Unified approach to H2 and H∞ optimal control of a hypersonic vehicle

The hypersonic vehicles (HSVs) have many desirable features such as large increase in speed, altitude and range and at the same time pose tremendous challenges to engineering community in terms of integration of aerodynamics and air-breathing propulsion, thermal management and absence of ground-based testing facilities at the hypersonic speeds. In this paper, a unified approach which alleviates the difficulties of “over crowding” of the roots inside the unit circle and the corresponding numerical difficulties in working with the traditional z-transform domain, is applied to design controllers for HSVs. A modification to unified approach to problems with quadratic performance index involving output is carried out. The unified approach has a very attractive feature of its applicability to both continuous-time and discrete-time domains simultaneously. In particular, some simple H₂ - and H_∞-based optimal controllers are designed for a linearized model of a typical HVS