  In this paper, we present a strictly negative imaginary state feedback
control methodology for relative degree two negative imaginary systems such as
flexible structures with collocated sensors and actuators. We show that by
augmenting a nominal model with a destabilising PID controller, we can apply
state feedback control to the system, resulting in a strictly negative
imaginary nominal closed loop system with a prescribed degree of stability.
Moreover, the overall system is guaranteed to be internally stable in the face
of unmodelled spillover dynamics.
