基于模式识别的压电精密驱动与控制系统

提出了基于图像识别技术的精密驱动与控制系统,以及将驱动系统分为步进电机丝杠的宏驱动系统和压电驱动器的精密驱动系统,并将两者有机地结合成完整宏/微的驱动系统。并且提出了基于计算机视觉技术与串口通信技术相结合的控制系统。这个精密驱动与控制系统的微操作平台连接上不同的机械执行机构就可以用于不同的精密加工和制造系统中。     

一种宏微双重驱动精密定位机构的建模与控制

提出一种宏微双重驱动精密定位机构,采用高性能直线电机直接驱动宏动平台,实现系统大行程微米级精度定位;安装在宏动平台上的压电陶瓷驱动微动平台,实现纳米级的分辨率和定位精度,以高频响动态补偿系统的定位误差;采用精密光栅尺反馈微动平台输出端的位置信号,实现定位机构的全闭环反馈控制。在分别建立宏动、微动、宏微机构模型的基础上,提出复合型宏动控制和模糊自校正PID微动控制的宏微控制策略。实验研究表明:系统的动态和稳态性能良好,该定位机构的最大工作行程100 mm,稳定时间小于40 ms,重复定位精度10 nm。     

基于神经网络的宏/微双驱动运动平台误差预测及补偿技术研究

宏/微双驱动平台是一种用于微切削加工的高精度切削平台,其定位精度受多种因素影响。为提高宏/微双驱动定位运动平台的定位精度,提出基于BP神经网络进行宏/微双驱动运动平台定位误差预测的方法。测量运动平台的定位精度,从而建立BP神经网络误差预测模型,并运用该模型对宏/微双驱动运动平台进行定位误差预测试验,最终证明BP神经网络定位误差预测模型精度高、抗变换性能好,适用于对宏/微双驱动运动平台的定位误差进行误差预测及补偿,使得宏/微双驱动平台达到10nm级精度设计要求。     

大行程超精密工作台的研究

该微动平台采用花岗岩作为机架材料,以压电陶瓷直线电机驱动平台,选择RENISHAW的RGH25光栅作为反馈和宏微双驱动协调控制伺服输出,并提出了提高定位精度的方案.为研究微动工作台提供了参考.通过实验对工作台的性能进行分析,证实平台设计的可行性.     

大行程高精度驱动系统的研究

首先对大行程高精度驱动系统结构研究进展进行介绍和评述,其次针对目前大行程高精度宏微两级定位系统结构复杂,体积大,驱动控制困难等问题,提出研究具有宏微双重运动功能的单一驱动结构将是大行程高精度驱动定位系统的发展方向;指出将超声电机与压电微驱动器结合成为单一驱动器将是大行程高精度驱动系统的一个发展方向;最后对单级超声电机宏微驱动系统建模方法、位置控制策略的研究进展进行了综述,指出了单级宏微驱动的超声电机研究的主要难点。     

宏/微双重驱动技术的研究和应用现状

宏/微双重驱动技术因具备大行程、快速响应、高精度定位等特点,近年来在微操作领域得到了广泛的应用.总结了目前常用的宏/微双驱动的宏、微定位部件,并分析了它们各自的优缺点及使用范围;并介绍了常见的宏/微双重驱动系统的集成方式,以及国内外这方面研究取得的成果.为即将从事这方面研究的人员提供了很好的参考.     

高加速度宏微运动平台研究

对高加速度宏微运动平台进行了研究,在分析宏微复合驱动技术的基础上,采用一种新型的宏微驱动方式,研制了基于压电陶瓷的高加速度宏微运动平台。宏运动由音圈电机驱动,可实现高加速度、大行程运动;微运动由安装在音圈电机轴上的压电陶瓷驱动,用以补偿宏动所产生的定位误差,达到高精度的设计目标。在微动过程中,由绝对式直线光栅尺实现闭环位置反馈。根据设计要求,搭建了宏微驱动高加速度高精度定位平台,通过实验验证其性能。实验结果表明,该宏微运动平台加速度大于10g,重复定位精度小于1μm。     

面向光学精密装配的微操作机器人

为完成复杂的光学精密装配任务,开发一种多传感器混合控制的宏/微结合微操作机器人系统.在分析光学装配原理的基础上,阐述机器人系统的组成.研制由交流伺服电动机驱动的6自由度并联机构和由压电陶瓷驱动的5自由度柔性铰链机构,分别实现光学器件的粗定位及精定位,由压电陶瓷驱动的二级杠杆放大机构实现光学器件的可靠夹持.建立包括位姿检测、显微视觉、激光损耗检测及力检测的多传感器控制系统,根据传感器采集的位姿信息、视觉信息、损耗信息及力信息协调控制宏/微定位工作台精确调整光学器件的位置和姿态,实现装配自动化.试验表明,开发的面向光学精密装配的微操作机器人能够成功地完成光学器件的精确装配.     

高精度定位平台X-Y方向振动误差补偿

为了减小定位平台在X,Y方向的振动误差,实现高精度定位,搭建了宏微结合精密定位系统,由高性能直线电机驱动,气体静压导轨支撑和导向的宏动平台实现系统的大行程微米级定位,并由安装在宏动平台上的压电陶瓷驱动的微动平台对系统进行定位精度补偿。建立了定位系统机电耦合振动模型,采用比例积分微分(proportion integral derivative,简称PID)控制与最小节拍响应控制相结合的策略控制宏动平台,采用前馈-PID控制驱动微动平台,通过电容式微位移传感器实时检测定位系统终端的位置输出信号作为微动台的输入信号,实现定位系统的闭环反馈控制,达到宏动平台的振动误差实时补偿的目的。实验结果显示,所设计的微动补偿平台具有良好的动态特性,定位系统具有良好的误差实时补偿效果,针对X,Y向的振动范围由补偿前的4和3.5μm,补偿后减小到1μm的范围内。结果表明,所研究的振动误差补偿方法可以有效减小定位系统的振动误差,提高系统的定位精度。     

超精密机床宏/微双驱动微位移机构的设计与控制

提出了一种宏/微双驱动微进给机构的设计与控制方法。介绍了宏/微双驱动微位移机构的结构设计,将宏动(大行程)和微动(高分辨率)两者串联以获得理想的运动性能。该机构用步进电机作为宏动的驱动装置以获得大行程和高响应速度,用压电陶瓷微位移器作为精密运动以提高运动分辨率和运动精度。设计了该机构的控制系统,用一个基于模型的开关控制器对微位移装置进行控制,并设计专门的运动分配模块对宏/微运动进行协调控制。最后,分别控制宏动和微动装置对该系统进行了实验,并用激光干涉仪检测。检测结果表明,宏动装置的行程为90 mm,运动分辨率为0.3 μm;压电陶瓷微动装置的行程为40 μm,定位精度为0.9 μm。理论分析和实验结果均表明了控制策略的有效性。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

OPTIMIZATION METHOD ON IMPELLER MERIDIONAL CONTOUR AND 3D BLADE

An optimization method for 3D blade and meridional contour of centrifugal or mixed-flow impeller based on the 3D viscous computational fluid dynamics (CFD) analysis is proposed. The blade is indirectly parameterized using the angular momentum and calculated by inverse design method. The design variables are separated into two categories: the meridional contour design variables and the blade design variables. Firstly, only the blade is optimized using genetic algorithm with the meridional contour remained constant. The artificial neural network (ANN) techniques with the training sample data schemed according to design of experiment theory are adopted to construct the response relation between the blade design variables and the impeller performance. Then, based on the ANN approximated relation between the meridional contour design variables and impeller performance, the meridional contour is optimized. Fewer design variables and less calculation effort is required in this method that may be widely used in the optimization of three-dimension impellers. An optimized impeller in a mixed-flow pump, where the head and the efficiency are enhanced by 12.9% and 4.5% respectively, confirms the validity of this newly proposed method.