Supporting Hydraulic Circuit Design by Efficiently Solving the Model Synthesis Problem

The design of hydraulic systems is founded on deep physical connections. It needs creativity and, at the present time, it cannot be automated. Nevertheless, powerful design support in hydraulics is still possible. This paper presents a new view to the design of hydraulic systems and shows how sophisticated subtasks of the hydraulic design procedure can be tackled. We identify the “model synthesis problem” as a crucial factor in the design procedure and develop methods to solve the problem. Although our approach is tailored to hydraulics, it reveals the nature of model synthesis, and thus it provides insights to tackle model synthesis in other domains as well. 1 Design of Hydraulic Systems This section replaces an introduction. Its purpose is twofold: To convey a rough idea of hydraulic circuit design, and to explain why such a sophisticated task can be supported at all. The starting point for a design process is a task that shall be performed by hydraulics. This task might be a lifting problem, the actuation of a press, or the realization of a robot’s kinematics. The result of the design process is a system consisting of hydraulic components. Hydraulic components are the building blocks in this design process; they can be divided into three classes: (i) cylinders, which transform hydraulic energy into mechanical energy, (ii) various forms of valves, which control flow and pressure of the hydraulic medium, and (iii) service components such as pumps, tanks, and pipes, which provide and distribute the necessary pressure p and flow Q. Figure 1 shows the basic structure of a differential cylinder and a proportional valve respectively. Below these figures a small extract of their behavior description is given. F = p A − p A − m v − d v Q p , B B ,Q pA A A K A R