Stanley (vehicle)
Encyclopedia
Stanley is an autonomous vehicle
Vehicle
A vehicle is a device that is designed or used to transport people or cargo. Most often vehicles are manufactured, such as bicycles, cars, motorcycles, trains, ships, boats, and aircraft....

 created by Stanford University's Stanford Racing Team in cooperation with the Volkswagen Electronics Research Laboratory (ERL)
Electronics Research Laboratory
The Volkswagen Electronics Research Laboratory is a division of the Volkswagen Group of America, Inc., with its headquarters in Silicon Valley ....

. It competed in, and won, the 2005 DARPA Grand Challenge
DARPA Grand Challenge (2005)
The second driverless car competition of the DARPA Grand Challenge was a off-road course that began at 6:40am on October 8, 2005. All but one of the 23 finalists in the 2005 race surpassed the distance completed by the best vehicle in the 2004 race...

, earning the Stanford Racing Team the 2 million dollar prize, the largest prize money in robotic history.

The Stanford Racing Team

Led by Associate Professor Sebastian Thrun
Sebastian Thrun
Sebastian Thrun is a Research Professor of Computer Science at Stanford University and former director of the Stanford Artificial Intelligence Laboratory . He led the development of the robotic vehicle Stanley which won the 2005 DARPA Grand Challenge, and which is exhibited in the Smithsonian...

, director of the Stanford Artificial Intelligence Lab, the Stanford Racing Team was developed solely for the purpose of competing in the 2005 DARPA Grand Challenge. Stanford did not participate in the 2004 DARPA Grand Challenge and was considered to have 20:1 chances of winning the 2005 competition. Stanley is currently located at the Smithsonian National Museum of American History, although it was displayed at the 2006 New York International Auto Show, and spent 2 years at the Volkswagen Autostadt Museum (Germany). The Stanford Racing Team entered a new vehicle, a modified Volkswagen Passat
Volkswagen Passat
The Volkswagen Passat is a large family car marketed by Volkswagen Passenger Cars through six design generations since 1973. Between the Volkswagen Golf / Volkswagen Jetta and the Volkswagen Phaeton in the current Volkswagen line-up, the Passat and its derivatives have been badged variously as...

 wagon, dubbed "Junior", in the 2007 DARPA Urban Challenge
DARPA Grand Challenge (2007)
The third driverless car competition of the DARPA Grand Challenge, was commonly known as the DARPA Urban Challenge. It took place on November 3, 2007 at the site of the now-closed George Air Force Base , in Victorville, California , in the West of the United States...

. Other key contributors on the team include Michael Montemerlo (software lead), Sven Strohband (lead engineer) and Cedric Dupont (vehicle lead), and Pamela Mahoney (communications lead).

Construction

Stanley's original frame was a standard European diesel model Volkswagen Touareg
Volkswagen Touareg
The Volkswagen Touareg is a mid-size crossover SUV produced by German automaker Volkswagen since 2002. The vehicle was named after the Tuareg people, a Berber-speaking group in North Africa...

 provided by Volkswagen's ERL for the competition. The Stanford Racing Team chose the Touareg for its "drive by wire
Drive by wire
Drive-by-wire, DbW, by-wire, or x-by-wire technology in the automotive industry replaces the traditional mechanical control systems with electronic control systems using electromechanical actuators and human-machine interfaces such as pedal and steering feel emulators...

" control system which could be adapted (and was done so by the ERL) to be run directly from an on-board computer without the use of actuators or servo motors (it is important to note however, that the steering wheel was driven by an electric motor and the gear shifting accomplished with a hydraulic piston).

To navigate, Stanley used five roof mounted Sick AG
Sick AG
Sick AG is a company based in Waldkirch, Germany. It produces sensors and sensor solutions for industrial applications. The company is active in the areas of factory and logistics automation and process automation....

 LIDAR
LIDAR
LIDAR is an optical remote sensing technology that can measure the distance to, or other properties of a target by illuminating the target with light, often using pulses from a laser...

 units to build a 3-D map of the environment, supplementing the position sensing GPS system. An internal guidance system utilizing gyroscopes and accelerometers monitored the orientation of the vehicle and also served to supplement GPS and other sensor data. Additional guidance data was provided by a video camera used to observe driving conditions out to eighty meters (beyond the range of the LIDAR) and to ensure room enough for acceleration. Stanley also had sensors installed in a wheel well to record a pattern imprinted on the tire and to act as an odometer
Odometer
An odometer or odograph is an instrument that indicates distance traveled by a vehicle, such as a bicycle or automobile. The device may be electronic, mechanical, or a combination of the two. The word derives from the Greek words hodós and métron...

 in case of loss of signal (such as when driving through a tunnel). Using the data from this sensor, the on-board computer can extrapolate how far it has traveled since the signal was lost.

To process the sensor data and execute decisions, Stanley was equipped with six low-power 1.6 GHz Intel Pentium M
Pentium M
The Pentium M brand refers to a family of mobile single-core x86 microprocessors introduced in March 2003 , and forming a part of the Intel Carmel notebook platform under the then new Centrino brand...

 based computers in the trunk, running different versions of the Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 operating system.

Programming

The School of Engineering developed the 100,000 lines of software run by Stanley to interpret sensor data and execute navigation decisions. Using what Popular Mechanics
Popular Mechanics
Popular Mechanics is an American magazine first published January 11, 1902 by H. H. Windsor, and has been owned since 1958 by the Hearst Corporation...

 calls a "common robot hierarchy", Stanley utilizes "low-level modules fed raw data from LIDAR, the camera, GPS sets and inertial sensors into software programs [to control] the vehicle's speed, direction and decision making.

Stanley was characterized by a machine learning
Machine learning
Machine learning, a branch of artificial intelligence, is a scientific discipline concerned with the design and development of algorithms that allow computers to evolve behaviors based on empirical data, such as from sensor data or databases...

 based approach to obstacle detection. Data from the LIDARs was fused with images from the vision system to perform more distant look-ahead. If a path of drivable terrain could not be detected for at least 40 meters in front of the vehicle, speed was decreased and the LIDARs used to locate a safe passage.

To correct a common error made by Stanley early in development, the Stanford Racing Team created a log of "human reactions and decisions" and fed the data into a learning algorithm tied to the vehicle's controls; this action served to greatly reduce Stanley's errors. The computer log of humans driving also made Stanley more accurate in detecting shadows, a problem that had caused many of the vehicle failures in the 2004 DARPA Grand Challenge.

External links

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