Predictive Driver

Predictive driver controller to track longitudinal speed and lateral path

• Library:
• Vehicle Dynamics Blockset / Vehicle Scenarios / Driver

Description

The Predictive Driver block implements a controller that generates normalized steering, acceleration, and braking commands to track longitudinal velocity and a lateral reference displacement. The normalized commands can vary between -1 to 1. The controller uses a single-track (bicycle) model for optimal single-point preview control.

Configurations

External Actions

Use the External Actions parameters to create input ports for signals that you can use to simulate standard test maneuvers. The block uses this priority order for the input commands: disable (highest), hold, override.

This table summarizes the external action parameters.

Goal

External Action Parameter

Input Ports

Data Type

Override the accelerator command with an input acceleration command.

Accelerator override

`EnablAccelOvr`

`Boolean`

`AccelOvrCmd`

`double`

Hold the acceleration command at the current value.

Accelerator hold

`AccelHld``Boolean`

Disable the acceleration command.

Accelerator disable

`AccelZero``Boolean`

Override the decelerator command with an input deceleration command.

Decelerator override

`EnablDecelOvr`

`Boolean`

`DecelOvrCmd`

`double`

Hold the decelerator command at current value.

Decelerator hold

`DecelHld``Boolean`

Disable the decelerator command.

Decelerator disable

`DecelZero``Boolean`

Override the steering command with an input steering command.

Steering override

`EnblSteerOvr`

`Boolean`

`SteerOvrCmd`

`double`

Hold the steering command at the current value.

Steering hold

`SteerHld``Boolean`

Disable the steering command.

Steering disable

`SteerZero``Boolean`

Controllers

Use the Longitudinal control type, cntrlType parameter to specify one of these control options.

Setting

Block Implementation

`PI`

Proportional-integral (PI) control with tracking windup and feed-forward gains.

`Scheduled PI`

PI control with tracking windup and feed-forward gains that are a function of vehicle velocity.

`Predictive`

Optimal single-point preview (look ahead) control model developed by C. C. MacAdam1, 2, 3. The model represents driver steering control behavior during path-following and obstacle avoidance maneuvers. Drivers preview (look ahead) to follow a predefined path. To implement the MacAdam model, the block:

• Represents the dynamics as a linear single track (bicycle) vehicle

• Minimizes the previewed error signal at a single point T* seconds ahead in time

• Accounts for the driver lag deriving from perceptual and neuromuscular mechanisms

Use the Lateral control type, controlTypeLat parameter to specify the type of lateral control. The table specifies the block implementation.

Setting

Block Implementation

`Predictive` (default)

Optimal single-point preview (look ahead) control model developed by C. C. MacAdam1, 2, 3. The model represents driver steering control behavior during path-following and obstacle avoidance maneuvers. Drivers preview (look ahead) to follow a predefined path.

`Stanley`

Controller that uses the Stanley4 method to minimize the position error and the angle error of the current pose with respect to the reference pose.

On the Reference Control pane, use the:

• Vector input for reference and feedback pose parameter to input the to specify the input.

SettingImplementation
`off` (default)

Block uses the longitudinal, lateral, and yaw reference (`LongRef`, `LatRef`, `LatRef`) input ports and the feedback (`LongFdbk`, `LatFdbk`, `LatFdbk`) input ports for the reference and feedback pose.

`on`

Block uses input ports, `RefPose` and `CurrPose`, for the reference and feedback pose, respectively.

• Include dynamics parameter to specify the type of model for the controller to use.

SettingImplementation
`off` (default)

Controller uses a kinematic bicycle model that is suitable for path following in low-speed environments such as parking lots, where inertial effects are minimal.

`on`

Controller uses a dynamic bicycle model that is suitable for path following in high-speed environments such as highways, where inertial effects are more pronounced.

Shift

Use the Shift type, ShftType parameter to specify one of these shift options.

Setting

Block Implementation

`None`

No transmission. Block outputs a constant gear of 1.

Use this setting to minimize the number of parameters you need to generate acceleration and braking commands to track forward vehicle motion. This setting does not allow reverse vehicle motion.

`Reverse, Neutral, Drive`

Block uses a Stateflow® chart to model reverse, neutral, and drive gear shift scheduling.

Use this setting to generate acceleration and braking commands to track forward and reverse vehicle motion using simple reverse, neutral, and drive gear shift scheduling. Depending on the vehicle state and vehicle velocity feedback, the block uses the initial gear and time required to shift to shift the vehicle up into drive or down into reverse or neutral.

For neutral gears, the block uses braking commands to control the vehicle speed. For reverse gears, the block uses an acceleration command to generate torque and a brake command to reduce vehicle speed.

`Scheduled`

Block uses a Stateflow chart to model reverse, neutral, park, and N-speed gear shift scheduling.

Use this setting to generate acceleration and braking commands to track forward and reverse vehicle motion using reverse, neutral, park, and N-speed gear shift scheduling. Depending on the vehicle state and vehicle velocity feedback, the block uses these parameters to determine the:

• Initial gear

• Upshift and downshift accelerator pedal positions

• Upshift and downshift velocity

• Timing for shifting and engaging forward and reverse from neutral

For neutral gears, the block uses braking commands to control the vehicle speed. For reverse gears, the block uses an acceleration command to generate torque and a brake command to reduce vehicle speed.

`External`

Block uses the input gear, vehicle state, and velocity feedback to generate acceleration and braking commands to track forward and reverse vehicle motion.

For neutral gears, the block uses braking commands to control the vehicle speed. For reverse gears, the block uses an acceleration command to generate torque and a brake command to reduce vehicle speed.

Units

Use the and Longitudinal velocity units, velUnits and Angular units, angUnits parameter to specify the units for the input and output ports.

Gear Signal

Use the parameter to create the `GearCmd` output port. The `GearCmd` signal contains the integer value of the commanded vehicle gear.

Gear

Integer

Park

`80`

Reverse

`-1`

Neutral

`0`

Drive

`1`

Gear

`Gear number`

Output Handwheel Angle

Use the Output handwheel angle parameter to specify the units for the steering ports.

Setting

Block Implementation

Port

`off` (default)

Commanded steer angle, normalized from -1 through 1. The block uses the tire wheel angle saturation limit Tire wheel angle limit, theta parameter to normalize the command.

`SteerCmd` — Output

Overrides the steering command with an input steering command normalized from -1 through 1.

`SteerOvrCmd` — Input

`on`

Commanded steer angle, in units specified by Angular units, angUnits.

`SteerCmd` — Output

Overrides the steering command with an input steering command, in units specified by Angular units, angUnits.

`SteerOvrCmd` — Input

Controller: PI Speed-Tracking

If you set the control type to `PI` or ```Scheduled PI```, the block implements proportional-integral (PI) control with tracking windup and feed-forward gains. For the `Scheduled PI` configuration, the block uses feed forward gains that are a function of vehicle velocity.

To calculate the speed control output, the block uses these equations.

Setting

Equation

`PI`

`$y=\frac{{K}_{ff}}{{v}_{nom}}{v}_{ref}+\frac{{K}_{p}{e}_{ref}}{{v}_{nom}}+\int \left(\frac{{K}_{i}{e}_{ref}}{{v}_{nom}}+{K}_{aw}{e}_{out}\right)dt+{K}_{g}\theta$`

```Scheduled PI```

`$y=\frac{{K}_{ff}\left(v\right)}{{v}_{nom}}{v}_{ref}+\frac{{K}_{p}\left(v\right){e}_{ref}}{{v}_{nom}}+\int \left(\frac{{K}_{i}\left(v\right){e}_{ref}}{{v}_{nom}}+{K}_{aw}{e}_{out}\right){e}_{ref}dt+{K}_{g}\left(v\right)\theta$`

`$\begin{array}{l}\text{where:}\\ \\ {e}_{ref}={v}_{ref}-v\\ {e}_{out}={y}_{sat}-y\\ \\ {y}_{sat}=\left\{\begin{array}{cc}-1& y<-1\\ y& -1\le y\le 1\\ 1& 1`

The velocity error low-pass filter uses this transfer function.

To calculate the acceleration and braking commands, the block uses these equations.

`$\begin{array}{l}{y}_{acc}=\left\{\begin{array}{cc}0& {y}_{sat}<0\\ {y}_{sat}& 0\le {y}_{sat}\le 1\\ 1& 1<{y}_{sat}\end{array}\\ \\ {y}_{dec}=\left\{\begin{array}{cc}0& {y}_{sat}>0\\ -{y}_{sat}& -1\le {y}_{sat}\le 0\\ 1& {y}_{sat}<-1\end{array}\end{array}$`

The equations use these variables.

 vnom Nominal vehicle speed Kp Proportional gain Ki Integral gain Kaw Anti-windup gain Kff Velocity feed-forward gain Kg Grade angle feed-forward gain θ Grade angle τerr Error filter time constant y Nominal control output magnitude ysat Saturated control output magnitude eref Velocity error eout Difference between saturated and nominal control outputs yacc Acceleration signal ydec Braking signal v Velocity feedback signal vref Reference velocity signal

Controller: Predictive Speed-Tracking

If you set the Longitudinal control type, cntrlType or Lateral control type, cntrlType to `Predictive`, the block implements an optimal single-point preview (look ahead) control model developed by C. C. MacAdam1, 2, 3. The model represents driver steering control behavior during path-following and obstacle avoidance maneuvers. Drivers preview (look ahead) to follow a predefined path. To implement the MacAdam model, the block:

• Represents the dynamics as a linear single track (bicycle) vehicle

• Minimizes the previewed error signal at a single point T* seconds ahead in time

• Accounts for the driver lag deriving from perceptual and neuromuscular mechanisms

Vehicle Dynamics

For lateral and yaw motion, the block implements these linear dynamic equations.

In matrix notation:

The single-point model assumes a minimum previewed error signal at a single point T* seconds ahead in time. a* is the driver ability to predict the future vehicle response based on the current steering control input. b* is the driver ability to predict the future vehicle response based on the current vehicle state. The block uses these equations.

`$\begin{array}{l}{a}^{*}=\left({T}^{*}\right){m}^{T}\left[I+\sum _{n=1}^{\infty }\frac{{F}^{n}{\left({T}^{*}\right)}^{n}}{\left(n+1\right)!}\right]g\\ {b}^{*}={m}^{T}\left[I+\sum _{n=1}^{\infty }\frac{{F}^{n}{\left({T}^{*}\right)}^{n}}{n!}\right]\\ {m}^{T}=\left[\begin{array}{cccccc}1& 1& 1& 0& 0& 0\end{array}\right]\end{array}$`

The equations use these variables.

 a, b Forward and rearward tire location, respectively m Vehicle mass I Vehicle rotational inertia CɑF Front tire cornering coefficient CɑR Rear tire cornering coefficient a*, b* Driver prediction scalar and vector gain, respectively x Predicted vehicle state vector v Lateral velocity r Yaw rate Ψ Front wheel heading angle y Lateral displacement F System matrix δ, δF Steer angle and front axle steer angle, respectively γ Grade angle g Control coefficient vector U Forward (longitudinal) vehicle velocity T* Preview time window ƒ(t+T*) Previewed path input T* seconds ahead u Tractive force mT Constant observer vector; provides vehicle lateral position ar Static rolling and driveline resistance br Linear rolling and driveline resistance cr Aerodynamic rolling and driveline resistance Fr Rolling resistance

Optimization

The single-point model implemented by the block finds the steering command that minimizes a local performance index, J, over the current preview interval, (t, t+T).

`$J=\frac{1}{T}{\int }_{t}^{t+T}{\left[f\left(\eta \right)-y\left(\eta \right)\right]}^{2}d\eta$`

To minimize J with respect to the steering command, this condition must be met.

`$\frac{dJ}{du}=0$`

You can express the optimal control solution in terms of a current non-optimal and corresponding nonzero preview output error T* seconds ahead1, 2, 3.

`${u}^{o}\left(t\right)=u\left(t\right)+\frac{e\left(t+{T}^{*}\right)}{{a}^{*}}$`

The block uses the preview distance and vehicle longitudinal velocity to determine the preview time window.

`${T}^{*}=\frac{L}{U}$`

The equations use these variables.

 T* Preview time window ƒ(t+T*) Previewed path input T* sec ahead y(t+T*) Previewed plant output T* sec ahead e(t+T*) Previewed error signal T* sec ahead u(t), uo(t) Steer angle and optimal steer angle, respectively L Preview distance J Performance index U Forward (longitudinal) vehicle velocity

Driver Lag

The single-point model implemented by the block introduces a driver lag. The driver lag accounts for the delay when the driver is tracking tasks. Specifically, it is the transport delay deriving from perceptual and neuromuscular mechanisms. To calculate the driver transport delay, the block implements this equation.

`$H\left(s\right)={e}^{-s\tau }$`

The equations use these variables.

 τ Driver transport delay y(t+T*) Previewed plant output T* sec ahead e(t+T*) Previewed error signal T* sec ahead u(t), uo(t) Steer angle and optimal steer angle, respectively J Performance index

Controller: Stanley Lateral Path-Tracking

If you set Lateral control type, controlTypeLat to `Stanley`, the block implements the Stanley method4. To compute the steering angle command, the Stanley controller minimizes the position error and the angle error of the current pose with respect to the reference pose. The driving direction of the vehicle determines these error values.

To compute the steering angle command, the controller minimizes the position error and the angle error of the current pose with respect to the reference pose.

• The position error is the lateral distance from the vehicle center-of-gravity (CG) to the reference point on the path.

• The angle error is the angle of the vehicle with respect to reference path.

Ports

Input

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Reference velocity, vref, in units specified by Longitudinal velocity units, velUnits.

Longitudinal center of mass (CM) displacement reference, in the inertial reference frame, in m.

Dependencies

To enable this port:

• Set Lateral control type, controlTypeLat to `Stanley`

• Clear Vector input for reference and feedback

Lateral center of mass (CM) displacement reference, in the inertial reference frame, in m.

Dependencies

To enable this port, do either of these:

• Set Lateral control type, controlTypeLat to `Stanley` and clear Vector input for reference and feedback.

• Set Lateral control type, controlTypeLat to `Predictive`.

Enable steering command override.

Dependencies

To enable this port, select Steering override.

Data Types: `Boolean`

Steering override command.

Use the Output handwheel angle parameter to specify the units for the steering ports.

Setting

Block Implementation

Port

`off` (default)

Commanded steer angle, normalized from -1 through 1. The block uses the tire wheel angle saturation limit Tire wheel angle limit, theta parameter to normalize the command.

`SteerCmd` — Output

Overrides the steering command with an input steering command normalized from -1 through 1.

`SteerOvrCmd` — Input

`on`

Commanded steer angle, in units specified by Angular units, angUnits.

`SteerCmd` — Output

Overrides the steering command with an input steering command, in units specified by Angular units, angUnits.

`SteerOvrCmd` — Input

Dependencies

To enable this port, select Steering override.

Data Types: `double`

Boolean signal that holds the steering command at the current value.

Dependencies

To enable this port, select Steering hold.

Data Types: `Boolean`

Disable steering command.

Dependencies

To enable this port, select Steering disable.

Data Types: `Boolean`

Enable acceleration command override.

Dependencies

To enable this port, select Acceleration override.

Data Types: `Boolean`

Acceleration override command, normalized from 0 through 1.

Dependencies

To enable this port, select Acceleration override.

Data Types: `double`

Boolean signal that holds the acceleration command at the current value.

Dependencies

To enable this port, select Acceleration hold.

Data Types: `Boolean`

Disable acceleration command.

Dependencies

To enable this port, select Acceleration disable.

Data Types: `Boolean`

Enable deceleration command override.

Dependencies

To enable this port, select Deceleration override.

Data Types: `Boolean`

Deceleration override command, normalized from 0 through 1.

Dependencies

To enable this port, select Deceleration override.

Data Types: `double`

Boolean signal that holds the deceleration command at the current value.

Dependencies

To enable this port, select Deceleration hold.

Data Types: `Boolean`

Disable deceleration command.

Dependencies

To enable this port, select Deceleration disable.

Data Types: `Boolean`

Gear

Integer

Park

`80`

Reverse

`-1`

Neutral

`0`

Drive

`1`

Gear

`Gear number`

Dependencies

To enable this port, set Shift type, shftType to `External`.

Reference pose, specified as an [x, y, Θ] vector. x and y are in meters, and Θ are in units specified by Angular units, angUnits.

x and y specify the reference point to steer the vehicle toward. Θ specifies the orientation angle of the path at this reference point and is positive in the counterclockwise direction.

The reference point is the point on the path that is closest to the vehicle CG. You can use the either the Z-up or Z-down vehicle coordinate system, as long you use the same coordinate system (Z-up or Z-down) for block inputs and parameters.

Dependencies

To enable this port, set Lateral control type, controlTypeLat to `Stanley` and select Vector input for reference and feedback pose.

Data Types: `single` | `double`

Longitudinal vehicle velocity, U, in the vehicle-fixed frame, in units specified by Longitudinal velocity units, velUnits.

Current pose of the vehicle, specified as an [x, y, Θ] vector. x and y are in meters, and Θ is in units specified by Angular units, angUnits.

x and y specify the location of the vehicle, which is defined as the vehicle CG. You can use the either the Z-up or Z-down vehicle coordinate system, as long you use the same coordinate system (Z-up or Z-down) for block inputs and parameters.

Dependencies

To enable this port, set Lateral control type, controlTypeLat to `Stanley` and select Vector input for reference and feedback pose.

Data Types: `single` | `double`

Lateral CM displacement, yo, in the inertial reference frame, in m.

Dependencies

To enable this port, do either of these:

• Set Lateral control type, controlTypeLat to `Stanley` and clear Vector input for reference and feedback.

• Set Lateral control type, controlTypeLat to `Predictive`.

Lateral vehicle velocity, vo , in the vehicle-fixed frame, in m/s.

Dependencies

To enable this port, Set Lateral control type, controlTypeLat to `Predictive`.

Vehicle yaw angle, Ψo, in the inertial reference frame, in units specified by Angular units, angUnits.

Dependencies

To enable this port, do either of these:

• Set Lateral control type, controlTypeLat to `Stanley` and clear Vector input for reference and feedback pose.

• Set Lateral control type, controlTypeLat to `Predictive`.

Yaw rate, ro, in the vehicle-fixed frame, in units specified by Angular units, angUnits per sec.

Dependencies

To enable this port, Set Lateral control type, controlTypeLat to `Predictive`.

Output

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Bus signal containing these block calculations.

SignalVariableDescription
`Steer`δF

Commanded steer angle, normalized from 0 through 1

`Accel`yacc

Commanded vehicle acceleration, normalized from 0 through 1

`Decel `ydec

Commanded vehicle deceleration, normalized from 0 through 1

`Gear`

Integer value of commanded gear

`Clutch`

Clutch command

`Err``LatErr``Err`eref

Difference in reference vehicle position and vehicle position.

`ErrSqrSum`$\underset{0}{\overset{t}{\int }}{e}_{ref}{}^{2}dt$

Integrated square of error.

`ErrMax`$\mathrm{max}\left({e}_{ref}\left(t\right)\right)$

Maximum error during simulation.

`ErrMin`$\mathrm{min}\left({e}_{ref}\left(t\right)\right)$

Minimum error during simulation.

`LngErr``Err`eref

Difference in reference vehicle speed and vehicle speed

`ErrSqrSum`$\underset{0}{\overset{t}{\int }}{e}_{ref}{}^{2}dt$

Integrated square of error

`ErrMax`$\mathrm{max}\left({e}_{ref}\left(t\right)\right)$

Maximum error during simulation

`ErrMin`$\mathrm{min}\left({e}_{ref}\left(t\right)\right)$

Minimum error during simulation

`ExtActions``EnblSteerOvr`

Override the steering command with an input deceleration command

`SteerOvrCmd`

Input steering override command

`SteerHld`

Hold the steering command at the current value

`SteerZero`

Disable the steering command

`EnblAccelOvr`

Override the accelerator command with an input acceleration command

`AccelOvrCmd`

Input accelerator override command

`AccelHld`

Hold the acceleration command at the current value

`AccelZero`

Disable the acceleration command

`EnblDecelOvr`

Override the decelerator command with an input deceleration command

`DecelOvrCmd`

Input deceleration override command

`DecelHld`

Hold the decelerator command at current value

`DecelZero`

Disable the decelerator command

Commanded steer angle, δF.

Use the Output handwheel angle parameter to specify the units for the steering ports.

Setting

Block Implementation

Port

`off` (default)

Commanded steer angle, normalized from -1 through 1. The block uses the tire wheel angle saturation limit Tire wheel angle limit, theta parameter to normalize the command.

`SteerCmd` — Output

Overrides the steering command with an input steering command normalized from -1 through 1.

`SteerOvrCmd` — Input

`on`

Commanded steer angle, in units specified by Angular units, angUnits.

`SteerCmd` — Output

Overrides the steering command with an input steering command, in units specified by Angular units, angUnits.

`SteerOvrCmd` — Input

Commanded vehicle acceleration, yacc, normalized from 0 through 1.

Commanded vehicle deceleration, ydec, normalized from 0 through 1.

Integer value of commanded vehicle gear.

Gear

Integer

Park

`80`

Reverse

`-1`

Neutral

`0`

Drive

`1`

Gear

`Gear number`

Dependencies

To enable this port, select Output gear signal.

Parameters

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Configuration

External Actions

Select to override the acceleration command with an input acceleration command.

Dependencies

Selecting this parameter creates the `EnblAccelOvr` and `AccelOvrCmd` input ports.

Select to hold the acceleration command.

Dependencies

Selecting this parameter creates the `AccelHld` input port.

Select to disable the acceleration command.

Dependencies

Selecting this parameter creates the `AccelZero` input port.

Select to override the deceleration command with an input deceleration command.

Dependencies

Selecting this parameter creates the `EnblDecelOvr` and `DecelOvrCmd` input ports.

Select to hold the deceleration command.

Dependencies

Selecting this parameter creates the `DecelHld` input port.

Select to disable the deceleration command.

Dependencies

Selecting this parameter creates the `DecelZero` input port.

Select to override the steering command with an input steering command.

Dependencies

Selecting this parameter creates the `EnblSteerOvr` and `SteerOvrCmd` input ports.

Select to hold the steering command.

Dependencies

Selecting this parameter creates the `SteerHld` input port.

Select to disable the steering command.

Dependencies

Selecting this parameter creates the `SteerZero` input port.

Control and Shift

Type of longitudinal control.

Setting

Block Implementation

`PI`

Proportional-integral (PI) control with tracking windup and feed-forward gains.

`Scheduled PI`

PI control with tracking windup and feed-forward gains that are a function of vehicle velocity.

`Predictive`

Optimal single-point preview (look ahead) control model developed by C. C. MacAdam1, 2, 3. The model represents driver steering control behavior during path-following and obstacle avoidance maneuvers. Drivers preview (look ahead) to follow a predefined path. To implement the MacAdam model, the block:

• Represents the dynamics as a linear single track (bicycle) vehicle

• Minimizes the previewed error signal at a single point T* seconds ahead in time

• Accounts for the driver lag deriving from perceptual and neuromuscular mechanisms

Use the Lateral control type, controlTypeLat parameter to specify the type of lateral control. The table specifies the block implementation.

Setting

Block Implementation

`Predictive` (default)

Optimal single-point preview (look ahead) control model developed by C. C. MacAdam1, 2, 3. The model represents driver steering control behavior during path-following and obstacle avoidance maneuvers. Drivers preview (look ahead) to follow a predefined path.

`Stanley`

Controller that uses the Stanley4 method to minimize the position error and the angle error of the current pose with respect to the reference pose.

On the Reference Control pane, use the:

• Vector input for reference and feedback pose parameter to input the to specify the input.

SettingImplementation
`off` (default)

Block uses the longitudinal, lateral, and yaw reference (`LongRef`, `LatRef`, `LatRef`) input ports and the feedback (`LongFdbk`, `LatFdbk`, `LatFdbk`) input ports for the reference and feedback pose.

`on`

Block uses input ports, `RefPose` and `CurrPose`, for the reference and feedback pose, respectively.

• Include dynamics parameter to specify the type of model for the controller to use.

SettingImplementation
`off` (default)

Controller uses a kinematic bicycle model that is suitable for path following in low-speed environments such as parking lots, where inertial effects are minimal.

`on`

Controller uses a dynamic bicycle model that is suitable for path following in high-speed environments such as highways, where inertial effects are more pronounced.

Shift type.

Setting

Block Implementation

`None`

No transmission. Block outputs a constant gear of 1.

Use this setting to minimize the number of parameters you need to generate acceleration and braking commands to track forward vehicle motion. This setting does not allow reverse vehicle motion.

`Reverse, Neutral, Drive`

Block uses a Stateflow chart to model reverse, neutral, and drive gear shift scheduling.

Use this setting to generate acceleration and braking commands to track forward and reverse vehicle motion using simple reverse, neutral, and drive gear shift scheduling. Depending on the vehicle state and vehicle velocity feedback, the block uses the initial gear and time required to shift to shift the vehicle up into drive or down into reverse or neutral.

For neutral gears, the block uses braking commands to control the vehicle speed. For reverse gears, the block uses an acceleration command to generate torque and a brake command to reduce vehicle speed.

`Scheduled`

Block uses a Stateflow chart to model reverse, neutral, park, and N-speed gear shift scheduling.

Use this setting to generate acceleration and braking commands to track forward and reverse vehicle motion using reverse, neutral, park, and N-speed gear shift scheduling. Depending on the vehicle state and vehicle velocity feedback, the block uses these parameters to determine the:

• Initial gear

• Upshift and downshift accelerator pedal positions

• Upshift and downshift velocity

• Timing for shifting and engaging forward and reverse from neutral

For neutral gears, the block uses braking commands to control the vehicle speed. For reverse gears, the block uses an acceleration command to generate torque and a brake command to reduce vehicle speed.

`External`

Block uses the input gear, vehicle state, and velocity feedback to generate acceleration and braking commands to track forward and reverse vehicle motion.

For neutral gears, the block uses braking commands to control the vehicle speed. For reverse gears, the block uses an acceleration command to generate torque and a brake command to reduce vehicle speed.

Vehicle velocity reference and feedback units.

Dependencies

If you set Longitudinal control type, CntrlType control type to `Scheduled` or ```Scheduled PI```, the block uses the Longitudinal velocity units, velUnits for the Nominal speed, vnom parameter dimension.

If you set Shift Type, shftType to `Scheduled`, the block uses the Longitudinal velocity units, velUnits for these parameter dimensions:

• Upshift velocity data table, upShftTbl

• Downshift velocity data table, dwnShftTbl

Input and output port angular units.

Specify to create output port `GearCmd`.

Use the Output handwheel angle parameter to specify the units for the steering ports.

Setting

Block Implementation

Port

`off` (default)

Commanded steer angle, normalized from -1 through 1. The block uses the tire wheel angle saturation limit Tire wheel angle limit, theta parameter to normalize the command.

`SteerCmd` — Output

Overrides the steering command with an input steering command normalized from -1 through 1.

`SteerOvrCmd` — Input

`on`

Commanded steer angle, in units specified by Angular units, angUnits.

`SteerCmd` — Output

Overrides the steering command with an input steering command, in units specified by Angular units, angUnits.

`SteerOvrCmd` — Input

Dependencies

To create the `SteerOvrCmd` input port, select Steering override.

Reference Control

Longitudinal

Proportional gain, Kp, dimensionless.

Dependencies

To create this parameter, set Control type to `PI`.

Proportional gain, Ki, dimensionless.

Dependencies

To create this parameter, set Control type to `PI`.

Velocity feed-forward gain, Kff, dimensionless.

Dependencies

To create this parameter, set Control type to `PI`.

Grade angle feed-forward gain, Kg, in 1/deg.

Dependencies

To create this parameter, set Control type to `PI`.

Velocity gain breakpoints, VehVelVec, dimensionless.

Dependencies

To create this parameter, set Control type to ```Scheduled PI```.

Velocity feed-forward gain values, KffVec, as a function of vehicle velocity, dimensionless.

Dependencies

To create this parameter, set Control type to ```Scheduled PI```.

Proportional gain values, KpVec, as a function of vehicle velocity, dimensionless.

Dependencies

To create this parameter, set Control type to ```Scheduled PI```.

Integral gain values, KiVec, as a function of vehicle velocity, dimensionless.

Dependencies

To create this parameter, set Control type to ```Scheduled PI```.

Grade angle feed-forward values, KgVec, as a function of vehicle velocity, in 1/deg.

Dependencies

To create this parameter, set Control type to ```Scheduled PI```.

Nominal vehicle speed, vnom, in units specified by the Reference and feedback units, velUnits parameter. The block uses the nominal speed to normalize the controller gains.

Dependencies

To create this parameter, set Control type to `PI` or `Scheduled PI`.

Anti-windup gain, Kaw, dimensionless.

Dependencies

To create this parameter, set Control type to `PI` or `Scheduled PI`.

Error filter time constant, τerr, in s. To disable the filter, enter 0.

Dependencies

To create this parameter, set Control type to `PI` or `Scheduled PI`.

Predictive

Driver response time, τ, in s.

Dependencies

To enable this parameter, Set Longitudinal control type, cntrlType or Lateral control type, controlTypeLat to `Predictive`.

Driver preview distance, L, in m. Used to determine the preview time window, T*.

Dependencies

To enable this parameter, Set Longitudinal control type, cntrlType or Lateral control type, controlTypeLat to `Predictive`.

Effective vehicle total tractive force, Kp, in N.

Dependencies

To create this parameter, set Longitudinal control type, cntrlType to `Predictive`.

Static rolling and driveline resistance coefficient, aR, in N. Block uses the parameter to estimate the constant acceleration or braking effort.

Dependencies

To create this parameter, set Longitudinal control type, cntrlType to `Predictive`.

Rolling and driveline resistance coefficient, bR, in N·s/m. Block uses the parameter to estimate the linear velocity-dependent acceleration or braking effort.

Dependencies

To create this parameter, set Longitudinal control type, cntrlType to `Predictive`.

Aerodynamic drag coefficient, cR, in N·s^2/m^2. Block uses the parameter to estimate the quadratic velocity-dependent acceleration or braking effort.

Dependencies

To create this parameter, set Longitudinal control type, cntrlType to `Predictive`.

Gravitational constant, g, in m/s^2.

Dependencies

To create this parameter, set Longitudinal control type, cntrlType to `Predictive`.

Stanley

Select this parameter to create the `RefPose` and `CurrPose` input ports.

Dependencies

To enable this parameter, Set Lateral control type, controlTypeLat to `Stanley`.

The controller computes this command using the Stanley method, whose control law is based on both a kinematic and dynamic bicycle model. To change between models, use this parameter.

SettingImplementation
`off`

Controller uses a kinematic bicycle model that is suitable for path following in low-speed environments such as parking lots, where inertial effects are minimal.

`on`

Controller uses a dynamic bicycle model that is suitable for path following in high-speed environments such as highways, where inertial effects are more pronounced.

Dependencies

To enable this parameter, Set Lateral control type, controlTypeLat to `Stanley`.

Position gain of the vehicle when it is in forward motion, specified as a positive scalar. This value determines how much the position error affects the steering angle. Typical values are in the range [1, 5]. Increase this value to increase the magnitude of the steering angle.

Dependencies

To enable this parameter, Set Lateral control type, controlTypeLat to `Stanley`.

Position gain of the vehicle when it is in reverse motion, specified as a positive scalar. This value determines how much the position error affects the steering angle. Typical values are in the range [1, 5]. Increase this value to increase the magnitude of the steering angle.

Dependencies

To enable this parameter, Set Lateral control type, controlTypeLat to `Stanley`.

Yaw rate feedback gain, specified as a nonnegative real scalar. This value determines how much weight is given to the current yaw rate of the vehicle when the block computes the steering angle command.

Dependencies

To enable this parameter, Set Lateral control type, controlTypeLat to `Stanley` and select Include dynamics.

Steering angle feedback gain, specified as a nonnegative real scalar. This value determines how much the difference between the current steering angle command, SteerCmd, and the current steering angle, CurrSteer, affects the next steering angle command.

Dependencies

To enable this parameter, Set Lateral control type, controlTypeLat to `Stanley` and select Include dynamics.

Vehicle Parameters

Forward location of tire, a, in m. Distance from vehicle cg to forward tire location, along vehicle longitudinal axis.

Rearward location of tire, b, in m. Absolute value of distance from vehicle cg to rearward tire location, along vehicle longitudinal axis.

Vehicle mass, m, in kg.

Dependencies

To enable this port, do either of these:

• Set Lateral control type, controlTypeLat to `Stanley` and select Include dynamics.

• Set Lateral control type, controlTypeLat to `Predictive`.

Cornering stiffness coefficient, CαF , in N/rad.

Dependencies

To enable this port, do either of these:

• Set Lateral control type, controlTypeLat to `Stanley` and select Include dynamics.

• Set Lateral control type, controlTypeLat to `Predictive`.

Cornering stiffness coefficient, CαR , in N/rad.

Dependencies

To enable this port, set Lateral control type, controlTypeLat to `Predictive`.

Vehicle rotational inertia, I, about the vehicle yaw axis, in N·m·s^2.

Dependencies

To enable this parameter, Set Lateral control type, controlTypeLat to `Predictive`.

Steering ratio, Ksteer. The value has no dimension.

Dependencies

To enable this parameter, select Output handwheel angle.

Tire wheel angle limit, θ, in rad.

Shift

Reverse, Neutral, Drive

Integer value of the initial gear. The block uses the initial gear to generate acceleration and braking commands to track forward and reverse vehicle motion.

Gear

Integer

Park

`80`

Reverse

`-1`

Neutral

`0`

Drive

`1`

Gear

`Gear number`

Dependencies

To create this parameter, set Shift type, shftType to `Reverse, Neutral, Drive` or `Scheduled`. If you specify ```Reverse, Neutral, Drive```, the Initial Gear, GearInit parameter value can be only `-1`, `0`, or `1`.

Time required to shift, tShift, in s. The block uses the time required to shift to generate acceleration and braking commands to track forward and reverse vehicle motion using reverse, neutral, and drive gear shift scheduling.

Dependencies

To create this parameter, set Shift type, shftType to `Reverse, Neutral, Drive`.

Scheduled

Integer value of the initial gear. The block uses the initial gear to generate acceleration and braking commands to track forward and reverse vehicle motion.

Gear

Integer

Park

`80`

Reverse

`-1`

Neutral

`0`

Drive

`1`

Gear

`Gear number`

Dependencies

To create this parameter, set Shift type, shftType to `Reverse, Neutral, Drive` or `Scheduled`. If you specify ```Reverse, Neutral, Drive```, the Initial Gear, GearInit parameter value can be only `-1`, `0`, or `1`.

Pedal position breakpoints for lookup tables when calculating upshift and downshift velocities, dimensionless. Vector dimensions are 1 by the number of pedal position breakpoints, `m`.

Dependencies

To create this parameter, set Shift type, shftType to `Scheduled`.

Upshift velocity data as a function of pedal position and gear, in units specified by the Reference and feedback units, velUnits parameter. Upshift velocities indicate the vehicle velocity at which the gear should increase by 1.

The array dimensions are `m` pedal positions by `n` gears. The first column of data, when `n` equals 1, is the upshift velocity for the neutral gear.

Dependencies

To create this parameter, set Shift type, shftType to `Scheduled`.

Downshift velocity data as a function of pedal position and gear, in units specified by the Reference and feedback units, velUnits parameter. Downshift velocities indicate the vehicle velocity at which the gear should decrease by 1.

The array dimensions are `m` pedal positions by `n` gears. The first column of data, when `n` equals 1, is the downshift velocity for the neutral gear.

Dependencies

To create this parameter, set Shift type, shftType to `Scheduled`.

Time required to shift, tClutch, in s.

Dependencies

To create this parameter, set Shift type, shftType to `Scheduled`.

Time required to engage reverse from neutral, tRev, in s.

Dependencies

To create this parameter, set Shift type, shftType to `Scheduled`.

Time required to engage park from neutral, tPark, in s.

Dependencies

To create this parameter, set Shift type, shftType to `Scheduled`.

References

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

[2] 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, Issue 6, June 1981.

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

[4] Hoffmann, Gabriel M., Claire J. Tomlin, Michael Montemerlo, and Sebastian Thrun. "Autonomous Automobile Trajectory Tracking for Off-Road Driving: Controller Design, Experimental Validation and Racing." American Control Conference. 2007, pp. 2296–2301. doi:10.1109/ACC.2007.4282788