Modeling And Robust Pi Control Of A Fluidized Bed Combustor For Sewage Sludge

Based on experimental data, a fluidized bed combustor is modeled as an interval system. Severe model uncertainty and large time delays lead to the main difficulties in solving the control problem. The design uses the stability test of closed‐loop systems as the main guideline for developing a robust PI controller. In particular, a new formula to compute the maximal magnitude of an edge rational function at a fixed frequency is derived, which provides a way to deal with time delay by transforming it into multiplicative uncertainty. Both the theoretical and the experimental results show that the designed PI controller can satisfy the desired performance requirements.     

基于预测控制的刨花板施胶比值系统研究

在刨花板生产线施胶过程中,刨花施胶精度对刨花板的物理性能和环保性能影响较大。为了提高刨花施胶效果,设计了基于KPFC-PI的比值控制系统,将比值器和PFC作为控制系统外环,用以提高胶液流量按照比值工艺跟踪刨花流量的速度和鲁棒性,系统内环路采用PI控制器,增强系统抗干扰性,并通过调节PI参数,拟合简化整个内环路,作为外环PFC的一阶加纯滞后广义处理对象,用来减少干扰引起的偏差。通过仿真实验,说明了该控制器与PID控制相比,可有效提高刨花板施胶精度、保持施胶量稳定性和具有较强抗干扰性能。     

DC/DC升压变换器自抗扰控制

本文设计了一种线性自抗扰控制器,直接对DC/DC升压变换器的电感电流实施控制,以抑制系统非最小相位特性时控制性能的影响.在此基础上,外环采用一个PI控制器对输出电压进行控制,并把电压控制器的输出作为内环电感电流控制的参考输入.由于自抗扰控制器则是一种不依赖丁系统模型的控制方法,因此被控系统不但具有良好的动态特性,而且对...     

积分加纯滞后系统的双预测PI控制及其应用

Smith预估控制器控制积分加大纯滞后过程时,鲁棒稳定性差,输出存在静态余差,无实际应用价值.提出了一类基于该过程的双预测PI控制器:具有内环和外环两种预测PI控制器.内环将系统稳定,外环消除输入干扰的影响和改善控制系统的动态性能.这种控制器结构简单,可调参数少,参数的调节方便、直观.仿真和实际应用表明:在干扰和模型失配的情况下,此类控制器仍然具有良好的控制性能和鲁棒稳定性能,是一种值得在实际工程中推广应用的新型控制器.     

飞翼布局无人机控制律设计

以某飞翼布局无人机为设计对象,进行内、外回路的控制律设计.在Matlab/Simulink仿真环境下,建立飞翼布局无人机线性小扰动模型,分析纵向、横航向模态特性,根据本体特性缺陷针对性地设计控制律内回路反馈支路及增益,经反馈补偿后的飞行品质满足GJB 185-1986相关要求.在内回路控制律的基础上设计外回路PI控制器...     

基于模糊线性自抗扰的柔性多状态开关控制研究

为抑制系统干扰对三端口柔性多状态开关(FMSS)直流侧电压的影响,提出了一种基于模糊线性自抗扰控制(LADRC)的三端口FMSS控制策略。首先,根据LADRC算法设计出LADRC控制器来替代电压外环和电流内环中的PI控制器,以此增强系统的抗干扰性能;其次,通过模糊控制改进电流内环的LADRC控制器,从而得到一种用于干扰抑制的模糊LADRC控制器,实现控制器参数可随扰动实时变化,以达到抑制干扰的目的;最后,在MATLAB/Simulink中建立三端口FMSS仿真模型,对控制策略进行仿真验证。仿真结果表明,与采用LADRC控制策略相比,所提控制策略具有更好的抗干扰性能和稳定性,能有效地抑制FMSS直流侧电压波动。     

基于PID和LQR的四旋翼无人机控制系统研究

为提高四旋翼无人机的飞行稳定性、无人飞行器控制系统的鲁棒性和控制精度,以建立的四旋翼无人机飞行控制系统模型为基础,采用现代控制理论与传统控制论相结合的方法,针对姿态角速率、姿态角分别设计内环LQR(线性二次型调节器)控制器,及外环PID控制的双回路闲环控制器.充分利用PID控制器易于掌握且对模型要求精度低、LQR控制器能改善内回路的动态特性和稳态性能的特点,完成四旋翼无人机的飞行控制.通过实验遴选该双闭环控制器相关参数并进行优化,实验结果表明所设计的双回路控制器控制性能指标良好.     

Robust Flight Control Using Nonsmooth Optimization for a Tandem Ducted Fan Vehicle

This work addresses the aerodynamic modeling and near‐hover‐flight control design for an unconventional aerial robot of the tandem ducted fan configuration, which is intended to be prototypical of a flight service vehicle. The main model elements of this novel unmanned vehicle, which exhibit highly nonlinear and unstable open‐loop modes, are presented. A frequency‐domain controllability analysis concerning the plant's behavior around the hovering flight condition is then adopted to determine the expected control performance, which is of important practical significance to controllability improvement through vehicle design changes. A robust controller that stabilizes the unmanned vehicle under wind disturbances is designed using a newly developed nonsmooth optimization algorithm, which rigorously and efficiently tunes the arbitrarily predefined structured controller against multiple control requirements. A successive two‐loop architecture is employed in the designed controller. In this architecture, the inner loop provides stability augmentation and decoupling, and the outer loop guarantees the desired velocity tracking performance. Simulation results under stochastic wind gusts are presented to verify the performance of the proposed controllers. Preliminary flight tests are also carried out to demonstrate the performance of the system.     

几种不稳定滞后对象的预测PID 控制

针对几种不稳定滞后过程，给出一种预测PID控制器的结构形式．该控制器具有内环和外环两种控制器：内环控制器主要用于稳定系统；外环控制器具有预测PID控制的结构形式，主要用于消除输入干扰的影响和改善控制系统的动态性能．这种控制器结构简单，可调参数少，且参数的调节方便、直观．仿真结果表明，在干扰和模型失配的情况下，此类预测PID控制器仍具有良好的控制性能和鲁棒稳定性能．     

奇异时滞系统对时滞参数的自适应控制

针对一类状态时滞奇异系统,研究状态反馈控制器的设计问题。基于Lyapunov稳定性理论和线性矩阵不等式（LMI）工具,当时滞常数精确已知时,设计带有记忆的状态反馈控制器,使得相应的闭环系统渐近稳定;当时滞常数不能精确已知时,通过求解相应的线性矩阵不等式,得到满足设计要求的对时滞参数的自适应控制器,使得时滞系统镇定。最后,仿真实例表明此方法的有效性。     

Closed-loop analysis and control of a non-inverting buck–boost converter

In this article, a cascade controller is designed and analysed for a non-inverting buck–boost converter. The fast inner current loop uses sliding mode control. The slow outer voltage loop uses the proportional–integral (PI) control. Stability analysis and selection of PI gains are based on the nonlinear closed-loop error dynamics incorporating both the inner and outer loop controllers. The closed-loop system is proven to have a nonminimum phase structure. The voltage transient due to step changes of input voltage or resistance is predictable. The operating range of the reference voltage is discussed. The controller is validated by a simulation circuit. The simulation results show that the reference output voltage is well-tracked under system uncertainties or disturbances, confirming the validity of the proposed controller.     

基于MPC的无传感器永磁同步电机NFTSMC仿真研究

为了提高注塑机中永磁同步电机控制系统的运行可靠性,优化永磁同步电机的调速系统动态性能,提出了一种基于模型预测电流控制的无速度传感器永磁同步电机非奇异快速终端滑模控制策略.以模型预测电流控制作为电流控制内环,取代传统的PI调节器,能够有效地抑制电流纹波,提高电流的动态跟踪性能.根据非奇异终端滑模的设计原理,构造外环速度控制器,从而生成期望的q轴电流,提高了系统的稳定性.设计无速度传感器对电机运行转速进行在线辨识,实现对转速和转子位置准确地估计.并与传统的PI调节器进行对比,仿真与实验结果表明该控制策略具有较高的可靠性和快速性.     

Plasma vertical stabilization with actuation constraints in the DIII-D tokamak

In the advanced tokamak (AT) operating mode of the DIII-D tokamak, an integrated multivariable controller takes into account highly coupled influences of plasma equilibrium shape, profile, and stability control. Time-scale separation in the system allows a multi-loop design: the inner loop closed by the nominal vertical controller designed to control a linear exponentially unstable plant and the outer loop closed by the nominal shape controller designed to control a linear stabilized plant. Due to actuator constraints, the nominal vertical controller fails to stabilize the vertical position of the plasma inside the tokamak when large or fast disturbances are present or when the references coming from the shape controller change suddenly. Anti-windup synthesis is proposed in this paper to find a nonlinear modification of the nominal vertical controller that prevents vertical instability and undesirable oscillations but leaves the inner loop unmodified when there is no input saturation.     

Robust control of a family of uncertain nonminimum‐phase systems via continuous‐time and sampled‐data output feedback

The problem of global robust stabilization is studied by both continuous‐time and sampled‐data output feedback for a family of nonminimum‐phase nonlinear systems with uncertainty. The uncertain nonlinear system considered in this paper has an interconnect structure consisting of a driving system and a possibly unstable zero dynamics with uncertainty, ie, the uncertain driven system. Under a linear growth condition on the uncertain zero dynamics and a Lipschitz condition on the driving system, we show that it is possible to globally robustly stabilize the family of uncertain nonminimum‐phase systems by a single continuous‐time or a sampled‐data output feedback controller. The sampled‐data output feedback controller is designed by using the emulated versions of a continuous‐time observer and a state feedback controller, ie, by holding the input/output signals constant over each sampling interval. The design of either continuous‐time or sampled‐data output compensator uses only the information of the nominal system of the uncertain controlled plant. In the case of sampled‐data control, global robust stability of the hybrid closed‐loop system with uncertainty is established by means of a feedback domination method together with the robustness of the nominal closed‐loop system if the sampling time is small enough.     

Cascade direct adaptive fuzzy control design for a nonlinear two-axis inverted-pendulum servomechanism.

This paper presents and analyzes a cascade direct adaptive fuzzy control (DAFC) scheme for a two-axis inverted-pendulum servomechanism. Because the dynamic characteristic of the two-axis inverted-pendulum servomechanism is a nonlinear unstable nonminimum-phase underactuated system, it is difficult to design a suitable control scheme that simultaneously realizes real-time stabilization and accurate tracking control, and it is not easy to directly apply conventional computed torque strategies to this underactuated system. Therefore, the cascade DAFC scheme including inner and outer control loops is investigated for the stabilizing and tracking control of a nonlinear two-axis inverted-pendulum servomechanism. The goal of the inner control loop is to design a DAFC law so that the stick angle vector can fit the stick angle command vector derived from the stick angle reference model. In the outer loop, the reference signal vector is designed via an adaptive path planner so that the cart position vector tracks the cart position command vector. Moreover, all adaptive algorithms in the cascade DAFC system are derived using the Lyapunov stability analysis, so that system stability can be guaranteed in the entire closed-loop system. Relying on this cascade structure, the stick angle and cart position tracking-error vectors will simultaneously converge to zero. Numerical simulations and experimental results are given to verify that the proposed cascade DAFC system can achieve favorable stabilizing and tracking performance and is robust with regard to system uncertainties.     

基于功率控制的三相电压型PWM整流器控制器设计

提出基于功率控制的三相电压型PWM(pulse width modulation)整流器控制器设计方法。根据能量守恒原理建立的VSR(voltage source rectifier)数学模型可通过忽略回路电阻及电感充放电所消耗的能量等效成线性定常系统。系统外环采用电容储能控制,内环采用电流控制,同时引入直流负载功率补偿,实现对电容储能变化率的直接控制。电流内环采用前馈解耦PI(proportional-integral)控制,将内环等效成一阶惯性环节。电容储能外环采用PI控制,利用代数分析及根轨迹分析,提出外环PI参数的设计方法。VSR系统整体等效为二阶系统。仿真结果表明：本文所提出的控制器设计方法能使得VSR达到优异的性能。     

Design of low cost universal artificial neuron controller for chopper fed embedded DC drives

Artificial neural network (ANN) has become very popular in many control applications due to their high computation rate and ability to handle nonlinear functions. This paper proposes an artificial neuron controller for closed loop speed control of DC drive fed by DC chopper. Neuron control is used to reduce the steady state error, overshoot and settling time. The signal corresponding to the motor speed error and change in speed error are used as inputs to ANN Controller. The controller outputs the required change in duty cycle of pulse width modulated gating signal applied to DC chopper. Thus the voltage fed to the armature of the DC motor is adjusted for achieving the desired speed response. The training patterns for the neuron controller are obtained from the conventional PI controller and the effectiveness of the proposed neuron controller is studied using simulation studies.The designed controller was implemented in a low cost 8051-based embedded system and the results are documented. Two-loop control system was implemented with an inner ON/OFF current controller and an outer ANN speed controller.A conventional controller has heavy computation burden whereas a trained neural network requires less computation time. The artificial neural network has the ability to generalize and can interpolate in between the training data. This advantage of ANN makes the ANN controller universal. The ANN controller designed was tested on two different motors and found to work effectively on driving both of them.     

Model reference adaptive impedance control for physical human-robot interaction

This paper presents a novel enhanced human-robot interaction system based on model reference adaptive control. The presented method delivers guaranteed stability and task performance and has two control loops. A robot-specific inner loop, which is a neuroadaptive controller, learns the robot dynamics online and makes the robot respond like a prescribed impedance model. This loop uses no task information, including no prescribed trajectory. A task-specific outer loop takes into account the human operator dynamics and adapts the prescribed robot impedance model so that the combined human-robot system has desirable characteristics for task performance. This design is based on model reference adaptive control, but of a nonstandard form. The net result is a controller with both adaptive impedance characteristics and assistive inputs that augment the human operator to provide improved task performance of the human-robot team. Simulations verify the performance of the proposed controller in a repetitive point-to-point motion task. Actual experimental implementations on a PR2 robot further corroborate the effectiveness of the approach.     

基于非线性L1自适应动态逆的飞行器姿态角控制

钊对常规动态逆控制器不能有效抵消系统中的不确定性这一缺点,提出了一种非线性L_1自适应动态逆控制方法.该方法能够克服常规动态逆的不足,在保证系统鲁棒性的前提下,提升飞行器姿态角控制效果.首先,采用时标分离原理,将姿态角控制系统分为内外两个回路:外回路采用常规动态逆控制器,用于姿态角的跟踪控制;内回路采用非线性L_1自适应控制器,用于角速率的控制.其中,L_1自适应控制器由静态反馈控制器和自适应控制器组成:静态反馈控制器通过状态反馈实现,用于保证内回路的稳定和具有期望的闭环特性;自适应控制器由状态观测器、自适应律和控制律组成,用于抵消系统中的不确定性.其次,对所提控制方法的稳定性进行了分析,结果证明了该控制方法能够保证内回路的稳定和外回路的误差有界.最后,在综合考虑多种不确定性的情况下,将本文提出的非线性L_1自适应动态逆控制方法用于某无人飞行器姿态角控制,仿真结果验证了该控制方法的有效性和鲁棒性.     

基于模糊PID的磁悬浮球控制系统研究

针对磁悬浮球系统的本质不稳定性,设计模糊PID算法实现系统的稳定控制,并使之动态性能及稳态性能满足要求;文中首先分析了磁悬浮球系统的基本原理,并进行力学分析,建立系统的数学模型,并对其中的非线性部分进行了平衡点处的线性化,而后采用用PID控制设计,PID可以实现系统的稳定控制,且控制精度较高,但对于动态性能的改善不足,且当模型中的参数改变时,PID参数的适应性较差;因此在PID参数的基础上,采用模糊PID控制,使得系统既可以满足三性要求,又可以使其具有参数变化的适应能力。