基于DSP智能型积分器设计

传统模拟积分器由于运放和积分电容的不理想,存在着零点漂移、非线性误差以及泄漏等问题。当积分时间t不断增加时,积分漂移随之线性增加,成为影响积分输出精度的重要因素之一。利用DSP算法灵活性以及其信号处理的卖时性,设计了一种智能型积分器。该积分器前端采用模拟积分器,后端采用DSP线性拟合算法处理进行积分补偿,实现对信号的长时间积分。同时采用Iqmath库函数实现定点处理器的运算来提高实时精度,很方便的实现了实时而准确的积分处理。     

基于PXI的数字式长时间积分器

传统模拟积分器存在着零点漂移、非线性误差和电容泄漏等问题,通过对传统模拟积分器及数字式积分器的深入调研,以及PXI系统的学习,设计了基于PXI的数字式长时间积分器,该积分器减小了非线性误差和泄漏现象。主要思想是首先对信号进行数字积分,然后通过某种算法扣除数字积分的零漂,来修正积分结果。测试结果证明基于PXI的数字式长时间积分器有效地降低了零点漂移,比传统模拟积分器更加灵活的功能。     

基于PXI的长时间低零漂斩波式积分器

为了避免传统模拟积分器积分电容泄漏,减小简单数字式积分器前端模拟器件的固有噪声及A/D的量化等误差,设计了基于PXI的长时间低零漂斩波式积分器系统。该系统由PXI机箱、数据采集卡和前端信号处理模块组成硬件平台,对信号进行调理和采集,采样率达到200 kS/s,LabVIEW语言和RTX实时系统构成软件设计平台,对信号进行积分、实时扣除零漂等软处理。通过对系统的测试,此积分器有效地降低了零点漂移,比传统模拟、数字积分器具有更加优越的性能。     

模型参考自适应控制的慢漂移分析

近年来,对完全模型匹配的MRAC已有许多研究,尤为重视MRAC的慢漂移不稳 定[1-7],但其机理并非很清楚. 本文用均值平衡位置内摄动分析法,分析了有正态零均值噪音及有未建模动态时MRAC 的慢漂移.指出用Ляцунов稳定性理论或超稳定性理论设计的自适应控制器中,完成相乘项 和平方项的积分,是MRAC慢漂移及慢漂移不稳定的根源.在MRAC中唯取缔积分器及相 乘项才能有转机.     

自动补偿低零漂积分器设计

传统模拟积分器存在着零点漂移、非线性误差和泄漏等问题,通过对其进行的深入调研,给出了实际积分电路的误差分析;提出一种自动补偿零漂的方法,采用CPLD控制时序,给出了两种实现方案,并对这两种方案做了比较;设计的积分器在100 s内漂移很低,在此基础上,提出了一种改进型积分器。比单个积分器效果更好,能够满足现有HT-7超导托卡马克实验的需要。     

压电式多功能冲击、振动测量仪设计

本文介绍以电荷放大器为主体的压电式宽频带多功能冲击、振动测量仪设计中的几个问题:高阻抗、低噪声、低漂移输入级设计;前馈及高速扩张电路设计;新型有源积分器的最佳参数及积分归一化电路设计。文中还给出该仪器样机的主要技术指标。     

混合式积分器

本文介绍一种由混合电路组成的新型积分器。该积分器克服了以往积分器最大的不足——漂移,并具有精高度,稳定性好,体积小的特点。目前已在某些自动控制系统中得到应用。     

基于非延时积分器Delta-Sigma调制的电容传感器探测电路

研究一种基于非延时积分器Delta-Sigma调制的差分电容探测接口电路,该电路的Delta-Sigma调制使用非延时积分器将采样与积分同时进行,减小普通Delta-Sigma调制型电容探测电路中积分保持阶段的电荷泄露效应,仿真结果表明该结构可明显提高探测较小电容的信噪比,增加了调制器可探测电容的动态范围.     

一种洛伦兹力微机械谐振磁传感器建模及数值仿真

针对微机械洛伦兹力谐振磁传感器灵敏度受驱动控制电路和谐振频率漂移影响问题,利用平均周期法分析了鉴相器为异或门的锁相环频率跟踪电路的动力学模型,并求解出频率跟踪的稳定条件和稳态振幅平衡点.设计的磁传感器数值建模及仿真实验表明:当锁相环积分器系数小于临界值时,环路频率跟踪稳定;当锁相环积分器系数大于临界值时,频率跟踪振荡;稳态振幅与理论分析一致,灵敏度与接口电路无关;频率跟踪动态过程与压控振荡器初始频率ω0、积分系数kI、滤波器时间常数ξ有关.     

基于积分自整定模糊控制的无刷直流电机伺服系统

为了解决基本模糊控制稳态精度欠佳的问题，提出无刷直流电机伺服系统积分自整定模糊控制器设计方法。该方法在基本模糊控制的基础上增加一个系数自整定积分器，根据实际工程经验并采用模糊控制规则确定积分因子，从而自动地调整积分系数。仿真结果表明，积分自整定模糊控制的动态和稳态性能均优于常规模糊控制。     

基于改进型积分器的直接转矩控制的仿真研究

目前,在直接转矩控制中大多采用电压模型来估算定子磁链.然而由于纯积分环节存在直流偏移和初始值误差,会使得估算的定子磁链不准确,特别在低速时会使整个系统性能下降.采用了一种改进的积分器来消除纯积分环节产生的直流偏移和初始值误差对电压模型定子磁链观测器的影响.该积分器采用自适应控制自动调整磁链补偿量到最优值,并且通过坐标变换将幅值和相位分离,在调整幅值的同时,保持磁链的相位不发生变化,从而从本质上消除了纯积分直流偏移和初始值问题,同时还能保证定子磁链辨识无稳态误差,适合于直接转矩控制系统低速情况下使用.仿真结果验证了这种方法的有效性.     

一种新型的改进型积分器定子磁链观测器

在直接转矩控制电压模型定子磁链观测器中,常用一阶低通滤波器代替纯积分器,解决纯积分环节存在的直流偏移和初始值误差,但却在磁链观测中产生了幅值和相位误差,使得估算的定子磁链不准确.一种新型的基于模糊截止频率可调的改进型积分器定子磁链观测器采用模糊控制器,根据感应电机的运行状态实时在线地调整低通滤波器的截止频率,减小了由于使用低通滤波环节而带来的磁链幅值和相位误差,从而提高了磁链观测的精度.在MATLAB6.5/SIMULINK下,对基于模糊截止频率可调的定子磁链观测器的直接转矩控制进行了仿真,仿真结果验证了这种方法的有效性.     

Finite-time state-feedback control for a class of stochastic high-order nonlinear systems

This paper discusses the problem of global finite-time stabilization in probability for a class of stochastic high-order nonlinear systems whose drift and diffusion terms satisfy lower-triangular growth conditions. By adopting adding one power integrator technique and constructing twice continuous differential Lyapunov functions, a continuous state-feedback controller is recursively designed. Based on stochastic finite-time stability theorem, it is proved that the solution of the closed-loop system is finite-time stable in probability. Several simulation examples are given to illustrate the effectiveness of the proposed design procedure.     

Global finite-time stabilisation for a class of stochastic nonlinear systems by output feedback

In this paper, the problem of global finite-time stabilisation by output feedback is considered for a class of stochastic nonlinear systems. First, based on homogeneous systems theory and the adding a power integrator technique, a homogeneous reduced order observer and control law are constructed in a recursive manner for the nominal system. Then, the homogeneous domination approach is used to deal with the nonlinearities in drift and diffusion terms; it is shown that the proposed output-feedback control law can guarantee that the closed-loop system is global finite-time stable in probability. Finally, simulation examples are carried out to demonstrate the effectiveness of the proposed control scheme.     

一种高精度磁性参数测试仪设计

设计了一种高精度磁性参数测试仪。该仪器以TMS320F2812为处理器,采用12位串行A/D TLC2588进行数据采集。使用复化Newton-Cotes数字积分算法快速求取磁通值,不仅可以很好地解决模拟积分器带来的零漂问题,而且也提高了积分精度。采用软件实现IIR数字滤波和系统零点的自动修正和补偿。同时通过数字压控恒流源和开关电源技术实现充退磁。与传统的磁性参数测试仪相比,该测试仪具有测试精度高、数据重复性好、性能稳定等特点。     

Output-feedback adaptive stabilization control design for non-holonomic systems with strong non-linear drifts

This paper investigates the problem of output-feedback adaptive stabilization control design for non-holonomic chained systems with strong non-linear drifts, including modelled non-linear dynamics, unmodelled dynamics, and those modelled but with unknown parameters. An observer and an estimator are introduced for state and parameter estimates, respectively. By using the integrator backstepping approach and based on the observer and parameter estimator, a constructive design procedure for output-feedback adaptive stabilization control is given. It is shown that, under some conditions, the control design ensures the closed-loop system is globally asymptotically stable when there is no non-linear drift in the first subsystem, and semiglobally asymptotically stable, otherwise. An example is given to show the effectiveness of the theory.     

Global adaptive output feedback control for a class of stochastic nonlinear systems with unknown homogeneous growth rates

This article focuses on the adaptive output feedback stabilization for a class of stochastic nonlinear systems whose drift and diffusion terms satisfy homogeneous growth conditions. Since the homogeneous growth rates are unknown, two dynamic gains are coupled into the full-order homogeneous observer. By virtue of adding a power integrator technique and the homogeneity theory, two adaptive laws and a homogeneous output feedback controller are designed. Based on the celebrated nonnegative semimartingale convergence theorem and the general stochastic Barbˇlat's lemma, it is indicated that all the signals of the closed-loop system are bounded almost surely, and all the system states of the closed-loop system converge to origin almost surely. Finally, the effectiveness of the proposed control scheme is verified by means of both numerical and practical examples.