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Reference Generator

Generate maneuver reference signals

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    Description

    The Reference Generator block sets the parameters that configure the maneuver and 3D simulation environment. By default, the block is set for the constant radius maneuver with the 3D simulation engine environment disabled.

    Model

    Use the Maneuver parameter to specify the type of maneuver. After you select the maneuver, use the parameters to specify the maneuver settings. By default:

    • Use maneuver-specific driver, initial position, and scene — Set to on

    • Maneuver start time — Set to 3s

    • Longitudinal velocity reference — Set to 30s

    • Longitudinal entrance velocity setpoint units — Set to mph

    Maneuver Setting

    Implementation

    Double Lane Change

    Double-Lane Change Maneuver

    • Vehicle width — Lane signals for the Visualization subsystem; used for the left and right lane boundaries

    • Lateral reference data — Lateral reference trajectory as a function of the longitudinal distance

    • Distance after target speed to begin reference — Start the maneuver at specified distance after the vehicle reaches the target speed

    Increasing Steer

    Slowly Increasing Steering Maneuver

    • Handwheel rate — Linear rate to increase steering wheel angle

    • Maximum handwheel angle — Maximum steering wheel angle

    Swept Sine

    Swept-Sine Steering Maneuver

    • Steering amplitude — Sinusoidal wave amplitude

    • Final frequency — Cut off frequency to stop the maneuver

    Sine with Dwell

    In the test, the vehicle:

    • Accelerates until it hits a target velocity.

    • Maintains the target velocity.

    • Responds to a sinusoidal with dwell steering command.

    • Steer frequency — Sinusoidal wave frequency

    • Steer amplitude — Sinusoidal wave amplitude

    • Dwell time — Dwell time

    Constant Radius

    Constant Radius Maneuver

    • Radius value — Turn radius

    Fishhook

    In the test, the vehicle:

    • Accelerates until it hits a target velocity.

    • Maintains the target velocity.

    • Responds to initial rapid steering input.

    • Responds to steering overcorrection.

    • Steer and countersteer speed — Steering rate

    • Initial dwell time — Initial steer time

    • Countersteer dwell time — Countersteer time

    3D Engine

    The 3D engine implements the 3D simulation environment. Vehicle Dynamics Blockset™ integrates the 3D simulation environment with Simulink® so that you can query the world around the vehicle for virtually testing perception, control, and planning algorithms. For 3D engine requirements, see Unreal Engine Simulation Environment Requirements and Limitations. To enable the 3D engine, on the 3D Engine tab, select Enabled.

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

    Examples

    Double Lane Change Reference Application

    Double Lane Change Reference Application

    Simulate a full vehicle dynamics model undergoing a double lane change maneuver standard ISO 3888-2. Use for vehicle dynamics ride and handling analysis and chassis controls development, including yaw stability and lateral acceleration limits.

    Ports

    Input

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    Bus containing vehicle feedback signals, including velocity, acceleration, and steering wheel torque.

    Output

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    Bus containing the visualization reference signals, including longitudinal and lateral displacement, and steering.

    Bus containing the vehicle reference signals, including longitudinal and lateral displacement, and steering.

    Bus containing vehicle location feedback signals, including position.

    Parameters

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    Configuration

    Specify the scene type.

    Maneuver start time, in s.

    Target velocity.

    Units for target velocity.

    Time, in s.

    Constant Radius

    Radius value, in m.

    Turn direction.

    Lateral acceleration threshold, in g.

    Stop simulation if vehicle exceeds lateral acceleration threshold.

    Double Lane Change

    Inertial longitudinal position of gate entrance, in m.

    Distance after target speed to begin reference, in m.

    Vehicle width, in m.

    The left and right lane boundaries are a function of the Vehicle width parameter.

    Lateral offset, in m.

    Lateral reference position breakpoints, in m.

    Use the Lateral reference position breakpoints and Lateral reference data parameters to specify the lateral reference trajectory as a function of the longitudinal distance.

    Use the Lateral reference position breakpoints and Lateral reference data parameters to specify the lateral reference trajectory as a function of the longitudinal distance.

    Increasing Steer

    Handwheel rate, in deg/s.

    Maximum handwheel angle, in deg.

    Steering hold, in s.

    Lateral acceleration threshold, in g.

    Stop simulation if vehicle exceeds lateral acceleration threshold.

    Swept Sine

    Sweep time, in s.

    Sinusoidal steering amplitude, in deg.

    Cut off frequency to stop the maneuver, in Hz.

    Fishhook

    Steer and countersteer speed, in deg/s.

    Steer amplitude, in deg.

    Initial dwell time, in s.

    Countersteer dwell time, in s.

    Return to center time, in s.

    Roll rate countersteer initiation zero crossing threshold, in deg.

    3D Engine

    Enable 3D visualization.

    Specify the name of the 3D scene.

    Graphics frame rate, in s. The graphics frame rate is the inverse of the sample time.

    Use vehicle positions that are recommended for the scene.

    Specify to set your own initial vehicle position values.

    Initial vehicle CG position along the earth-fixed X-axis, in m.

    Initial vehicle CG position along the earth-fixed Y-axis, in m.

    Initial vehicle CG position along the earth-fixed Z-axis, in m.

    Rotation of the vehicle-fixed frame about the earth-fixed X-axis (roll), in rad.

    Rotation of the vehicle-fixed frame about the earth-fixed Y-axis (pitch), in rad.

    Rotation of the vehicle-fixed frame about the earth-fixed Z-axis (yaw), in rad.

    Version History

    Introduced in R2019a

    See Also

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