Slowly Increasing Steer

R2026b

Generate commands to conduct linearly increasing steering maneuver

Since R2024b

• 

Slowly Increasing Steer block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Vehicle Dynamics Blockset / Vehicle Scenarios / Drive Cycle and Maneuvers

Description

The Slowly Increasing Steer block generates steering, accelerator, and brake commands to conduct a linearly increasing steering maneuver. The steering command begins at the specified rate once the vehicle reaches the longitudinal velocity setpoint. After the vehicle achieves the maximum steering angle, the vehicle maintains the steering angle for a set duration. The block then reduces the steering angle to zero at the same rate. A longitudinal controller regulates the vehicle at the prescribed speed throughout the maneuver. You have the option to stop the simulation at a lateral acceleration threshold.

The slowly increasing steer maneuver is a foundational test to help assess the vehicle's lateral dynamics and understeer characteristics. You can also use the maneuver to set up additional tests such as swept sine, sine with dwell, and fishhook.

Ports

Input

xdot — Vehicle longitudinal velocity

scalar

Vehicle longitudinal velocity in the body fixed frame, specified as a scalar, in m/s.

Data Types: single | double

ay — Vehicle lateral acceleration threshold

scalar

Vehicle lateral acceleration needed to stop the simulation, specified as a scalar, in m/s^2.

Dependencies

To enable this parameter, select Stop simulation at lateral acceleration threshold.

Data Types: single | double

Output

DrvRef — Driver reference data

bus

Driver reference data, returned as a bus containing these block values.

Signal	Description	Units
LngRef	Longitudinal reference velocity	m/s
LtrRef	Lateral reference displacement	m
XRef	Vehicle global longitudinal reference position	m
YRef	Vehicle global lateral reference position	m
PsiRef	Vehicle global yaw reference position	rad
CurvRef	Reference path curvature	1/m
CurvGradRef	Reference path curvature gradient	1/m^2

Data Types: bus

DrvCmd — Driver command data

bus

Driver command data, returned as a bus containing these block values.

Signal		Description	Units
SteerCmd	EnblSteerCmd	Boolean signal used to override driver model steering commands	one
	SteerCmd	Handwheel angle	one
	SteerZero	Boolean signal used to override driver model steering commands with zero when value is true	one
	SteerHld	Boolean signal used to hold the current driver model steering output when true	one
AccelCmd	EnblAccelCmd	Boolean signal used to override driver model acceleration commands	one
	AccelCmd	Normalized accelerator input	one
	AccelHld	Boolean signal used to hold the current driver model acceleration output when true	one
	AccelZero	Boolean signal used to override driver model acceleration commands with zero when value is true	one
DecelCmd	EnblDecelCmd	Boolean signal used to override driver model deceleration commands	one
	DecelCmd	Normalized decelerator or brake input	one
	DecelHld	Boolean signal used to hold the current driver model deceleration output when true	one
	DecelZero	Boolean signal used to override driver model deceleration commands with zero when value is true	one
	HndBrkCmd	Normalized handbrake or park brake input	one
TransCmd	TransModeCmd	Command to specify the transmission mode	one
	GearCmd	Command to specify manual gear number or automatic transmission shifter position	one
	UpShiftCmd	Command to upshift	one
	DwnShiftCmd	Command to downshift	one
	ClutchCmd	Normalized clutch open command for manual transmissions	one

Note

By default, the TransCmd bus is not actively used. Use a Bus Assignment block to override the TransCmd signal to customize and extend the scenario.

Data Types: bus

Parameters

To edit block parameters interactively, use the Property Inspector. From the Simulink^® Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Maneuver Parameters

Maneuver start time, tStart [s] — Start time

2 (default) | positive scalar

Maneuver start time, in s.

Tunable: Yes

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	tStart
Values:	2 (default) | positive scalar
Data Types:	double

Longitudinal velocity setpoint, velRef — Target velocity

50 (default) | positive scalar

Target velocity.

Tunable: Yes

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	velRef
Values:	50 (default) | positive scalar
Data Types:	double

Reference velocity unit [] — Units

mph (default)

Units for reference velocity.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	velRefUnit
Values:	mph (default) | character vector
Data Types:	character vector

Steer and countersteer speed, steerRate [deg/s] — Steer and countersteer rate

13.5 (default) | positive scalar

Steer and countersteer rate, in deg/s.

Tunable: Yes

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	steerRate
Values:	13.5 (default) | positive scalar
Data Types:	double

Steer amplitude, steerAmp [deg] — Handwheel steer amplitude

270 (default) | positive scalar

Handwheel steer amplitude, in deg.

Tunable: Yes

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	steerAmp
Values:	270 (default) | positive scalar
Data Types:	double

Steering hold time after max angle reached, tDwekkSteer [s] — Steering hold time

2 (default) | positive scalar

Steering hold time after maximum steer amplitude is reached, in s.

Tunable: Yes

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	tStop
Values:	2 (default) | positive scalar
Data Types:	double

Lateral acceleration absolute threshold, ay_max [g] — Lateral acceleration threshold

0.5 (default) | positive scalar

Lateral acceleration threshold at which the simulation is stopped, in gn.

Tunable: Yes

Dependencies

To enable this parameter, select Stop simulation at lateral acceleration threshold.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	ay_max
Values:	0.5 (default) | positive scalar
Data Types:	double

Initial steer direction — Initial steer direction

Right (default) | Left

Set the initial steer direction as Right or Left.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	steerDir
Values:	Right (default) | Left
Data Types:	character vector

Stop simulation at lateral acceleration threshold — Option to stop simulation at lateral acceleration threshold

off (default) | on

Select this parameter to stop the simulation at the input lateral acceleration threshold.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	ayStop
Values:	off (default) | on
Data Types:	character vector

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"vehdynlibscenario/Slowly Increasing Steer"

Example: add_block("vehdynlibscenario/Slowly Increasing Steer","myModel/myBlock",MakeNameUnique="on")

For information about programmatic access to individual block parameters, see the Programmatic Use section of parameter descriptions on this page.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2024b

R2026a: Output port DrfRef bus signal name change

The output port DrvRef bus signal PhiRef is renamed to PsiRef. The signal contains the vehicle global yaw reference position, in rad.