Predefined Paths

There are several predefined paths that can be provided as a demand path for Altair Driver.

CONSTANT RADIUS

[FEEDFORWARD_STEERING]
TAG = 'FEEDFORWARD'
LOOK_AHEAD_TIME = 0.5
PATH = 'PREDEFINED' 
BLOCK = ‘PATH'
INTEGRATION_STEP_SIZE = 0.01 

[PATH]
TYPE = 'CONSTANT_RADIUS'
RADIUS = 40
INITIAL_STRAIGHT = 10
ENTRY_ANGLE = 0.39

The vehicle follows the path as shown in the figure below:

[CONSTANT RADIUS]
`TYPE`	Attr - string	REQUIRED <CONSTANT_RADIUS>
`RADIUS`	Attr - real	REQUIRED Radius of the circle.
`INITIAL_STRAIGHT`	Attr - real	REQUIRED Length of the initial straight before entering the turn.
`TURN`	Attr - string	OPTIONAL LEFT Vehicle turns to the left. RIGHT (Default) Vehicle turns to the right.
`ENTRY_ANGLE`	Attr - real	OPTIONAL If provided, a transient length is added after the straight where the curvature is increased linearly to the final curvature before entering the constant radius path. Entry angle defines the angle with respect to the straight section at which the vehicle enters into the Constant Radius path. The greater the entry angle, the longer the transient section.

SLALOM

[FEEDFORWARD_STEERING]
TAG = 'FEEDFORWARD'
LOOK_AHEAD_TIME = 0.5
PATH = 'PREDEFINED' 
BLOCK = ‘PATH'
INTEGRATION_STEP_SIZE = 0.01

[PATH]
TYPE = 'SLALOM'
NUMBER_OF_CONES = 3
DESIRED_CG_LATERAL_DISP = 3
CONE_SPACING = 50
RECOVERY_LENGTH = 20
INITIAL_STRAIGHT = 20

[SLALOM]
`TYPE`	Attr - String	REQUIRED <SLALOM>
`NUMBER_OF_CONES`	Attr - int	REQUIRED Number of cones.
`DESIRED_CG_LATERAL_DISP`	Attr - real	REQUIRED Desired CG lateral displacement.
`CONE_SPACING`	Attr - real	REQUIRED Distance between adjacent cones.
`INITIAL_STRAIGHT`	Attr - real	REQUIRED Straight section before entering slalom.
`RECOVERY_LENGTH`	Attr - real	REQUIRED Straight section after completing slalom.
`ATTACK_DIRECTION`	Attr - String	OPTIONAL First cone if attacked from the specified direction. Default is RIGHT.

SINGLE LANE CHANGE

[FEEDFORWARD_STEERING]
TAG = 'FEEDFORWARD'
LOOK_AHEAD_TIME = 0.5
PATH = 'PREDEFINED' 
BLOCK = 'PATH'
INTEGRATION_STEP_SIZE = 0.01 

[PATH]
TYPE = 'SLC'
LATERAL_OFFSET = 3
SECTION_1 = 20
SECTION_2 = 20
SECTION_3 = 50
TURN_DIRECTION = 'LEFT'
ENTRY_ANGLE = 0.04963         
MAX_CURVATURE = 1.42857e-02

[SINGLE LANE CHANGE]
`TYPE`	Attr - String	REQUIRED <SLC>
`LATERAL_OFFSET`	Attr - int	REQUIRED Lateral distance between two lanes.
`SECTION_1`	Attr - real	REQUIRED First lane distance in longitudinal direction.
`SECTION_2`	Attr - real	REQUIRED Distance between lanes in longitudinal direction.
`SECTION_3`	Attr - real	REQUIRED Second lane distance in longitudinal direction.
`TURN_DIRECTION`	Attr - real	OPTIONAL LEFT Vehicle turns to the left. RIGHT (Default) Vehicle turns to the right.
`ENTRY_ANGLE`	Attr - real	OPTIONAL If provided, it enables path easements around the lane corners. ENTRY_ANGLE is the angle with respect to straight lane section at which path easement section goes to maximum curvature and continues before reducing the curvature to zero on next lane. Used for first and second lane corners.
`MAX_CURVATURE`	Attr - real	OPTIONAL If provided, it enables path easements around the lane corners. MAX_CURVATURE is the maximum curvature of the path easement section at the lane corners. Used for first and second lane corners.

DOUBLE LANE CHANGE

[FEEDFORWARD_STEERING]
TAG = 'FEEDFORWARD'
LOOK_AHEAD_TIME = 0.5
PATH = 'PREDEFINED' 
BLOCK = ‘PATH'
INTEGRATION_STEP_SIZE = 0.01 
[PATH]
TYPE = 'DLC'
SECTION_1 = 20
SECTION_2 = 20
SECTION_3 = 20
SECTION_4 = 20
SECTION_5 = 50
TURN_DIRECTION = 'LEFT'
ENTRY_ANGLE_1 = 0.04963         
MAX_CURVATURE_1 = 1.42857e-02         
ENTRY_ANGLE_2 = 0.04963         
MAX_CURVATURE_2 = 1.42857e-02

[DOUBLE LANE CHANGE]
`TYPE`	Attr - String	REQUIRED <DLC>
`LATERAL_OFFSET`	Attr - int	REQUIRED Lateral distance between two lanes.
`SECTION_1`	Attr - real	REQUIRED First lane distance in longitudinal direction.
`SECTION_2`	Attr - real	REQUIRED Distance between first and second lane in longitudinal direction.
`SECTION_3`	Attr - real	REQUIRED Second lane distance in longitudinal direction.
`SECTION_4`	Attr - real	REQUIRED Distance between second and third lane in longitudinal direction.
`SECTION_5`	Attr - real	REQUIRED Third lane distance in longitudinal direction.
`TURN_DIRECTION`	Attr - real	OPTIONAL LEFT Vehicle turns to the left. RIGHT (Default) Vehicle turns to the right.
`ENTRY_ANGLE_1`	Attr - real	OPTIONAL If provided, it enables path easements around the lane corners. ENTRY_ANGLE_1 is the angle with respect to straight lane section at which the path easement section goes to maximum curvature and continues before reducing the curvature to zero on next lane. Used for first and second lane corners.
`MAX_CURVATURE_1`	Attr - real	OPTIONAL If provided, it enables path easements around the lane corners. MAX_CURVATURE_1 is the maximum curvature of the path easement section at the lane corners. Used for first and second lane corners.
`ENTRY_ANGLE_2`	Attr - real	OPTIONAL If provided, it enables path easements around the lane corners. ENTRY_ANGLE_2 is the angle with respect to straight lane section at which the path easement section goes to maximum curvature and continues before reducing the curvature to zero on next lane. Used for third and fourth lane corners.
`MAX_CURVATURE_2`	Attr - real	OPTIONAL If provided, it enables path easements around the lane corners. MAX_CURVATURE_2 is the maximum curvature of the path easement section at the lane corners. Used for third and fourth lane corners.