December 1, 2007 Computer scientists and engineers worked together to create a robotic car that can operate autonomously. Computers process information from the navigation system, laser sensors, and video cameras to recognize the road, signs, and any obstacles like cars or pedestrians. The laser sensors emit beams that reflect back from objects near the car. The car can also be operated by a human driver.
- Robot calibration
- Global Positioning System
- Traffic engineering (transportation)
- User interface design
You've seen cars with rear-view cameras, even cars that can parallel park themselves … but imagine seeing a car completely drive itself!
Started by a remote control -- this is a totally autonomous car.
“The Spirit of Berlin is a car that senses the environment … and then actually moves around without a driver,” Raul Rojas, Ph.D., Professor of Artificial Intelligence at Freie University in Berlin, Germany said. Dr. Rojas created this car and says there are three main differences between it and the one you drive. “The important things are the antennas. They are for the navigation system.” Dr. Rojas said.
Laser scanners track everything around the car ten times per second. “They send out many pulses of light and they see the obstacles with the reflection of the light,” Dr. Rojas said.
Video cameras detect the street. A computer sends commands to the brakes, gas pedal, and steering wheel. “The sensors are already much better than what humans can do because they can sense obstacles in the front, in the back, to the left, to the right of the car … with very high resolution.” Dr. Rojas said.
You can see the Spirit of Berlin in action on this test track. The sensors pick up one million points per second. But Dr. Rojas says the biggest problem -- unlike people, computers can’t reason.
“We try to predict what pedestrians are going to do, and that’s very difficult for a computer,” Dr. Rojas said.
But so far, this car is accident free!
BACKGROUND: Computer scientists at Freie Universitat in Berlin, Germany, have built an autonomous mini-van called the “Spirit of Berlin,” working jointly with the Berlin Police Department. Much like a robot, the car is completely controlled by computers, with no need for a human operator. The car can steer, brake and accelerate, as well as turn all its components on or off, solely through its computer. However, the car can also be driven conventionally. Future innovations will enable the car to recognize and react to red traffic lights and traffic signs.
HOW IT WORKS: Various sensors on the car work together to recognize pedestrians, cars, motorcycles and other road users, with the aid of laser scanners installed on the car. The scanners emit laser beams around the car and the light is reflected back from objects in its proximity. The sensors measure how long it takes the reflecting laser beam to return to determine where nearby objects are located, as well as how far away they are. Computers process all this information collected by the navigation system, laser sensors and video cameras to produce an accurate map of the mobile and immobile objects on the road. The laser sensors’ range is 150 meters.
WHAT IS GPS?: The Spirit of Berlin’s navigation is driven by the Global Positioning System. GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers take this information and use triangulation to calculate the user's exact location. Essentially, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. With distance measurements from a few more satellites, the receiver can determine the user's position and display it on an electronic map. Should the satellite signal temporarily be lost – due to interference from a high-rise building, for example – the navigation system compensates by precisely assessing the vehicle’s position using data from gyroscopes and throttle sensors.
COMPUTERS RULE THE ROAD: Four computers process all that data as quickly as possible. The circuit boards receive all the data from the sensors and process it along with the GPS-position data. The car also has video cameras mounted on the roof to further aid in determining the position of the road markings and sidewalks. A separate computer processes the video data. Once all the data has been combined, the computer can “decide” the car’s next action.