Robust Takagi–Sugeno fuzzy control of a spark ignition engine

This work deals with the nonlinear control of a three cylinders spark ignition (SI) engine using a fuzzy control strategy based on a Takagi–Sugeno (TS) modeling and robust control approach. A physical model of the SI engine is presented and transformed into a TS model. Then, a robust nonlinear fuzzy control algorithm is developed and applied to two different engine torque control structures. This approach is tested on a three cylinder SI engine test bench to prove the effectiveness of the method.     

鲁棒PID算法在船舶柴油机控制中应用

基于闭环增益成形算法给出鲁棒PID算法,并将之应用于船舶柴油机的控制中。从仿真结果可知,该算法的控制性能和鲁棒稳定性良好,算法简单、实用。     

典型时滞时变过程的鲁棒数字双PI 控制

针对具有时滞时变以及负载干扰等复杂特性的时滞系统，在强时滞鲁棒数字PID控制方法的基础上，结合二自由度的IMC结构，给出一种数字双PI调节器的设计，在已知闭环系统时滞时变范围内，对确定性定值负载干扰的影响实现了无静差鲁棒调节控制。     

Robust quantization for digital finite communication bandwidth (DFCB) control

The problem of digital finite communication bandwidth (DFCB) control has come to the attention of the research community in connection with a growing interest in the development of distributed and/or networked control systems. In these systems, actuators, sensors, and other components are connected via data-rate constrained links such as wireless radio, etc. In this paper, we consider a scalar model of DFCB control that accommodates time-varying data-rate constraints, such as might occur with intermittent network congestion, and asynchronism of sampling and control actuation. Because of the possibly unpredictable fluctuation of the data-rate, we are interested in feedback control designs that will tolerate significantly constrained data-rates on feedback loops, while providing acceptable performance when such data-rate constraints are not in force. In light of a very basic notion of acceptable performance, we show that control designs with different number of quantization levels tolerate constrained data-rates differently. This leads to the conclusion that binary control represents the most robust control quantization under data-rate constraints imposed by time-varying congestion on the feedback communication channel. The advantage margin of binary control is further investigated numerically with and without the sampling-control asynchronism being considered. We show that the advantage margin is more substantial when the sampling-control asynchronism is significant. A design of quantized (binary) feedback with side channel information is proposed, and stability properties are discussed. We conclude the paper by examining performance limitations of our binary coding in the presence of noise.     

Robust digital model predictive control for linear uncertain systems with saturations

Actuator saturation constraint is inevitable in industrial process. In this note, we consider a discrete receding horizon control, a piecewise constant robust model predictive control, for a continuous-time plant with actuator saturation constraint through a sampled-data control approach. The solution is formulated as an optimization problem subject to linear matrix inequalities. A numerical example is used to demonstrate the effectiveness of the proposed design procedure.     

Robust digital control approach for high performance tunneling current measurement system

This paper is devoted to the digital control system design for high performance measurement of tunneling current. A common approach for such applications is to use a conventional Proportional Integral (PI) control. In this paper, a robust digital design method is instead considered, based on combined pole placement with sensitivity function shaping, and allowing for better performance tuning in terms of precision, robustness and disturbance rejection. The resulting control scheme looks like some enhanced PID controller, and is validated over an experimental setup, developed in GIPSA-lab (Grenoble Image Parole Signal Automatique) research center. The corresponding simulation and experimental results show improved performances with respect to those obtained with the more conventional PI control technique.     

Design and VLSI implementation of a high-performance face detection engine

This paper proposes a novel hardware structure and field-programmable gate array (FPGA) implementation method for real-time detection of multiple human faces with robustness against illumination variations. These are designed to greatly improve face detection in various environments with using MCT techniques and the AdaBoost learning algorithm which is robust against variable illumination. We have designed, implemented, and verified the hardware architecture of the face detection engine for high-performance face detection and real-time processing. The face detection chip is developed by verifying and implementing it using a FPGA and an application-specific integrated circuit (ASIC). To verify and implement the chip, we used a Virtex5 LX330 FPGA board and a 0.18 μm 1-poly and 6-metal CMOS logic process. Performance results of the implementation and verification showed it is possible to detect at least 32 faces of a wide variety of sizes at a maximum speed of 147 frames per second.     

Observer-based sampled-data control for nonlinear systems: Robust intelligent digital redesign approach

This paper suggests a solution for a robust digital implementation of the output-feedback control system by utilizing intelligent digital redesign (IDR). The general IDR method involves designing a digital fuzzy controller which is comparable to a pre-designed analog one via state-matching. However, under containing the parametric uncertainties, the new problem about the structural property of the uncertainties is inevitably occurred in the procedure of discretization. For solving that, we use the bilinear and inverse-bilinear approximation method and the concerned IDR is viewed as a convex minimization problem of the norm distances between linear operators to be matched. Also, we consider the state estimation error in the plant dynamics so that we attempt to improve the control performance. The robust stability property is preserved by the proposed IDR method and its condition is represented in terms of linear matrix inequalities (LMIs). The simulation results for permanent magnet synchronous motor (PMSM) system are demonstrated to visualize the feasibility of the proposed method.     

Robust control design of an air‐breathing engine for a supersonic vehicle using backstepping and UKF

This paper presents an efficient robust control design approach for an air‐breathing engine for a supersonic vehicle using the Lyapunov stability theory based nonlinear backstepping control, augmented with unscented Kalman filter (UKF). The primary objective of the control design is to ensure that the thrust produced by the engine tracks the commanded thrust by regulating the fuel flow to the combustion chamber. Moreover, as the engine operates in a supersonic range, an important secondary objective is to manage the shock wave location in the intake for maximum pressure recovery with adequate safety margin by varying the throat area of the nozzle simultaneously. To estimate the states and parameters as well as to filter out the process and sensor noises, a UKF has been incorporated for robust output feedback control computation. Furthermore, independent control designs for the actuators have been carried out to assure satisfactory performance of the engine. Additionally, a guidance loop is designed to generate a typical flight trajectory of the representative vehicle using a nonlinear suboptimal input constrained model predictive static programming formulation for testing the performance of the engine. Simulation results clearly indicate quite successful robust performance of the engine during both climb and cruise phases.     

鲁棒的数字语音取证算法

提出数字语音信号的FDCR(frequency domain coefficient residuals)特征,分析该特征对信号处理操作的鲁棒性和恶意攻击的脆弱性.将语音信号分帧、帧号映射为二进制的水印序列,通过量化FDCR特征的方法将水印嵌入到载体信号中.提取端通过判断提取帧号是否完整来对各帧内容进行取证,篡改定位....     

Injection engine as a control object. II. Problems of automatic control of the engine

Specific features of injection engine as a control object are discussed, strict formulations of problems of engine automatic control and principles of their solution are presented. Examples of solution of the problem of stabilization of air-fuel ratio and engine torque control problems are presented as illustrations for demonstration of application of modern methods of automatic control theory for solution of control problems of injection engines.     

高效匹配引擎的设计与实现

针对软件模式匹配引擎速度慢、占用系统资源大的问题,提出了一种基于Bloom Filter的FIBF结构,结合FPGA NIOSII微处理器(MUP),设计了软硬核相结合的匹配引擎方案。引擎通过FIBF过滤过滤掉大部分正常数据,将过滤出的可疑字符串输入到NIOSII软核进行精确匹配,两者之间通过一个指针产生器连接,整个系统以流水线方式工作。FIBF结构资源消耗低,n-FIBF并行处理,系统引擎可以达到较高的吞吐率。实验表明,在使用相同资源的情况下,本方案系统吞吐率要优于其他算法。     

Robust nonlinear motion control of a helicopter

We consider the problem of controlling the vertical motion of a nonlinear model of a helicopter, while stabilizing the lateral and horizontal position and maintaining a constant attitude. The reference to be tracked is given by a sum of a constant and a fixed number of sinusoidal signals, and it is assumed not to be available to the controller. This represents a possible situation in which the controller is required to synchronize the vehicle motion with that of an oscillating platform, such as the deck of a ship in high seas. We design a nonlinear controller which combines recent results on nonlinear adaptive output regulations and robust stabilization of systems in feedforward form by means of saturated controls. Simulation results show the effectiveness of the method and its ability to cope with uncertainties on the plant and actuator model.     

Robust control of a nonlinear time-delay system

Experiments dealing with the heating of living tissue have resulted in four completely different temperature response characteristics as a result of the application of four different constant power levels. The four response characteristics can be classified as overdamped, critically damped, underdamped, and undamped oscillations. A particular nonlinear, time-delay dynamic equation has previously been shown to exhibit the same type of temperature response characteristics as those in the experiments. Herein, a control strategy is applied to the nonlinear, time-delay equation to inhibit the oscillatory behavior. A proportional plus integral (PI) controller with antiwindup, that is restricted to be nonnegative, is shown to be an effective controller in eliminating the oscillatory responses. This effectiveness is shown by analyzing and explaining the robustness properties of this controller as applied to this nonlinear, time-delay system.This work was supported by National Cancer Institute Grant CA 36428. An earlier version of this article appears in the proceedings of the31st IEEE Conference on Decision and Control.     

Robust control for a nonlinear servomechanism problem

This paper deals with the design of output feedback control to achieve asymptotic tracking and disturbance rejection for a class of nonlinear systems when the exogenous signals are generated by a known linear exosystem. The system under consideration is single-input single-output, input-output linearizable, minimum phase, and modelled by an input-output model of the form of an nth-order differential equation. We assume that, at steady state, the nonlinearities of the system can only introduce a finite number of harmonics of the original exosystem modes. This assumption enables us to identify a linear servo-compensator which is augmented with the original system. Moreover, we augment a series of m integrators at the input side, where m is the highest derivative of the input, and then represent the augmented system by a state model. The augmented system is stabilized via a separation approach in which a robust state feedback controller is designed first to ensure boundedness of all state variables and tracking error convergence; then, a high gain observer and control saturation are used to recover the asymptotic properties achieved under state feedback.     

Robust control applications

This paper (first presented as a plenary lecture at the Fifth IFAC Symposium on Robust Control Design, Toulouse, July 2006) demonstrates the practical importance of robust control theory by describing its application to two non-trivial practical control problems. Part 1 considers helicopter control and Part 2 addresses saturation problems in high-performance head-positioning servo systems in high-density hard-disk drives.In Part 1, we present the design and flight test of a new batch of H_∞ controllers for the Bell 205 helicopter. At the heart of each controller is an H_∞ loop-shaping controller, augmented with a hand-tuned reference filter to improve tracking performance and to reduce a perceived phase lag which pilots had complained of previously. Flight testing revealed that, with such an architecture, it was relatively easy to get Level 1 handling qualities ratings in low aggression manoeuvres. Further fine tuning resulted in Level 1 qualities for high aggression manoeuvres and one controller performed to Level 1 standard in all manoeuvres tested.In Part 2, we consider how robust control techniques can be used to design anti-windup compensators to counter performance and stability problems associated with saturating actuators in state-of-the-art hard-disk drive servo systems. A promising two-stage approach is given and illustrated with experimental results.     

Robust and adaptive control of a beam deflector

A DC-motor driven beam-deflector is to be controlled such that the beam moves with constant velocity for 12 ms out of a 20-ms period before swinging back to the original position. One control system must serve any deflector without retuning. The problem is difficult because the dynamics vary from one deflector to another. It is found that a closed-loop system with poles in a Bessel filter configuration will satisfy the specifications. A straightforward pole-placement design is insufficiently robust. Redesigning it yields greater, but still insufficient, robustness against the known extent of plant parameter variation. The problem is solved by adding an adaptive control loop     

数字化校园工作流引擎的设计与实现

阐述了Web服务工作流引擎对于数字化校园建设的必要性,提出了数字化校园工作流引擎的系统框架,从数据模型出发,详细论述了工作流管理、并联审批与分支选择、双向流转与约束、Web服务封装等关键技术的实现,给出了引擎的调用示例,基于LoadRunner做了压力测试。实验和实践表明该引擎系统性能良好,可以为数字化校园信息系统提供统一标准的服务。     

Robust two-stage non-linear control of a hydraulic servo-system

Unparalleled practical advantages of a hydraulic servo-system, epitomized by high power, fast response and compact size, have led to its widespread use in industrial and military applications, despite its limitations such as leakage, contamination and low efficiency, etc. Classical control approaches have been popularly adopted in most practical hydraulic servo-systems and have enjoyed remarkable success. On the other hand, it is generally agreed that the nonlinear and uncertain dynamics of a hydraulic system must be explicitly addressed in order to achieve robust performance over a range of operating conditions. In this paper, a robust two-stage non-linear control law is proposed, based on the Lyapunov redesign technique. It turns out that the proposed two-stage control strategy guarantees uniform ultimate boundedness for a hydraulic servo-system with more general non-linearities and uncertainties that does not satisfy the matching condition. Furthermore, an explicit stability criterion is provided for such a system. Simulation study shows that the tracking performance of the proposed non-linear controller is superior to those of a popular proportional-plusderivative controller (PDC) or a non-linear controller designed for a nominal system (NC) with respect to rectangular and sinusoidal inputs. In addition, the proposed non-linear controller is shown to be more robust to uncertainties.     

Robust sampled-data control

Robust stabilization of a class of linear systems using sampled-data feedback control is studied. It is shown that a linear, time-invariant system subject to additive perturbations can be stabilized using high-gain periodic feedback from sampled values of the state, provided that the perturbations satisfy certain structural conditions. This result is also extended to decentralized sampled-data control of interconnected systems