Active damping system for an automobile suspension

In a vehicle having an unsprung mass subject to random input vibration from a road surface, a sprung mass and a spring supporting said sprung mass on said unsprung mass, an active damping system comprising:

• an electrical current conducting coil spatially fixed with respect to one of said sprung mass and said unsprung mass;
• a magnetic element spatially fixed with respect to one other of said sprung mass and said unsprung mass so that relative motion is imparted between said coil and said element in response to relative motion between said sprung mass and said unsprung mass, said magnetic element developing magnetic flux intersecting said winding to develop an induced current through said coil in response to said relative motion between said coil and said element wherein said induced current develops an electromotive force on said magnetic element opposing said relative motion;
• and
• means for developing a control current through said coil to oppose motion of said sprung mass relative to said road surface occurring below a selected frequency.

In a vehicle having an unsprung mass subject to random input vibration from a road surface, a sprung mass and a spring supporting said sprung mass on said unsprung mass, an active damping comprising:

• an electrical current conducting coil spatially fixed with respect to one of said sprung mass and said unsprung mass;
• a magnetic element spatially affixed with respect to one other of said sprung mass and said unsprung mass so that relative motion is imparted between said coil and said element in respect to relative motion between said sprung mass and said unsprung mass;
• circuit means for developing an induced current in said coil in response to said relative motion between said coil and said magnetic element wherein said magnetic element develops magnetic flux intersecting said coil and further wherein said induced current develops an electromotive force on said magnetic element opposing said relative motion, said circuit means further including means for limiting said induced current to frequencies above a selected frequency;
• and
• means for developing a control current through said coil to oppose motion of said sprung mass relative to said road surface occurring below said selected frequency.