Multi-parametric optimization of a pulse width/phase modulated controller for a high frequency active electro-hydraulic pump system

In this article, an adaptive width/phase differential modulated controller is designed for an Active electro-hydraulic Pump (AehP) system. The controller adjusts the duty cycle and relative phase between the incoming and outgoing valve. The adjustment relies on the maximization of a multiparametric cost function which is comprised of the net outflow rate, the energy delivered by the piston to the fluid and the maximum pressure evaluated on the piston surface. The developed model relies on Computational Fluid Dynamics (CFD). Transient CFD analysis shows that the pressure propagation causes the pump performance to be highly dependent to the overall dimensions of the hydraulic system, the fluid's properties and the operating conditions, thus constraining and complicating the controller design process. The controller's adaptation mechanism relies on the cyclic coordinate method, which adjusts each parameter in a periodic manner. Simulation studies are used to investigate the efficiency of the proposed optimization scheme for the adaptive controller with respect to the variation of the fluid properties due to the change of the operating conditions.