Nonlinear control of the air spindle testbed with constraints

In this paper we design nonlinear feedback controllers for the air spindle testbed, a multibody attitude testbed consisting of a freely rotating platform and two proof mass actuators. We take into account stroke limits and velocity limits of the proof mass actuators. Two control methods are proposed: one is based on a time-state strategy; the other is based on a hybrid scheme. Detailed design procedures are given; simulations demonstrate the effectiveness of the controllers for this constrained stabilization problem.