On performance recovery and bumpless switch of disturbance observer based control

The performance recovery ability of disturbance observer based control (DOBC) is revealed based on equivalent transfer function transformation. It is found that, with the help of DOB, the open-loop characteristics of perturbed condition can be reshaped as similar to the nominal one. A nonlinear fluidized bed combustor is used to validate the ability. To implement the DOBC in practice, the bumpless switch is necessary for safety. A practical bumpless switch strategy is first proposed based on MATLAB/SIMULINK. Finally, a bumpless DOB enhanced PI controller is configured in Ovation DCS.