Predefined Paths

[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:


Figure 1.
[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.

Similarly,

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


Figure 2.
[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.

Path as sequence of straights and arcs:

[FF_STEER_CONTROLLER]                     
TAG                     = 'FEEDFORWARD'   
LOOK_AHEAD_TIME         = 0.5   
PATH                    = 'SEQUENCE_OF_ST_CRV' 
BLOCK                   = 'PATH'     
INTEGRATION_STEP_SIZE   = 0.010000        
AGGRESSIVE              = 'TRUE'     
[PATH]                                
{KEY        PAR0              PAR1}   
'ST'        20.000000         0.000000
'ARC'       40.000000        -6.283184
This creates a path that is sequence of a straight (20 m) and arc (Radius 40 m, Angle 6.283184 rad. clockwise).


Figure 3. 
[PATH]                                 
{KEY        PAR0              PAR1}    
'ST'        17.033191         0.000000
'ARC'       20.000000         -0.148890
'ST'        17.240436         0.000000
'ARC'       20.000000         0.148890
'ST'        17.033191         0.000000


Figure 4.