Straight Line Braking
A Straight line Braking event simulates a vehicle slowing in a straight line.
The steering wheel is normally held fixed. The Altair Driver applies torque at the wheels to slow the vehicle and appropriate output requests are included. The Straight-line Braking event follows the ISO +21994-2007 - Passenger cars - Stopping distance at straight-line braking with ABS - Open loop test method.
The Straight-line Braking event is supported by the Cars & Small Trucks, Heavy Trucks, and Two-Wheeler vehicle libraries. Automated output reports are available to plot the results.
Parameters
Parameter Name | Description |
---|---|
Units | Describes the Length, Velocity, and Acceleration units.
|
Velocity | Initial vehicle velocity. |
Desired deceleration | Desired Acceleration rate of the vehicle. |
Brake start time | Time at which the vehicle deceleration starts. |
Transient time | Time period for which the vehicle decelerates. |
Controller Settings
- Non-leaning events (Cars/Trucks)
- LONGITUDINAL – TRACTION CONTROLLER SETTINGS
- Use additional control: Enables the additional feedback control for the traction
control. The gains for the controller can be edited by toggling this check
box.
Kp Proportional gain for the feedback PID controller Ki Integral gain for the feedback PID controller Kd Derivative gain for the feedback PID controller
- Use additional control: Enables the additional feedback control for the traction
control. The gains for the controller can be edited by toggling this check
box.
- Leaning events (Two-wheelers)
- LONGITUDINAL – TRACTION CONTROLLER SETTINGS
- Use additional control: Enables the additional feedback control for the traction
control. The gains for the controller can be edited by toggling this check
box.
Kp Proportional gain for the feedback PID controller Ki Integral gain for the feedback PID controller Kd Derivative gain for the feedback PID controller
- Use additional control: Enables the additional feedback control for the traction
control. The gains for the controller can be edited by toggling this check
box.
Signal Settings
Use the signal settings to set minimum, maximum, smooth frequency and initial values for Steering, Throttle, Brake, Gear, and Clutch signals output by the driver.
The smoothing frequency is used to control how fast the Driver changes signals. Only closed loop control signals from the Driver are smoothed. Open loop signals are not smoothed.
Road Settings
- Flat Road
- Uses a flat smooth road for the event with no required road file.When the Flat Road is selected, the Graphics Setting option is available with the following parameters:
- View path centerline: Enables the visualization of the event path.
- This check box is disabled for open loop events without a path.
- View grid graphics: Enables the visualization of the road grid graphics.
- When view grid graphics check box is toggled, road grid parameters can be edited in the Grid Settings tab.
Grid length Defines the length of the road. Enter a positive value in the model units. Grid Width Defines the width of the road. Enter a positive value in the model units. Grid X offset Gives a distance offset to the road graphics in the longitudinal direction. Enter a positive value in the model units. Grid Y offset Gives a distance offset to the road graphics in the lateral direction. Enter a positive value in the model units.
- View path centerline: Enables the visualization of the event path.
- Road File
- The road file option enables the selection of a road file to be used in the event. Using this option, all tires in the model consider the event specified road file instead of the file included in the tire entities.
- Tires
- Using Tire as road selection option, the road file specified in the tire entity is used in the events simulation.
Automated Output Report
Report Name | Report Signals |
---|---|
Vertical Tire Forces |
|
Longitudinal Tire Forces |
|
Tire Longitudinal Slip |
|
Vertical Longitudinal Deceleration and Velocity |
|
Suspension Travel |
|
Steering Wheel Angle and Torque |
|
Brake Torque |
|
Pitch, Front Dive and Rear Lift |
|
Vehicle Tire Forces |
|
Axle Loads |
|
Longitudinal Load Transfer |
|