MS Thesis Presentation by Scott Driscoll
Wednesday, June 8, 2005

(Dr. Wayne Book, Chair)

"The Design and Qualification of a Hydraulic Hardware-in-the-Loop Simulator"


The goal of this work was to design and evaluate a hydraulic Hardware-in-the-Loop (HIL) simulation system based around electric and hydraulic motors. The idea behind HIL simulation is to install real hardware within a physically emulated environment, so that genuine performance can be assessed without the expense of final assembly testing. In this case, coupled electric and hydraulic motors were used to create the physical environment emulation by imparting flows and pressures on test hardware. Typically, servo-valves are used for this type of hydraulic emulation, and one of the main purposes of this work was to compare the effectiveness of using motors instead of the somewhat standard servo-valve. Towards this end, a case study involving a Sauer Danfoss proportional valve and emulation of a John Deere backhoe cylinder was undertaken. The design of speed and pressure controllers used in this emulation is presented, and results are compared to data from a real John Deere backhoe and proportional valve. While motors have a substantially lower bandwidth than servo-valves due to their inertia, they have the ability to control pressure at zero and near-zero flows, which is fundamentally impossible for valves. The limitations and unique capabilities of motors are discussed with respect to characteristics of real hydraulic systems.