Innovations: Project Skyhook; May 2001; Scientific American Magazine; by Gary Stix; 2 Page(s)
In the early 1970s Dean C. Karnopp of the University of California at Davis and Michael J. Crosby of Lord Corporation wanted to create the perfect ride for a car, truck or bus. They imagined the ultimate shock absorbers: attached to the car body over each wheel on one end but extending up to imaginary hooks in the sky that moved along with the vehicle. As the wheels bounced on hitting a bump, the sky shocks would thrust downward to keep the body in a level position, making a dirt road feel like a plush carpet.
That, in fact, is what a conventional shock absorber is supposed to do. But a shock from the local garage, although it provides some cushioning, can actually transmit, not absorb, energy when you go over a big bump too fast. A down-to-earth version of a skyhook would have to turn off the shock-absorbing qualities of the device gradually as the tire moved up after hitting a bump-and then turn the shock on bit by bit as the tire dropped into a pothole. The difference between a passive and an active device is the difference between stepping directly into a fist in the face or rolling with a punch.