Optimizing the track guidance controller

To optimize the track guidance controller, proceed as follows:

Optimizing the encoder signal

  1. Increase the filter time tFiltertimeActualOffset until the sensor signal no longer displays discontinuity.
  2. Set the limit value for the extrapolation rNoiseLimitforExtrapolation so that the value is greater than the background noise when the vehicle is stationary.
    • As soon as the current offset is greater than the specified value, extrapolation is undertaken. If you do not want extrapolation, you can set a value greater than the maximum sensor offset.

Setting controller parameters for distinctive speeds

To optimize the controller parameters, gradually increase the speed and adapt the controller parameters for the speeds.

Observe the following:

  • rSetPointOffset must not be too large.
  • You should avoid increasing the amplitude of the vehicle’s track deviation ("rocking up").
  • You should avoid rocking up the torque (can be seen from how the current controller behaves).
  • A small value for the time constant TN ensures a more stable control response when cornering, however the vehicle is then more likely to rock (rocking over).
  • The amount by which the vehicle rocks can be reduced using an additional D component. However the torque noise then increases.

Proceed as follows:

  1. Start with the following parameter settings:
    • large time constant TN
    • small proportional factor KP
    • TV = 0
  2. Check whether there is continuous control deviation during the control response. If there is, take further steps to optimize the control response.
  3. Increase KP until the vehicle starts to visibly rock.
  4. Decrease KP until the control response is stable.
  5. If the way in which the vehicle is driving is not satisfactory, reduce KP and increase TN.
  6. As an option, you can add the D component. The encoder signal should not display any discontinuity and may have to be filtered.