High-tech system keeps electric car on road

A car with four electric-powered wheels that track independently can turn on a dime but needs sophisticated software to operate, its U.S. developers say. Ohio State University researchers say their vehicle weights half as much as a sports car and is extremely maneuverable but because of its innovative design needs an exceptional traction and motion control system to keep it on the road. Where conventional cars are limited in maneuverability by the transmission and differential systems that link the wheels together mechanically, the four independent wheels of the OSU electric car give drivers greater control and more freedom of movement. An on-board computer samples input data from the steering wheel, accelerator pedal and brake and calculates how each wheel should respond, and because the wheels are independent, one or more can brake while the others accelerate, providing enhanced traction and motion control, the researchers said. A driver accustomed to conventional cars would have a difficult time driving a car of this design without the help of the vehicle motion and traction control system, mechanical engineering Professor Junmin Wang said. With its ability to turn sharply and change direction very quickly, the car could be hard to control, Wang said -- and he's tried it. "Without the controller, it's very hard to drive. With the controller, it's quite nice -- quiet, and better control than commercial four-wheel drive," he said. It's unlikely a car with this technology will be seen on the road for another five to 10 years, Wang said, as researchers will need to develop new algorithms to control the car more efficiently and add more safety features.