This paper deals with bumpless transfer between a number of observer-based controllers in a gain scheduling architecture. Linear observer-based controllers are designed for a number of linear approximations of a nonlinear system in a set of operating points, and gain scheduling control can subsequently be achieved by interpolating between each controller. The Youla-Jabr-Bongiorno-Kucera (YJBK) parameterisation is used to achieve a smooth scheduling between the controllers. This approach produces a scheduled controller as a linear fractional transformation between a fixed controller and a scheduling parameter. The approach is tested on a simple, but highly nonlinear model of a fossil fuel power plant.
Bendtsen, J. D., Stoustrup, J., & Trangbæk, K. (2005). Bumpless Transfer between Observer-based Gain Scheduled Controllers. International Journal of Control, 78(7), 491-504. https://doi.org/10.1080/00207170500111028