基于自由摆的平板精确控制与激光追踪系统

以TI公司的MSP430F5438单片机为控制核心,结合步进电机和精密电位器WDD35D-4,实现了基于自由摆的平板控制与激光追踪系统。当摆杆摆角为45°～60°时,平板可以承载8枚一元硬币,并在5个摆动周期内维持稳定;当摆杆摆角为30°～60°时,固定在摆杆平板上的激光笔可以在15s内找到并跟踪1.5m远处的靶心。     

基于微电压调节的太阳能充放电系统设计

基于微电压调节的太阳能充放电系统,是以微控制器LPC1114为核心的太阳能电池板充放电电路,是实现高效率的智能充放电设计方案。微电压调节理论整合了经典电压回授法和多种太阳能最大功率点追踪思想,利用简单合理的DC／DC平衡技术,充分考虑系统功耗等问题,以简单的电路设计和创新的软件思想实现更高效率的太阳能系统。随着能源危机的加剧,高效率、低成本的太阳能系统备受社会关注,其在民用、交通等领域的运用也更加重要。     

Optimal tracking performance of MIMO discrete‐time systems with communication constraints

The optimal tracking problem for multiple‐input multiple‐output linear‐time‐invariant discrete‐time systems with communication constraints in the feedback path is studied in this paper. The tracking performance is measured by the energy of the error signal between the output of the plant and the reference signal. The objective is to obtain an optimal tracking performance, attainable by all possible stabilizing compensators. It is shown that the optimal tracking performance consists of two parts, one depends on the nonminimum phase zeros and zero direction of the given plant, as well as the reference input signal direction, and the other depends on the nonminimum phase zeros, unstable poles, and pole direction of the given plant, as well as the bandwidth and additive white Gaussian noise of the communication channel. It is also shown that, if the constraint of the communication channel does not exist, the optimal tracking performance reduces to the existing tracking performance of the control system without communication constraints. A typical example is given to illustrate the theoretical results. Copyright © 2011 John Wiley & Sons, Ltd.     

Optimal Performance in Tracking Stochastic Signal Under Disturbance Rejection

The analysis method of optimal tracking performance is proposed for multiple‐input multiple‐output (MIMO) linear time‐invariant (LTI) systems under disturbance rejection. An H₂ criterion of the error signal between the output of the plant and the reference signal is used as a measure for the tracking performance. Spectral factorization is applied to obtain the optimal solution of the system tracking error. The explicit expressions are derived for this minimal tracking error with respect to random reference signals under disturbance rejection. It is shown that the nonminimum phase zeros, the zero direction, the unstable poles, the pole direction of a given plant, statistical characteristics of the reference input signal, and disturbance signal have a negative effect on a feedback system's ability to reduce the system error with disturbance rejection. The results show that the optimal tracking performance will further be damaged because of disturbance rejection. Some typical examples are given to illustrate the theoretical results.     

An Intelligent Robust Tracking Control for a Class of Electrically Driven Mobile Robots

This paper addresses the problem of designing robust tracking control for a class of uncertain wheeled mobile robots actuated by brushed direct current motors. This class of electrically‐driven mechanical systems consists of the robot kinematics, the robot dynamics, and the wheel actuator dynamics. Via the backstepping technique, an intelligent robust tracking control scheme that integrates a kinematic controller and an adaptive neural network‐based (or fuzzy‐based) controller is developed such that all of the states and signals of the closed‐loop system are bounded and the tracking error can be made as small as possible. Two adaptive approximation systems are constructed to learn the behaviors of unknown mechanical and electrical dynamics. The effects of both the approximation errors and the unmodeled time‐varying perturbations in the input and virtual‐input weighting matrices are counteracted by suitably tuning the control gains. Consequently, the robust control scheme developed here can be employed to handle a broader class of electrically‐driven wheeled mobile robots in the presence of high‐degree time‐varying uncertainties. Finally, a simulation example is given to demonstrate the effectiveness of the developed control scheme.     

Design of a two‐level controller for an active suspension system

The paper focuses on a control design for a vehicle suspension system in which a balance between different performance demands is achieved. The starting point of the control design is a full–car model which contains nonlinear components, i.e. the dynamics of the dampers and springs and nonlinear actuator dynamics. In order to handle the high complexity of the problem this paper proposes the design of a two‐level controller of an active suspension system. The required control force is computed by applying a high‐level controller, which is designed using a linear parameter varying (LPV) method. For the control design the model is augmented with weighting functions specified by the performance demands and the uncertainty assumptions. The actuator generating the necessary control force is modelled as a nonlinear system for which a low‐level force‐tracking controller is designed. To obtain the low‐level controller a backstepping method is proposed. As an alternative solution a feedback linearization method is also presented. The operation of the controller is illustrated through simulation examples. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Effective vehicle width in self-paced tracking

In self-paced tracking tasks, such as driving, the speed is related to the lateral tolerance. This lateral tolerance has been varied in two ways in previous studies by changing the track width for constant vehicle width and vice versa. The current study used both an automobile driving task and a computer/mouse task to show that these two ways of varying lateral tolerance did not produce equivalent results. Subjects behaved as if vehicle width were less important than track width. Speeds and errors both increased as vehicle width increased for a constant lateral tolerance. This could have safety consequences when driving in confined spaces.     

均衡化特征匹配的非刚体细胞形态跟踪

提出利用均衡化特征匹配来进行非刚性细胞形体跟踪的方法。采用重启动的随机游走方法建立并求解特征匹配概率模型,利用双向均衡方法对匹配邻接矩阵进行均衡化处理,得到指定目标与待跟踪目标之间的精确匹配,以获得目标的定位跟踪结果。同时利用特征匹配结果进行目标的自动标定,并应用图像分割方法进行目标的精确轮廓跟踪。实验结果表明,将该方法应用于视频中动态背景下的运动细胞形态跟踪时,在背景相似度较高及目标迅速移动的条件下,表现出了良好的性能,与同类方法相比可获得较高的定位精度以及更为准确的目标轮廓。     

视频图像活动轮廓目标检测跟踪研究

研究视频图像目标跟踪定位精确度问题。由于在图像中通常会发生缩放,造成图像目标模糊不清。传统的目标跟踪算法该类算法仅以目标发生平移运动为假设前提,图像质量差。为解决上述问题,提出了一种活动轮廓目标跟踪定位检测算法。首先选择合适的滑窗,采用减背景法来确定视频对象的运动区域,采用卡尔曼形态滤波来消除残余的噪声,然后针对目标在活动轮廓局部内具有较高灰度值的特征,通过自适应阈值来判别滑窗中心位置是否存在目标。当滑窗遍历整幅图像后,就可以得到目标的定位结果。仿真结果表明,改进算法不仅能够消除差分图像中的显露背景,从而得到运动视频对象精确的轮廓,并且可进行多目标的分割与跟踪,具有一定的实际应用价值。     

基于单片机的皮带秤变频调速控制仪的设计与实现

介绍了皮带秤调速控制仪系统实现的原理和方法,提出了在皮带秤调速控制仪的动态跟踪问题,采用模糊-数字PID复合控制算法,既可计量也可以实时跟踪控制产量。实践表明,该控制方法理想地解决了实时跟踪问题,取得了较好的控制效果。