输入受限的非仿射纯反馈不确定系统自适应动态面容错控制

针对存在执行器故障和输入饱和受限的非仿射纯反馈不确定动态系统,提出了一种自适应动态面容错控制策略.在不损失模型精度和考虑系统输入饱和受限的前提下,基于中值定理将非仿射系统转化为具有线性结构的时变不确定系统,在此基础上,再利用参数自适应投影技术对有界不确定时变参数进行在线估计,参数估计误差和外界扰动采用非线性动态阻尼技术进行补偿,并利用双曲正切函数和Nussbaum函数处理系统输入饱和受限和控制增益函数方向未知的问题,同时将反演法和动态面法相结合设计鲁棒自适应控制器,消除了反演法的计算膨胀问题,并且在系统出现执行器失效故障的情况下可确保稳定跟踪.最后,根据解耦反推法,基于Lyapunov稳定性定理证明了闭环系统的半全局一致最终有界.仿真结果验证了所设计控制方案的可行性与有效性.

自适应动态面控制在火箭炮伺服系统中应用

针对实际系统运行过程中所存在的转动惯量和负载力矩变化大等各种不确定因素,设计了一种基于动态面滤波法的自适应鲁棒位置控制器(ADSC)。首先对于模型中的不确定参数,采用投影算法进行有效估计,利用动态面滤波器简化控制器的设计,通过对模型的等价变换和选择适当的Lyapunov函数,最终给出系统的自适应控制器设计方法。仿真和实验结果表明,该方案与自适应反步滑模控制(ABSMC)相比,该控制器能够有效抑制抖振,跟踪性能好,对参数摄动及外界负载扰动具有较强的鲁棒性。

区域一致趋同的分布式负荷频率控制方法研究

随着可再生能源发电比例的上升,电力系统呈现源荷双重不确定性,对频率稳定产生不利影响。提出一种结合多智能体一致算法与动态面控制的分布式负荷频率控制方法,以增强电力系统的频率调节性能。首先,给出频率控制模型结构,并设计系统框架与分散式区域观测器;其次,考虑通信时滞的影响,设计出各区域控制器结构;最后,基于互联电力系统算例验证了方法的有效性与优越性。与传统控制方法相比,该控制方法改善了电力系统负荷频率控制性能,提高了区域间频率调节的一致性。

基于干扰观测器的输入受限非线性系统鲁棒控制

针对一类单输入单输出非线性系统,提出了一种有效处理输入饱和及未知外部干扰的控制方法,并应用于近空间飞行器的控制设计。利用双曲正切函数及Nussbaum函数的特殊性质对输入饱和进行处理。通过干扰观测器实现对复合扰动的有效逼近。考虑到反步控制中存在的计算膨胀和虚拟控制信号光滑性的问题,结合反步法和动态面法设计了相应的控制器。通过Lyapunov分析证明了所设计的控制律可以使闭环系统所有信号半全局最终一致有界,且跟踪误差和干扰逼近误差最终有界。仿真结果证明了该方法的有效性。

基于修正LuGre模型的自适应鲁棒控制在机电伺服系统中的应用

机电位置伺服系统是典型的非线性系统,且存在诸多不确定性,使得传统方法设计的闭环控制器往往不能满足系统的高性能需求。针对动态摩擦参数和系统负载特性未知的情况,为伺服系统设计一种基于动态面滤波法的自适应鲁棒跟踪策略。构造一个非线性观测器来估计摩擦力矩,利用动态面滤波器简化控制器的设计,设计自适应鲁棒控制器以提高系统的稳态控制精度及鲁棒性。基于Lyapunov稳定性定理证明闭环系统的所有信号半全局一致有界,通过适当选择设计参数及初始化误差变量,跟踪误差可收敛到原点的一个任意小邻域内。仿真和试验结果表明,该控制器能够能有效地抑制摩擦干扰对伺服系统的不利影响,显著提高了系统的控制精度,为提高伺服系统的动态跟踪性能奠定基础。

控制受限的火箭炮位置伺服系统鲁棒自适应反步控制

针对火箭炮位置伺服系统运行过程中所存在的转动惯量和负载力矩变化大,输入控制受限等各种不确定因素,提出了一种基于动态面滤波法的自适应鲁棒位置控制器。对于模型中的不确定参数,采用投影算法进行有效估计,利用鲁棒滑模滤波器简化控制器的设计,引入一个辅助分析系统来对控制输入限制的影响进行有效分析,同时将辅助分析系统与反步方法结合,通过对模型的等价变换和选择适当的Lyapunov函数,给出系统的自适应控制器的设计方法。仿真结果表明,该方法保证了系统的响应速度和控制精度,对参数摄动及外界负载扰动具有较强的鲁棒性。

Dynamic experiments on flocculation and sedimentation of argillized ultrafine tailings using fly-ash-based magnetic coagulant

In order to accelerate the sedimentation of super-large-scale argillized ultrafine tailings with bad features such as low settling velocity, muddy overflow water, and large flocculant dosage, a fly-ash-based magnetic coagulant （FAMC） was used in a dynamic experimental device. To obtain the best possible combination of the impact factors （magnetic intensity, FAMC dosage, flocculant dosage, and feed speed） for minimum overflow turbidity, a response surface methodology test coupled with a four-factor five-level central composite design was conducted. The synergy mechanism of FAMC and flocculant was analyzed based on the potential measurement and scanning electron microscopy. The results show that the flocculant dosage, overflow turbidity, and solid content can be reduced by 50%, 90%, and 80%, while the handling capacity per unit and efficiency of backfill and dry stacking can be promoted by 20%, 17%, and 13%, respectively, with a magnetic intensity of 0.3 T, FAMC dosage of 200 mL/t, flocculant dosage of 30 g/t, and feed speed of 0.6 t/（m^2·h）. Therefore, synergy of FAMC and flocculant has obvious efficiency in saving energy and protecting the environment by allowing 70×10^6 t/a of argillized ultrafine tailings slurry to be disposed safely and efficiently with a cost saving of more than 53×106 Yuan/a, which gives it great promise for use in domestic and foreign mines.

Environmental Regulation,Pollution Treatment Productivity,and Industrial Environmental TFP in China

Amidst growing environmental protection intensity by the Chinese government, this paper investigates the effects of environmental regulation on China＇s industrial pollution treatment productivity and environmental TFP. By estimating China＇s pollution treatment productivity between 2001 and 2008 and analyzing environmental regulation intensity and the effects of the relevant factors and pollution treatment productivity using panel data, this paper discovers that （1） pollution treatment productivity contributed a significant share of about 40% to industrial environmental TFP during the investigation period; （2） environmental regulation may not necessarily cause adverse impacts on pollution treatment efficiency and productivity but demonstrates a U-shaped relationship： when the share of pollution treatment cost in industrial value-added is above the range of 3.8%-5.1%, environmental regulation is likely to promote pollution treatment productivity and thus environmental TFP Judging by the estimation result, enhancing environmental protection and expediting the development of ecological civilization are conducive to China ＂s economic transition towards an intensive, efficient, circular, and sustainable development pattern. China＇s current industrial development has the capacity to tolerate a rather demanding level of pollution treatment and management and China needs to further rely on energy conservation and the environmental production industries to promote the progress of pollution treatment technologies.

控制受限的直流伺服系统非线性摩擦补偿

针对机电位置伺服系统实际运行时不可测摩擦状态和控制输入限制问题,设计了一种基于辅助系统的鲁棒饱和补偿跟踪策略。该控制策略将包含未知外摩擦状态项视为未知输入,构造不可测摩擦状态观测器。为了解决输入控制受限问题,基于辅助系统设计鲁棒饱和补偿控制器,把它考虑到自适应鲁棒控制器设计进行补偿。仿真和实验结果表明,该补偿策略提高了直流伺服系统的精度,为该类伺服系统高性能控制的分析与设计提供一种理论参考。

Directly searching method for slip plane and its influential factors based on critical state of slope

In order to determine the slip plane of slope directly by the calculation results of strength reduction method, and analyze the influential factors of slope stability, a numerical model was established in plane strain mode by FLAC3D for homogeneous soil slope, whose parameters were reduced until the slope reached the critical state. Then FISH program was used to get the location data of slip plane from displacement contour lines. Furthermore, the method to determine multiple slip planes was also proposed by setting different heights of elastic areas. The influential factors for the stability were analyzed, including cohesion, internal friction angle, and tensile strength. The calculation results show that with the increase of cohesion, failure mode of slope changes from shallow slipping to the deep slipping, while inclination of slip plane becomes slower and slipping volume becomes larger; with the increase of friction angle, failure mode of slope changes from deep slipping to shallow slipping, while slip plane becomes steeper and upper border of slip plane comes closer to the vertex of slope; the safety factor increases little and slip plane goes far away from vertex of slope with the increase of tensile strength.

Online dynamic measurement of saturation-capillary pressure relation in sandy medium under water level fluctuation

An online dynamic method based on electrical conductivity probe, tensiometer and datataker was presented to measure saturation-capillary pressure （S-p） relation in water-light nonaqueous phase liquid （LNAPL） two-phase sandy medium under water level fluctuation. Three-electrode electrical conductivity probe （ECP） was used to measure water saturation. Hydrophobic tensiometer was obtained by spraying waterproof material to the ceramic cup of commercially available hydrophilic tensiometer. A couple of hydrophilic tensiometer and hydrophobic tensiometer were used to measure pore water pressure and pore LNAPL pressure of the sandy medium, respectively. All the signals from ECP and tensiometer were collected by a data taker connected with a computer. The results show that this method can finish the measurement of S-R relation of a complete drainage or imbibition process in less than 60 min. It is much more timesaving compared with 10-40 d of traditional methods. Two cycles of water level fluctuation were produced, and four saturation-capillary pressure relations including two stable residual LNAPL saturations of the sandy medium were obtained during in 350 h. The results show that this method has a good durable performance and feasibility in the porous medium with complicated multiphase flow. Although further studies are needed on the signal stability and accuracy drift of the ECP, this online dynamic method can be used successfully in the rapid characterization of a LNAPL migration in porous media.

Optical Measurement System for Motion Characterization of Surface Mount Technology

Advanced testing methods for the dynamics of mechanical microdevices are necessary to develop reliable, marketable microelectromechanical systems. A system for measuring the nanometer motions of microscopic structures has been demonstrated. Stop-action images of a target have been obtained with computer microvision, microscopic interferometry, and stroboscopic illuminator. It can be developed for measuring the in-plane-rigid-body motions, surface shapes, out-of-plane motions and deformations of microstructures. A new algorithm of sub-pixel step length correlation template matching is proposed to extract the in-plane displacement from vision images. Hariharan five-step phase-shift interferometry algorithm and unwrapping algorithms are adopted to measure the out-of-plane motions. It is demonstrated that the system can measure the motions of solder wetting in surface mount technology(SMT).

Gas–Liquid Mass Transfer Characteristics in a Gas–Liquid–Solid Bubble Column under Elevated Pressure and Temperature

abstract The volumetric mass transfer coefficient kLa of gases （H2, CO, CO2） and mass transfer coefficient kL on liquid par-affin side were studied using the dynamic absorption method in slurry bubble column reactors under elevated temperature and elevated pressure. Meanwhile, gas-holdup and gas-liquid interfacial area a were obtained. The effects of temperature, pressure, superficial gas velocity and solid concentration on the mass transfer coeffi-cient were discussed. Experimental results show that the gas-liquid volumetric mass transfer coefficient kLa and interfacial area a increased with the increase of pressure, temperature, and superficial gas velocity, and decreased with the slurry concentration. The mass transfer coefficient kL increased with increasing superficial gas velocity and temperature and decreased with higher slurry concentration, while it changed slightly with pressure. Ac-cording to analysis of experimental data, an empirical correlation is obtained to calculate the values of kLa for H2 （CO, CO2） in the gas-paraffin-quartz system in a bubble column under elevated temperature and elevated pressure.

Diffusion-Controlled Adsorption Kinetics of Triton X-100 at Air/Solution Interface

In this paper, the equilibrium surface tension and the dynamic surface tension of aqueous Triton X-100 solution at temperature 25 ℃ were measured by means of Wilhelmy plate method and maximal bubble pressure method respectively. The determined critical micellar concentration（cmc） of Triton X-100 at 25 ℃ is (2.2×10-4) mol/dm3. The adsorption mechanics of Triton X-100 at air/solution was determined. For the submicellar concentrations it is diffusion-controlled. The diffusion coefficient was calculated from the experimental data in the range of short limit. In the range of long time adsorption, the subsurface concentration is fitted from the measured dynamic surface tensions.