Double-Lane Change Maneuver

This reference application represents a full vehicle dynamics model undergoing a double-lane change maneuver according to standard ISO 3888-2[1]. You can create your own versions, establishing a framework to test that your vehicle meets the design requirements under normal and extreme driving conditions. Use the reference application to analyze vehicle ride and handling and develop chassis controls. To perform vehicle studies, including yaw stability and lateral acceleration limits, use this reference application.

ISO 3888-21 defines the double-lane change maneuver to test the obstacle avoidance performance of a vehicle. In the test, the driver:

  • Accelerates until vehicle hits a target velocity

  • Releases the accelerator pedal

  • Turns steering wheel to follow path into the left lane

  • Turns steering wheel to follow path back into the right lane

Typically, cones mark the lane boundaries. If the vehicle and driver can negotiate the maneuver without hitting a cone, the vehicle passes the test.

To test advanced driver assistance systems (ADAS) and automated driving (AD) perception, planning, and control software, you can run the maneuver in a 3D environment. For the 3D visualization engine platform requirements and hardware recommendations, see 3D Visualization Engine Requirements.

To create and open a working copy of the double-lane change reference application project, enter

This table summarizes the blocks and subsystems in the reference application. Some subsystems contain variants.

Reference Application ElementDescriptionVariants

Lane Change Reference Generator

Generates lane signals for the visualization subsystem and trajectory signals for the Predictive Driver block

 

Predictive Driver

Generates normalized steering, acceleration, and braking commands that track the reference trajectory

 

Environment

Implements wind and ground forces

Controllers

Implements controllers for engine control units (ECUs), transmissions, and brakes

Passenger Vehicle

Implements the:

  • Engine

  • Steering, transmission, driveline, and brakes

  • Body, suspension, and wheels

Visualization

Provides the vehicle trajectory, driver response, and 3D visualization

To override the default variant, on the Modeling tab, in the Design section, click the drop-down. In the General section, select Variant Manager. In the Variant Manager, navigate to the variant that you want to use. Right-click and select Override using this Choice.

Lane Change Reference Generator

Use the Lane Change Reference Generator block to generate:

  • Lane signals for the Visualization subsystem — The left and right lane boundaries are a function of the Vehicle width parameter.

  • Velocity and lateral reference signals for the Predictive Driver block — Use the Lateral reference position breakpoints and Lateral reference data parameters to specify the lateral reference trajectory as a function of the longitudinal distance.

To specify the target velocity, use the Longitudinal entrance velocity setpoint parameter.

Predictive Driver

The reference application uses the Predictive Driver block to generate normalized steering, acceleration, and braking commands that track the reference trajectory.

The Predictive Driver block implements an optimal single-point preview (look ahead) control model developed by C. C. MacAdam[2], [3], [4]. The model represents driver steering control behavior during path-following and obstacle avoidance maneuvers. Drivers preview to follow a predefined path.

Environment

The Environment subsystem generates the wind and ground forces. The reference application has these environment variants.

EnvironmentVariantDescription

Ground Feedback

3D Engine

Uses Vehicle Terrain Sensor block to implement ray tracing in 3D environment

Constant (default)

Implements a constant friction value

Controllers

The Controllers subsystem generates engine torque, transmission gear, and brake commands. The reference application has these brake variants.

ControllerVariantDescription

Brake Pressure Control

Bang Bang ABS

Anti-lock braking system (ABS) feedback controller that switches between two states

Open Loop (default)

Open loop braking controller

Passenger Vehicle

The Passenger Vehicle subsystem has an engine, controllers, and a vehicle body with four wheels. Specifically, the vehicle contains these subsystems.

Body, Suspension, Wheels SubsystemVariantDescription

PassVeh7DOF

PassVeh7DOF (default)

Vehicle with four wheels:

  • Vehicle body has three degrees-of-freedom (DOFs) — Longitudinal, lateral, and yaw

  • Each wheel has one DOF — Rolling

PassVeh14DOF

PassVeh14DOF

Vehicle with four wheels.

  • Vehicle body has six DOFs — Longitudinal, lateral, vertical and pitch, yaw, and roll

  • Each wheel has two DOFs — Vertical and rolling

Engine SubsystemVariantDescription

Mapped Engine

SiMappedEngine (default)

Mapped spark-ignition (SI) engine

Steering, Transmission, Driveline, and Brakes Subsystem

VariantDescription

Driveline Ideal Fixed Gear

Driveline model

All Wheel Drive

Configure the driveline for all-wheel, front-wheel, or rear-wheel drive

Specify the type of torque coupling

Front Wheel Drive

Rear Wheel Drive (default)

Transmission

Ideal (default)

Ideal fixed gear transmission

Visualization

When you run the simulation, the Visualization subsystem provides driver, vehicle, and response information. The reference application logs vehicle signals during the maneuver, including steering, vehicle and engine speed, and lateral acceleration. You can use the Simulation Data Inspector to import the logged signals and examine the data.

ElementDescription

Driver Commands

Driver commands:

  • Handwheel angle

  • Acceleration command

  • Brake command

Vehicle Response

Vehicle response:

  • Engine speed

  • Vehicle speed

  • Acceleration command

Lane Change Scope block

Lateral vehicle displacement versus time:

  • Red line — Cones marking lane boundary

  • Blue line — Reference trajectory

  • Green line — Actual trajectory

Steer vs Ay Scope block

Steering angle versus lateral acceleration

Steer, Velocity, Lat Accel Scope block

  • SteerAngle — Steering angle versus time

  • <xdot> — Longitudinal vehicle velocity versus time

  • <ay> — Lateral acceleration versus time

Vehicle XY Plotter

Vehicle longitudinal versus lateral distance

ISO 15037-1:2006 block

Display ISO standard measurement signals in the Simulation Data Inspector, including steering wheel angle and torque, longitudinal and lateral velocity, and sideslip angle

3D Visualization

Optionally, you can enable or disable the 3D visualization environment. For the 3D visualization engine platform requirements and hardware recommendations, see 3D Visualization Engine Requirements. After you open the reference application, in the Visualization subsystem, open the 3D Engine block. Set these parameters.

  • 3D Engine to Enabled.

  • Scene to one of the scenes, for example Straight road.

  • To position the vehicle in the scene:

    1. Select the position initialization method:

      • Recommended for scene — Set the initial vehicle position to values recommended for the scene

      • User-specified — Set your own initial vehicle position

    2. Select Apply to modify the initial vehicle position parameters.

    3. Click Update the model workspaces with the initial values to overwrite the initial vehicle position in the model workspaces with the applied values.

When you run the simulation, view the vehicle response in the AutoVrtlEnv window.

Note

  • To open and close the AutoVrtlEnv window, use the Simulink® Run and Stop buttons. If you manually close the AutoVrtlEnv window, Simulink stops the simulation with an error.

  • When you enable the 3D visualization environment, you cannot step the simulation back.

To change the camera views, use these key commands.

KeyCamera View

1

Back left

2

Back

3

Back right

4

Left

5

Internal

6

Right

7

Front left

8

Front

9

Front right

0

Overhead

References

[1] ISO 3888-2: 2011. Passenger cars — Test track for a severe lane-change manoeuvre.

[2] MacAdam, C. C. "An Optimal Preview Control for Linear Systems". Journal of Dynamic Systems, Measurement, and Control. Vol. 102, Number 3, 1980.

[3] MacAdam, C. C. "Application of an Optimal Preview Control for Simulation of Closed-Loop Automobile Driving ". IEEE Transactions on Systems, Man, and Cybernetics. Vol. 11, Number 6, 1981.

[4] MacAdam, C. C. "Development of Driver/Vehicle Steering Interaction Models for Dynamic Analysis". Final Technical Report UMTRI-88-53. The University of Michigan Transportation Research Institute. 1988.

See Also

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