Active Steering Assist, Basic Function - GF54.71-S-9903A
Model All (Light transporter)
With Code CA3 (Active Steering Assist)
Active Steering Assist, shown on model 420
Overview
This document contains information on:
- General information
- Function requirements
- Function
- Steering and touch detection
General information
The "Steering torque specification" function assists the driver in keeping the vehicle in the center of the lane on a straight stretch of road and when in slight corners. Up to a speed of 210km/h, the system uses the lane markings for orientation, and up to 130km/h, it then uses vehicles driving in front. This means that active track guidance is also still available when lane markings are not visible or not clearly visible or when a structured traffic situation is present (clustering characteristic). To evaluate the lane markings, the system uses a multifunction camera just behind the windshield, close to the inside mirror.
If the driver indicates that they wish to change lane by turn signaling and the system does not detect another vehicle in the adjacent lane, the system assists the lane change with the aid of steering torques.
The vehicle is routed off-center in the lane in stop-and-go traffic (traffic jam) on freeways. This enables an emergency corridor to be formed when required.
The system relieves the driver through active track guidance on freeways and highways, thereby improving safety and comfort. The system is active in a vehicle speed range of 0to210km/h. It is switched on and off together with Active
Distance Assist and can be deactivated in the media system using the Assistance menu.
The system decides whether the vehicle driving in front is to be pursued or if it should follow the lane markings instead.
Torque-assisted traffic jam driving is still possible even where lane markings are not visible or not clearly visible or where structured traffic situations are present (cluster characteristic).
Function requirements
- Engine running or drivetrain operational
- ESP® functional
- Distance control switched on
- Active track guidance switched on
- No trailer operation (vehicles with trailer hitch)
- Tire pressure of all wheels within the tolerance range (no run-flat mode active)
- Standstill comparison successfully completed
Function
The system evaluates the traffic area monitoring data to calculate any necessary reactions. To do so, the front and rear radar sensors and multifunction camera provide the corresponding information. The system also evaluates the following function-relevant parameters:
- Vehicle speed/direction of travel/acceleration
- Electric power steering, status
- Multifunction camera lane data
- Location information (position finding) for traffic assessment (map data)
- Intention to change lane (flashing)
- Steering torque from the driver and wheel angle ("Hands-Off Detection" status)
- Steering wheel angle
- Drive range engaged
The system evaluates all relevant influencing parameters and calculates the required steering torque, which is then implemented by the electric power steering.
For longitudinal control, the system controls engine output, the transmission and the brakes as needed. For lateral control, the system controls the electric power steering as needed. The driver receives perceptible feedback through the steering wheel. The system status is indicated to the driver by a steering wheel symbol.
The system is only intended to assist the driver. The driver must always be aware that, at any given time, the system may make a track-aligning intervention. The responsibility for maintaining a safe distance, for speed, timely braking and for staying within the lane remains with the driver.
Steering and touch detection
Steering and touch detection monitors the torque at the steering wheel or if the driver's hand touches the steering wheel in vehicles with a capacitive steering wheel. If it does not detect any torque on the steering wheel or torque that is too low, or if it determines that the steering wheel is not being touched, it issues a message to the driver. The steering wheel symbol flashes. A warning message also appears. If the driver fails to respond to these messages, warning tones are then issued prompting the driver to take-over (hands-off warning).
The system regards active steering or system operations using the buttons on the multifunction steering wheel as reactions to these messages.
The volume of active audio sources is reduced during the warnings. Warnings are also only issued when tangible hazardous situations are detected.
| Function schematics | |||
| Specify steering torque, function schematic | Model 447 with code CA3 (Active Steering Assist) with code XM7 (MOPF II) | PE54.71-S-2504-97A | |
| Additional basic functions | |||
| Distance control, basic function | Model all (Light transporter) with code CA3 (Active Steering Assist) with code ET4 (Active Distance Assist DISTRONIC) |
GF30.30-S-9903A | |
| Brakes, basic function | Model all (Light transporter) with code CA3 (Active Steering Assist) |
GF42.00-S-9900A | |
| Driver activity detection, basic function | Model all (Light transporter) with code CA3 (Active Steering Assist) |
GF54.30-S-1000A | |
| Traffic area monitoring, basic function | Model all (Light transporter) with code CA3 (Active Steering Assist) |
GF54.71-S-1000A | |
| Hand detection, basic function | Model all (Light transporter) with code CA3 (Active Steering Assist) |
GF82.90-S-9904A |