Road Profile

R2026b

Road profile with varying elevation and friction properties

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Road Profile 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:
Simscape / Driveline / Tires & Vehicles

Description

The Road Profile block represents a road profile with varying elevation and friction properties. As a vehicle travels, the axle parameters and the position of the center of gravity (CG) determine the position of the front and rear axles. The block uses the axle positions to compute vehicle angle and, optionally, tire friction coefficients. The block models friction using either Magic Formula or kinetic and static friction coefficients.

Variables

To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.

Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. Nominal values can come from different sources, one of which is the Nominal Values section in the block dialog box or Property Inspector. For more information, see Modify Nominal Values for a Block Variable.

Ports

Conserving

H — Horizontal motion

mechanical translational

Conserving port associated with the horizontal motion. Connect to the H port of the Vehicle Body block.

Programmatic Use

Port: H

Output

MF — Front axle friction coefficients

vector

Physical signal output port for the friction coefficients of the front axle.

The vector contains four elements for the Magic Formula friction model or two elements for the friction coefficients friction model. Connect to the M port of a front axle Tire (Friction Parameterized) or Tire (Magic Formula) block.

Dependencies

To enable this port, set Friction output to either:

• Physical signal Magic Formula coefficients

• Physical signal friction coefficients

Programmatic Use

Port: MF_M

MR — Rear axle friction coefficients

vector

Physical signal output port for the friction coefficients of the rear axle.

The vector contains four elements for the Magic Formula friction model or two elements for the friction coefficients friction model. Connect to the M port of a rear axle Tire (Friction Parameterized) or Tire (Magic Formula) block.

Dependencies

To enable this port, set Friction output to either:

• Physical signal Magic Formula coefficients

• Physical signal friction coefficients

Programmatic Use

Port: MR_M

beta — Vehicle angle

scalar

Physical signal output port for the vehicle angle.

Programmatic Use

Port: beta

Parameters

Main

Horizontal distance from CG to front axle — Distance between CG and front axle

1.4 m (default) | positive scalar

Horizontal distance from the center of gravity (CG) to the front axle. Specify the same value as is specified for the Horizontal distance from CG to front axle parameter of the connected Vehicle Body block.

Programmatic Use

Parameter: x_f

Horizontal distance from CG to rear axle — Distance between CG and rear axle

1.6 m (default) | positive scalar

Horizontal distance from the center of gravity (CG) to the rear axle. Specify the same value as is specified for the Horizontal distance from CG to rear axle parameter of the connected Vehicle Body block.

Programmatic Use

Parameter: x_r

Horizontal distance for vertical profile — Vertical profile horizontal distance

[-10, 0, 10] m (default) | vector

Table lookup corresponding to the distance that the CG of the vehicle moves relative to the reference frame x-axis. For example the figure shows a horizontal profile of [-10, 0, 10]. Table lookup extrapolation is nearest.

Programmatic Use

Parameter: x_height_vector

Vertical profile — Vertical profile

[0, 0, .25] m (default) | vector

Table lookup corresponding to the distance that the CG of the vehicle moves relative to the reference frame y-axis. For example the figure shows a vertical profile of [2, 0, 5]. Table lookup extrapolation is nearest.

Programmatic Use

Parameter: height_vector

Profile interpolation method — Road profile interpolation method

Smooth (default) | Linear

Whether to use smooth interpolation or linear interpolation when the block interpolates the profile coordinates.

Programmatic Use

Parameter:	profile_interp_method
Values:	"simscape.enum.interpolation.smooth" | "simscape.enum.interpolation.linear"

Friction

Friction output — Friction coefficient output type

None (default) | Physical signal Magic Formula coefficientsPhysical signal friction coefficients

Type of friction coefficient that the block outputs. Select Physical signal Magic Formula coefficients to vary friction for Tire (Magic Formula) blocks. Select Physical signal friction coefficients to vary friction for Tire (Friction Parameterized) blocks.

Programmatic Use

Parameter:	friction_output
Values:	"sdl.enum.tire_friction_model.none" | "sdl.enum.tire_friction_model.Magic" | "sdl.enum.tire_friction_model.Friction"

Horizontal distance for friction profile — Horizontal distance for friction profile

[-10, 2, 2.1, 6, 6.1, 10] m (default) | vector

Friction profile horizontal distance.

Dependencies

To enable this parameter, set Friction output to either:

• Physical signal Magic Formula coefficients

• Physical signal friction coefficients

Programmatic Use

Parameter: x_friction_vector

Magic Formula coefficients for front axle — Front axle Magic Formula coefficients

[10, 2, 1, 1; 10, 2, 1, 1; 8, 3, 1, 1; 8, 3, 1, 1; 9, 4, 1, 1; 9, 4, 1, 1] (default) | matrix

Magic Formula coefficients specified as an n-by-4 matrix, where n is the number of points in the vector specified by the Horizontal distance for friction profile parameter.

Dependencies

To enable this parameter, set Friction output to Physical signal Magic Formula coefficients.

Programmatic Use

Parameter: MF_M_matrix

Magic Formula coefficients for rear axle — Rear axle Magic Formula coefficients

[10, 2, 1, 1; 10, 2, 1, 1; 8, 3, 1, 1; 8, 3, 1, 1; 9, 4, 1, 1; 9, 4, 1, 1] (default) | matrix

Magic Formula coefficients specified as an n-by-4 matrix, where n is the number of points in the vector specified by the Horizontal distance for friction profile parameter.

Dependencies

To enable this parameter, set Friction output to Physical signal Magic Formula coefficients.

Programmatic Use

Parameter: MR_M_matrix

Static and kinetic friction coefficients for front axle — Front axle friction coefficients

[.9, .7; .9, .7; .7, .5; .7, .5; .8, .6; .8, .6] (default) | matrix

Front axle static and kinetic friction coefficients specified as an n-by-2 matrix, where n is the number of points in the vector specified by the Horizontal distance for friction profile parameter.

Dependencies

To enable this parameter, set Friction output to Physical signal friction coefficients.

Programmatic Use

Parameter: MF_F_matrix

Static and kinetic friction coefficients for rear axle — Rear axle friction coefficients

[.9, .7; .9, .7; .7, .5; .7, .5; .8, .6; .8, .6] (default) | matrix

Rear axle static and kinetic friction coefficients specified as an n-by-2 matrix, where n is the number of points in the vector specified by the Horizontal distance for friction profile parameter.

Dependencies

To enable this parameter, set Friction output to Physical signal friction coefficients.

Programmatic Use

Parameter: MR_F_matrix

Extended Capabilities

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

Version History

Introduced in R2019a

R2026a: Profile Enhancements

The block uses a improved equations to calculate the road profile. Results may differ slightly from previous releases.

You can use the Interpolation method parameter to specify whether the block uses smooth or linear interpolation to calculate the road profile.