Evasive Steering Assist, Function - GF30.30-P-0022FH
Model 238
Up To Model Year 2021
With Code 23P (Drive package)
Function requirements, general
- No undervoltage or overvoltage
- System fault-free (no faults detected by function-specific error management)
- Engine running or drivetrain operational
- Stereo multifunction camera soiling and function test completed successfully
The stereo multifunction camera performs a soiling and function test to ensure proper operation after each engine start. The function test requires an object to be located in the detection area (this object is used as a reference value). If a malfunction is established or if there are no objects in the detection area, the Steer Assist cannot be activated. The stereo multifunction camera sends the status via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
- Short and long range radar sensor soiling and function test completed successfully
Object recognition (e.g. vehicle moving directly ahead) via the radar sensor system is based on the radar measuring procedure.
The short and long range radar sensor performs a soiling and function test to secure its perfect function after every engine start. The function test requires an object to be located in the detection area (this object is used as a reference value). If a malfunction is established or if there are no objects in the detection area, the Steer Assist cannot be activated. When functioning properly, the short and long-range radar sensor transmits the status "radar sensor system operational" to the Mercedes-Benz Intelligent Drive control unit via the suspension FlexRay.
- Electronic Stability Program (ESP®) not switched to passive mode
- No active ESP® intervention recognized (vehicle not in sliding movement)
- Gear range "D" engaged (vehicle not in backward movement)
- Vehicle speed from 20 to 70 km/h
- Straight ahead running
- Pedestrian recognized
The Evasion-Steer-Assist, general points
The Evasion-Steer-Assist function supports the driver in cases of imminent collisions with pedestrians. If Evasive Steering Assist detects an evasion desire on the part of the driver in this situation, the system supports the evasive maneuver with additional steering torque, thereby making it easier to straighten the vehicle up after the evasive maneuver. In doing so the support is always driver initiated; the evasion direction is specified by the driver. The driver can therefore either follow the system activity or override the system.
The Evasion Steer Assist has no menu of its own; it is activated with other functions over the Active Brake Assist menu. The following options are available for navigation in the operating menu of the headunit:
- Except code 446 (Touchpad only), the navigation takes place with the Audio/COMAND control panel. The Audio/COMAND control panel sends the corresponding control signals (except code 446 (Touchpad only)) to the head unit via the telematics CAN.
- With code 446 (Touchpad only) or code 448 (Touchpad), the navigation takes place with the Touchpad. The touchpad (with code 446 (Touchpad only)) or code 448 (Touchpad)) transmits the respective control signals via the telematics CAN to the head unit.
- With code 531 (COMAND APS), navigation can be carried out using voice control. The driver hands-free system microphone transmits the signals directly to the head unit.
- The navigation can occur over the head unit finger navigation pad and the "Back" button on the steering wheel. The head unit finger navigation pad and the "Back" button transmit the corresponding operation signals via the steering wheel electronics, the steering LIN (up to model year 2019) or steering wheel CAN (as of model year 2019), the steering column tube module control unit, the suspension FlexRay, the electronic ignition lock control unit, and the user interface CAN to the head unit.
- The operating menu can be called up over vehicle button the upper control panel control unit (with code 246 (Analog clock)). The status of the Vehicle button is transmitted by the upper control panel control unit via the LCP-LIN, the Audio/COMAND control panel (except code 446 (Touchpad only)) or the touchpad (with code 446 (Touchpad only)) and the telematics CAN to the head unit.
The head unit sends the Evasive Steering Assist status via the user interface CAN, electronic ignition lock control unit, and suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Model 238
up to model year 2021
with code 23P (Drive package)
with code 550 (Trailer coupling)
The Evasion Steer Assist cannot be used in AHB.
The philosophy of the Evasion-Steer-Assist is to noticeably support the driver; the initiative to evade collision must however come from him. For an automatic evasive movement a previously unaware driver might be so shocked by the spontaneous movement of the steering wheel that he could react wrongly and could intuitively try to steer against it. To do this the Mercedes-Benz Intelligent Drive control unit evaluates the traffic situation in front of the vehicle via the stereo multifunction camera and the short and long range radar sensor.
Detection ranges of the short and long range radar sensor/stereo multifunction camera, shown on model 238.3
Evasive Steering Assist
The following information, among others, is evaluated by the Mercedes-Benz Intelligent Drive control unit:
- Engine running or drivetrain operational
- Evasion-Steer-Assist status
- Status of the brake and the ESP®
- Vehicle in forward movement, vehicle speed
- Straight ahead running
- Electric power steering, status
- Steering wheel angle and steering speed
- Driving stage engaged
- Turning angle and current steering wheel torque
- Tire pressure of all wheels within the tolerance range (run-flat mode not active) (with CODE 475 (Tire pressure monitor) or CODE 477 (Tire pressure loss warning))
- Status of AHB (with code 550 (Trailer hitch))
Engine running or drivetrain operational:
The CDI control unit or the ME-SFI [ME] control unit sends the "Engine running" or "Drivetrain operational" signal to the Mercedes-Benz Intelligent Drive control unit via drive CAN, powertrain control unit and suspension FlexRay.
Evasion-Steer-Assist status:
The head unit sends the Evasive Steering Assist status via the user interface CAN, electronic ignition lock control unit, and suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Status of the brake and the ESP®:
The Electronic Stability Program control unit transmits the brake and the ESP® status to the Mercedes-Benz Intelligent Drive control unit via the suspension FlexRay.
Vehicle in forward movement, vehicle speed:
Forward movement is defined via the wheel rotation direction. The vehicle speed is calculated from the wheel speed. The Electronic Stability Program control unit sends this information to the Mercedes-Benz Intelligent Drive control unit via the suspension FlexRay.
Straight ahead running:
The acceleration/yaw rate is detected by the acceleration sensor integrated into the Supplemental Restraint System control unit. The Supplemental Restraint System control unit sends the corresponding values via the vehicle dynamics CAN, the Electronic Stability Program control unit, and the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Electric power steering, status:
Information about the status of the electric power steering is transmitted by the electric power steering control unit via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Steering wheel angle and steering speed:
The steering wheel angle sensor detects and the steering wheel angle. The steering column tube module control unit directly reads in the signals from the steering wheel angle sensor and transmits the information about the steering wheel angle via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Engaged gear range:
The fully integrated transmission control control unit sends information about the selected drive range via drive CAN, powertrain control unit and suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Turning angle and current steering wheel torque:
The torque sensor of the electric power steering detects the wheel angle and the current steering wheel torque. The electric power steering control unit reads in the signals from the electric power steering torque sensor directly, and sends these via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Tire pressure of all wheels within the tolerance range (run-flat mode not active) (With Code 475 (Tire pressure monitor) or code 477 (Tire pressure loss warning)) :
For vehicles with code 475 (tire pressure monitoring system), the tire pressure monitoring system control unit sends information on the respective tire pressure to the Mercedes-Benz Intelligent Drive control unit via the user interface CAN, electronic ignition lock control unit, and suspension FlexRay.
On vehicles with CODE 477 (Tire pressure loss warning), the tire pressure is determined based on the rolling circumference. The tire pressure loss warning (RDW) system is functionally integrated in the Electronic Stability Program control unit. The Electronic Stability Program control unit sends information about the tire pressure to the Mercedes-Benz Intelligent Drive control unit via the suspension FlexRay.
Status of AHB (With Code 550 (Trailer hitch)) :
When a trailer is detected, the trailer recognition control unit sends the "trailer detected" status to the Mercedes-Benz Intelligent Drive control unit via the interior CAN, electronic ignition lock control unit, and suspension FlexRay.
The Evasion-Steer-Assist assumes that the following conditions are given when implementing the function:
- Recognition of pedestrians
- Recognition of an evasive maneuver incl. direction of evasion
Recognition of pedestrians:
A pedestrian is either only recognized by the stereo multifunction camera or by the short and long range radar sensor in combination with the stereo multifunction camera.
Stereo multifunction camera:
The stereo multifunction camera is located in the upper area of the windshield and supplies the following data:
- Relative position of the pedestrian to the driving corridor
- Side closing speed
The stereo multifunction camera consists of two high-resolution mono cameras and an integrated control unit for evaluation and a plausibility check of the supplied picture data. The laterally offset location of the two mono cameras creates a difference in perspective (parallax displacement) between the left and right optical path. The distance to the object ahead and other variables such as the height, sized and scope or the speed of movement thereof are calculated on the basis of the differences between the image data.
The data from both mono cameras is prepared by the integrated control unit, and sent to the Mercedes-Benz Intelligent Drive control unit via the suspension FlexRay.
Short and long-range radar sensor:
The short and long-range radar sensor detects pedestrians and can determine their position within a defined area, dependent on the distance to the pedestrian and the vehicle speed.
The short and long-range radar sensor sends corresponding information via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Recognition of an evasive maneuver incl. direction of evasion The Mercedes-Benz Intelligent Drive control unit uses the data from the short and long range radar sensor, the stereo multifunction camera, the steering wheel angle sensor, and the electrical power steering control unit to calculate the required rack force. The Mercedes-Benz Intelligent Drive control unit transmits the corresponding request via the suspension FlexRay to the electrical power steering control unit, which then directly actuates the electric power steering actuator motor.
Warning tones:
The Evasive Steering Assist outputs warning tones at the start of the support phase. The Mercedes-Benz Intelligent Drive control unit sends the corresponding request to actuate the instrument cluster speaker via the suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the instrument cluster. The instrument cluster directly actuates the instrument cluster speaker.
Evasion desire, shown on model 238.3
The risk of a collision with a pedestrian is recognized by the stereo multifunction camera and the short and long-range radar sensor. The driver starts the evasive maneuver through rapid steering.
Evasion desire, shown on model 238.3
Evasive Steering Assist supports the driver with additional steering torque during the evasive maneuver.
Straightening up, shown on model 238.3
At the end of the evasive maneuver the Evasion-Steer-Assist supports the driver in straightening up the front wheels by providing additional steering rack force of the electric power steering.
Evasive maneuver ended, shown on model 238.3
| Electrical function schematic for Evasive Steering Assist | PE30.30-P-2071-97DCA | ||
| Overview of system components for driver assistance systems | GF54.00-P-9998FH |