Bose Electromagnetic Suspension System
What is the point of the suspension system in a car? Passenger comfort and vehicle control. But many times a suspension system can’t achieve this two goals: 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. And what can we do to have both?
After more than 20 years of research, Bose come with a solution: the electromagentis suspension system. 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.
The System
The Bose® suspension system includes a linear electromagnetic motor and power amplifier at each wheel, and a set of control algorithms. This proprietary combination of suspension hardware and control software makes it possible, for the first time, to combine superior comfort and superior control in the same vehicle.
Linear electromagnetic motor
A linear electromagnetic motor is installed at each wheel of a Bose equipped vehicle. Inside the linear electromagnetic motor are magnets and coils of wire. When electrical power is applied to the coils, the motor retracts and extends, creating motion between the wheel and car body.
One of the key advantages of an electromagnetic approach is speed. The linear electromagnetic motor responds quickly enough to counter the effects of bumps and potholes, maintaining a comfortable ride. Additionally, the motor has been designed for maximum strength in a small package, allowing it to put out enough force to prevent the car from rolling and pitching during aggressive driving maneuvers.
Power amplifier
The power amplifier delivers electrical power to the motor in response to signals from the control algorithms. The amplifiers are based on switching amplification technologies pioneered by Dr. Bose at MIT in the early 1960s — technologies that led to the founding of Bose Corporation in 1964.
The regenerative power amplifiers allow power to flow into the linear electromagnetic motor and also allow power to be returned from the motor. For example, when the Bose suspension encounters a pothole, power is used to extend the motor and isolate the vehicle’s occupants from the disturbance. On the far side of the pothole, the motor operates as a generator and returns power back through the amplifier. In so doing, the Bose suspension requires less than a third of the power of a typical vehicle’s air conditioner system.
Control algorithms
The Bose suspension system is controlled by a set of mathematical algorithms developed over the 24 years of research. These control algorithms operate by observing sensor measurements taken from around the car and sending commands to the power amplifiers installed in each corner of the vehicle. The goal of the control algorithms is to allow the car to glide smoothly over roads and to eliminate roll and pitch during driving.
Vehicle performance
Vehicles equipped with the Bose suspension have been tested on a variety of roads and under many different conditions, demonstrating the comfort and control benefits drivers will encounter during day-to-day driving. In addition, the vehicles have undergone handling and durability testing at independent proving grounds.
When test drivers execute aggressive cornering maneuvers like a lane change, the elimination of body roll is appreciated immediately. Similarly, drivers quickly notice the elimination of body pitch during hard braking and acceleration. Professional test drivers have reported an increased sense of control and confidence resulting from these behaviors. When test drivers take the Bose suspension over bumpy roads, they report that the reduction in overall body motion and jarring vibrations results in increased comfort and control.
Source:Bose
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