Electro-hydraulic drive networks for use in multi-actuator systems are an emerging field within fluid power technology. The development of such drive networks is motivated by their ability to improve energy efficiency compared to conventional valve technology and to reduce the power installation requirements compared to standalone electro-hydraulic drives. These features are enabled by variable-speed hydraulic displacement units connected to hydraulic cylinders and/or motors, and potential chamber short-circuits in various relevant ways, enabling electro-hydraulic power sharing capabilities. A class of drive networks, so-called minimal realizable electro-hydraulic drive networks , appear especially feasible in this regard as they comprise the minimum number of hydraulic displacement units in the presence of the maximum number of sensible short circuits. However, these properties also cause such drive networks to be strongly coupled high order systems, substantially complicating their control designs. At this stage decoupling schemes have been proposed, allowing to decouple the motion states from the system sum-pressure, but not decoupling of the motion states. Hence motion control remains challenging unless detailed mathematical models and numerical tools are available. This article proposes a general observer-based state control structure with analytic parameter design, applicable to any minimal realizable electro-hydraulic drive networks regardless of the number of hydraulic cylinders/motors. The proposed control structure is elaborated theoretically when applied to a generally representative model structure. Design examples and simulation results for two and three cylinder minimal realizable electro-hydraulic drive networks are presented, demonstrating the strength of the proposed control structure.
Schmidt et al. (Fri,) studied this question.