AutomobileLaneChange:

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   Implements lane change control by pointing the wheels at the target.
   Generates a steering angle demand and torque demand.
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   Form:
   passer = AutomobileLaneChange( passer, dY, v, gain )
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   Inputs
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   passer	(1,1)  Car data structure
                   .mass      (1,1) Mass (kg)
                   .delta     (1,1) Steering angle (rad)
                   .r         (2,4) Position of wheels (m)
                   .cD        (1,1) Drag coefficient
                   .cF        (1,1) Friction coefficient
                   .torque	   (1,1) Motor torque (Nm)
                   .area      (1,1) Frontal area for drag (m^2)
                   .x         (6,1) [x;y;vX;vZ;theta;omega]
                   .errOld    (1,1) Old position error
                   .passState (1,1) State of passing maneuver
   dX      (1,1)  Lead in x
   dY      (1,1)  Relative position in y
   dV      (1,1)  Relative velocity in x
   gain    (1,3)  Gains [position velocity position derivative]

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   Outputs
   -------
   passer	(1,1)  Car data structure with updated fields:
                   .delta 
                   .errOld
                   .torque

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