果,基于液-电馈能式油气悬架系统中液压马达排量对车身垂向加速度和馈能功率的影响,提出一种改进型天棚阻尼半主动控制算法。在馈能式油气悬架的1/4车辆模型中,以随机路面为激励信号,对被动控制、传统天棚阻尼半主动控制和改进型天棚阻尼半主动控制三种控制方算法的进行了仿真对比。结果表明:与另外两种控制算法相比,改进型天棚阻尼半主动控制算法有效地兼顾了车辆的平顺性的和悬架的馈能功率。     

船筏减振双线性系统的最优半主动阻尼控制

本文以船筏减振双线性系统为分析对象,利用极大值原理,通过受约束的梯度法数值求得船筏减振双线性系统的最优半主动阻尼控制曲线。由于控制曲线的非线性特性很强,甚至存在不可导的问题,引入脉冲函数并进行理论推导,解决了不可导曲线无法求解的缺陷,从而适用于双线性建模的系统。本文最后还比较了新方法与被动阻尼系统,半主动天棚阻尼系统在随机和冲击信号激励下的减振效果。结果显示：船筏双线性系统最优半主动阻尼控制策略是本文所述五种控制策略中减振效果最好的,并且对冲击信号的减振效果明显好于对随机信号减振。     

考虑能控特性的天棚阻尼半主动控制算法性能分析

为实现电磁作动器(Electric Actuator,EA)与磁流变减振器(Magneto-rheological Damper,MRD)并联组成的复合式电磁悬挂(Composite Electrical-magnetic Suspension,CES)在半主动馈能工况条件下的自供能,需同时考虑降低车身垂直加速度及降低控制功耗两方面因素。为解决算法控制性能评价的问题,在原有评价指标的基础上,提出能控比(Energy Consume and Control Performance Ratio,ECR)的概念并对其进行理论分析。在C级随机路面条件下,分析车速对天棚ON-OFF、连续天棚及改进型天棚3种天棚阻尼半主动控制算法的ECR的影响,并从时域的角度对ECR评价3种算法控制性能的有效性进行验证,得到最优天棚控制算法。结果表明:天棚ON-OFF、改进天棚及连续天棚对乘坐舒适性性能的改善依次增大;ECR可有效对3种控制算法性能进行评价,连续天棚半主动控制算法综合控制性能最优,适用于CES的自供能。     

高速车辆横向减振器模糊天棚半主动控制研究

为了研究减少高速列车运行中车体横向振动,利用ADAMS/Rail与Matlab建立了联合仿真高速列车车辆动力学模型,并利用开关型天棚控制算法和连续型天棚控制算法对高速列车车辆横向减振器进行了半主动控制仿真研究.结果表明：开关型天棚控制算法简单实用,但控制效果逊于连续型天棚控制算法,还有可能发生颤振;连续型天棚控制算法控制效果好,但对系统的实时性和减振器结构的要求较高.针对这2种控制器的优缺点,同样基于上述模型,结合模糊理论和天棚速度阻尼控制,开发了一种新的控制方法,经研究表明,该控制方法具有很好的控制效果,并能弥补上述2种方法的不足.     

车辆主动座椅悬架的天棚反步控制器设计

为提高车辆的乘坐舒适度,针对车辆主动座椅悬架提出一种新的基于近似天棚阻尼参考模型的反步控制方法。在建立并分析 1/4车辆座椅悬架动力学模型的基础上,把近似天棚阻尼系统作为参考模型,将实际被控系统和参考模型之间的动态误差引入到反步的思想中,在保证系统达到一致渐进稳定的前提下,通过反步设计方法完成控制器设计 ,最终获得基于加速度反馈的实时作动力。最后通过与 PID和被动悬架仿真结果的对比,证明该系统的动态误差是指数渐近稳定的,且该方法可明显增强车辆座椅悬架系统减振效果,所提出的反步控制方法对于座椅悬架的实际控制具有参考价值。     

半主动悬架SH-LQR阻尼控制策略仿真研究

半主动悬架在被动悬架和主动悬架之间实现了成本和效果的良好结合。以半主动悬架控制策略作为分析研究对象。根据分析表明,传统的开关天棚控制方法和LQR方法分别在低频段和高频段有较好的效果,两种方法具备一定的互补特性。因此给出一种结合的分频方式,提出SH-LQR联合控制的方法并首先在1/4 车辆模型上进行验证,证明该算法在全频域段的有效性。而后将该算法从1/4 模型移植到半车模型上,通过MATLAB/Simulink 进行了验证。结果表明,使用SH-LQR控制的半主动悬架有较好的减振效果。     

半主动悬架改进ADD控制策略研究

半主动悬架具有成本适中、控制效果好的优势。通过仿真分析经典的加速度阻尼控制策略。仿真结果表明,加速度阻尼控制在降低簧上质量加速度的同时会导致悬架动行程恶化,且开关型控制策略会产生“振颤”现象。在加速度阻尼控制基础上提出一种阻尼连续可变的加速度阻尼控制。在1/4车辆模型上对控制策略进行仿真分析。结果表明,改进加速度阻尼控制策略保留了加速度阻尼控制策略对簧上质量加速度的优化效果,同时避免了动行程的恶化。     

阻尼连续可调半主动悬架平滑天棚控制策略研究

为了验证平滑天棚控制的有效性和其有效的参数优化算法，以2自由度悬架系统模型为研究对象，建立综合性能评价指标，经过粒子群算法优化参数，仿真结果表明，与被动悬架相比，综合性能评价指标提升11.17%。以舒适性为控制目标，采用随机路面激励，平滑天棚控制的簧上质量加速度均方根值与被动悬架和开关天棚控制相比，都有显著的降低；采用正弦扫频激励，对系统振动传递特性进行分析，仿真结果表明，在中高频段，平滑天棚控制对簧上质量振动有较好的抑制效果。最后，通过半主动需悬架机械硬件在环试验，试验结果表明，平滑天棚控制可以减少振颤，降低簧上质量加速度。     

高速动车组悬挂系统横向半主动控制仿真分析

摘要：提出一种基于加速度阻尼原理的改进型半主动控制,可以克服天棚阻尼半主动控制在高频范围内抑制振动效果差的缺点。突破了以往研究半主动控制只针对单车车辆的限制,利用ADAMS(Automatic Dynamic Analysis of Mechanical Systems)建立了2动2拖104个自由度动车组模型,并结合Matlab/Simulink对提出的半主动控制方法进行设计和联合仿真。根据联合仿真的结果,从时域和频域两个角度对比两种半主动控制方法对车辆运行平稳性和安全性的影响,并分析控制中时滞对系统性能的影响。结果发现,改进型半主动控制在提高车辆运行平稳性和抗时滞方面效果更佳。     

Bioavailability of Hydrochlorothiazide Suspension

Flocculated and deflocculated suspensions of hydrochlorothiazide stabilized with certain natural stabilizers, some earthy silicates and one member of carbomers were submitted for dissolution studies in simulated gastric juice. Also, the flow rate, PH, sodium and potassium content of urine of five human volunteers administering the drug suspensions were determined as well. The correlation between the dissolution rate and the pharmacologic response of the drug suspensions was declared.     

混合型主动悬架电磁反力作动器的匹配研究

针对由电磁反力作动器与被动悬架构成的混合型主动悬架系统,建立了1/4车辆模型,在Matlab环境下计算动力吸振器分别安装在悬挂质量和非悬挂质量时的车身响应特性,以分析作动器参数及不同安装位置对平顺性的影响。结果表明:电磁反力作动器布置在非悬挂质量环节比较有利。对作用在非悬挂质量环节的作动器,以吸振器状态进行了参数优化,并就混合型悬架与被动悬架的车身幅频特性进行了比较,分析混合型主动悬架作动器与轮胎之间的力传递特性,指出用车辆不同路面下被动悬架的轮胎最大动载荷,作为选择作动器控制能力的参考依据。     

In-Vitro Evaluation of Antacid Suspension

Abstract

Three conceptually different titration procedures are used to evaluate the performance of several antacid suspension products: RIOPAN, RIOPAN PLUS, MAALOX, MAALOX PLUS, AND MYLANTA. When the static acid neutralization capacity test is performed, both RIOPAN and RIOPAN PLUS possess more acid neutralizing capacity, on an equal weight basis, than MAALOX, MAALOX PLUS or MYLANTA. The results of a pH-stat titration test show the RIOPAN products react 10 times faster with acid than other produced based on time to half-neutralization. The dynamic acid neutralizing capacity test (modified Beekman procedure) shows onset of action at pH 3 for the RIOPAN product to be 20 times faster than for MAALOX PLUS and 56 times faster than for MYIANTA. Duration of acid neutralization at pH above 3 for the RIOPAN products is two times longer than for MAALOX or MAALOX PLUS and 1.6 times longer than for MYIANTA.     

Suspension biomechanics of swimming microbes

Micro-organisms play a vital role in many biological, medical and engineering phenomena. Some recent research efforts have demonstrated the importance of biomechanics in understanding certain aspects of micro-organism behaviours such as locomotion and collective motions of cells. In particular, spatio-temporal coherent structures found in a bacterial suspension have been the focus of many research studies over the last few years. Recent studies have shown that macroscopic properties of a suspension, such as rheology and diffusion, are strongly affected by meso-scale flow structures generated by swimming microbes. Since the meso-scale flow structures are strongly affected by the interactions between microbes, a bottom-up strategy, i.e. from a cellular level to a continuum suspension level, represents the natural approach to the study of a suspension of swimming microbes. In this paper, we first provide a summary of existing biomechanical research on interactions between a pair of swimming micro-organisms, as a two-body interaction is the simplest many-body interaction. We show that interactions between two nearby swimming micro-organisms are described well by existing mathematical models. Then, collective motions formed by a group of swimming micro-organisms are discussed. We show that some collective motions of micro-organisms, such as coherent structures of bacterial suspensions, are satisfactorily explained by fluid dynamics. Lastly, we discuss how macroscopic suspension properties are changed by the microscopic characteristics of the cell suspension. The fundamental knowledge we present will be useful in obtaining a better understanding of the behaviour of micro-organisms.     

Air Suspension Coating for Multiparticulates

Abstract

Fluidized bed systems are widely used in the pharmaceutical industry for production of core material and for film coating. Top spray coaters, evolving from the fluid bed dryers of nearly 40 years ago, produce batches of fine, coated particles in excess of 500 kg. Wurster bottom spray equipment is used to manufacture pellets as well as to coat products ranging from powders to tablets. Rotary tangential spray systems generate micro pellets (approximately 100–600 microns) from powders, macro pellets (about 700–2000 microns) by layering, and apply coatings for all types of release. For all processes, films may be applied using water, organic solvents, or via hot melt to provide sustained or controlled release, taste masking, enteric release, improved stability, or aesthetics. However, depending on the type of substrate and coating material, the air suspension method selected may be a significant process variable. In addition to formulation considerations in product development, an understanding of these types of processing techniques is essential.     

车辆能量回馈式主动悬架系统研究

提出了一类新的主动悬架系统,被称为"能量同馈式主动悬架系统".其特点是在对车辆进行减振的同时,将车辆振动的能量吸收,转化为电能贮存起来,并可将存贮的能量用于作动器产生主动控制作用力.以四自由度半车模型为例,阐述了能量回馈式主动悬架的基本结构和原理,分析了系统能量平衡存在的条件.最后在Matlab/Simulink中对系统的运行效果进行了仿真.仿真结果表明系统在实现主动减振控制的同时还能够反馈能量.     

Stability of Extemporaneous Norfloxacin Suspension

The stability of norfloxacin as extemporaneous suspensions compounded from two brands of film-coated tablets (formulas I and II) was studied. The vehicle consisted of tragacanth, saccharin sodium, sorbitol solution, glycerin, paraben concentrate, peppermint spirit BP, purified water, and syrup USP. The final concentration of norfloxacin in the suspensions was 20 mg/ml. Formulas I and II were chemically stable for 28 days when stored in amber glass bottles at ambient temperature; however, their physical characteristics were different.     

Air Suspension Coating for Multiparticulates

Fluidized bed systems are widely used in the pharmaceutical industry for production of core material and for film coating. Top spray coaters, evolving from the fluid bed dryers of nearly 40 years ago, produce batches of fine, coated particles in excess of 500 kg. Wurster bottom spray equipment is used to manufacture pellets as well as to coat products ranging from powders to tablets. Rotary tangential spray systems generate micro pellets (approximately 100-600 microns) from powders, macro pellets (about 700-2000 microns) by layering, and apply coatings for all types of release. For all processes, films may be applied using water, organic solvents, or via hot melt to provide sustained or controlled release, taste masking, enteric release, improved stability, or aesthetics. However, depending on the type of substrate and coating material, the air suspension method selected may be a significant process variable. In addition to formulation considerations in product development, an understanding of these types of processing techniques is essential.     

金红石复相体系浓悬浮体的制备

胶态成型工艺要求制备高固相含量、低粘度的浓悬浮体。由于复杂的胶体特性，金红石典型配方中含有的多种烧结助剂对金红石粉料在水介质中的分散行为往往产生较大影响。本文采用高温煅烧金红石复相体系的方法，消除了烧结助剂对制备金红石浓悬浮体的不良影响。通过调节pH值和分散剂用量，优化了金红石粉料在水介质中的分散条件，从而成功地制备了体积分数为51．7％的金红石复相体系浓悬浮体。     

半主动悬架控制的联合仿真

对某汽车的半主动悬架进行了联合仿真。首先,用ADAMS软件建立汽车悬架的多体动力学模型。其次,通过Matlab/simulink编写模糊控制算法。最后,通过连接Adams软件和对其进行联合仿真。将采用半主动悬架系统得到的仿真结果与采用被动悬架系统得到的仿真结果进行性能对比, 结果表明半主动悬架系统改善车辆的行驶平顺性。