Earthmoving vehicle powertrain controller design and evaluation

Previous work [Zhang, R et al., 2003 and 2002] examined the control of a nonlinear multi-input multi-output electrohydraulic system representative of an earthmoving vehicle powertrain. The system layout incorporates a prime mover, a variable displacement pump, several flow valves and motors representing different loads on the powertrain. A gain-scheduled H/sub /spl infin// controller [Zhang, R et al., 2002] was successfully developed and tested on a hardware-in-the-loop (HIL) system. However, previous results were for relatively simple reference tracking tasks. In this paper, the previously developed systems and load emulation environments are implemented and used to provide a test environment for the human-centered evaluation of powertrain controller designs. Measures for performance and efficiency are first discussed and defined for the earthmoving powertrain. The H/sub /spl infin// control problem is then presented along with a brief summary of the earthmoving vehicle powertrain simulator (EVPS) plant model developed previously. Various design plant models (DPMs), based on maximizing performance and/or efficiency, are described and controllers are synthesized using commonly available H/sub /spl infin// control design software. Experimental comparisons of working cycle times, tracking performance, system efficiencies, and component efficiencies are made between the different controller designs. The task used for comparison is an ISO-degree closed-loop working cycle for a medium sized wheel loader.