1、 外文资料翻译 INTELLIGENT CONTROL Intelligence and intelligent systems can be characterized in a number of ways and along a number of dimensions. There are certain attributes of intelligent systems, common in many definitions, which are of particular interest to the control community. In the following, se
2、veral alternative definitions and certain essential characteristics ofintelligent systems are first discussed. A brief working definition of intelligent systems thatcaptures their common characteristics is then presented. In more detail, we start with a rathergeneral definition of intelligent system
3、s, we discuss levels of intelligence, and we explain the roleof control in intelligent systems and outline several alternative definitions. We then discussadaptation and learning, autonomy and the necessity for efficient computational structures inintelligent systems, to deal with complexity. We con
4、clude with a brief working characterizationof intelligent (control) systems. We start with a general characterization of intelligent systems: An intelligent system has the ability to act appropriately in an uncertain environment, wherean appropriate action is that which increases the probability of
5、success, and success is theachievement of behavioral subgoals that support the systems ultimate goal. In order for a man-made intelligent system to act appropriately, it may emulate functions ofliving creatures and ultimately human mental faculties. An intelligent system can becharacterized along a
6、number of dimensions. There are degrees or levels of intelligence that canbe measured along the various dimensions of intelligence. At a minimum, intelligence requiresthe ability to sense the environment, to make decisions and to control action. Higher levels ofintelligence may include the ability t
7、o recognize objects and events, to represent knowledge in aworld model, and to reason about and plan for the future. In advanced forms, intelligenceprovides the capacity to perceive and understand, to choose wisely, and to act successfully undera large variety of circumstances so as to survive and p
8、rosper in a complex and often hostileenvironment. Intelligence can be observed to grow and evolve, both through growth incomputational power and through accumulation of knowledge of how to sense, decide and act ina complex and changing world. The above characterization of an intelligent system is ra
9、ther general. According to this, agreat number of systems can be considered intelligent. In fact, according to this definition, even athermostat may be considered to be an intelligent system, although of low level of intelligence. Itis common, however, to call a system intelligent when in fact it ha
10、s a rather high level ofintelligence. There exist a number of alternative but related definitions of intelligent systems and in thefollowing we mention several. They provide alternative, but related characterizations ofintelligent systems with emphasis on systems with high degrees of intelligence. T
11、he following definition emphasizes the fact that the system in question processesinformation, and it focuses on man-made systems and intelligent machines: A. Machine intelligence is the process of analyzing, organizing and converting data intoknowledge； where (machine) knowledge is defined to be the
12、 structured information acquired andapplied to remove ignorance or uncertainty about a specific task pertaining to the intelligentmachine. This definition leads to the principle of increasing precision with decreasingntelligence, which claims that: applying machine intelligence to a database generat
13、es a flow ofknowledge, lendingananalytic form to facilitate modeling of the process. Next, an intelligent system is characterized by its ability to dynamically assign subgoals andcontrol actions in an internal or autonomous fashion: B. Many adaptive or learning control systems can be thought of as d
14、esigning a control lawto meet well-defined control objectives. This activity represents the systems attempt to organizeor order its “knowledge” of its own dynamical behavior, so to meet a control objective. Theorganization of knowledge can be seen as one important attribute of intelligence. If thiso
15、rganization is done autonomously by the system, then intelligence becomes a property of thesystem, rather than of the systems designer. This implies that systems which autonomously (self)-organize controllers with respect to an internally realized organizational principle are intelligentcontrol syst
16、ems. A procedural characterization of intelligent systems is given next: C. Intelligence is a property of the system that emerges when the procedures of focusingattention, combinatorial search, and generalization are applied to the input information in order toproduce the output. One can easily dedu
17、ce that once a string of the above procedures is defined,the other levels of resolution of the structure of intelligence are growing as a result of therecursion. Having only one level structure leads to a rudimentary intelligence that is implicit inthe thermostat, or to a variable-structure sliding
18、mode controller. The concepts of intelligence and control are closely related and the term “IntelligentControl” has a unique and distinguishable meaning. An intelligent system must define and usegoals. Control is then required to move the system to these goals and to define such goals.Consequently,
19、any intelligent system will be a control system. Conversely, intelligence isnecessary to provide desirable functioning of systems under changing conditions, and it isnecessary to achieve a high degree of autonomous behavior in a control system. Since control isan essential part of any intelligent sy
20、stem, the term “Intelligent Control Systems” is sometimesused in engineering literature instead of “Intelligent Systems” or “Intelligent Machines”. Theterm “Intelligent Control System” simply stresses the control aspect of the intelligent system. Below, one more alternative characterization of intel
21、ligent (control) systems is included.According to this view, a control system consists of data structures or objects (the plant modelsand the control goals) and processing units or methods (the control laws) : D. An intelligent control system is designed so that it can autonomously achieve a high le
22、velgoal, while its components, control goals, plant models and control laws are not completelydefined, either because they were not known at the design time or because they changedunexpectedly. There are several essential properties present in different degrees in intelligent systems. Onecan perceiv
23、e them as intelligent system characteristics or dimensions along which differentdegrees or levels of intelligence can be measured. Below we discuss three such characteristicsthat appear to be rather fundamental in intelligent control systems. Adaptation and Learning. The ability to adapt to changing
24、 conditions is necessary in anintelligent system. Although adaptation does not necessarily require the ability to learn, forsystems to be able to adapt to a wide variety of unexpected changes learning is essential. So theability to learn is an important characteristic of (highly) intelligent systems
25、. Autonomy and Intelligence. Autonomy in setting and achieving goals is an importantcharacteristic of intelligent control systems. When a system has the ability to act appropriately inan uncertain environment for extended periods of time without external intervention, it isconsidered to be highly au
26、tonomous. There are degrees of autonomy； an adaptive control systemcan be considered as a system of higher autonomy than a control system with fixed controllers, asit can cope with greater uncertainty than a fixed feedback controller. Although for low autonomyno intelligence (or “low” intelligence)
27、is necessary, for high degrees of autonomy, intelligence inthe system (or “high” degrees of intelligence) is essential. Structures and Hierarchies. In order to cope with complexity, an intelligent system musthave an appropriate functional architecture or structure for efficient analysis and evaluation ofcontrol strategies. This structure should be “sparse” and it
