Feedback Traction Controller  PID Controller
A ProportionalIntegralDerivative (PID) controller is a feedback controller that computes a vehicle input using the error, the integral of error, and the rate of change of error between a desired vehicle response and the actual vehicle response.
To use a PID control you enter proportional (KP), integral (KI), and derivative (KD) gains, the type of desired response (for example, longitudinal speed or acceleration), and reference the desired response (for example, a table of speed vs time). The Altair Driver then applies the ProportionalIntegralDerivative (PID) control law to calculate the throttle and brake signals.
Algorithm
Parameters  

Demand Signal  U 
Feedback or response signal  X 
Error  e 
Proportional gain  Proportional gain 
Derivative gain  Derivative gain 
Integral gain  Integral gain 
Integral control flag  Integral control flag 
Integral band  Integral band 
Driver throttle output  O _{throttle} 
Driver brake output  O _{brake} 
Drive Ratio  
Gear Ratio 
Types
 VELOCITY CONTROL  Demand signal is a velocity profile with time or distance traveled as independent variable.
 ACCELERATION CONTROL  Demand signal is an acceleration profile with time or distance traveled as independent variable.
 Demand signal can be constant, expression driver, user defined curve, or MotionView Signal (similar to Open Loop controller).
[LONG_PID_CONTROLLER]
TAG = 'PID'
TYPE = 'FOLLOW_VELOCITY'
DEMAND_SIGNAL = 'DEMAND_SPEED'
I_ACTIVE_BAND = 2
KP = 100
KD = 20
KI = 10
INITIAL_ERROR = 5
[FEEDFORWARD LONGITUDINAL CONTROLLER]  

TAG  Attr  string  REQUIRED <PID > 
Attr  string  OPTIONAL


DEMAND_SIGNAL  Attr  string  REQUIRED Block name that contains the demand signal. See the Demand Signal Block topic to learn more about all of the available methods. 
I_ACTIVE_BAND  Attr  real  OPTIONAL
If absent:

KP  Attr  real  OPTIONAL
If absent:

KD  Attr  real  OPTIONAL
If absent:

KI  Attr  real  OPTIONAL
If absent:

INITIAL_ERROR  Attrreal  OPTIONAL
If absent:
