自适应阈值的快速运动估计算法

分析了视频序列运动场的基本特征,利用运动和匹配误差两种相关性,提出自适应阈值的快速运动估计算法(AT-FME),随编码对象的内容和运动情况自适应地调整阈值和搜索模式.实验结果表明,在匹配质量和码率相同情况下,AT-FME可比UMHexagonS节省62%的运算量,是提高视频压缩编码效率的有效方法.     

Neural fuzzy motion estimation and compensation

Neural fuzzy systems can improve motion estimation and compensation for video compression. Motion estimation and compensation are key parts of video compression. They help remove temporal redundancies in images. But most motion estimation algorithms neglect the strong temporal correlations of the motion field. The search windows stay the same through the image sequences and the estimation needs heavy computation. A neural vector quantizer system can use the temporal correlation of the motion field to estimate the motion vectors. First- and second-order statistics of the motion vectors give ellipsoidal search windows. This algorithm reduced the search area and entropy and gave clustered motion fields. Motion-compensated video coding further assumes that each block of pixels moves with uniform translational motion. This often does not hold and can produce block artifacts. We use a neural fuzzy system to compensate for the overlapped block motion. This fuzzy system uses the motion vectors of neighboring blocks to map the prior frame's pixel values to the current pixel value. The neural fuzzy system used 196 rules that came from the prior decoded frame. The fuzzy system learns and updates its rules as it decodes the image. The fuzzy system also improved the compensation accuracy. The paper derives both the fuzzy system and the neural learning laws that tune its parameters     

自适应模糊滑模控制器设计

针对传统滑模控制的抖振问题,利用线性化反馈技术,将模糊自适应和滑模控制相结合,设计一种新型的模糊滑模控制器。通过模糊推理和基于Lyapunov函数的稳定性分析,获得模糊控制规则的自适应律,构成自适应模糊滑模控制器,有效解决了传统滑模控制中,需要确定参数摄动和外部干扰上确界不确定性问题,倒立摆上的运行结果表明该方法的有效性。     

An adaptive fuzzy sliding-mode controller for servomechanismdisturbance rejection

A two-level spring-lumped mass servomechanism system was constructed for disturbance rejection control investigation. This dynamic absorber is similar to a model of the serial-type vehicle suspension system. The lower level is actuated by two DC servo motors, to provide the specified internal and external disturbances to the vibration control system. The upper level has another DC servo motor to control the main body balancing position. In order to tackle the system's nonlinear and time-varying characteristics, an adaptive fuzzy sliding-mode controller is proposed to suppress the main mass position variation due to external disturbance. This intelligent control strategy combines an adaptive rule with fuzzy and sliding-mode control technologies. It has online learning ability for responding to the system's time-varying and nonlinear uncertainty behaviors, and for adjusting the control rules and parameters. Only seven rules are required for this control system, and its control rules can be established and modified continuously by online learning. The experimental results show that this intelligent control approach effectively suppresses the vibration amplitude of the body, with respect to the external disturbance     

一种新的自适应二值运动估计算法

利用增强位平面的二值特性和运动矢量场自适应思想,提出了一种新的自适应二值运动估计算法.算法在图像的位平面中完成运动矢量的搜索;匹配时对静止块进行判定直接中止搜索,同时采用了起始点预测和运动类型判定,自适应使用LDSP和SDSP模板进行搜索.实验结果表明:该算法的搜索速度优于绝大多数现有的运动估计算法,且预测精度接近于FS算法.     

一种自适应模糊PID控制器应用仿真

研究了一种误差驱动型自适应模糊PID控制器在二阶时滞系统中的应用。选择系统的稳态误差和误差变化率为PID参数自适应模糊调整的前件变量,将前件变量模糊化为7个论域期间,建立了PID参数调整的模糊规则表,查表得PID参数的后件参数,采用极大值反模糊化规则得到具体PID控制参数。仿真结果表明采用该控制器后系统的调节时间大大缩短,控制效果令人满意。     

Fault-tolerant switched reluctance motor drive using adaptive fuzzy logic controller

An adaptive fuzzy controller has been designed to develop a high-performance fault-tolerant switched reluctance motor (SRM) drive. The fuzzy controller continuously adapts its properties to regulate the machine torque as desired by the drive system even under fault conditions. The adaptation of the fuzzy membership functions results in extended conduction period and increased peak current of the healthy phases to deliver the commanded torque, as much as possible. The adaptive fuzzy controller provides smooth torque output with minimum ripple, even under fault conditions, yielding a high-performance SRM drive with fault-tolerant capability.     

基于FPGA的温度模糊自适应PID控制器的设计

针对桌恒温箱控制系统中存在的非线性、时变等特点,结合传统PID与现代模糊控制理论,以EPIC12型FP-GA为核心控制器,采用模块化思想,设计并实现温度模糊自适应PID控制.实际运行结果表明,采用该方法可明显改善控制效果,在简化设计的同时,也可提高系统的运算速度和可靠性.     

An adaptive fuzzy logic controller: its VLSI architecture andapplications

Most previous work about the hardware design of a fuzzy logic controller (FLC) intended to either improve its inference performance for real-time applications or to reduce its hardware cost. To our knowledge, there has been no attempt to design a hardware FLC that can perform an adaptive fuzzy inference for the applications of on-line adaptation. The purpose of this paper is to present such an adaptive memory-efficient FLC and its applications. Taking advantage of the adaptability provided by a symbolic fuzzy rule format and the dynamic membership function generator, as well as the high-speed integration capability afforded by VLSI, the proposed adaptive fuzzy logic controller (AFLC) can perform an adaptive fuzzy inference process using various inference parameters, such as the shape and location of a membership function, dynamically and quickly. Three examples are used to illustrate its applications, and the experimental results show the excellent adaptability provided by AFLC     

基于模糊控制的电气电压自适应控制器设计

电气设备上的碰撞性负载会造成电气电压波动,以往用于防止电气电压波动的设备存在使用效果不理想的问题。因此,设计基于模糊控制的电气电压自适应控制器,建立模糊控制数学模型和电气设备中电容、电感的虚拟控制通路,将控制通路的工作频率和电气电压设为模型输入项,将工作频率因子设为输出项,使用多向传导晶体阀门连接控制通路,交换通路电气电压并进行补偿,改善电气电压波动情况。进一步介绍了控制器数据采集卡AD760x的高精度采集电路,并对模糊控制下电气电压控制延时的估计过程进行设计,提高控制效果。实验结果表明,所设计的控制器控制效果好,鲁棒性强。     

Balancing control of a unicycle robot with double gyroscopes using adaptive fuzzy controller

This paper presents a unicycle robot which utilizes the precession effect of a double-gyroscope for lateral balancing and designs an adaptive fuzzy controller to realize the balance control according to its dynamic model. The double gyroscope structure of the unicycle robot can eliminate the pitch angle interference caused by the precession effect and improve the robot's lateral anti-interference ability. An adaptive fuzzy controller is designed based on the dynamic equations of the unicycle robot to improve its robustness. The adaptive controller part improves the anti-interference ability of the unicycle robot, and the fuzzy controller part is used as decoupling controller to reduce the interference of coupling. Simulation and experimental results to verify the anti-interference ability and decoupling effect of the designed controller.     

An optimal and adaptive design of the feedforward motion controller

The zero phase error tracking controller (ZPETC) in motion control, as proposed by Tomizuka (1987) , renders the desirable zero phase error, but with a limited gain response. Moreover, a ZPETC, which is basically in a feedforward control structure, is very sensitive to modeling error. To improve the tracking accuracy of the ZPETC, this paper presents an optimal ZPETC design with a concise polynomial digital prefilter (DPF). The parameters of this well-designed DPF are obtained through the derived L₂-norm optimization. By cascading the developed DPF to the ZPETC, the resultant optimal ZPETC greatly improves the bandwidth of the tracking control systems while maintaining the zero phase error. Compared with other optimal approaches, the present design leads to much simpler procedures and fewer computations. Furthermore, the proposed optimal ZPETC can be adequately implemented as an adaptive ZPETC by including real-time estimation technique to cope with the external load perturbation and parameter variation. Compared with the other adaptive approaches, the optimal concept is used in the present adaptive ZPETC, and it also renders more accurate results because of its improved magnitude response. Experimental results on a DC servo table with different controllers indicate that when there is no loading, the present optimal ZPETC achieves the best tracking performance. Moreover, the adaptive ZPETC achieves the most satisfactory results when an external load is applied     

Nonlinear adaptive torque control of electro-hydraulic load system with external active motion disturbance

This paper develops a high performance nonlinear adaptive control method for electro-hydraulic load simulator (EHLS). The tracking performance of EHLS is mainly affected by the following factors: actuator’s active motion disturbance, flow nonlinear and parametric uncertainties, etc. Most previous studies on EHLS pay too much attention on actuator’s active motion disturbance, while deemphasize the other two factors. This paper concerns EHLS as a motion loading system. Besides actuator’s motion disturbance, both the nonlinear characteristics and parametric uncertainties of the loading system are addressed by the present controller. First, the nonlinear model of EHLS is developed, and then a Lyapunov-based control algorithm augmented with parameters update law is developed using back-stepping design method. The stability of the developed control algorithm is proven via Lyapunov analysis. Both the co-simulation and experiment are performed to validate the effectiveness of the developed algorithm.     

Just-in-time adaptive disturbance estimation for run-to-run control of semiconductor processes

Run-to-run control is the term used for the application of discrete parts manufacturing control as practiced in the semiconductor industry. This paper presents a new algorithm for use in run-to-run control that has been designed to address some of the challenging issues unique to batch-type manufacturing. Just-in-time adaptive disturbance estimation (JADE) uses recursive weighted least squares parameter estimation to identify the contributions to variation that are dependent upon manufacturing context. The strengths and weaknesses of the JADE algorithm are demonstrated in a series of test cases developed to separate the various disturbances and processing issues a control system would be expected to encounter.     

自适应模糊PID控制的太阳光跟踪伺服系统

针对太阳光跟踪伺服系统中应用的传统PID控制过程中的一些问题,本文通过对自适应模糊PID控制系统的分析,设计了双轴跟踪伺服系统自适应模糊PID控制器,并在Simulink环境中建立方位角跟踪传动机构仿真模型且完成仿真。仿真结果表明,太阳光跟踪伺服系统自适应模糊PID控制器较传统PID控制器具有较强的稳定性、适应性与鲁棒性,这在太阳光跟踪伺服系统控制领域具有重要的实用价值与应用空间。     

GA and Lyapunov theory-based hybrid adaptive fuzzy controller for non-linear systems

In this present article, a new hybrid methodology for designing stable adaptive fuzzy logic controllers (AFLCs) for a class of non-linear system is proposed. The proposed design strategy exploits the features of genetic algorithm (GA)-based stochastic evolutionary global search technique and Lyapunov theory-based local adaptation scheme. The objective is to develop a methodology for designing AFLCs with optimised free parameters and guaranteed closed-loop stability. Simultaneously, the proposed method introduces automation in the design process. The stand-alone Lyapunov theory-based design, GA-based design and proposed hybrid GA–Lyapunov design methodologies are implemented for two benchmark non-linear plants in simulation case studies with different reference signals and one experimental case study. The results demonstrate that the hybrid design methodology outperforms the other control strategies on the whole.     

A refined motion estimation strategy for adaptive interpolation filter

Adaptively selecting the filter coefficients for interpolating fractional pixels (sub-pel) can significantly improve the quality of reference pictures. However, the complexity of implementation is greatly increased by performing motion estimation (ME) and mode decision (MD) for multiple passes. This paper briefly introduces the adaptive interpolation filter (AIF) technique and proposes a refined ME strategy for realizing the AIF process with low complexity. By using this method, the 2-pass encoding procedure can be avoided while the coding efficiency of the AIF is maintained. The proposed method is implemented and verified on the AVS video software platform.     

一种适用于AVS-M的自适应快速运动估计算法

为了减小移动视频编码标准(AVS-M)中运动估计模块的复杂度,提出了一种快速、有效的块匹配运动估计算法.该算法充分利用了视频图像中运动矢量场的中心偏置特性和时空相关性,根据运动类型自适应的选择搜索起点和搜索策略,结合改进的搜索模板和高效搜索中止准则,有效地降低了运动估计的运算量.实验结果表明,该算法在保证搜索精度的同时,大大减少了搜索点数.