Nonlinear Adaptive Feedforward in a Two-Degrees-of-Freedom Controller

An adaptive feedforward steady-state gain in a two-degrees-of-freedom controller for a nonlinear SISO plant is investigated. The examination of a less complicated structure gives hints to how an update law may be constructed in the nonlinear case. Stability is shown in the simpler case for an update law based on an estimation error using projection, and simulations show that Altering may lead to improved performance. By using an adaptive feedforward function inspired by gain-scheduling techniques, a simulation example for the nonlinear structure is also shown. The conclusions are that the scheme has potential but that more research is needed for the nonlinear setup.