自动控制原理期末试卷试卷06-07

2006—2007学年第二学期期终试题

踏实学习，弘扬正气；诚信做人，诚实考试；作弊可耻，后果自负。课程名称自动控制原理（一）A卷使用专业电气信息类05级

班级姓名学号

一(15) Judge True or False (True tick√, False tick×)

1.One of the prime reasons for the utilization of negative feedback

in control systems is to decrease in the sensitivity of the system to variations in the parameters of the process G(s). （）2.The transfer function of a linear system is defined as the ratio of

the Laplace transform of the output variable to the Laplace transform of the input variable. ( ) 3.The stability of linear system is related to the structure parameters

and the input/output variables. ( )

4. A stable system is a dynamic system with a bounded response to

a bounded input; a sufficient and necessary condition for a

feedback system to be stable is that all the poles of the system transfer function have negative real parts. ( )

5.The effect of the zero on the step response is to decrease the

overshoot and the increase the settling time. ( ) 6.The poles of T(s) determine the particular response modes that

will be present, moving a zero closer to a specific pole will reduce the relative contribution of the mode function corresponding to the pole. ( ) 7.A ny point in the root locus should satisfy the angle requirement;

the point which satisfies the angle requirement must be the point of root locus. ( )

ω) of a system, the 8.The greater the magnitude of bandwidth (

B

more rapidly the response approaches the desired steady-state value. ( ) 9. A time delay,Ts

e-, in a feedback system introduces an additional phase lag and result in a less stable system. Therefore, as pure time delay are unavoidable in many systems, it is often necessary to increase the loop gain in order to obtain a stable response. ( ) 10.The phase-lag network is utilized to provide magnitude

attenuation at low frequency and to increase the steady-state error constant. ( )

二（15）A control system is shown in Figure 2.1(a)and Figure2.1(b), find the transfer function

()()Y s R s (()0D s =), ()()

E s R s (()0D s =), ()()Y s D s (()0R s =),

Figure 2.1 (a)

Figure 2.1 (b)

三 (10) A unity feedback system has a plant

2)

1()(+=s K s G . (1) Plot the polar plot for )(s G when 4=K ；

(2) Calculate the phase and magnitude at 1=ω；

(3) Determine the range of K for which the system is stable;

(4) Calculate the steady-state error ss e for input ()sin r t t =.

四（20）A control system is shown in Figure 4.1,

Where )(s G C =1+s K I , )(s G P =25(2)

s s +.

Figure 4.1

(1) To assure the system is stable, determine the condition

that I K ,t K should satisfy ;

(2) When I K =0, t K ≠0, determine the value of t K when the percent

overshoot (P.0%) is 16.3%; (..%P O =)

(3) For the condition of (2), find the time response y(t) for a step input

r(t)=A, for t>0;

(4) When I K ≠0, t K ≠0, find the steady-state error ss e for input

r(t)=10+2t.

五 (15) A unity feedback system has a plant

2)

4()(+=s s K s G (1) Sketch the root locus for 0

(2) Determine the value of the roots on the axis j -ω and the gain K required for those roots;

(3) Determine the range of K , that result in a system that satisfy step response with no overshoot.