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The success of mobile construction machinery owes a great deal to the proper use of hydraulic power. Hydraulic power systems are usually configured with a positive displacement hydraulic pump. Different work functions require a variety of hydraulic flow and pressure values to provide the desired operations. System branches, therefore, must include a variety of specialized flow and pressure regulating valves. The correct configuration of these valves can be accomplished by building and testing variations of a valve until desired conditions are achieved. However, since machinery build programs are expensive; the use of mathematical modeling of a fluid power component is often well worth the time required to establish the model. Use of the model to study the operation of a component will then lead to fewer hours of shop testing. This example discusses the design and mathematical model of a pressure control valve that provides priority to selected circuits on a mobile machine.

The success of agricultural and construction machinery owes a great deal to the effective use of fluid power. Most fluid power systems are configured with a positive displacement fluid pump that is large enough to meet the flow requirements of many work circuits. Different work functions require a variety of fluid flow and pressure values to provide the desired operation. System branches, therefore, must include specialized flow and pressure regulating valves. The development of a mathematical model of a fluid flow control valve follows.

Many types of mechanical linkages are in use on fluid power equipment. Linkages are often used in hydromechanical servomechanisms and in actuator powered machine members used to accomplish desired working functions. Agricultural and construction equipment have many examples of linkages in use with fluid power systems. The motion of hydraulically actuated linkages is usually quite complex, because of the versatility of fluid power machinery. This paper explores some helpful concepts from kinematics to describe motion analysis of linkages. Linkage position, velocity, and acceleration may be covered by the method.