高精度数控机床直线电机的改进型自抗扰控制研究

针对高精度数控机床伺服系统中,直线电机对扰动量高度敏感而影响系统稳态特性和控制精度的问题,提出了一种改进型永磁同步直线电机(PMLSM)自抗扰控制(ADRC)策略。将新型非线性函数引入扩张状态观测器,克服了传统型ADRC扩张状态观测器中非线性函数的不平滑性,并对系统总扰动进行了估算,并给予实时动态补偿;采用比例微分器代替非线性反馈控制规律,降低了系统参数调节的难度;利用Matlab对基于改进型ADRC控制策略的PMLSM调速控制系统进行了仿真,针对系统的空载启动响应特性和突加负载扰动对系统稳态性能的影响进行了测试。研究结果表明:与传统型ADRC控制策略相比,改进型ADRC控制策略具有更好的负载扰动抑制力和更小的超调量;系统控制精度得到提升。     

基于自抗扰控制器的磁浮平台水平推力控制

介绍一种新型的磁浮平台,针对该磁浮平台水平运动这一多变量、非线性、强耦合的系统,提出一种改进的自抗扰控制器,克服常规自抗扰控制器非线性状态误差反馈控制律中非线性函数的不平滑性,并探索出一套行之有效的控制器参数整定规则,同时利用扩张状态观测器观测出内部扰动和外部扰动,并对它们进行补偿。仿真对比分析和试验结果表明,这种改进的自抗扰控制器具有很好的动态、静态特性及鲁棒性。     

永磁直线同步电机一阶速度抗扰动控制

永磁直线同步电机(PMLSM)采用直接驱动方式,其动子上存在包括负载力、摩擦力和磁阻力在内的多重扰动力,这些直接作用在动子上的扰动严重地影响到直线电机的速度稳定性。提出了一种PMLSM抗扰动速度控制策略,基于扩张状态观测器(ESO)观测出多重扰动力对PMLSM的速度动态过程的扰动作用,引入跟踪微分器(TD)和非线性状态误差反馈(NLSEF)对这个扰动作用进行补偿,进而实现PMLSM一阶速度抗扰动控制。     

数控机床用磁悬浮系统自抗扰控制仿真研究

为了实现磁悬浮系统悬浮气隙的精确控制,提出运用自抗扰控制技术对横梁悬浮系统进行悬浮气隙控制,自抗扰控制器可以将系统模型参数变化和外扰作用均当作对系统的扰动而自动在线估计并予以补偿.对横梁磁悬浮系统建立的原始数学模型选择状态变量,得到系统的非线性状态方程,以线圈两端电压为控制量,设计悬浮气隙位置环和电流环双环自抗扰控制器,实现横梁悬浮系统的非线性控制.仿真结果表明,自抗扰控制具有良好的动态性能和抑制外来扰动能力,可以实现横梁无摩擦稳定悬浮.     

线性/非线性自抗扰切换控制在变载荷气动加载系统中的应用

针对气动加载系统压力跟踪控制中强非线性、强耦合性、模型不精确性等问题,提出一种线性/非线性自抗扰切换控制器,该控制器结合了线性自抗扰控制器参数整定简便、理论分析简单和非线性自抗扰控制器跟踪精度高、响应快的优点,设计线性/非线性切换扩张状态观测器对系统的耦合项以及不同幅值的扰动等不确定项进行估计,并采用切换状态误差反馈控制律给予实时主动补偿,进而实现系统加载压力的实时控制,并完成了线性/非线性切换扩张状态观测器的收敛性证明。最后,在气动变载荷摩擦磨损试验机试验平台上进行试验验证,与线性自抗扰和非线性自抗扰进行对比,试验结果表明,改进的控制器具有抗干扰性强、跟踪精度高、应用性强等特点。     

基于扩张状态观测器和非线性状态误差反馈设计自抗扰振动控制器

智能桁架结构作为一种控制结构一体化的新型空间结构,具有几何、物理可自调性,但这类结构同时具有柔性大、阻尼小、低频模态密集、模态耦合程度高以及存在多种不确定性和耦合等特点,给振动控制带来很大挑战。基于此,研究如何基于扩张状态观测器和非线性状态误差反馈设计不依赖于模型的自抗扰振动控制器。采用扩张状态观测器实时估计对象模型摄动及外扰的总和作用量,并在控制信号中补偿掉,实现不确定非线性系统的动态补偿线性化。针对线性的"积分器串联型"对象,设计非线性状态误差反馈控制律。对不确定参数空间83杆智能桁架结构进行自抗扰振动控制仿真研究。结果表明在外部扰动或模型结构参数发生变化时,自抗扰振动控制器仍可以获得理想的控制效果,具有很好的适应性和鲁棒性。     

四辊卷板机侧辊位移线性自抗扰控制

侧辊位移的精确控制对实现四辊卷板机高效加工至关重要,其核心问题是提高阀控非对称缸电液伺服系统的抗扰能力。由于电液伺服系统具有高度非线性和时变不确定性,传统非线性控制方法很难有效处理包含未知动态、外部扰动以及参数变化等的多源不确定扰动。提出一种四辊卷板机侧辊位移线性自抗扰控制方法。综合考虑各种不确定扰动因素的影响,设计了线性扩张状态观测器进行实时估计,采用状态误差反馈控制律给予主动补偿,并消除跟踪误差,证明了线性扩张状态观测器状态观测误差的收敛性和电液伺服系统的闭环稳定性。试验结果表明,所设计的线性自抗扰控制器能有效抑制电液伺服系统中多源不确定性扰动,实现侧辊位移的快速、精确轨迹跟踪。     

交流伺服系统分数阶PID改进型自抗扰控制

针对采用永磁同步电机驱动的火箭炮交流伺服系统存在摩擦、惯性力矩、变负载及不同工况下内外扰动等复杂非线性问题,考虑到自抗扰控制(ADRC)抗内外干扰能力强和分数阶PID控制动态性能好,设计了一种分数阶PID改进型自抗扰控制器(FOPID-IADRC)。为了取得良好的动态性能和减少参数计算量,采用分数阶PID控制器取代非线性状态误差反馈器;引入粒子群优化算法,对FOPID控制器的5个控制参数进行实时在线自整定。仿真和半实物台架实验结果表明：该控制策略能够有效抑制位置扰动,具有良好的动态性能和较强的抗干扰能力。     

线性自抗扰控制在电动汽车异步电机驱动系统中的应用

通常采用矢量控制结合效率最优原则来提高电动汽车异步电机驱动系统的效率,延长电动汽车的续驶里程,达到节能环保的目的。但效率优化系统由于各种干扰等不确定因素的存在,很难实现基于电机模型的准确解耦,严重影响磁通和转矩的动态性能。为此,设计了异步电机调速系统的二阶线性自抗扰控制器。线性自抗扰控制器不依赖系统的精确模型,利用扩张状态观测器估计出电机模型中的内扰和外扰并加以补偿。仿真和实验结果表明,与经典的PI控制器相比线性自抗扰控制器在效率优化的异步电机驱动系统中,具有更好的动态性能和抗干扰性能。     

基于自抗扰控制的转台伺服系统摩擦非线性补偿仿真研究

为克服非线性摩擦在转台伺服系统低速运行时对控制性能的影响,设计一种线性自抗扰控制器.该控制器采用线性扩张状态观测器及线性反馈,将摩擦作为系统总扰动进行实时估计,并加以补偿.基于Lugre摩擦模型建立转台伺服系统的数学模型,对这种线性自抗扰控制器进行仿真实验.结果表明,和传统PID控制器相比,所设计的控制器对非线性摩擦有良好的抑制作用,同时具有响应速度快、稳态误差小,抗扰能力强的特点.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.