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Bose® Suspension System


Introduction
Bose Corporation has created a unique electromagnetic suspension system for automobiles. This
paper outlines the 24-year ongoing research project that led to the Bose suspension, describes the
key innovations in the system, and summarizes the system’s performance.
Project Background
Every automotive suspension has two goals: passenger comfort and vehicle control. Comfort is
provided by isolating the vehicle’s passengers from road disturbances. Control is achieved by
keeping the car body from rolling and pitching excessively, and maintaining good contact between
the tire and the road. Unfortunately, these goals are in conflict. In a luxury sedan the suspension is
usually designed with an emphasis on comfort, but the result is a vehicle that rolls and pitches while
driving and during turning and braking. In sports cars, where the emphasis is on control, the
suspension is designed to reduce roll and pitch, but comfort is sacrificed.
In 1980, Dr. Bose conducted a mathematical study to determine the optimum possible performance
of an automotive suspension, ignoring the limitations of any existing suspension hardware. The
result of this 5-year study indicated that it was possible to achieve performance that was a large step
above anything available. After evaluating conventional and variable spring/damper systems as well
as hydraulic approaches, it was determined that none had the combination of speed, strength, and
efficiency that is necessary to provide the desired results. The study led to electromagnetics as the
one approach that could realize the desired suspension characteristics.
The Bose suspension required significant advancements in four key disciplines: linear
electromagnetic motors, power amplifiers, control algorithms, and computation speed. Bose took on
the challenge of the first three disciplines, and bet on developments that industry would make on the
fourth item.
Prototypes of the Bose suspension have been installed in standard production vehicles. These
research vehicles have been tested on a wide variety of roads, on tracks, and on durability courses.