Collective term for all hydraulic feedback controls with electrical (electronic) signal processing. As the to the hydraulics - the servo valves and proportional valves - has already been in use for some time, all control system-related developments in microelectronics can be used in hydraulics, up to and including continuous digital signal processing. The term "electro-hydraulic control technology" is to be preferred over the term "servo technology", as with the latter the reference to the hydraulic application is missing.
Electro-hydraulic control technology permits in the majority of cases a high gain between the weak electrical input signal and the hydraulic (gain factor 104 to 106). The variables controlled are as a rule mechanical variables such as distance, force and speed, and therefore correspond to the analogous hydraulic variables flow rate and pressure.
Electro-hydraulic control technology therefore combines the advantages of electrical signal processing - such as the ease of linking, saving and amplifying electrical signals, ease of compliance with priorities as well as the design of redundant circuits with hydraulic systems.
The alternative is: mechanical-hydraulic or pneumatic-hydraulic control technology.