Comparison of Several Flow Control Strategies for Proportional Valves

Abstract

In mobile hydraulic applications, such as the bucket functions of a wheel loader, there are often repetitive tasks which would benefit from some level of automation. Machine efficiency, working accuracy and reduced operator fatigue are possible benefits. From an economic stand point, the automation must be realized with inexpensive and reliable components, which means minimizing the complexity and number of physical components. For these reasons, it was of interest to introduce some level of automation to the bucket functions of a wheeled loader using proportional valves. In this paper the problems of achieving flow control in a load sensing system employed on the wheel loader using proportional valves are addressed. In particular, development of a flow control strategy involving mapping of the valve pressure/flow characteristics is investigated.