Bumpless transfer synthesis in the MIMO systems with a large online/offline controller mismatch using the state/output feedback topology

The simultaneous use of the state and the output of the offline controller in bumpless transfer design for multi-input-multi-output (MIMO) systems is proposed. Under a large online/offline controller mismatch, the recently introduced MIMO bumpless transfer design based on the feedback of the offline controller state and the online controller input and output is found to produce significant deviations between the output signals of the online and the offline controller. These deviations are shown to result in the plant output bumps in the wake of the controller transfer. While retaining the main features of this design, an additional internal model based controller is introduced that uses both the online and the offline controller output signals to form the novel state/output feedback bumpless transfer topology. The latter is shown to be capable of eliminating the online/offline MIMO controller output tracking errors under large mismatch of the online/offline controller dynamics, as well as to permit more flexible manipulation of the error decay rates. The new topology is demonstrated to solve a longstanding problem of the steady state bumpless transfer from standard PID-based controllers to MIMO robust controllers in the megawatt/throttle pressure control of a boiler/turbine unit. The convergence speed-up provided by the topology proposed is shown to facilitate the use of the latter in designing the agile switching controllers with an improved closed-loop performance in electrical motor control applications. The topology proposed is also demonstrated to extend the applicability of the steady state design to bumpless transfer in the oscillatory quasi-stationary regimes.