Classification of Hydraulic Drive Networks & Their Key Elements

Hydraulic drive networks enable efficient actuation of multi-actuator hy-<br/>draulic transmission systems which incorporate different coupling mecha-<br/>nisms between the actuators. So far, the topics of hydraulic drive networks<br/>have mainly been centered around the use of variable-speed electric machines<br/>combined with fixed hydraulic displacement machines for enabling actuation.<br/>However, actuation in hydraulic drive networks may be realized in multi-<br/>ple ways, including the use of variable hydraulic displacement machines in<br/>through-drive configuration with a single electric motor, hydraulically sup-<br/>plied hydraulic motor-pump configurations and so forth. This paper makes a<br/>classification of a hydraulic drive network and its different coupling layers<br/>in the form of fluid short circuit connections, flow couplings through hy-<br/>draulic displacement machines, and couplings related to the rotational speed<br/>of the hydraulic displacement machines. Requirements for the hydraulic dis-<br/>placement machines are discussed and different component configurations<br/>and their control degrees of freedom are discussed considering the different<br/>coupling mechanisms.