Adaptive step rate control of a stair stepper exercise machine

Adaptive control of a stair stepper exercise machine is considered. The dynamics of the functional components of the exercise machine are modeled and experimentally identified. Based on this identified system, a regulator is designed to control the step rate both under nominal conditions and when disturbances are acting. The disturbances acting on the system result from the unpredictable behavior of the user. Using the multivariable circle criterion, the closed loop error dynamics of the system are proven to be locally asymptotically stable. Experimental results confirm the analysis and demonstrate the nominal and disturbance rejection properties of the controller