Digital control of wheel loader implement system using closed center valve and variable displacement pump

The earth moving equipment industry has been quickly adapting new computer control technologies to achieve great gains in efficiency, performance, safety, and operator comfort. There are two major types of earth moving equipment operating in large numbers: excavators and wheel type loaders. The long term goal is to develop an autonomous product that no longer relies on the operator skill and endurance to maximize performance. The performance is measured in the form of tons per hour of the material processed. The goal is to develop controlled sub-systems that (1) improve operator/machine performance, reduce operation cost and (2) that would serve as lower level control sub-system in the future autonomous controller hierarchy.;In this research, the integrated control of closed center valves and variable displacement pump was implemented for the bucket hydraulic control system of a medium size wheel type loader (WTL). The results are applicable to any electrohydraulic (EH) control system application where variable displacement pump and closed center EH valve combination are used. The real time control of the EH system has been tested and compared to the current production machines using WTL Caterpillar model 950G.