Modeling and H ₂/H _∞ MIMO control of an earthmoving vehicle powertrain

Coordination of the power distribution in a Multi-Input Multi-Output (MIMO) electrohydraulic transmission is investigated for the case of an earthmoving vehicle powertrain. A generalized model of a representative system is presented along with the development of both H ₂ and H _∞ MIMO controller designs. The controllers are developed based on a linearized model of the system about some nominal operating point. Multiple inputs are coordinated to control multiple load outputs simultaneously. Since typical MIMO electrohydraulic transmission systems have significant nonlinear dynamics that vary with system operating conditions, a robust controller design is paramount. The increased robustness of the H _∞ controller over the H ₂ scheme is demonstrated qualitatively in the time domain through both disturbance rejection and trajectory tracking comparisons. A frequency domain criterion quantitatively provides quantifiable comparisons between the two methods. Hardware-in-the-Loop experiments validate the modeling and control performance on an Earthmoving Vehicle Powertrain Simulator (EVPS).