Combined Fluid Power and Mechatronic Technology Optimizes Solutions Current electro-hydraulic actuation products employ technologies that provide greater functionalities and practically eliminate many drawbacks of hydraulics. Additionally, some new electro-hydraulic actuators on the market today come as a highly integrated unit with advanced electronic control and plug and play design for modern distributed architecture. These advancements in electro-hydraulics technology create opportunities for users to optimize their investments in automation solutions by selectively using both electric and electro-hydraulic actuation.

1. THOUGHT LEADERS FOR MANUFACTURING & SUPPLY CHAIN
ARC INSIGHTS
By Himanshu Shah
& Sal Spada
Some users increasingly employ electric
and electro-hydraulic actuation
technologies side by side on the same
machinery to create optimum solutions.
These solutions offer increased
productivity and higher quality output
while keeping capital expenditure low.
INSIGHT# 2003-32MD&H
AUGUST 13, 2003
Combined Fluid Power and Mechatronic
Technology Optimizes Solutions
Keywords
Electro-hydraulics, Actuators, Intelligent Axis, Combined Technologies
Summary
Current electro-hydraulic actuation products employ technologies that
provide greater functionalities and practically eliminate many drawbacks of
hydraulics. Additionally, some new electro-hydraulic actuators on the
market today come as a highly integrated unit
with advanced electronic control and plug and
play design for modern distributed architecture.
These advancements in electro-hydraulics tech-
nology create opportunities for users to optimize
their investments in automation solutions by se-
lectively using both electric and electro-hydraulic
actuation.
Analysis
Many industry groups forecasted the demise of hydraulic actuators in
many machine segments as the technology was characterized as having
significant drawbacks compared with electric actuation. As machine build-
ers continued to push leading edge technology with each generation of
machinery to achieve higher productivity and a higher quality output, the
move to electrical actuation was perceived as inevitable since it is all about
creating a competitive advantage in the market. However, the mass exodus
from hydraulics to electric actuation has not materialized.
In a recent survey, ARC found that the primary reasons that machine
builders converted machinery from hydraulic actuated to electric were re-
lated to both environmental concerns and issues of cleanliness of the overall
system.

2. ARC Insights, Page 2
©2003 • ARC • 3 Allied Drive • Dedham, MA 02026 USA • 781-471-1000 • ARCweb.com
Primary Reasons for Switching to Electric Actuators Percent
Cleanliness of the Overall System 38.9%
Environmental Concerns and Disposing of Hydraulic Fluid 33.3%
Customers are asking for Electric Actuation 27.8%
ARC Advisory Group Survey Results
In light of this, manufacturers’ use of hydraulic actuation persists in the
market for numerous reasons: (1) Replacement of existing equipment, (2)
Relatively low cost; and (3) Other technologies do not offer similar form,
function, or performance.
High torque without a gearbox
No need to translate rotational motion to linear motion
Actuators are smaller and lighter
No energy consumption at zero speed or pressure
Low audible noise
No sparks in hazardous environment
Hydraulic Actuation Usage Persists for Numerous Reasons
With the availability of sophisticated electronic controls for hydraulic actua-
tion, the selection between electric and hydraulic actuation is evermore
difficult, albeit this situation is to the user’s advantage.
Hydraulic Actuation Improved in Recent Years
A new generation of electro-hydraulic actuation, complete with servo
valve, hydraulic cylinder, feedback unit, and advanced control electronics
offers a host of additional benefits due to the use of digital technology.
• External Feedback Configurations Eliminated
Servo valves integrated with hydraulic cylinders with closed loop con-
trol electronics improve performance and reduce wiring.
• Networked
CANopen, Profibus DP, Ethernet/IP, SERCOS, or DeviceNet integrated
Field Busses reduce wiring and facilitate diagnostics.
• Adaptable
Hydraulic valves adapt to changing process or load conditions during
operation using addressable control loop algorithms.

3. ARC Insights, Page 3
©2003 • ARC • 3 Allied Drive • Dedham, MA 02026 USA • 781-471-1000 • ARCweb.com
• Plug and Play in Distributed Architecture
Smart configurations make the actuator easy to integrate into a distrib-
uted system along with electric actuators.
• Reducing Leakage and Extending Mechanical Life
Jerk limiting profiles eliminate high pressure spikes
• Enabling Collaboration
Embedded or integrated smart electronics with hydraulics allow fast in-
formation exchange over networks for a modern collaborative
manufacturing environment.
While standard networking interfaces, remote diagnostic capability, closed
loop control, and over load features make electro-hydraulic units compara-
ble to intelligent electro-mechanical actuators, electro-hydraulic actuations
offer specific advantages over electric actuation. The integrated concept
transfers the system responsibility from the machine builder or end user to
the actuator manufacturer. With built-in programmability, the user can
eliminates the higher cost controller and can use simple PLC control to re-
duce the cost.
Combining Hydraulic and Electric Actuation Offers Optimal
Solutions
For many applications, electric actuations offer superior performance due
to higher bandwidth with greater positioning accuracies, better axis-to-axis
coordination, and lower maintenance. Hydraulics requires complex non-
linear compensation compared with linear compensation that electro-
mechanical actuation requires. But if higher power density and lower cost
are important criteria in an application, electro-hydraulic now becomes a
competitive technology. Hydraulic offers the strength and flexibility of
Programmable Parameters
Hydraulic Actuation Electric Actuation
Pressure/Force Torque
Position Position
Velocity Velocity
Ramp generation Ramp generation
Analog and Digital I/Os Analog and Digital I/Os
Motion Sequence Motion Sequence
Combining Technologies Offers Optimal Solutions

4. ARC Insights, Page 4
©2003 • ARC • 3 Allied Drive • Dedham, MA 02026 USA • 781-471-1000 • ARCweb.com
fluid power and can exercise very precise and smooth motion
with the right control system, shunning the imprecise ‘bang-
bang’ valve control.
Today, electro-hydraulic actuation enables a smooth transition
from precise position to pressure control required in many appli-
cations such as plastic molding, powder metal parts, and the
lumber industry. These industries increasingly employ both
technologies, side by side, on the same machinery creating opti-
mum solutions. These solutions offer increased productivity and
higher quality output while keeping capital expenditure low. While hy-
draulic and electric actuation technologies are generally not offered by the
same suppliers, few suppliers offer both of these technologies. Users now
can have a single source in forming optimum automation solutions using
combined technologies.
Recommendations
• Adoption of electro-hydraulic solutions is increasing. Users should un-
derstand its benefits and evaluate its use on plant machinery to increase
performance and reduce cost of ownership of plant assets.
• Users need to be ready for the servicing and maintaining machinery
with a combination of electro-hydraulic and electric actuations.
Please help us improve our deliverables to you – take our survey linked to this
transmittal e-mail or at www.arcweb.com/myarc in the Client Area. For further
information, contact your account manager or the author at hshah@arcweb.com
and sspada@arcweb.com . Recommended circulation: All MAS-D and MAS-H
clients. ARC Insights are published and copyrighted by ARC Advisory Group.
The information is proprietary to ARC and no part of it may be reproduced without
prior permission from ARC.
Automation Suppliers
Bosch Rexroth
Delta Computer Systems
Moog
Parker Hannifin
Electro Hydraulic and
Electric Actuation for
Industrial Applications