Steering-Pilot, Function - GF30.30-P-0019FH
Model 238
Up To Model Year 2021
With Code 23P (Drive package)
Function requirements, general
- No undervoltage or overvoltage
- Engine running or drivetrain operational
- ESP® status
- DISTRONIC Distance-Pilot controller unit switched on
- 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 close and long range radar sensor and the rear bumper radar sensors perform a soiling and function test after each engine start to ensure that they are functioning correctly. 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 Pilot cannot be activated. The Mercedes-Benz Intelligent Drive control unit receives the signals of the rear outer bumper radar sensors via the rear radar CAN 2 and sends them via the suspension FlexRay to the close and long range radar sensor. The short and long range radar sensor evaluates these signals in combination with its own signals and, if all radar sensors are functioning flawlessly, transmits the status "Radar sensor system operational" via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
- Stereo multifunction camera soiling and function test:
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 Pilot cannot be activated. The stereo multifunction camera sends the status via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
- No trailer recognized (with CODE 550 (Trailer hitch))
- 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))
- Standstill comparison successfully completed
After engine start, the vehicle must be at a standstill for 500 ms.
- Steer Pilot switched on using the Steer Pilot button
Steer Pilot, general points
The Steering Pilot assists the driver in performing vehicle lateral guidance with limited steering torque up to a speed of 210 km/h. On straight roads and even on slight bends, it generates a steering torque that helps keep the vehicle in the center of the lane. To do this system orientates itself with the aid of a stereo camera on easily visible track markings and, up to a speed of 130 km/h, also on a vehicle moving immediately ahead.
The Steer Pilot is designed in such a way that the vehicle stays in its lane and unintentional movement towards the lane markings is prevented. The Steer Pilot does not relieve the driver of his/her task of keeping the vehicle in the lane. The Steer Pilot serves more to relieve the load and therefore to facilitate the resultant increase in comfort. Assistance is also only provided within defined limits, i. e. no assistance can be provided for large steering angles at slow speeds, e.g. caused by driving on roads going over passes.
The Steer Pilot is designed to be so sensitive that it recognizes whether the driver has his hands on the steering wheel. The Steer Pilot will warn about this if this is not the case. The Steering Pilot is implemented in the Mercedes-Benz Intelligent Drive control unit. The course of the road in front of the vehicle and the vehicles ahead are recorded via the stereo multifunction camera and the radar sensor system. The steering movements that are requested are carried out by the electric steering.
The input factors evaluated by the Mercedes-Benz Intelligent Drive control unit include the following:
- Signal "Engine running" or "Drivetrain operational" (function requirements)
- Status of ESP® (function requirements)
- Vehicle speed/direction of travel/acceleration
- Steer Pilot status
- Electric power steering, status
- Object recognition through the radar sensor system
- Object detection by the stereo multifunction camera
- Lane data
- GPS signals (Global NAV) /signals for traffic evaluation
- Intention of a change of lane (through actuation of the combination switch)
- Steering torque from the driver and wheel angle (Hands-Off Detection status)
- Steering wheel angle
- Status of tire pressure monitoring (with code 475 (Tire pressure monitoring)) or code 477 (Tire pressure loss warning))
- Trailer recognition (with CODE 550 (Trailer hitch))
- Driving stage engaged
- Engine drive torque
Signal "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.
ESP® status
The Electronic Stability Program control unit sends the ESP® status over the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Vehicle speed/direction of travel/acceleration
The vehicle speed is calculated from the wheel speed. The direction of travel is defined by the wheel rotation direction, the acceleration by the increase in the wheel rotation speed. The Electronic Stability Program control unit transmits the wheel speed signals via the suspension FlexRay to the stereo multifunction camera and the Mercedes-Benz Intelligent Drive control unit.
Steer Pilot status
The Steer Pilot can be switched on and off by pressing the Steer Pilot button on the driver side instrument panel button group. The front SAM control unit reads in the status of the Steering Pilot button via the instrument panel LIN and sends this via interior CAN, electronic ignition lock control unit and suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit. The status of the Steer Pilot is displayed to the driver by activation or deactivation of the LED in the Steer Pilot button, among other things. The Mercedes-Benz Intelligent Drive control unit sends the corresponding request via the suspension FlexRay, the electronic ignition lock control unit and interior CAN to the front SAM control unit. The front SAM control unit actuates the LED in the Steer Pilot button via the instrument panel LIN. The IC shows the message "Steer Pilot ON/OFF". The Mercedes-Benz Intelligent Drive control unit sends the request to display the message via the suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the instrument cluster.
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.
Object recognition by the radar sensor system
The traffic area in front of the vehicle is monitored by the close and long range radar sensor.
The traffic area at the side and the rear of the vehicle is monitored by the bumper radar sensors.
The long range radar sensors operate according to the pulse Doppler effect which allows the distances and speeds of individual objects (e. g. vehicles) to be measured independently of each other.
The short and long-range radar sensor sends corresponding object information via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
The rear bumper radar sensors transmit respective object information via radar CAN 2 at the rear to the Mercedes-Benz Intelligent Drive control unit.
Object detection by the stereo multifunction camera
The stereo multifunction camera consists of two high-resolution mono cameras and an integrated control unit. 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 thereof are calculated on the basis of the differences between the image data.
The stereo multifunction camera records vehicles in the same lane under the following conditions:
- Preceding vehicle in the detection range from 1 to 40 m (speed-dependent)
- Vehicle width of the preceding vehicle 1.30 to 3.20 m
- Center axis offset of vehicle to preceding vehicle: 35 cm (at start of control)
- Vehicle speed 0 to 200 km/h
- No lane change (turn signal not set)
The integrated control unit evaluates image data from both cameras, processes it and transmits appropriate data via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit. The Mercedes-Benz Intelligent Drive control unit compares the image data with the signals from the radar sensor system.
Lane data
The stereo multifunction camera records pictures of the lane markings on the road regularly with a fixed sampling rate. The integrated control unit calculates a lane from the picture sequences and the measurements resulting from the pictures of the road markings. The stereo multifunction camera sends the lane data via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Stereo multifunction camera lane recording
GPS signals/signals for traffic assessment:
The head unit evaluates the received GPS data using further information for traffic assessment, and transmits corresponding information via the user interface CAN, the electronic ignition lock control unit, and the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
Intention to change lane
An intended change of lane is defined through actuation of the combination switch. The steering column tube module control unit reads in the switch position of the combination switch directly, and sends it over the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit. If the traffic situation allows it and the intended lane change was shown for longer than 2 s the Mercedes-Benz Intelligent Drive control unit initiates an automatic lane change.
Steering torque from the driver and wheel angle (Hands-Off Detection status)
The electric power steering torque sensor records the steering torque applied by the driver and the wheel angle. 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. Based on these values, the Mercedes-Benz Intelligent Drive control unit determines whether and in what interval the driver makes steering interventions (hands-off detection).
Steering wheel angle
The steering angle is recorded by the steering wheel angle sensor. 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.
Status of tire pressure monitoring (With Code 475 (Tire pressure monitoring)) or code 477 (Tire pressure loss warning))
Vehicles with CODE 475 (Tire pressure monitor) :
The tire pressure monitoring system control unit sends information about the status of the "Tire pressure monitoring warning message" request to the Mercedes-Benz Intelligent Drive control unit via the user interface CAN, electronic ignition lock control unit and suspension FlexRay.
Vehicles with code 477 (Tire pressure loss warning) :
The tire pressure loss warning (RDW) system is functionally integrated in the Electronic Stability Program control unit. The Electronic Stability Program control unit transmits information about the status of the tire pressure loss warning system to the Mercedes-Benz Intelligent Drive control unit via the suspension FlexRay.
Trailer recognition (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.
Driving stage engaged
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.
Engine drive torque
Information about the currently available engine torque is transmitted by the CDI control unit or the ME-SFI [ME] control unit via the drive CAN, the powertrain control unit and the suspension FlexRay to the Electronic Stability Program control unit, which then evaluates this accordingly and transmits it via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit.
The Mercedes-Benz Intelligent Drive control unit evaluates the input factors and transmits, among other things, the following information and requests:
- DISTRONIC Distance-Pilot, status
- Requests for additional steering torque/steering angle
- Emit warning tones, system or warning messages
- Increase/reduce engine torque
- Engage targeted gear (back or upshift)
- Increase/reduce the braking torque
DISTRONIC Distance-Pilot, status
The Mercedes-Benz Intelligent Drive control unit transmits the status of the Distance Pilot DISTRONIC via the suspension FlexRay to the electrical power steering control unit.
Requests for additional steering torque/steering angle
The Mercedes-Benz Intelligent Drive control unit requests the required additional steering torque (additional toothed rack force) or the required steering movement (wheel angle) via the suspension FlexRay from the electrical power steering control unit. The Mercedes-Benz Intelligent Drive control unit calculates the additive toothed rack force from the following variables for this purpose:
- Steering torque of the driver
- Lateral acceleration
- Vehicle speed
- Object and vehicle lane data of the MFK stereo
The electrical power steering control unit checks the plausibility of the incoming request and actuates the electric power steering actuator motor accordingly. What the requests (additive toothed rack force or wheel angle) takes account of depends on the quality of the vehicle lane data and the vehicle steering behavior. The additive toothed rack force is only available up to a defined limit value. The additional steering torque is therefore limited in its expression.
The additive toothed rack force of the Steer Pilot is reduced as the speed increases, when the vehicle is driven on narrow streets or with a limited field of view of the stereo multifunction camera.
Emit warning tones, system or warning messages
The Mercedes-Benz Intelligent Drive control unit transmits the requests to output warning tones, system or warning messages via the suspension FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster that outputs the corresponding system or warning messages and directly actuates the instrument cluster speaker.
Increase/reduce engine torque
The Mercedes-Benz Intelligent Drive control unit transmits the "Increase engine torque" or "Reduce engine torque" request via the suspension FlexRay to the Electronic Stability Program control unit. The Electronic Stability Program control unit processes this request and further driving dynamics requests and sends them according to their relevance via the suspension FlexRay, powertrain control unit and engine CAN to the CDI control unit or the ME-SFI [ME] control unit. The CDI control unit or the ME-SFI [ME] control unit implements this request.
Engage targeted gear (back or upshift)
The Mercedes-Benz Intelligent Drive control unit transmits the "Engage requested gear" request via the suspension FlexRay to the Electronic Stability Program control unit. The Electronic Stability Program control unit processes this request as well as further driving dynamics requests and transmits it according to its relevance via the suspension FlexRay, powertrain control unit and drive train CAN to the fully integrated transmission control unit. This request is however to be understood as a switching recommendation. Downshifting or upshifting of the A/T takes place autonomously itself by the fully integrated transmission control unit, dependent on the current operating condition.
Increase/reduce the braking torque
The Mercedes-Benz Intelligent Drive control unit transmits the "Increase braking torque" or "Reduce braking torque" request via the suspension FlexRay to the Electronic Stability Program control unit. The Electronic Stability Program control unit evaluates this request and actuates the traction system hydraulic unit appropriately. The traction system hydraulic unit reacts by increasing or reducing the braking torque.
Steer Pilot functionality
The steer pilot is active in a vehicle speed range from 0 to 210 km/h. Status of the Steer Pilot, representation in the IC.
Status of the Steer Pilot, representation in the IC
Track guidance
The Steering Pilot relieves the driver on both monotonous and overcrowded stretches of road. Through targeted engagements, the vehicle stays on route.
For example, if no lane markings are detected in urban traffic because of the proximity to the vehicle in front, the stereo multifunction camera evaluates object-related data of the vehicle in front.
The Mercedes-Benz Intelligent Drive control unit evaluates the information of the radar sensor system and the stereo multifunction camera, calculates the required steering torque and requests it via the suspension FlexRay from the electric power steering control unit. The electrical power steering control unit then actuates the electric power steering actuator motor accordingly.
Automatic lane change
An automatic lane change is only executed on multi-lane roads similar to an freeway in a vehicle speed range of 75 to 180 km/h.
If the driver is shown through actuation of the combination switch that he wishes to change the lane for longer than 2 s and the neighboring lane is cut off by a broken line, the Steer Pilot steers to the neighboring lane. The vehicle now only undertakes the change of lane itself when no vehicles are in the relevant safety area. In doing so it not important whether the vehicle moves to the left to overtake or again wishes to merge onto the right lane. The short and long-range radar sensor and the MFK stereo monitor the area in front of the vehicle while the bumper radar sensor at the rear monitor the area to the rear and to the side. Both take account in the process of the speed of recognized vehicles in the area. The driver himself needs just to monitor the lane change. If the driver countersteers or if no lane change is possible within the following 3 s because, for example, the neighboring lane is occupied, the Steer-Pilot breaks of the automatic lane change. The icon changes from green to gray. The Steer-Pilot is passivated. For every change of status from active to passive, the icon flashes yellow three times. Also the lane change is broken off when the Steer-Pilot is switched off.
Steer and touch recognition
If the electric power steering control unit detects zero or insufficient torque at the steering wheel ("Hands-Off Detection"), it sends corresponding information via the suspension FlexRay to the Mercedes-Benz Intelligent Drive control unit and a message via the suspension FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster.
The respective icon displays in the IC (gray with gray hands). If the driver does not respond to the message, a warning tone is output via the instrument cluster speaker in addition. As reactions the active steering or system conditions are evaluated over the buttons on the MFL.
The Mercedes-Benz Intelligent Drive control unit transmits the request to output a warning tone via the suspension FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster. The IC directly actuates the speaker IC, and the volume of active audio sources is reduced simultaneously. In this case the Mercedes-Benz Intelligent Drive control unit renders the Steering Pilot passive. The status of the Steer Pilot is continuously shown to the driver in the instrument cluster. A message (optical and acoustic) is also always issued if there is a concrete danger situation recognized.
Active Emergency Stop Assist
If the driver still does not react after the third acoustic Hands-Off warning, the vehicle is braked in stepped decelerations to a standstill. The optical and acoustic Hands-Off warning remains active during the whole braking process.
The Mercedes-Benz Intelligent Drive control unit sends the requests to reduce the vehicle speed via the suspension FlexRay to the Electronic Stability Program control unit which then directly actuates the traction system hydraulic unit.
During deceleration by the active Emergency Stop assistants the distance control interval of the distance pilots DISTRONIC and Steer-Pilot remain active. The intervals to the vehicles ahead are maintained and the track guidance support continues to be active within the technical system limits). After vehicle stillstand, the vehicle is secured by the standstill control system, the doors are unlocked, and an automatic emergency call is triggered.
The Mercedes-Benz Intelligent Drive control unit sends the request to unlock the doors via the suspension FlexRay to the electronic ignition lock control unit, which initiates unlocking.
The Mercedes-Benz Intelligent Drive control unit transmits (as of model year 2019) the request for an automatic emergency call via the suspension FlexRay, the electronic ignition lock control unit, and the diagnostics CAN to the HERMES control unit (with code 360 (HERMES UMTS) or code 362 (HERMES LTE)).
If the Steer-Pilot changes due to impairments of the system from an active into a passive condition (for example due to dazzling from direct solar radiation), the Active Emergency-Stop assistant does not decelerate without the Steer-Pilot to a standstill. Track guidance support cannot occur. After vehicle stillstand, the vehicle is secured by the standstill control system.
The vehicle deceleration is canceled under the following conditions:
- Active steering
- Active braking or pressing on the accelerator
- Active system operation by the driver
System limits
The following traffic situations lead to object guidance being aborted or Steer Pilot being rendered passive:
- If the vehicle in front changes lane, the Mercedes-Benz Intelligent Drive control unit stops object-related lateral vehicle guidance and switches to lane-related guidance, provided that a lane has been detected. Otherwise the vehicle in front is followed.
- If there is another vehicle in the blind spot when the vehicle in front changes lane, the Steer Assist is rendered passive and object-related lateral vehicle guidance is aborted in order to avoid a collision.
- If a vehicle is being followed that narrowly misses a parked vehicle, for example, object-related vehicle guidance is aborted and the Steer Assist is rendered passive in order to avoid a collision with the parked vehicle.
| Electrical function schematic for Steering-Pilot | PE30.30-P-2069-97DCA | ||
| Overview of system components for driver assistance systems | GF54.00-P-9998FH |