Optimal Mode Decomposition for Control

Abstract: We present an extension of optimal mode decomposition (OMD) for autonomous systems to systems with controls. The extension is developed along the same lines as the extension of dynamic mode decomposition (DMD) to DMD with control (DMDc). DMD identifies a linear dynamic system from high-dimensional snapshot data. DMD is often combined with a subsequent reduction by a projection to a truncated basis for the space spanned by the snapshots. In OMD, the identification and reduction are essentially integrated into a single optimization step, thus avoiding the somewhat adhoc decoupled, a posteriori reduction that is necessary if DMD is to be used for model reduction. DMD was devised for autonomous systems and later extended to DMD for systems with control inputs (DMDc). We present the analogous extension of OMD to OMDc, i.e. OMD for systems with control inputs. We illustrate the proposed method with an application to coupled diffusion-equations that model the drying of a wood chip. Reduced models of this type are required for the efficient simulation of industrial drying processes.