ECE 429, Spring 2002

OBJECTIVE: To design a compensator for the given system such that the closed-loop system satisfies a set of time-domain performance objectives.

TASKS:

1. The system to be controlled is the heading angle of a ship. The input to the system is the rudder angle, and the output is the heading angle.  The transfer function for a linear model of the Mariner-class cargo ship with nominal parameter values is shown below. The closed-loop response for a unit step input must satisfy the following specifications:

   • the controller must contain an integrator to offset constant disturbances acting at the ship input;

   • the settling time (2%) must be less than 150 seconds;

   • the overshoot must be less than 15%; and

   • the maximum absolute value of the rudder angle must be less than 5.

2. Design a compensator which accomplishes this.  Determine the actual closed-loop step response overshoot and settling time for the compensated system and also for the uncompensated system (closed-loop and with a gain of -1 in series with the uncompensated system's transfer function).  Determine the rudder angle for the compensated system.

REPORT:

Write a report which documents your design process.  Discuss how satisfying the performance specifications is related to the locations of the closed-loop poles.  Include time domain plots, and other plots if appropriate, to illustrate and justify your work.