Electromagnetic automobile suspension demonstrated
By Ben Coxworth
April 5, 2011
Last December at the Future of Electric Vehicles conference in San Jose, a representative from The Netherlands' Eindhoven University of Technology presented research that his institution had been doing into a novel type of electromagnetic vehicle suspension. Now that a test car equipped with the suspension is about to appear at the AutoRAI exhibition in Amsterdam, the university has released some more details about the technology. For starters, it is claimed to improve the overall ride quality of cars by 60 percent.
The Eindhoven suspension is not only electromagnetic but also active, meaning that it doesn't just mechanically respond to bumps in the road, but is controlled by an onboard computer. That computer receives input from accelerometers and other sensors on the vehicle, and adjusts the suspension accordingly within a fraction of a second. While active suspension is nothing new (at least, not for cars), it has previously mainly been integrated into hydraulic systems. According to the Eindhoven researchers, however, hydraulics can't react as quickly as their electromagnetic system, and therefore can't match the smoothness of its ride.
As with existing active suspension systems, this one should also make driving safer, as it would reportedly keep cars from swaying into corners.
About the same size as a conventional shock absorber, the system consists of a passive spring, an electromagnetic actuator, a control unit and batteries. The spring – appropriately enough – provides springing action, while the magnets provide passive shock absorption. If the batteries should fail, the system will still work as a purely mechanical suspension.
With a peak consumption of 500 watts, the suspension uses about a quarter of the power of hydraulic systems. It also stretches its battery life by using road vibrations to generate electricity. The designers believe that with refinements, the suspension's energy-efficiency could be improved even further.
The 60 percent ride improvement figure was obtained when a single wheel equipped with the system was mounted on a laboratory testbed that simulates road conditions. Last month, a test car had the system installed on two of its wheels, for actual on-road testing. At the moment, each wheel equipped with the suspension acts independently, so the researchers are now developing systems for allowing the individual suspension units to communicate with one another and coordinate their actions.
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