Nonlinear H∞ controllers for electromagnetic suspension systems

This note presents a unified framework to derive nonlinear state and output feedback controllers for magnetically levitated (Maglev) vehicles with controlled dc electromagnets, referred to as electromagnetic suspension systems. The theoretical exposition, based on the Taylor series expansion solution to the Hamilton–Jacobi–Isaacs inequality, is followed by an assessment of some of the practical issues in realizing the nonlinear controllers with a digital signal processor and embedded hardware. A select set of experimental results froma single-degree-of-freedom suspension system is included to highlight the effectiveness of the proposed nonlinear stateand output-feedback controllers to suppress guideway-induced disturbances.