基于MRAI的伺服系统转动惯量辨识及改进研究

针对伺服系统控制参数自整定所需转动惯量参数的辨识问题,对基于模型参考自适应辨识(MRAI)思想的转动惯量辨识方法进行了研究。根据离散递推辨识机制构建了自适应辨识律,并通过分析辨识增益大小对惯量辨识响应的影响,提出了一种辨识增益自适应调整的改进算法;基于惯量辨识结果评价标准,建立了分段函数以实现辨识增益的动态调整;在仿真模型和实际系统中对不同辨识增益对惯量辨识的影响进行了对比测试。研究结果表明:改进的惯量辨识方法可以解决惯量辨识响应快速性和稳定性的矛盾,能够快速跟踪系统转动惯量的变化,可用于伺服控制参数的自整定。     

PI自整定永磁伺服系统转动惯量的辨识研究

针对永磁同步电机伺服系统中转动惯量变化问题,设计了一种带PI参数自整定的永磁同步电机转动惯量辨识系统,并提出了一种基于电机机械方程的转动惯量辨识方法。在系统匀加速阶段以相同时间间隔的速度为参量,计算出电机匀加速阶段的加速度,利用加速度与转动惯量的关系,由机械方程解调出电机转动惯量。以转动惯量为基准,利用速度环带零点Ⅱ型系统对PI参数进行补偿,并将此方法与传统PI控制方法在同一环境中进行仿真实验。研究结果表明,带转动惯量辨识PI自整定控制器的系统与传统PI控制器系统相比,启动无超调,且速度误差率降低0.16%左右。该方法具有更好的动静态性能,能够广泛应用于高精密数控系统,为解决转动惯量变化问题提供依据。     

基于梯度矫正方法的PMSM转动惯量辨识研究

为了使控制系统在复杂的环境中正常、稳定的运行,伺服驱动器必须具有参数辨识和参数自整定的功能,以保证系统具有强鲁棒性。在提高系统动态抗扰能力研究过程中,转动惯量辨识为其首要解决问题。在对离线式转动惯量辨识方法研究的基础上,提出了梯度矫正方法的转动惯量辨识策略,仿真研究表明梯度矫正方法进行转动惯量辨识具有一定的准确性和实时性。     

基于驱控一体的伺服压力机控制系统研究

针对曲柄伺服压力机工作行程中,冲头滑块对电机轴等效转动惯量变化的问题,对伺服压力机电流环、速度环比例—积分(PI)控制器控制参数整定方法进行了研究。对曲柄滑块机构进行了运动学分析,确定了曲柄转角与滑块等效转动惯量之间的函数关系;提出了一种基于固高科技GTSD14系列智能驱动器的PI参数分段控制方法;在单个行程内根据曲柄处于不同位置区间时相对应的转动惯量,确定了控制器PI参数,以提升系统速度环、位置环的跟随性能;搭建了实验平台,以带有不同配重的伺服电机为对象进行了模拟实验。实验及研究结果表明:当系统实际惯量与控制器PI参数不匹配时,系统可以在线调整PI参数,使得电机速度环、位置环的跟随能力得到改善,从而验证了随着各段转动惯量变化而实时整定PI参数的可行性。     

未知负载转矩下机械臂关节参数在线辨识及控制参数在线研究

机械臂运行过程中,关节伺服系统的负载转动惯量和阻尼系数呈现时变特性,现有方法在未知负载转矩的情况下无法完成转动惯量和阻尼系数同时辨识。提出一种基于离散模型参考自适应算法在线同时辨识负载转动惯量和阻尼系数的方法,通过对关节伺服系统电机的机械方程离散化得到含有转动惯量和阻尼系数的模型自适应参考模型,采用朗道离散时间递推参数辨识机制推导模型自适应率进行参数辨识;利用参数辨识结果和设定的误差阈值在线优化控制参数。此方法能在线同时辨识转动惯量和阻尼系数并根据辨识结果优化速度环PI控制器参数值,提高速度的动态响应性能。仿真结果证明了参数辨识方法和控制器参数在线优化方法的有效性。     

基于降阶负载扰动观测器的永磁同步电机控制

针对永磁同步电动机(PMSM)的负载扰动问题,提出了一种基于降阶负载扰动观测器的永磁同步电机前馈控制方法。通过设计降阶负载观测器来实时观测电机负载转矩变化,并将观测值作为电流前馈补偿来增加系统鲁棒性;考虑到转动惯量对观测器的影响,引入了梯度校正参数估计法,对电机的转动惯量进行了实时辨识;最后,将负载转矩观测与永磁同步电机的矢量控制相结合,对永磁同步电机的q轴分量进行了转矩前馈补偿以提升系统的动态性能。仿真结果表明,采用梯度校正参数估算法能快速准确地迭代计算永磁同步电机的转动惯量,所设计的降阶负载扰动观测器能有效地估计转矩变化。研究结果表明,基于降阶负载转矩观测器的前馈补偿与永磁同步电机矢量控制相结合,能有效地提升永磁同步电动机转速控制的鲁棒性。     

机器人系统中交流伺服电机控制研究

针对工业机器人应用中快速启动、频繁启停以及抗干扰能力强等方面的技术要求。提出了基于模糊控制理论与经典PID控制理论相结合的模糊参数自整定PI控制方法。可以在交流伺服控制系统运行中实时调整控制器的参数,改善经典PI控制器固定控制参数在系统参数变化及负载突变情况下的稳态和动态性能。对所提出的控制方案进行了详细的理论介绍和方案设计,并且实验测试表明模糊参数自整定PI控制方式相对于经典PI控制器在速度稳定性及抗负载扰动方面有着明显的优越性,验证了该方案的有效性,对工程应用具有一定的指导意义。     

基于参数自整定模糊PID控制策略的电机模型仿真研究

基于参数自整定模糊PID的控制理论和设计思想,利用PID参数在线整定方法,设计模糊推理规则,根据模糊控制原理对PID的三个参数进行在线修改,并对电机模型参数进行分析整定。MATLAB仿真结果表明该类控制器与常规PID相比较,具有良好的稳态精度和自适应能力,明显的改善了系统的动态性能,便于工程应用。     

并联机构主模块伺服系统参数辨识与整定

研究一种小型可重构并联机构主模块伺服系统参数辨识与整定方法。首先导出外移动副驱动,含平行四边形支链结构的位置、速度及加速度逆解模型,并利用虚功原理建立其刚体动力学逆解模型。在此基础上,提出辨识该类伺服系统参数的一种方法。该方法采用变频三角波输入,克服了伪随机二位式序列信号幅值变化大,易造成对伺服电动机冲击,引起其速度环开环等问题,且通过附加惯性负载,可将包括伺服系统转动惯量在内的所有参数辨识出来。进而,以超调量和上升时间为优化目标,考虑随位姿变化的极限负载,对伺服系统控制器参数进行了整定,给出了伺服系统控制器参数的范围。最后,试验验证了该方法的有效性和正确性。     

基于dsPACE的直线音圈电机模糊PID控制研究

针对直线音圈电机在运动过程中受负载扰动等非线性因素的影响时,常规PID控制参数不能在线整定难以满足系统性能指标要求,提出了模糊PID参数自整定位置控制策略。结合实验室ds PACE的硬件配置,在MATLAb/Simulink中设计了平均值滤波和可调占空比双路互补PWM波发生子系统。仿真和实验结果表明,基于ds PACE直线音圈电机控制系统设计合理,能快速实现控制算法的验证。与常规PID控制相比,模糊PID参数自整定控制具有更好的电机响应性能,对负载扰动有良好的鲁棒性。     

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.     

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....     

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。     

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.