1.4 The Design Process of Control System,Questions: Do you know the design process of a control system? What factors may be influence the control system design?,1,The Design Process of Control System,(一) 过程设计的概述 (p33. 1-7段) 好的设计很难定义； 好的设计技巧需要经验、直觉和敏锐的感觉； 好的设计技巧需通过实际经验来获得和完善； 控制系统的设计过程是一个进化的过程； 常用的设计方法：改进现有技术、模仿法； 创新性设计受到标准、规范、工程约束等限制。,2,The Design Process of Control System,(二) 一个全新的工程设计过程 (p34. 1-p36. 4段) (1) 确定被控物理量，给出系统描述； (2) 明确所要求的性能指标； (3) 尝试性的选择控制硬件； (4) 判断控制硬件是否可行； (5) 选择设计方法，建立真实模型； (6) 简化真实模型，得出设计模型；,3,The Design Process of Control System,(二) 一个全新的工程设计过程 (p34. 1-p36. 4段) (7) 基于设计模型，采用选择的设计方法，进行设计计算； (8) 基于真实模型进行仿真，验证设计性能； (9) 如果仿真验证设计可行，进入样机制造调试阶段； (10) 如果设计无法满足性能要求，则需重新选择设计方法，或改进控制硬件。,4,The Design Process of Control System,(三) 说明实际设计与数学优化问题的差距 (p36.5 p37.6) 以飞行控制为例说明了一个实际的控制器设计不能完全归结为一个带约束的优化问题。,5,The Design Process of Control System,Good design eludes (避免) definition (好的设计很难定义), but you can usually recognize something that is well designed. One characteristic of good design is that it is exactly right for the specific application. Everything necessary is present, but everything unnecessary is absent.,6,“好的设计”很难定义，但通常你会认可一些好的设计。,好的设计的一个特征是, 它准确适用于特定应用的场合。,提出所有需要的，而排除一切所不需要的。,The Design Process of Control System,The skills needed for good design entail (需要) experience, intuition (直觉), and esthetic (感觉的) sensibility. They are not easily learned from books. The most you ought to expect from any textbook on design (including this one) is to learn about some useful tools.,7,好的设计所需要的技巧包括经验、直觉和敏锐的感觉。,这些并不容易从课本中学到。在设计方面，你最应该从教科书中期望得到的是学到一些有用的工具。,The Design Process of Control System,Like most books on control system design, this book presents tools that can be reduced to mathematical equations: analysis and simulation. Skill in the other aspects of design (such as conceptualization （概念化） of the overall system, selection of components, dealing with constraints on time and money), which is as important as the mathematical analysis, is acquired and perfected through practical experience.,8,就像大多数关于控制系统设计的书一样，本书提供了一些能够被简化成数学公式的工具：分析和仿真。,其它方面的设计技巧（比如整个系统的概念化，部件的选型，处理时间和金钱上的限制等）,The Design Process of Control System,In practice one learns that most systems develop through evolution: not only biological systems, but also human inventions such as the automobile and the airplane. The sleek (光滑的), high-performance automobile can be traced to (上溯到) the humble (粗陋的) model T; the advanced tactical fighter, still on the contractors (承包商) drawing boards, has its roots at Kitty Hawk (基蒂霍克：即莱特兄弟首次两个成功飞行的地点 1903年12月17日).,9,实际上，大多数系统都通过进化发展的，不仅是生物系统,人类的发明，如汽车和飞机也是这样。,The Design Process of Control System,Much of engineering is modifying existing designs. A new model of an existing product is designed to incorporate new technological advances: a new or improved sensor or actuator, a digital processor to replace an analog controller.,10,很多工程是把现有的设计做进一步修改,现有产品的新型号设计就是引进新的先进技术：,一个新型的或改进的传感器或执行器，一个用于替换模拟控制器的数字处理器。,The Design Process of Control System,Imitation (模仿) (often called “reverse engineering ”) is another common design technique. In its most obvious and least creative form you dissect (仔细研究，解剖) an existing product, and copy the design. The process is legal unless the product copied has patent protection (专利保护).,11,模仿法（常被称为反转工程）是另一种常用的设计方法。,通过这种最明显但也最缺乏创意的方法，你可以仔细研究现有产品，然后复制设计方法。,这个过程是合法的，除非产品复制受专利保护。,The Design Process of Control System,A more creative use of imitation is to borrow ideas from one application and use them in another. You need to control the level of the liquid in a vessel; consider how it is done in your toilet tank. You must control the temperature of the liquid in the vessel; think of how it is done in your tropical fish tank.,12,更有创意的模仿法是将一个产品的思想应用到另一个产品中去。,当你需要控制容器中的液位时，可以考虑一下在你的厕所中这是怎样实现的。,当你要控制容器中的液体温度时，可以考虑一下你的热带鱼缸是如何做到的。,The Design Process of Control System,Innovation is often limited by codes (规范), standards, and engineering conservatism (保守主义). The aircraft industry, for example, took many years to accept the “fly-by-wire” (靠电线飞行) concept, by which the mechanical connections (rods or cables) between the pilots controls (the stick and pedals) and the moveable aerodynamic control surfaces (the rudder, elevator, and ailerons) are replaced by electric wires carrying signals from the pilots controls to a flight control computer and from the computer to actuators located at the control surface.,13,创新总是受规范、标准和工程保守主义的限制。,例如，飞机制造厂用了许多年才接受了“靠电线飞行”的概念，“靠电线飞行”使飞行员控制器（如操纵杆和脚踏板）和可移动的空气动力控制翼面（如方向舵，升降机和副翼）之间的机械连接（如连杆或绳索）被携带信号的电线所取代。电线把信号从驾驶员控制器传递给飞行控制计算机,然后从计算机传递给位于控制翼面的执行器。,The Design Process of Control System,While engineering standards may retard progress, they are nevertheless necessary to prevent technological anarchy (混乱). For all these reasons, you rarely get the opportunity to design an entirely new control system. But suppose the opportunity does arise. How would you proceed? The procedure you might follow is depicted (描述) in the form of a flow chart in Figure 1. 4. 1.,14,尽管工程标准会延迟发展，但在防止技术混乱上仍然是必要的。,由于