This paper addresses the problem of implementing predictive controllers for supervisory level control systems. In this configuration the manipulated variables calculated by the Predictive controller are used as comman...
详细信息
Software cybernetics is a newly proposed area in software engineering. It makes better use of the interplay between control theory/engineering and software engineering. In this paper, we look into the research potenti...
详细信息
This paper is concerned with a unified methodology for sub-optimal design of proportional-integral and proportional-integral-derivative delta domain controllers for SISO plants. Problems of how to satisfy both the nom...
详细信息
Most of the existing techniques for document clustering rely on a "bag of words" document representation. Each word in the document is considered as a separate feature, ignoring the word order. We investigat...
详细信息
ISBN:
(纸本)9810475241
Most of the existing techniques for document clustering rely on a "bag of words" document representation. Each word in the document is considered as a separate feature, ignoring the word order. We investigate the use of phrases rather than words as document features for the document clustering. We present a phrase grammar extraction technique, and use the extracted phrases as the features in a self-organizing map based document clustering algorithm. We present clustering results using the REUTERS corpus and show an improvement in clustering performance using both entropy and F-measure evaluation measures.
Closed-loop control systems are dynamic systems subject to perturbations. One of the main concerns of the control is to design controllers to correct or limit the deviation that transient perturbations cause in the co...
详细信息
Closed-loop control systems are dynamic systems subject to perturbations. One of the main concerns of the control is to design controllers to correct or limit the deviation that transient perturbations cause in the controlled system response. The smaller and shorter the deviation, the better the achieved performance. However, such controllers have been traditionally implemented using fixed timing constraints (periods and deadlines). This precludes controllers to execute dynamically, accordingly to the system dynamics, which may lead to sub-optimal implementations: although higher execution rates may be preferable when reacting to perturbations in order to minimize the response deviations, they imply wastage of resources when the system is in equilibrium. In this paper we argue and demonstrate that the responsibility of maximizing the performance of closed-loop systems relies on both the controller designer and the scheduler. We show that the dynamic optimization of the quality of the controlled system response calls for (a) flexible control task timing constraints that deliver effective control performance; flexible constraints allow us to achieve faster reaction by adaptively choosing the controller sampling rate and completion time upon transient perturbations, (b) a quality-of-control (QoC) metric; it associates with each control task timing a quantitative value expressing control performance (in terms of the closed-loop system error), and (c) new scheduling approaches; their goal is to quickly react to perturbations by dynamically scheduling tasks based on the chosen control task execution parameters to maximize the QoC. This combination offers the possibility of taking scheduling decisions based on the control information for each control task invocation, rather than using fixed timing constraints with constant periods and deadlines.
We study an image-based visual servoing system implemented on a non-dedicated network with non-deterministic computational nodes. A problem is that time delays are typically non-deterministic and variable and may caus...
详细信息
We study an image-based visual servoing system implemented on a non-dedicated network with non-deterministic computational nodes. A problem is that time delays are typically non-deterministic and variable and may cause significant degradation of control system performance, stability and robustness if not compensated for. Another problem is the presence of noise due to information loss and measurement errors in the image and vision processing part of the loop also resulting in decreased control performance. This paper focuses on an image plane linear prediction strategy implemented using time-stamped data and a nonuniformly updating Kalman filter to compensate for time delays and noise. control performance is experimentally verified by presenting prediction error measurements from an image-based visual servoing experiment of gripping a moving object using a 6-DOF industrial robot and uncalibrated cameras.
Differential linear repetitive processes are a distinct class of 2D continuous-discrete linear systems of both applications and systems theoretic interest. In applications, they arise in iterative learning control sch...
详细信息
Differential linear repetitive processes are a distinct class of 2D continuous-discrete linear systems of both applications and systems theoretic interest. In applications, they arise in iterative learning control schemes and in iterative solution algorithms for nonlinear dynamic optimal control algorithms based on the maximum principle. Repetitive processes cannot be analysed/controlled by direct application of the existing systems theory and hence a 'mature' systems theory must be developed for them followed (where appropriate) by onward translation into efficient controller design algorithms. This paper continues the development of the former area by developing some significant new results on the application of currently available delay differential systems theory to these processes.
Most of iterative learning control (ILC) methods requires that the relative degree of the plant is less than 2 for a linear system or the plant is passive for a non-linear system. A new model reference parametric adap...
详细信息
This paper is on the digital control of a continuous-time non-linear system by observer-based state feedback. Some discrete-time observer and controller are built online at each sample time according to the linear app...
详细信息
This paper is on the digital control of a continuous-time non-linear system by observer-based state feedback. Some discrete-time observer and controller are built online at each sample time according to the linear approximation of the system about the current estimation point. This methodology is exemplified through numerical simulation of some load speed control in a mechanical system subjected to backlash and only using the measurement of the driving motor speed.
Repetitive processes are a distinct class of 2D linear systems with applications in areas ranging from long-wall coal cutting and metal rolling operations through to iterative learning control schemes. The main featur...
详细信息
Repetitive processes are a distinct class of 2D linear systems with applications in areas ranging from long-wall coal cutting and metal rolling operations through to iterative learning control schemes. The main feature which makes them distinct from other classes of 2D linear systems is that information propagation in one of the two independent directions only occurs over a finite duration. This, in turn, means that a distinct systems theory must be developed for them, which can then be translated (if appropriate) into efficient routinely applicable controller design algorithms for applications domains. In this paper, we give some new results on LMI based stabilization and robust control of so-called discrete linear repetitive processes and illustrate them by application to a metal rolling process.
暂无评论