基于LS-SVM的一类非线性系统直接自适应H∞输出反馈控制

针对一类状态不可测的单输入单输出非线性不确定系统,提出了一种基于最小二乘支持向量机（LS-SVM）的直接自适应H∞输出反馈控制方法．该方法首先设计一种误差观测器,间接地估计出系统的状态;然后利用LS-SVM构造白适应控制器,并给出了LS-SVM权向量和偏移值的在线学习规则,通过引入如控制器减弱外部干扰及LS-SVM近似误差对输出误差的影响,利用李亚普诺夫理论证明了整个闭环系统的稳定性．仿真研究表明了该控制方案的可行性和有效性．     

具有预设性能的切换系统输出反馈自适应动态面控制

本文针对一类具有未建模动态和预设性能的输出反馈非线性切换系统,提出基于公共Lyapunov函数法的自适应输出反馈动态面控制方案.通过设计K滤波器和观测器估计不可测量的状态.引入动态信号处理动态不确定性.利用Nussbaum函数解决增益符号未知的问题.神经网络用于逼近由设计过程和理论分析所产生的未知连续函数.引入性能函数和误差转换器将预设性能控制问题转换为稳定性问题.通过适当选取切换子系统的初值,并利用动态面控制系统证明的特点,证明了闭环切换系统所有信号半全局一致终结有界.仿真例子验证了所提方案的有效性.     

全状态约束的时滞系统神经网络输出反馈控制

针对一类严格反馈形式的单输入单输出时滞系统,研究在全状态约束下的输出反馈控制.首先,设计状态观测器估计不可测量的状态;其次,利用RBF神经网络逼近未知的非线性函数,利用障碍Lyapunov函数确保全状态约束及Lyapunov-Krasovskii方法消除时滞对系统的影响;最后,设计输出反馈控制器,并且有更少的更新参数减少了计算负荷.所设计的控制器可以保证闭环系统中所有信号半全局一致最终有界,信号误差收敛到小的领域内.仿真例子进一步验证了所提出方法的有效性.     

随机时滞系统的神经网络输出反馈动态面控制

针对一类具有未知控制方向的随机时滞系统设计自适应神经输出反馈控制器.首先,利用状态观测器估计不可测量的系统状态;其次,选择合适的Lyapunov-Krasovskii函数消除未知延迟项对系统的影响,利用Nussbaum-type函数处理系统的未知控制方向问题,通过神经网络逼近未知的非线性函数,以及用动态表面控制(DSC)解决控制器设计中出现的复杂性问题;最后,通过Lyapunov稳定性理论,构造一个鲁棒自适应神经网络输出反馈控制器,可以保证闭环系统中所有信号在二阶或四阶矩意义下一致最终有界,跟踪误差能收敛到零值小的领域内.仿真实例验证了所提出方法的有效性.     

面向控制性能的一类非线性关联系统输出反馈动态面控制

针对一类含有完全未知关联项的多输入/多输出非线性系统,提出了输出反馈动态面自适应控制方案,克服了反推控制中的微分爆炸问题;利用神经网络逼近系统中的未知关联项,对于每个子系统只需对一个参数设计自适应律;引入性能函数和输出误差变换,跟踪误差信号的收敛速率、最大超调量和稳态误差等控制性能指标均可得到保证.理论证明了闭环系统的所有信号半全局一致有界,仿真结果验证了所提方案的有效性.     

传感器电路

<正> 把传感器信号输入到计算机进行处理,将使许多工作变得方便。而作为传感技术系统,A/D(模数)转换器是不可缺少的装置。因为传感器的输出信号几乎都是模拟信号。为此各公司已生产出很多的A/D转换器。本文就基本原理和误差以实际使用方法进行论述。     

STC12C5A60S2与PC机的交流电机闭环调速系统

采用宏晶STC12C5A60S2 (1T)高速单片机和PC机设计了三相异步电机闭环变频调速系统.系统分为下位机和上位机两部分.下位机以STC12C5A60S2单片机为核心,采用片上A/D转换器实现转速给定和反馈;采用D/A转换芯片输出模拟电压,控制西门子工业变频器实现调速.PC机作上位机,采用Visual BASIC配...     

一种速度反馈的简单处理方法

<正> 在单板机组成的控制系统中,如果对电机实行双方向控制,其速度反馈信号有正有负。这时一般多采用双极性的A/D转换处理,但用双极性A/D转换器造价较高。如用单极性A/D转换器,常用的方法是把速     

具有未建模动态和输出约束系统的自适应输出反馈控制

针对一类具有未建模动态和输出约束的输出反馈非线性系统, 提出一种自适应输出反馈动态面控制方案. 利用神经网络逼近未知连续函数, 分别设计K滤波器和动态信号估计不可测量的状态, 并处理动态不确定性. 引入障碍李雅普诺夫函数并设计自适应控制器以保证BLF有界, 从而实现输出约束. 理论分析表明, 闭环控制系统是半全局一致终结有界的, 且满足输出约束, 仿真结果验证了所提出方案的有效性.     

基于遗传算法的输出反馈动态面优化控制

针对一类只有输出信号可测且非线性项含不可测状态的不确定系统,基于输入信号置换思想构建了神经网络状态观测器,结合动态面理论设计了输出反馈自适应控制方案。通过理论分析确定了控制律参数选取范围,保证了闭环控制系统所有信号半全局一致终结有界; 利用遗传算法提出一种参数寻优策略,选取了最优的输入初始值和控制律参数,解决了控制冲击问题,提高了跟踪精度。     

Design and implementation of an autonomous EGR cooling system using deep neural network prediction to reduce NOx emission and fuel consumption of diesel engine

Neural Computing and Applications - This study includes the design of an autonomous exhaust gas recirculation (EGR) cooling system and implementation of the system on diesel engine by using deep...     

Quantitative feedback design of air and boost pressure control system for turbocharged diesel engines

For modern diesel engines, variable geometry turbocharger (VGT) is used to boost engine power output. In addition, exhaust gas recirculation (EGR) is utilized to reduce engine out NO_x emission. To realize these functions, a multivariable control system needs to control both VGT and EGR valve to deliver desired intake manifold (or boost) pressure, and desired EGR flow rate. This two-input and two-output system is nonlinear with cross-couplings between the boost and EGR responses to the input actuators, the system parameters are varying with different engine operating conditions. This paper proposes a closed loop design of a multivariable VGT/EGR control system for a turbocharged diesel engine. The control system is synthesized based on quantitative feedback theory to maintain robust stability and performance via sequential MIMO loop shaping in the frequency domain. Experiment results are included from a turbocharged diesel engine to show the effectiveness of the proposed control design.     

Nonlinear Observer-based Control Design and Experimental Validation for Gasoline Engines with Exhaust Gas Recirculation

This paper presents a nonlinear observer-based control design approach for gasoline engines equipped with exhaust gas recirculation (EGR) system. A mean value engine model is designed for control which includes both the intake manifold and exhaust manifold dynamic focused on gas mass flows. Then, the nonlinear feedback controller based on the developed model is designed for the state tracking control, and the stability of the close loop system is guaranteed by a constructed Lyapunov function. Since the exhaust manifold pressure is usually unmeasurable in the production engines, a nonlinear observer-based feedback controller is proposed by using standard sensors equipped on the engine, and the asymptotic stability of the both observer dynamic system and control dynamic system are guaranteed with Lyapunov design assisted by the detail analysis of the model. The experimental validations show that the observer-based nonlinear feedback controller is able to regulate the intake pressure and exhaust pressure state to the desired values during both the steady-state and transient conditions quickly by only using the standard sensors.     

Control of diesel engine dual-loop EGR air-path systems by a singular perturbation method

This paper presents a singular perturbation based method for controlling the dual-loop exhaust gas recirculation (DL-EGR) air-path systems on advanced diesel engines. A DL-EGR air-path system, consisting of a high-pressure loop EGR (HPL-EGR) and a low-pressure loop EGR (LPL-EGR), has significantly different time-scales (fast and slow) due to the inherent difference in the HPL-EGR’s and LPL-EGR’s corresponding control volumes. Such a feature of the DL-EGR systems makes the cooperative control of intake manifold gas conditions challenging. By considering the DL-EGR air-path system as a singularly perturbed system, a composite control law was devised to achieve systematic control of the air-path conditions including gas pressure, temperature, and oxygen fraction in the intake manifold. The effectiveness of the control method is experimentally evaluated on a medium-duty diesel engine.     

车用氧传感器热应力场的数值分析

车用氧传感器是汽车电控系统的闭环控制（对空燃比）反馈信号发生器,它的作用是将汽车尾气中氧气的浓度信号发送到ECU（电子控制单元）,从而保持空燃比恒定为14．7左右。本文对一种典型的车用氧传感器在汽车启动时产生的热应力情况进行了数值分析,并采用大型通用有限元分析软件ANSYS得到了具体的分析过程和结果。     

嵌入式时栅传感器高精度激励设计方法

介绍了嵌入式时栅传感器的基本原理,分析了两相激励信号不一致性主要是幅值不等和相位不正交对传感器测量精度的影响。基于DDS原理结合反馈控制设计了高精度的激励信号模块,采用反馈电路控制可程控放大电路调理两相信号幅值,实现了激励信号的幅值相等,基于闭环反馈控制直接修改数字激励信号实现了信号的相位正交。实验研究结果表明,采用这种闭环控制的方法,传感器短周期测角误差从±65″降低到±16″左右,常值误差基本消除,传感器精度大幅度提高。     

柴油机排气颗粒物传感器研究综述

柴油机排气颗粒物检测是排放检测与控制的重要部分。介绍了柴油机排气颗粒物车载测试2种测试排气颗粒物的测试方法;重点讨论了颗粒物传感器的研制与应用;分析了目前颗粒物传感器的研究中存在的问题。     

A parameter-varying filtered PID strategy for air–fuel ratio control of spark ignition engines

In this paper, a new synthesis method is presented to control air–fuel ratio (AFR) in spark ignition engines to maximize the fuel economy while minimizing exhaust emissions. The major challenge in the control of AFR is the time-varying delay in the control loop which restricts the application of conventional control techniques. In this paper, the time-varying delay in the system dynamics is first approximated by Padé approximation to render the system dynamics into non-minimum phase characteristics with time-varying parameters. Application of parameter-varying dynamic compensators is invoked to retrieve unstable internal dynamics. The associated error dynamics is then utilized to construct a filtered PID controller combined with a parameter-varying dynamic compensator to track the desired AFR command using the feedback from the universal exhaust gas oxygen sensor. The proposed method achieves desired dynamic properties independent of the matched disturbances. It also accommodates the unmatched perturbations due to the dynamic compensator features. The results of applying the proposed method to experimental numerical data demonstrate the closed-loop system stability and performance against time-varying delay, canister purge disturbances and measurement noise for both port fuel injection engines and lean-burn engines.     

A battery charge controller realized by a flyback converter with digital primary side regulation for mobile phones

A flyback converter with digital control designed and implemented for a lithium battery charging system is proposed in this study. As opposed to the requirement of both voltage and current feedbacks for a conventional flyback converter, this study proposes a converter structure that needs only one voltage feedback to stabilize converter output for implementing the designed battery charging techniques. This single feedback of voltage is made possible by so-called “primary side regulation (PSR)”, which in hardware senses the output voltage using an auxiliary winding in the isolating transformer of the flyback converter that is operated in DC–DC discontinuous current mode. The adoption of PSR also enables the elimination of the opto-coupler that is often used in conventional converters for feedback signals. Another essential part of the converter is the proposition of a new a duty control method which regulate successfully the output current by only one feedback voltage signal. The proposed battery charging design consists of three consecutive modes, trickle current (TC), CC and CV. At TC and CC, a duty control method is adopted, which is able to regulate the output current by sensing only the output voltage. Both simulation and experimental results show a 7 % error deviated from targeted output current. As for CV, a proportional-integral controller is designed and implemented to regulate the output voltage. The overall experimental results show a favorable performance of the proposed charging method with proposed PSR-flyback converter.     

基于遗传算法的小波神经网络在多组分气体检测中的应用

由于利用不分光红外吸收法（NDIR）的多组分气体传感器对汽车尾气（主要成分为CO2、CO、HC化合物）进行同时测量时,所测气体浓度是交叉吸收干扰后的结果,造成测量误差大,分析精度低。针对此问题,将遗传算法优化的小波神经网络用于建立基于红外光谱的三组分气体定量分析模型中。采集CO2、CO、HC的浓度信号,作为模型输入,通过模型回归分析,得到对应的混合气体组分浓度,解决气体之间相互干扰的问题。最后通过实验数据对模型性能进行仿真分析,结果表明,该模型的平均误差相比于传统模型明显减低,取得较好的精度。