This $3 Million Machine Tests Car Chassis While They're Sitting Still

From the June 2017 issue

There is no such thing as a clean-sheet vehicle design in 2017. In its relatively brief existence, the automobile illustrates Darwin’s natural-selection theory better than the platypus, which has persisted—mostly inexplicably—for somewhere between 19 million and 48 million years. Unlike a duck-billed, beaver-tailed, egg-laying mammal, every modern vehicle is an adaptation of intelligent designs, most of which strengthen the breed and are logically passed down through the generations—in this case, through university lecture halls, technical papers, and CAD files.

Suspension tuning is no exception. Chassis engineers start with proven concepts and aim to improve on those ideas. Put plainly, they benchmark. They measure and analyze the outgoing model and the competitors, and when ambitions grow large, automakers occasionally end up buying $90,000 rear-­engined German sports cars to advance the development of a Ford Mustang.

It’s not enough to recognize dynamic excellence, though. Chassis engineers seek attributes that are tangible in the real world, such as chassis feedback, better ride quality, and predictable, manageable behaviors at the limit. But they operate in the deeply nerdy world of spring rates and tire compounds and suspension geometry, where everything interacts and nothing can be gained without compromise. To translate between the two—to trace vehicle behaviors back to the tuning knobs at their disposal—engineers need to find the correlations. Why does this car feel so natural when driven over that bump at that speed? They often pinpoint the answer using a kinematics-and-­compliance (K&C) machine, the yardstick for a science where suspension compression is measured in thousandths of an inch and body roll in fractions of a degree.

A K&C machine simulates suspension events in a controlled environment where the vehicle’s reactions can be precisely measured. An electrically actuated table clamped to the car’s pinch seams can pull the body down onto the suspension’s bump stops or lift it until the wheels droop, as if it’s gone airborne. Ever seen a car corner at 1.00 g while it’s sitting still? A K&C machine does just that.