LIDAR moves self-driving car closer to reality
In April of last year, EU governments signed the European Road Safety Charter to halve road deaths by 2010.
RÜSSELSHEIM, GERMANY - In April of last year, EU governments signed the European Road Safety Charter to halve road deaths by 2010. One method toward achieving this goal is the fitting of expensive Jaguars and BMWs with automatic cruise control that uses either radar or infrared beams to measure the distance to the car in front and keep the distance constant through automated acceleration and braking. Problem is, these systems fail at speeds less than 20 mph (32 km/hr). To eliminate this shortcoming and improve overall vehicle safety, a light detection and ranging (LIDAR) system is being evaluated for the Opel Vectra, a mid-sized family car manufactured at General Motors’ Opel subsidiary in Germany.
“The intent of the system is not to allow the driver to read magazines during the commute, but rather to enhance the driver’s own capabilities with certain safety features enabled by LIDAR,” said Bruno Praunsmaemdel, leader of the Advanced Engineering Electronics Department of GM Europe. “We see a big future for LIDAR in vehicle safety-if we cannot entirely eliminate accidents, at least we can use the ranging system to automatically move the car out of a lane, for example, to lessen the impact of a collision.”
Because a laser’s wavelength is much shorter than radio waves, LIDAR technology works at shorter distances (0.5 to 150 m) and lower speeds. And, in addition to LIDAR, the Opel is being fitted with a lane-departure warning system: a camera mounted on the windshield behind the rear-view mirror works in concert with laser beams in the headlamp unit to track the white lines in the roadway and correct the steering of the vehicle if it strays out of its lane. A similar system exists on Nissan’s Infiniti FX45 for the US market, Europe’s Citroën C4 and C5, and some Toyota models in Japan, but uses near-range radar or camera images with a reduced field of view compared to the Opel laser/vision system.
Despite a high level of reliability for the GM Opel system during its development stage, several obstacles to commercial acceptance stand in the way. First, self-steering cars are currently illegal in most European countries. Carmakers are working to change the law to allow these automated systems (and to have more flexibility over the speed limitations they specify), but don’t want to be held legally responsible should the units fail. Second, people feel that they have better control when driving their own vehicle compared to public transportation. And finally, the system relies on monitoring a car ahead that is traveling to the same destination (and in the same lane) as the driver; should that car move to a new lane, the system is instructed to automatically shut off. As a result, automated cruise control is only possible during stop-and-go traffic in a rush-hour situation; on the open road, the driver must pilot the vehicle.
General Motors is targeting a price of less than €1500 ($1830) for the self-steering system, and plans to fit it to a new range of cars due in 2008 for the European market. Praunsmaemdel notes that the LIDAR system was chosen due to its lower cost structure compared to radar (roughly half as expensive). While the technical specifications behind the system are proprietary, Praunsmaemdel did say that they are using a commercially available laser source. Eventually, they hope that the technology will enable a car to cruise automatically at speeds up to 180 km/hr (112 mph).