ECE 429, Spring 2002

CONTROL SYSTEMS LAB -- UNIT A.2

OBJECTIVE: To use MATLAB to analyze the time domain response of a third-order dynamic system, and to design closed-loop feedback control systems using cascade compensation in order to satisfy desired time domain specifications.

TASKS:

1. The plant transfer function is the one given in experiment A.1 (with K = 1).  The following specifications are imposed on the closed-loop system:
   • steady-state error for a ramp input must not exceed 0.01;
   • overshoot to a step input must not exceed 10%;
   • settling time for a step input (to within 2% of the final value) must not exceed 15 seconds; and
   • ratios of compensator zero to pole must satisfy alfa_lead = z_c-lead/p_c-lead > 0.05 and alfa_lag = z_c-lag/p_c-lag < 20 for any single stage of compensation.

2. Design a compensator such that the closed-loop system satisfies all of the specifications.  Possible compensator types might include phase lead, phase lag, lag-lead, PID, PD, or PI.  More than one section of compensator can be used if necessary.  The design of the compensator should be accomplished by theoretical analysis aided by the time-domain response capabilities of MATLAB.  Random trial and error will not be acceptable.

3. Verify that the final closed-loop system satisfies the requirements. Time domain plots of the step and ramp responses are required for this.  Make sure that "steady-state" can be easily identified in each of the plots.

Write a report containing a description of the design problem and your approach to designing a compensator. Include your reasons for choosing the particular compensator type and how the compensator parameter values were obtained.  Include all plots necessary to verify that the specifications have been satisfied.

Click the icon to return to the Dr. Beale's home page

Latest revision on Thursday, June 8, 2006 9:29 AM