Energy Efficient Digital Hydraulic Power Management of a Multi Actuator System
|Kustantaja||Tampere University of Technology|
|Tila||Julkaistu - 26 toukokuuta 2016|
|Nimi||Tampere University of Technology. Publication|
A dream of the perfect valve has been a driving force behind the development of digital hydraulic valves. Simple question: what makes a valve perfect and how to realize it? One answer is simple: a digital valve system - a DVS. The same questions have been asked considering the hydraulic supply unit. The perfect supply unit supplies exactly the required power for multiple actuators and handles also the recuperation. The chase of this dream has resulted in a digital hydraulic power management system - a DHPMS, or more likely the DHPMS as it is currently the only one of its kind in the world. Combining these two "dream-come-true" pieces of technology together, efficient hydraulic circuit design is made feasible. However, the control of such combination is not trivial; hence holistic control system design is inspected.
The objective of the thesis is to study DHPMS capability to work as an ideal sink/source of hydraulic power. The test setup emulates realistic application and energy efficiency is taken into consideration. The origin of losses is inspected and analysed and solutions are presented. Simulations and measurements are used to prove the potential of the technological advancements. The functionality of the system is considered; power flow within the system lines is matched to the independent demands of different actuators and the power can be routed from an actuator to another- if there is a negative load on one actuator while positive on the other. There is no need to have the same load pressures as the DHPMS has a built in transformer feature.
The results show that the DHPMS works, but in order to gain all the benefits made feasible by of the DHPMS, also DVSs are required. Applying digital hydraulic innovations into a two-degree-of-freedom test system, 40% energy savings are achievable compared with the state of the art system. Similar results are gained from both simulations and measurements.Generalization of the results and future insight is discussed.