课程名称︰ 控制系统 课程性质︰ 系定选修 课程教师︰ 陈永耀 开课学院： 电资院 开课系所︰ 电机系 考试日期（年月日）︰2010/11/11 考试时限（分钟）：180分钟 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : NOTE: (1) Exam starts at 2:20PM,ends at 5:20PM (2) NO turn-in after 5:10PM (3) Calculator allowed (4) Please make sure you put down your name and student ID on the sheet before turn in it. (5) Please make sure you turn n all the anwer sheets if they are more than one. 1. For a dynamical system to be controlled to perform a certain task, the first step is to construct a system model to describe the synamical behavior of the system. (a) Usually, the system "input" and "output" have to be defined first. Why and how? (Please elaborate more on the basic defination of the system input and the system output.) (10%) (b) How to tell from a "good" model to a "bad" model? (10%) 2.(a) Please plot the block daigram of a "closed-loop" control system with all the key words, such as plant, actuator, sensor, controller, comparator, reference input, output, error, sensor noise, disturbance, used and marked in the daigram. (10%) (b) Then please describe the pros and cons of the "closed-loop" control system to the "open-loop"control system. (Itemized description is most preferred.) (10%) 3. Give a closed-loop system as in Figure 1 with G(s) to be : G(s) = (s^2+s+1)/(s^4+4s^3+4s^2+3s+3) (a) For k=0, please determine the stability of the open-loop system. (5%) (b) For k=1, please find the pole and zero locations of the closed-loop system and determine its stability. (10%) 4. (a) Please decribe the design process of a PID control system. (10%) (b) Specifically, please indicate how you would tune the control parameters and the reasons for the tunung actions, given the specifications to be: steady-state error e_ss ≦ 0.1, rise time ≦ 0.1sec, overshoot M_p ≦ 15%, settling time t_s ≦ 2 sec and the existing numbers to be: steady-state error e_ss = 0.3, rise time = 0.1sec, overshoot M_p = 20%, settling time t_s = 1.8 sec (5%) (c) What is the phenomenon of "integrator windup"? How does ot affect the performance of the system? How can the problem be solved? (10%) 5. Short Questions (Please determine if the following statments are correct or false. Please also provide explanations on your answers.) (5% each, 20% in total) (a) A unity-feed back system as in Figure 1 is always stable with stable open-loop system G(s). (b) The closed-loop system can always achieve better steady-stae error performance than the open-loop system. (c) A dynamic system is stable if there are no poles in the left-half plane. (d) If System A has a damping ratio 0.25 and a natural frequency 10 rad/sec which are both half as large as the ones with System B. Please estimate the ratio between the settling time of System A, t_sA, to the settling time of System B, t_sB. (Please refer to Figure 2) 　　　　　　r　　　e ┌──┐ u ┌──┐ y 　　　　　──→○─→│ K │──→│G(s)│─┬→ 　　　　　+ ↑- └──┘ └──┘ │ 　　　　　└──────────────┘ 　　　　　　　　　　　　Figure 1 Figure 2 in text book P.97 Figure 3.22 --

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