[SOLVED] EE6203 - HW1 - ASSIGNMENT 

Description

 

 

1. A system is described by the following difference equation

 

c k(  3) 3 (c k 2) 5 (c k 1) 7 ( )c k  9 ( )u k

 

where the output y k( ) c k( ). Define the state variables as

 

x k₁( )  c k x k( ); ₂( )  c k( 1);x k₃( )  c k(  2)

 

Obtain a state-space representation for the system.

(10 marks)

 

2. Consider the two systems connected as shown below.

 

 

The respective state-space representations are given as follow:

 

System S₁ :

0.1 (u k 1) 0.2 ( )u k  0.3 ( )e k

System S₂ :

 

x k₁( 1) 0.4 0.5x k₁( ) 0.8

                                u k( )

x k₂( 1) 0.6 0.7x k₂( ) 0.9

x k₁( )

( )y k 1 2_       

x k₂( )

If x k₃( ) u k( ), give a state-space representation for the overall system,

x k₁( )

       

x(k 1) Ax( )k Be k( );     x( )k ^x k₂( ) 

x k₃( )

( )y k Cx( )k de k ( )

(15 marks)

 

 

 

 

3. Given the state equation of a linear system as



x( )t Ax( )t Bu t( )

The ZOH equivalent, with a sampling period of T seconds, is of the following form:

x(k 1) A x_d ( )k B_du k( )

 

If

 0    1        0

A4 5;B  1 ;T  0.5 sec

(i)  Find  A_d and  B_d .

X( )z (ii) Find the transfer function  .

U z( )

(iii) Determine the characteristic equation of the discretised system and obtain           the eigenvalues of A_d .

(30 marks)

4. A discrete-time system is given by

 

1  2         3

x(k 1)      x( )k  u k( )

1  2         4

( )y k 5 6x( )k

 

• Determine a co-ordinate transformation, i.e. find Q in the following

 

w_Q( )k =Q x^1 ( )k

 

that transforms the system into the observable canonical form (OCF). Hence, using Q,  determine a state-space representation which is in the OCF form.

 

• Determine a co-ordinate transformation, i.e. find P in the following

 

w_P( )k =P x^1 ( )k

 

that transforms the system into the controllable canonical form (CCF). Hence, using P,  determine a state-space representation which is in the CCF form.

(20 marks)

 

 

 

 

5. A continuous-time system is as shown below. Let M  625,K_S 10.

 

• Obtain a state-space representation for the continuous-time system with the state variables as indicated and the output variable y t( )  x t₁( ).

 

• The system is sampled with a zero-order hold and the sampling period is 0.5 second. Obtain a zero-order hold equivalent of the continuous-time system.

 

• Find the deadbeat control law of the following form u k( ) Kx( )k

Show that the response is indeed deadbeat.

(25 marks)