数字闭环加速度计系统模型分析与校正设计

模数转换环节引入的精度损失是基于模拟伺服方案的石英挠性加速度计的主要缺陷.提出了一种数字闭环检测方法,该方法在实现加速度信号闭环检测的同时,直接提供数字输出,理论上不存在精度损失.建立了数字闭环检测系统的数学模型,通过阻尼修正部分将摆片的模型改善为最佳阻尼状态,利用积分环节和补偿校正消除系统的一阶静态误差,保证足够的相角裕度.依据国军标测试方法对试验样机进行测试,结果表明:系统超调量在20％左右,-3 dB带宽接近300 Hz.实验结果与理论仿真基本一致,验证了数字闭环检测方法的正确性和可行性.     

时分复用数字闭环电容式微加速度计接口电路

为实现电容式微加速度计的数字输出闭环,设计了一种数字输出闭环ASIC(Application Specific Integrated Circuit)接口电路,以降低电路输出噪声并提高测量量程。对已有的电容式微加速度计ASIC电路进行了改进,分时段在中间极板上加载差分电容读出信号和由脉宽调变(PWM)波控制的反馈信号,然后由控制器实现闭环,利用Sigma Delta调制器实现模数转换。通过分析差分电容读出电路和Sigma Delta调制器的原理和特性,建立了该数字输出闭环电容式微加速度计的模型,进行了系统的设计与仿真。实验结果表明,该数字输出闭环电容式微加速度计的噪声水平为9.6μg/√Hz,量程为±3g。这些结果验证了时分复用方案的可行性和本文所提出模型的正确性。     

结构滤波器在望远镜主轴控制系统中的应用

为了提高望远镜控制系统的闭环带宽和动态性能,研究了结构滤波器对控制系统闭环性能的影响。根据望远镜机械跟踪架的弹簧质量模型推导了系统的传递函数,分析了电机和负载转动惯量与谐振频率的关系,设计了基于系统开环频率特性的结构滤波器。将设计的结构滤波器串联入控制回路,用于减小机械谐振的幅值。介绍了结构滤波器的设计方法,以及加入结构滤波器后对控制系统闭环性能的影响。最后,在2m望远镜跟踪架转台上进行了验证实验。结果表明,加入结构滤波器后系统的闭环带宽由10Hz提高到了13 Hz,有效地抑制了速度的稳态谐振,提高了望远镜控制系统的速度跟踪性能。得到的实验结果验证了结构滤波器能够有效地提高系统的动态性能。     

一种嵌入式虚拟动态信号分析仪的设计

为了实现为远程化控制的光电跟踪系统设计提供抗恶劣环境的设计工具,设计了一种嵌入式虚拟动态信号分析仪。对该系统采用的系统辨识等算法进行研究。基于某型号光电跟踪系统平台,结合虚拟仪器概念和嵌入式技术,建立了嵌入式虚拟动态信号分析仪的系统架构,设计了仪器系统架构中各层软件。利用该仪器测试了实际运行中的某光电跟踪系统速度回路和电流回路,实验结果表明光电跟踪系统满足设计要求,电流回路带宽为266.05Hz,速度回路带宽为20.3Hz,虚拟仪器具有较好的精确度和实用性。满足了光电跟踪系统设计工具准确、方便、快捷等要求,提高光电跟踪系统设计水平和设计效率。     

全角半球谐振陀螺控制回路的动态特性研究

全角半球谐振陀螺是一种高精度、高可靠性、长寿命的速率积分陀螺。 针对全角半球谐振陀螺闭环控制回路的系统带 宽问题,分析了全角半球谐振陀螺的工作原理,分别建立了全角半球谐振陀螺的输入-输出控制回路模型和扰动-输出控制回路 模型。 利用 SIMULINK 工具箱对两种模型进行了搭建和仿真研究,分析了两种控制回路的动态特性,最后进行了全角半球谐振 陀螺的转台实验。 仿真结果显示:外界输入角速度超过 532. 8°/ s 后,扰动信号导致的输出量波动达到最大且保持恒定,此时控 制回路的带宽为 1. 48 Hz。 仿真和实验结果表明:全角半球谐振陀螺控制回路的带宽过低会导致扰动信号引起椭圆参数的波 动,控制效果变差,且扰动信号频率与外界输入转速成正比,当外界输入转速超越控制回路截止频率的对应转速后,椭圆参数的 波动幅值趋于稳定。 本文的研究成果为全角半球谐振陀螺的动态性能分析提供了理论基础。     

利用模拟退火优化快速反射镜控制策略

由于快速反射镜(FSM)系统在不同应用场合下需要不同有效带宽和闭环带宽,本文基于压电FSM控制系统建立系统模型,通过分析系统光轴抖动情况,对FSM控制算法进行了优化。首先,测得系统闭环Bode图,利用模拟退火算法求取系统传递函数;然后,结合辨识模型与模拟退火算法,提出了一种满足不同应用场合的全局最优PID控制器。最后,通过阶跃响应测试验证辨识模型的正确性,通过闭环实验测试验证最优控制器的有效性。结果表明,辨识模型与实际系统在中低频段符合得很好,阶跃响应曲线基本一致。采用最优控制器控制的系统有效带宽为35 Hz,闭环带宽为70Hz,跟踪精度提高了47%,基本满足当前实验环境下对FSM性能的要求。提出的系统显示良好的低频跟随能力和高频干扰抑制能力,跟踪精度高,器件损耗小。     

2D数字伺服阀

2D数字伺服阀的阀体部分采用伺服螺旋机构将阀芯的旋转运动转换为阀芯轴向运动,实现伺服阀液压功率放大,并利用步进电机驱动阀芯在一定的角度范围内运动实现电-机械信号的转换作用。为了保证步进电机作为电-机械转换器具有较高的响应速度和定位精度,应用DSP设计了一种嵌入式数字阀专用控制器,对其进行闭环伺服控制,保证对输入信号的连续快速跟踪,以该控制思想设计的电-机械转换器实现了对步进电机的控制,其频响达200Hz以上。为了获得2D数字伺服阀的性能,建立实验平台对阀的性能进行实验研究。实验结果表明,2D数字伺服阀具有良性的静态特性,其分辨率和滞环皆在1%以内,2D数字伺服阀同时还具有良好的动态特性,在幅值25%的最大阀开口的正弦输入信号下,对应-3dB频宽约为130Hz。     

数字闭环光纤电流互感器动态特性仿真与测试

基于Farady磁光感应原理及数字闭环信号处理技术的光纤电流互感器(FOCT),克服了电磁式电流互感器在暂态响应方面的弱点,满足现代电力系统对电流值实时精确测量的需求.针对数字闭环FOCT的动态特性,分析FOCT功能结构及信号传递过程,建立FOCT的数字闭环反馈模型,推导FOCT的传递函数,评估FOCT的幅频特性、相频特性、动态范围及频响特性;将故障瞬态电流的数学模型与FOCT的闭环反馈模型相结合,仿真FOCT对故障电流的暂态响应能力;构建电流实验平台,完成FOCT的动态性能测试.仿真与实验结果表明:FOCT的频带宽度大于7 kHz,电流测量范围可达200 kA,具有50次谐波的测量能力,并且FOCT的动态测量能力可根据具体应用需求调整.     

动力调谐陀螺再平衡回路数字化的研究与实现

为克服模拟再平衡回路时由控制补偿和温度补偿引起的各种问题,研究了动力调谐陀螺仪再平衡回路的数字化设计和实现方法。采用基于DSP的SVPWM数字化方法设计了频率可调的高精度三相逆变电源,解决了传统陀螺电机电源频率调整困难、相位稳定性低、效率低等问题;基于dSPACE半实物仿真系统设计了双输入双输出频率特性分析仪,辨识出数字再平衡回路的开环离散传递函数矩阵;利用矩阵求逆法与经典控制器设计方法设计了数字解耦合校正环节,使陀螺系统能够获得更好的动态性能。实验结果表明:所设计的陀螺电机电源频率稳定性优于±1.5×10^－6,波形失真度＜5%,满足陀螺使用要求;控制后的锁定回路带宽＞70Hz,阶跃响应超调量＜5%,上升时间＜5ms,输入信号频率为10Hz时,两轴交叉耦合＜1%。在保证稳定裕度的前提下,实现了比模拟再平衡回路更好的系统动态性能,为深入研究现代控制方法在动调陀螺再平衡回路中的应用奠定了基础。     

一种石英挠性加速度计表头参数辨识方法研究

由于石英挠性加速度计表头参数理论值与实际值不一致,会影响加速度计的一些性能指标。为了获得石英挠性加速度计正常工作下的实际表头参数,研究了采用电激励法测试加速度计系统的闭环幅频特性,在幅频特性测试数据的基础上,运用MATLAB中的最小二乘曲线拟合方法编制程序辨识出石英挠性加速度计表头的3个参数。结果表明,这种方法简单可行,具有很大的实用性。     

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.     

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。     

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.     

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...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

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.