Applying Smart Hydraulic Cylinders

Mac Stuhler / July 9th, 2014

What is a Smart (Hydraulic) Cylinder?

Smart hydraulic cylinders gain their name from the fact that highly accurate position sensing electronics are integrated with the hydraulics in a single actuator.  Thus these cylinders are “smart” about understanding cylinder position allowing robust position information to be fed to more complex feedback systems.

CPI Linear Transducer Usage In The SeaSLICE

Enter the Lockheed Martin “SeaSLICE” technology, a twin hull ship design at the cutting edge of affordable, high speed vessel operation. The SeaSLICE is 105 feet long and only 52 feet wide but is as stable in rough seas as a 350 foot conventional mono-hull ship.

Key to achieving SeaSLICE performance is the precise reliable control of the rudders. Closed loop feedback is also used to define preset fin positions. Early systems used external position sensors and mechanical linkages but these systems were complex, failure prone, and hard to adjust. When Lockheed Martin went looking for a smart cylinder solution, they chose one integrated with CPI’s SL Series Linear Position Sensors.  The CPI smart cylinder implementation eliminates these problems because its linear displacement transducer resides completely inside the hydraulic cylinder. In fact, these CPI based smart cylinders are not discernable from standard hydraulic cylinders except for the M12-style electrical connector on the side.

In the CPI application a shielded cable carrying power and feedback signals, plugs into the cylinder through the M 12-style connector. The transducer’s in-line signal conditioner accepts any voltage from 12- to 24- V DC and provides the controller with a highly repeatable 0.5- to 4.5- V DC analog output. Because it’s vehicle hardened to ASAE EP455, the CPI position sensor stands up to the extremely rugged operating environment on the SeaSLICE.

Lockheed Martin sees wide and varying uses for the SeaSLICE platform including law enforcement patrol/interdiction, search and rescue, oceanographic research, cargo transport, ferry operation and border protection.  Wherever they go, the robust smart cylinder implementation of the CPI SL-Series goes with them.

About CPI SL-Series Linear Position Transducers

CPI is a US based manufacturer of precision waterproof switches, electro-mechancial thermal switches and LVDT based, non-contacting,  linear position sensors. Heavy duty materials and robust performance characterize all of CPI’s products. Custom designed and off the shelf products in each category satisfy the most demanding operational environments. And all products are designed and manufactured in the USA.

For more information on how to apply SL-Series position sensors in your hydraulics application (smart or otherwise!) give us a call.