3D Spline Road

The 3D Spline Road allows racetracks, parking spaces and various other 3-Dimensional smooth road surfaces, to be defined. When a road surface, with a curvature less than that of the tire is present, it is defined as a smooth road.

Additionally, the 3D Spline Road allows you to model 3-Dimensional road obstacles, placed atop the underlying smooth road surface. The centerline, width, bank angle, and left and right friction levels define the road surface.

Coordinates of the road centerline can be specified by to construct any line in 3-Dimensional space. A flat cross-section is assumed, for which the width and bank angle can be specified for each data point. Additionally, friction levels for left and right road sides can be specified.

3D Spline Road Obstacle Types

POTHOLE
RAMP
PLANK
ROOF
SINE
SWEEP

Placing an Obstacle

The obstacles are based on “distance travelled “ methodology. The keyword START in each obstacle tells the relative distance of start of the obstacle to the spline’s coordinate where it is mentioned in the table. So by mentioning 0 it means the obstacle starts immediately. In the attached 3D spline road sample OBSTACLE1 starts at x,y = 5,0 as its START value is 0.

Keywords

Global Keywords

The keywords which are required for all obstacles are:


Keyword	Description
START	The start position of the obstacle. '0.0 0.0 0.0' A local coordinate system. '0.0' A distance-defined obstacle.
LENGTH	The length of the obstacle. LENGTH is to be defined along the length of the road.
ROAD_TYPE	The obstacle type.

Note: The above data must be specified in the .rdf file, independent of the type of obstacle.

POTHOLE

A single pothole of rectangular shape.

If ROAD_TYPE = 'POTHOLE', then the 'DEPTH' keyword must be specified. Depth can be positive indicating a depression or negative indicating a bump in the road.

Add a table for pothole like the one below with corresponding terms:


Keyword	Description
DEPTH	Positive / negative depth of the obstacle.

RAMP

A single ramp, either rising or falling.

If ROAD_TYPE = 'RAMP', then the following parameters must be specified:


Keyword	Description
HEIGHT	Height of the ramp.
SLOPE	Slope of ramp in deg(°).

PLANK

A single plank perpendicular, or in oblique direction relative to x-axis, with or without bevel edges.

If ROAD_TYPE = 'PLANK', then the following parameters must be specified:


Keyword	Description
HEIGHT	Height of the plank.
BEVEL_EDGE_LENGTH	BEVEL_EDGE_LENGTH < 0, 3D Spline Road uses rounded corners instead of beveled edges. In this case, the radius of the corner is BEVEL_EDGE_LENGTH.

ROOF

A single roof-shaped, triangular obstacle.

If ROAD_TYPE = 'ROOF', then the following parameters must be specified:


Keyword	Description
HEIGHT	Height of the roof.
LENGTH	Length of the base of the triangular roof.

SINE

Sine waves with constant wave length.

If ROAD_TYPE = 'SINE', then the following parameters must be specified:


Keyword	Description
AMPLITUDE	Amplitude of the sine wave (A).
WAVE_LENGTH	Wave length of the sine wave ().
START	Start of the sine waves (travel distance) (s_s).

The road profile height z, is given by:

SWEEP

If ROAD_TYPE = 'SWEEP', then the following parameters must be specified:


Keyword	Description
AMPLITUDE_AT_START	Amplitude of the sine wave at start ()
AMPLITUDE_AT_END	Amplitude of the sine wave at end ()
WAVE_LENGTH_AT_START	Wave length of the sine wave at start ().
WAVE_LENGTH_AT_END	Wave length of the sine wave at end ().
SWEEP_TYPE	If SWEEP_TYPE = 0, then the frequency changes linearly. If SWEEP_TYPE = 1, then the frequency changes logarithmically. Depending on the value of SWEEP_TYPE, the road profile height is given by the following functions: Linear Sweep The frequency changes linearly with distance s. The road profile height z is given by: Logarithmic Sweep With every cycle, the wavelength decreases by a constant factor. The road profile is given by: where, is the distance at which, theoretically, an infinitely high frequency is reached, with respect to the start s_s.

3D Spline Road Property File

MDI_HEADER

The first block of data [MDI_HEADER] describes the TeimOrbit file:

[MDI_HEADER]
FILE_TYPE = 'rdf'
FILE_VERSION = 5.00
FILE_FORMAT = 'ASCII'
{COMMENTS}
'User entered comments go here'


Keyword	Description
FILE_TYPE	The file type.
FILE_VERSION	The version of file; to be changed when modifications to this file are made.
FILE_FORMAT	The format of the data; for TiemOrbit this is always ASCII.
{COMMENTS}	Descriptive comments about the file, such as what road this represents, when the data was acquired, etc.

Units details

The [UNITS] block defines the units for the road:

[UNITS]
LENGTH	= 'meter'
FORCE 	= 'newton'
ANGLE 	= 'radians'
MASS 	= 'kg'
TIME 	= 'sec'

[UNITS]


Keyword	Description
LENGTH	Unit of length.
FORCE	Unit of force.
ANGLE	Angle in degrees or radians.
MASS	Unit of mass.
TIME	Unit of time.

Model details

The [MODEL] block defines the road model and version for the road:

[MODEL]
METHOD	= '3D_SPLINE'
VERSION 	= 1.00

[MODEL]


Keyword	Description
METHOD	3D_SPLINE

Global Parameters

The [GLOBAL_PARAMETERS] block defines parameters applicable to the entire road:

[GLOBAL_PARAMETERS]
MU_LEFT = 0.5
MU_RIGHT = 0.6
WIDTH = 5.000
BANK = 0.0

[GLOBAL_PARAMETERS]


Keyword	Description
MU_LEFT	Road friction value on the left side of the road with respect to the centerline. Specifying road friction under [GLOBAL_PARAMETERS] overwrites any specification of road friction values in the [DATA_POINTS] block.
MU_RIGHT	Road friction value on the right side of the road with respect to the centerline. Specifying road friction under [GLOBAL_PARAMETERS] overwrites any specification of road friction values in the [DATA_POINTS] block.
WIDTH	Width of the road. If user specifies WIDTH, it takes precedence over the WIDTH value specified in the [DATA_POINTS] block. Even if this parameter is set, user must specify the WIDTH parameter in [DATA_POINTS]. If this parameter is not required, then user can omit it from the road data file (.rdf).
BANK	Slope angle of the road around its centerline in each data point. Zero bank means a horizontal width line. A positive value specifies a slope along a clockwise direction in ISO-reference frame. If you specify this dimension, then it will take precedence over the BANK value specified in the [DATA_POINTS] block. Even if you set this dimension, they must specify a BANK value. If this dimension is not required, then you can omit it from the .rdf file.

Data Points Information

The [DATA_POINTS] block contains the road information in a tabular form.

The following information needs to be supplied for each entry:

[DATA_POINTS]
{ X Y Z WIDTH BANK MU_LEFT MU_RIGHT OBSTACLE}

[DATA_POINTS]


Keyword	Description
X	The X coordinate of sampled road data point.
Y	The Y coordinate of sampled road data point.
Z	The Z coordinate of sampled road data point.
WIDTH	The width of road at the sampled point.
BANK	The angle of road at the sampled point; a positive value specifies a slope along a clockwise direction in ISO-reference frame.
MU_LEFT	Road friction on the left side of the road with respect to the centerline at the sample point.
MU_RIGHT	Road friction on the right side of the road with respect to the centerline at the sample point.
OBSTACLE	The name of block that contains the obstacle information. This entry is optional.