Estimate of discrete-time PID controller parameters for H-infinity complementary sensitivity design: Autonomous sailboat application

This paper presents some of the successful design methodologies used to predict the robustness of a heading controller for a 2 meter autonomous sailing vessel. A graphical technique is introduced to estimate the discrete-time proportional integral derivative (PID) controller coefficients to satisfy H-infinity complementary sensitivity constraints for vessel control. We show that this problem can be solved by finding all achievable PID controllers that simultaneously stabilize the closed-loop characteristic polynomial and satisfy constraints defined by a set of related complex polynomials. Experimental data taken from this vessel at the U. S. Coast Guard Academy is used to demonstrate the application of this methodology.