加热炉炉温智能控制系统的一种设计方案

针对步进式加热妒炉温控制系统中存在时变、非线性等特征,设计了燃气、空气回路流量设定值调节系统,并在该系统中了采用RBF神经网络整定PID控制器参数;针对炉温控制系统中参数耦合和系统模型不确定的问题,分别在燃气和助燃空气回路中设计了一种基于最小二乘支持向量机(LS-SVM)的逆控制解耦系统,并对燃气和空气回路流量设定值进行动态跟踪.仿真结果表明:该步进式加热炉炉温智能控制系统具有鲁棒性好、抗干扰能力强、超调小,动态跟踪品质好和稳态精度高等特点.     

直驱式永磁风力发电机软并网与功率调节的控制集成

为实现直驱式永磁同步风力发电机无冲击并网与风能最大跟踪控制, 设计了一种软并网与功率调节一体化的控制集成装置. 基于广义功角特性, 提出了一种对逆变器输出功率进行直接控制, 从而实现最大风能跟踪的控制策略. 新的控制策略可使发电机的转速按所期待的动态运动, 因而具有良好的静态与动态性能. 另外, 该控制律中对电机参数具有很强的鲁棒性, 因而该控制器能适应各种不同参数的同步风力发电机, 成为同步风力发电并网与功率调节的独立装置.     

四旋翼飞行器带速度补偿的多回路PID位置跟踪控制

针对四旋翼飞行器的位置跟踪问题,采用ADAMS(automatic dynamic analysis of mechanical system)软件搭建了四旋翼飞行器的非线性数学模型,并将模型导入到Matlab中,采用多回路PID位置控制策略对飞行器的位置跟踪进行控制,并在此基础上提出采用速度PID进行补偿多回路PID的位置跟踪控制策略.仿真结果表明:所设计的速度PID对多回路PID的位置跟踪控制策略进行补偿,对于四旋翼飞行器位置控制具有响应速度快、超调小、鲁棒性强等特点;所采用的联合仿真方法效果直观.     

进气道调节系统数字式控制器的控制策略分析

飞机进气道调节系统使用数字式控制器与进气道斜板位置传感器,形成斜板控制指令,改变进气道斜板开度,使进气道和发动机流量匹配。基于进气道调节系统的工作原理及系统结构,利用Simulink建立仿真模型,分析进气道调节系统数字式控制器的控制策略,提出基于线性叠加原理的调节电压输出控制策略,并通过进气道斜板的阶跃响应,验证采用此控制策略的数字式控制器的超调量和响应时间可以满足进气道调节系统的动态特性需求。     

LPV动态补偿的风能转换系统变桨距控制

当风速超过额定值时,风能转换系统需要控制节距角来实现额定恒功率控制.同时控制电机电磁转矩使转速维持在其额定值以减少系统振荡.建立了风能转换系统的机理模型并得到其线性参数变化(LPV)系统模型;在多变量(MV)控制策略的基础上,设计了基于LPV模型的增益调度控制器,对节距角和电磁转矩进行动态补偿;基于dSPACE的风能转换系统硬件在回路仿真平台进行实验研究,结果表明补偿后系统的功率误差更小,电机转速及转矩的波动明显减小,体现了更好的动态性能.     

基于转速反馈的动力翼伞纵向串级控制

为提高动力翼伞纵向跟踪效果,并针对现有模型及控制方法的局限性,着眼于实际飞行试验,提出一种基于转速反馈调节的串级自抗扰控制策略.首先在动力翼伞纵向模型的基础上,改进引入无刷直流电机模型,并利用转速测量装置实时更新电机转速信息,应用最小二乘法拟合电机转速与螺旋桨静推力的非线性关系.设计纵向轨迹控制器,内环实现对电机转速的...     

一种高超音速飞行器轨迹线性化控制方法研究

研究一种新的非线性控制结构.针对强非线性和不确定性高超音速飞行器,对跟踪性能和鲁棒性提出更高要求的特点,内环快回路通过动态逆的方法来设计,保证飞行器的性能,外环慢回路用轨迹线性化的方法进行跟踪控制;并提出了一种基于小脑模型关节控制器(Cerebellar Model Articulation Controller,CMAC)的神经网络自适应逆控制策略以提高系统的鲁棒性,对算法收敛条件和控制器稳定性进行了证明.最后利用改进设计方案在高超音速飞行条件下进行仿真验证.仿真结果表明整个控制系统具有很好的跟踪性能和鲁棒性.     

霍尔阀门控制器的设计

针对单纯电动的阀门只是可以调节阀门开关而不能调节其流量这一状况,提出了设计一种新型可调流量的阀门控制器,利用霍尔元器件可以解决转速的问题,主要是利用STC12C5608AD单片机来记录转速、控制转速,从而来实现对阀门的开度进行精确调节。这样就可以对阀门的流量进行合理地控制,从而提高其流量的精确度。     

粘度测量直流电机调速系统自适应控制器的建模与仿真

基于旋转法的液体粘度测量需要不同等级稳定的电机旋转速度。采用电流转速双闭环来实现对直流电机调速系统的控制。电流内环使用PI控制,转速外环采用大增益比例控制结合PID控制,PID参数使用模糊逻辑进行自整定,这种控制方式可根据输入偏差大小选择不同控制策略实现转速的自适应快速调节与准确跟踪。在Matlab/Simulink平台上搭建基于这种控制器的仿真模型,对直流电机调速系统进行仿真。仿真结果表明这种系统具有良好的控制性能,这种自适应控制器具有良好的动态响应特性,可以消除稳态误差。     

离心泵变频调速与节流分程协调节能控制

离心泵的变频调速是目前广泛采用的流量调节方法,高效节能是其最大优点,但是当流量降低时,可能造成压头过低而影响后续流程.对此,提出离心泵的变频调速与节流分程协调节能控制方法,当阀后压力大于一定值时,由流量控制器调节离心泵转速以改变泵的出口流量,当阀后压力小于一定值时,由流量控制器调节阀门开度以保持控制点需要的实际压头基本恒定,而中间段由转速和阀门开度协调控制,从而能够同时满足管路控制点所需的压力及流量.实验模拟效果证明了控制方案的可行性,并且流量与压力二者分程协调控制的节能效果显著.     

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.     

Unified FDI and FTC Scheme for Air Path Actuators of a Diesel Engine Using ISM Extended with Adaptive Part

A unified fault detection and isolation (FDI) and fault tolerant control (FTC) strategy for the diesel engine's air management system has been formulated. Diesel engines need to comply with the strict emission requirements for which they are equipped with specialized sub‐systems for the purpose, such as the variable geometry turbo (VGT) charger and exhaust gas recirculation (EGR). Hardware‐based controls tend to make the system more complex and prone to structured and unstructured faults. This calls for an advanced FTC technique that can ensure desired level of emissions even in the presence of minor system malfunctions. The scheme proposed in this paper detects, isolates and estimates the structured faults and minimizes their effects by re‐positioning the actuators using integral sliding mode (ISM) control. Estimating the magnitude of structured faults help to reduce the ISM controller gains, eventually reducing the chattering. The stability of the system is analyzed using Lyapunov stability criterion. Simulations have been performed using fully validated industrial scale model of a diesel engine to elucidate the effectiveness of our scheme.     

Diesel engine air path control based on neural approximation of nonlinear MPC

This paper deals with a control design problem for a diesel engine air path system that has strong nonlinearity and requires multi-input and multi-output control to satisfy requirements and constraints. We focus on a neural network based approximation of nonlinear model predictive control (NMPC) for high-speed computation. Most neural approximation methods are verified only through simulation; further, the influence of approximation on the closed-loop performance has been not sufficiently discussed. In this study, we discuss this influence, and propose a new method to improve stability against degradation due to an approximation error. The control system is assembled using a neural network based controller, obtained by the proposed method, and an unscented Kalman filter. This system is verified both numerically and experimentally; the results demonstrate the capability of the proposed method to track the boost pressure, EGR rate, and pumping loss according to the reference values, and satisfy the constraints of compressor surge and choke. The high computation speed that can be achieved using a standard on-board ECU is also demonstrated using the approximated controller.     

基于观测器的发动机转矩跟踪模型预测控制

针对如何实现发动机转矩快速精准地跟踪期望转矩的问题,提出一种基于观测器的模型预测控制策略.首先,利用均值模型对汽油发动机的进气歧管压力动态、转矩和转速动态进行建模,考虑到发动机真实转矩不可测的情况,采用Lyapunov稳定性理论和可测转速信号设计观测器对进气歧管压力进行在线估计,进而获得发动机的实时估计转矩;然后,利用基于观测器的模型预测控制算法设计转矩跟踪控制器,通过C/GMRES数值优化算法在线求解滚动时域优化问题,实现转矩的实时跟踪控制;最后,利用汽油发动机实验台进行实验验证以表明所提出算法的有效性.     

Soot emission prediction of a waste-gated turbo-charged DI diesel engine using artificial neural network

This study is about soot emission prediction of a waste-gated turbo-charged DI diesel engine using artificial neural network (ANN). For training the ANN model, six ranges of experimental data in previous study were used, and one range of data was kept for testing the accuracy of ANN predictions. The input parameters for the ANN are inlet manifold pressure, inlet manifold temperature, inlet air mass flow rate, fuel consumption, engine torque, and speed. Output parameter is the density of soot in the exhaust. The results show the ANN approach can be used to accurately predict soot emission of a turbo-charged diesel engine in different opening ranges of waste-gate (ORWG). Root mean-squared error (RMSE), fraction of variance (R ²), and mean absolute percentage error (MAPE) for predictions were found to be 1.19 (mg/m³), 0.9998, and 6.4%, respectively.     

Robust oxygen fraction estimation for conventional and premixed charge compression ignition engines with variable valve actuation

In-cylinder oxygen fraction serves as a critical control input to advanced combustion strategies, but is extremely difficult to measure on production engines. Fortunately, the in-cylinder oxygen levels can be estimated based on accurate estimates or measurements of the oxygen fraction in the intake and exhaust manifolds, the in-cylinder charge mass, and the residual mass. This paper outlines such a physically based, generalizable strategy to estimate the in-cylinder oxygen fraction from only production viable measurements or estimates of exhaust oxygen fraction, fresh air flow, charge flow, fuel flow, turbine flow and EGR flow. While several of these flows are accurately measured or estimated, significant errors in the turbine and EGR flows are commonly observed and can highly degrade the accuracy of any calculations which utilize these flows. An EGR flow estimator was developed to improve the accuracy of this flow measurement over the stock engine control module (ECM) method and is detailed in this paper. Furthermore, the in-cylinder oxygen estimation algorithm is developed, and proven, to be robust to turbine flow errors. Regulation of in-cylinder oxygen levels is of interest for not only in conventional combustion modes but also in advanced combustion strategies such as premixed charge compression ignition. The proposed oxygen fraction estimator is designed such that its performance and stability is ensured in both conventional and advanced combustion modes. The model-based observer estimates the oxygen fractions to be within 0.5% O₂ and is shown to have exponential estimator error convergence with a time constant less than 0.05 s, even with turbine flow errors of up to 25%.     

增程器用天然气发动机转速双闭环自适应控制

针对增程器用天然气发动机参数不确定,输出扭矩难以精确计算,存在未知干扰,且需要大范围调速等问题,设计发动机转速的双闭环自适应控制策略,并分析系统的稳定性.所提策略的外环为发动机转速环,控制器输出为目标进气压力,内环为进气歧管压力环,控制器输出为节气门开度.该策略结构简单,不需要知道发动机各个参数的具体值,抗干扰性能强,能够满足增程器发动机大范围调速的特点.分别在Matlab/Simulink平台和增程器台架上验证了所提策略的有效性和实用性.