Volkswagen’s 10-year evolution of Park Assist; heading toward trained parking and higher levels of autonomy
Volkswagen first introduced a parking assistance system based on ultrasonic sensors in the early 1990s. However, it was the “Park Assist” Gen 1 system presented in the Touran in 2007 that marked a foundational point in the commercial development of the technology. After it was activated, Park Assist was able to detect parallel parking spaces on the left and right sides of the road as the car passed them using special, side-oriented ultrasonic sensors, enabling semi-automatic parking for the first time.
Volkswagen engineers have continued to enhance the functionality, leading to the release of Gen 3 Park Assist in 2014, with a clear roadmap to the deployment of higher levels of autonomy, including trained parking: fully automated parking with a one-off training process. At a recent visit to Volkswagen’s Ehra proving ground (Prüfgelände Ehra), Green Car Congress had the opportunity to see a prototype of trained parking in action.
The functionality of Park Assist Gen 1 was rather limited. A maximum of two moves were possible and only reverse parking into parallel spaces was supported. Parking space detection occurred as a distance of 0.5 to 1.5m, at speed of up to 30 km/h (18 mph). The target space needed to ample: “vehicle length plus 1.40 meters”.
Two ultrasonic sensors acquired the dimensions of parking spaces (either the left or right side of the street. The sensors reliably acquired parked cars and associated parking spaces up to a maximum distance of 1.5 meters.
After evaluating the sensor data and detecting the parking space, the system automatically computed the ideal path for parking the car. The driver indicated his/her intention to park by pressing a button. The system then gave the driver the necessary information on parking spaces and the parking process.
The driver activated steering assistance by shifting to reverse gear. The Parking Steering Assistance control module then drove the electromechanical power steering to guide the vehicle into the parking space independently. During the entire parking process—completed in about 15 seconds—the driver just needed to press the gas pedal and brake.
At the 2008 Hanover Fair, Volkswagen presented the “Park Assist Vision” concept in a Passat, which introduced parking in a perpendicular space. The concept relied on two cameras located in the left and right exterior mirrors, two additional cameras at the front and rear of the vehicle as well as the system’s ultrasound sensors.
In 2010, Volkswagen introduced Park Assist Gen 2, which introduced multi-maneuver parking, reverse parking into bay parking spaces (perpendicular parking), and a space requirement of 40 cm (15.8 inches) front and rear for parallel parking.
Complex scenarios such as parking on the curb (half or entirely), between trees or on curves were also added. Integrated braking assistance allowed braking the vehicle to a stop before obstacles to minimize or avoid damage.
|Park Assist 2.0. Click to enlarge.|
The augmented functionality relied on twelve ultrasonic sensors on the vehicle as well as increasingly complex algorithms.
Park Assist Gen 3 in 2014 introduced forward parking into bay parking spaces, with 35 cm (13.8 inches) clearance required left and right. Parking space detection occurred up at speeds up to 40 km/h (25 mph).
In addition, Park Assist 3.0 can automatically brake before an obstacle in critical situations to prevent damage or at least minimize it. The basic functions of the park steering assistant were also further improved by the use of a new feature that is known as a surroundings map. By determining the precise positions of all four wheels, the vehicle can be parked precisely on the curb.
Volkswagen has also added a “late decision” capability; a use case is a driver suddenly spotting a parking opening and essentially lunging for it: aiming the nose of the car into the space. Park Assist can then take over, clean up the approach, and park the vehicle. (Likely to be highly useful in parking lot mêlées over the holidays, although the Gen 3 assistant is not currently available in the US.)
Park Assist Gen 3 is categorized as SAE Level 1 driving automation: Driver Assistance. SAE J3016 defines Driver Assistance as “the driving mode-specific execution by a driver assistance system of either steering or acceleration/deceleration using information about the driving environment and with the expectation that the human driver perform all remaining aspects of the dynamic driving task.”
|An e-Golf demonstrates trained parking at Ehra. Click to enlarge.|
With trained parking, Volkswagen is making a jump to SAE Level 4 functionality: High Automation, defined as “the driving mode-specific performance by an automated driving system of all aspects of the dynamic driving task, even if a human driver does not respond appropriately to a request to intervene.”
Trained Parking is a logical progression from Park Assist. It uses existing sensors and makes innovative new functions possible using artificial intelligence.— Dr. Andreas Titze, Head of Interactive Electronics, Volkswagen AG
During the training run, the vehicle uses its cameras to make a 3D map of the surroundings. The car can then recognize the surroundings and locate itself precisely (<10 cm (3.94 inches) of precision).
With this system, the key is not the sensors; trained parking occurs in well-defined scenarios, with the human driver being the training expert. The sensors will be used to detect obstacles in the way, but the essential task of the vehicle deciding whether or not it can drive on the given surface has already been answered implicitly by the training.
Volkswagen engineers are considering allowing stored maps to be transmitted to another car.