Acceleration and Braking

Generate steering, accelerator, and brake commands

Since R2024b

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  • Acceleration and Braking block icon

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

Description

The Acceleration and Braking block generates a straight reference trajectory as a function of longitudinal displacement or time. Initial reference acceleration and deceleration are tunable. Once the target longitudinal velocity is achieved, the block executes a deceleration signal. This deceleration signal can be executed either with specified time or longitudinal displacement.

An additional option for fault tracking allows you to monitor the uniformity of parameters just before braking. The default set values are upper bounds for the standard split-mu test (ISO Standard 141512).

Note

For information on the reference generator block used in the braking test reference application, see Straight Maneuver Reference Generator.

Ports

Input

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

Data Types: double

Vehicle yaw rate, specified as a scalar, in rad/s.

Dependencies

To enable this parameter, select Enable fault tracking before braking.

Data Types: double

Vehicle handwheel angle, specified as a scalar, in rad.

Dependencies

To enable this parameter, select Enable fault tracking before braking.

Data Types: double

Output

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

SignalDescriptionUnits

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

PhiRef

Vehicle global yaw reference position

rad

CurvRef

Reference path curvature

1/m

CurvGradRef

Reference path curvature gradient

1/m^2

Data Types: bus

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

SignalDescriptionUnits

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 bus to customize and extend the scenario.

Block diagram where the Bus Assignment block overrides the TransModeCmd output from the Acceleration and Braking block.

Data Types: bus

Parameters

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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, in s.

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 acceleration at the simulation start time, tStart, in m/s^2.

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

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

Units for target 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

Method to start deceleration. To specify a time to start decelerating the vehicle, select Time. To specify a displacement to start decelerating the vehicle, select Longitudinal displacement.

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: brakingType
Values: Time (default) | Longitudinal displacement
Data Types: character vector

Simulation time when braking is initiated, in s.

Dependencies

To enable this parameter, set Brake pedal actuation to Time.

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: tBrake
Values: 15 (default) | positive scalar
Data Types: double

The longitudinal displacement of the vehicle when braking is initiated, in m.

Dependencies

To enable this parameter, set Brake pedal actuation to Longitudinal displacement.

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: xBrake
Values: 200 (default) | positive scalar
Data Types: double

Deceleration rate when braking is initiated, in g.

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: axDecel
Values: 1 (default) | positive scalar
Data Types: double

Select this parameter to set the handwheel angle to zero degrees after braking.

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

Tracking Parameters

Select this parameter to enable fault tracking before braking.

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

Transport delay buffer size. This parameter is used for the online diagnostic calculations. Use the simulation step size or hardware memory availability to specify the buffer size.

Dependencies

To enable this parameter, select Enable fault tracking before braking.

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: bufferSize
Values: 4096 (default) | positive scalar
Data Types: double

Maximum allowable difference between the longitudinal velocity and the mean longitudinal velocity during the eight-second time interval prior to when braking is initiated, in m/s.

Set value to comply with ISO 14512 for braking on surfaces with split coefficient of friction.

Dependencies

To enable this parameter, select Enable fault tracking before braking.

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: velMaxDiff
Values: 1 (default) | positive scalar
Data Types: double

Maximum allowable difference between the mean longitudinal velocity and longitudinal velocity reference during the eight-second time interval prior to when braking is initiated, in m/s.

Set value to comply with ISO 14512 for braking on surfaces with split coefficient of friction.

Dependencies

To enable this parameter, select Enable fault tracking before braking.

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

Maximum allowable difference between the yaw velocity and mean yaw velocity during the eight-second time interval prior to when braking is initiated, in deg/s.

Set value to comply with ISO 14512 for braking on surfaces with split coefficient of friction.

Dependencies

To enable this parameter, select Enable fault tracking before braking.

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: rMaxDiff
Values: 1 (default) | positive scalar
Data Types: double

Maximum allowable difference between the handwheel angle and the mean handwheel angle during the eight-second time interval prior to when braking is initiated, in deg.

Set value to comply with ISO 14512 for braking on surfaces with split coefficient of friction.

Dependencies

To enable this parameter, select Enable fault tracking before braking.

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: steerMaxDiff
Values: 3 (default) | positive scalar
Data Types: double

Select this parameter to stop simulation when fault occurs.

Dependencies

To enable this parameter, select Enable fault tracking before braking.

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

Extended Capabilities

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

Version History

Introduced in R2024b

See Also

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