

Thirty-seven years after Dr. Amar Bose hit on the idea of beefing up a loudspeaker’s electromagnetic driver to be an adaptive car suspension, Bose is selling off the technology to ClearMotion, another Boston-area tech company founded by MIT graduates. Bose got as far as developing prototype cars that were exhibited in 2004, though it did bring to market an offshoot, electromagnetically suspended seats for long-haul truck drivers.

Unmodified- and Bose-suspension Lexus LS400s on a bumpy road, 2004.

Genesis of the Electromagnetic Suspension

At a 2004 technology rollout at Bose headquarters in Framingham, Massachusetts, Amar Bose said, “This is the first time a suspension system is the same for a sports car and for a luxury car.” He was drawn to develop alternatives to the traditional springs-and-shocks suspensions after experiences owning a 1957 Pontiac with a fledgling air suspension and a 1967 Citroën with an always-leaking hydraulic suspension.

Bose believed a loudspeaker driver comprising a magnet and electromagnetic coil, which pushed the speaker cone in and out, could be seriously scaled up to move not just a paper cone but 1,000 pounds of automobile at each corner. Bose created a mathematical model of the suspension. It called for better and beefier electromagnetic motors, power amplifiers, control algorithms, and microprocessor power — all of which he believed would come available over time.

Bose set up a skunkworks project in 1980 and code-named it Project Sound to hide the true nature from the Bose accounting department. Twenty-four years later, the company felt comfortable enough with Project Sound to showcase it for the media and analysts.

Bose suspension in a 1994 Lexus LS400.

Day-and-Night Difference in Ride Quality

Linear motor at each corner replaced the traditional springs, shock absorbers.

At that summer 2004 unveiling, Bose showed off a modified and unmodified 1994 Lexus LS400 and a Porsche 911. They were driven hard around corners and over bumps that hit the front and then rear axles, and another set of bumps that raised the left tire but not the right front, then the rears.

The front-then-rear bumps were uncomfortable on the short road course in the stock Lexus and, amazingly, almost unnoticeable with the Bose suspension. Project Sound was not just damping the roadway bumps but actively counteracting them.

The alternating left-right bumps with the stock suspension were so vicious in the Porsche that the test driver had to wear a helmet to avoid concussing his head when it repeatedly struck the side window.

A repeat visitor to Bose knows the company always has a can-you-top-this moment for visitors. In this case, it was said to be a test of the Lexus driving at speed over a railroad tie. The driver approached the railroad tie at speed, the car hunkered down (the suspension had 8 inches of travel), then the linear motors went to full expansion mode, and the car lifted off the ground and sailed over the railroad tie with inches to spare. After that, the driver got out, bowed to the crowd, pointed to the car, clicked a button, and the front suspension dipped down, too, and bowed as the headlamps winked.

At the end of the demo, Bose representatives explained what was needed to bring the suspension to market in a production car by the end of the decade: the cost would have to come down to a reasonable level for a high-end car, and the weight would have to come down to no more than 50 pounds per corner more than the existing suspension. Meaning a production car would weigh an extra 200 pounds.

Many of the world’s premiere automakers met with Bose, but no Bose-suspension cars ever came to market. There was also talk of adapting the suspension for ambulances or luxury tour buses.

Bose Ride System seat for long-haul truck drivers uses a similar electromagnetic suspension.

Bose Suspension Trucker Seats

As it tried to bring the air suspension to market, Bose hit on the idea of installing the electronics and mechanicals inside the seats used by long-haul truck drivers. The previous state of the art was air suspension seats that softened the ride, but not enough for many truckers with back problems.

In the Bose Ride seat, precision sensors detect up-and-down motion. Bose proprietary algorithms calculate how to adjust the seat, and the electromagnetic motor in the base counteracts the bumps. The seat is $3,700, less in quantity. In a survey of truckers who reported back problems that affected their ability to drive the stiffly sprung tractor units, 97 percent said the Bose seat significantly reduced discomfort.

ClearMotion Takes Over the Bose Project

ClearMotion’s acquisition of the Bose suspension and Bose Ride seat technology may help ClearMotion develop what it calls a digital chassis. Without going into detail, ClearMotion says it will go beyond the current adaptive suspensions using air damping or magnetorheological adaptive dampers (using magnetic particles in shock absorber fluid, typically called MagneRide technology).

With the addition of the Bose portfolio, ClearMotion says it is “a step closer to achieving its mission to be the leading motion control company in mobility.”

Shakeel Avadhany, ClearMotion’s CEO and co-founder. said it will scale its own and the Bose’s technologies across self-driving platforms, consumer SUVs and pickups, commercial truck, bus, agriculture, and off-highway vehicles. He said passengers in self-driving cars will be looking for a smooth ride so they can work on a laptop, tablet, or traditional paper notebook while en route.