Hybrid and Self-Contained Electrohydrostatic Actuation Technology

Moog is committed to a technology neutral approach to selecting the right technology for a customer’s machine. This approach involves a rigorous analysis of the pros and cons of hydraulic, electric and hybrid technology based on the exact requirements of a machine or application. With over extensive expertise in each technology across a range of applications, we can offer an innovative approach to a solve problems our customers have faced for many years.

Comparison of EHA vs. Electric or Hydraulic Actuation

  • EHA is an option for traditionally hydraulic applications where there are high force requirements but also the need for specific advantages of electric technology such as energy savings, environmental cleanliness or cost of hydraulic piping.
  • EHA is an option for traditionally electric applications that have high forces and require redundant and/or advanced failsafe systems

Benefits of the Moog Solution

  • Moog uses our proven motion control products as the core of the system which enables a more flexible mechanical packaging to optimize the size and efficiency
  • Self-contained package that removes the need for long hydraulic line lengths and rotary couplings, offering enormous cost savings in applications such as subsea oil exploration and wind turbines
  • An integrated systems approach means greater reliability for the customer as less individual components will lower system failure rate
  • Redundancy and fail-safe features have been fully integrated in the system offering minimal impact on cost, weight, envelope and reliability
  • Gear reduction is obtained by reducing the size of the pump, facilitating the use of small low-torque servomotors to save overall system costs

A typical package includes the following Moog motion control building block products:

Examples of Development Projects for Industrial Machinery

Moog has been providing industry-leading EHA actuation for flight controls for over 18 years.  This expertise gained through practical experience and proven through trade studies in the aircraft industry has now also been applied to industrial applications to provide innovative results.

Subsea Oil Exploration   

  • Ideal application for Moog EHA due to the high forces and the cost savings for eliminating the need for over 10,000 feet of hydraulic hose as well as preventing any environmental concerns.
  • Patent pending self-contained EHA actuation system can handle 1,500,000 lbf and only requires electrical power and communication

Wind Turbine Pitch Control

  • Ideal application for Moog EHA due to the need for failsafe redundancies to protect the turbine in the case of a catastrophic event, resolving issues sometimes experienced with batteries in electric pitch control solutions.
  • Saves the high cost of hydraulic piping required in hydraulic solutions


Hybrid Actuation is a term commonly used to describe systems that have both hydraulic and electric technology in a self-contained package.  The resulting system has characteristics of both technologies.

Electrohydrostatic Actuation (EHA) is sometimes known as “powered by wire” as actuation can be provided in a self contained unit combining both electric (e.g. servomotors) and hydraulic (e.g. pumps and valves) with a common controller and software system. The self-contained package has the advantage of no hydraulic piping required.

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