Cadillac STS Forum - 2005 through 2012 Discussion, MRC for Dummies in Past Cadillac Vehicle Discussion; No, I am NOT trying to put anyone down, It filled gaps "I" had about Magnetic Ride Control.
You can also Google "lord magnetorheological suspension control". DELPHI and Lord worked with GM/Seville design and Ferrari Italia to develop the first MRC suspensions. Our 2002.5 - 2003 STS was the test mule.
Clever system - NO moving parts other than the center piston/rod.
I saw writeups on magnetorheological systems at least 40 years ago. Computer systems were in their infancy so the applications were analog rather than digitally controlled. One idea was shock absorbers that could be controlled by a rheostat like the volume control on your radio. Another was a transmission that the torque convertor could be replaced by controlled slippage of a magnetorheological clutch. The suspension idea didn't take root until digital computers and the Lotus active hydraulic suspension appeared.