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[WorkerBee]

NGP Settings Guide

Last updated: 2016-10-22

Setup Validation

The NGP plugin checks all setup parameters relevant for the car's performance
just before the stage is being started, and sets invalid setup parameter
values to reasonable values.
Invalid values are being logged in a file named «NGP_SetupErrors.log» located
in the «Temporary» directory specified by the operating system's settings.

The following setup parameters are being checked:
* MaxSteeringLock (maximum steering lock)
* FrontRollBarStiffness
* RearRollBarStiffness
* MaxBrakePressureFront
* MaxBrakePressureRear
* CenterDiffThrottle (locking percentage of center diff in throttle map)
* LfCenterDiffThrottle (locking percentage of center diff in LFB throttle map)
* CenterDiffBrake (locking percentage of center diff in brake map)
* LfCenterDiffBrake (locking percentage of center diff in LFB brake map)
* CenterSpeedMap (locking percentage of center diff in speed map)
* LfCenterSpeedMap (locking percentage of center diff in LFB speed map)
* FrontDiffThrottle (locking percentage of front diff in throttle map)
* FrontDiffBrake (locking percentage of front diff in brake map)
* FrontSpeedMap (locking percentage of front diff in speed map)
* RearDiffThrottle (locking percentage of rear diff in throttle map)
* RearDiffBrake (locking percentage of rear diff in brake map)
* RearSpeedMap (locking percentage of rear diff in speed map)
* CenterDiffHandbrakeRelease (percentage of handbrake to be applied to unlock the center diff)
* LeftFootBrakeThreshold (percentage of brake to be applied to use the LFB maps of the center diff)
* CenterDiffMaxTorque (maximum locking torque of the center diff, or preload torque when mechanical)
* FrontDiffMaxTorque (maximum locking torque of the front diff, or preload torque when mechanical)
* RearDiffMaxTorque (maximum locking torque of the rear diff, or preload torque when mechanical)
* StrutPlatformHeight
* SteeringRodLength
* WheelAxisInclination (inclination of the wheel/strut axis to generate camber)
* SpringLength
* SpringStiffness
* HelperSpringLength
* HelperSpringStiffness
* DampingBump (low piston speed bump damping value)
* DampingRebound (rebound damping value)
* DampingBumpHighSpeed (high piston speed bump damping value)
* BumpHighSpeedBreak (fast bump brake threshold value)
* Pressure (tyre pressure)

Differential mapping velocities are not validated, as these parameters have no
impact on the performance of the car.


Differential Settings

* mechanical and active diff torque settings

The following figure shows the setup of the differential torque of the Lancer Evo IX, which has mechanical front and rear diffs and an active center differential.




First row:
The center diff is being setup as active diff, like in genuine RBR.
You specify the absolute (!) locking torque which should be applied according to the throttle/brake/speed mapping.
For details consult the RBR manual.

Second row:
Here you specify the (absolute) preload torque of the front diff, which gets always applied, no matter the torque difference at the front wheels.
The higher the preload, the more understeer and less precise steering.

Third row:
Here you specify the (absolute) preload torque of the rear diff, which gets always applied, no matter of the torque difference at the rear wheels.
The higher the preload, the more oversteer and a happier tail.

* active diff lock mapping

Here the setup is like in genuine RBR, see RBR's manual for details.

The following figure shows the mapping of an active center diff:




The following figure shows the mapping of an active center diff for left-foot-braking:





* mechanical rear diff locking

The following figure shows the setup of the locking of a mechanical rear differential (eg. Lancer Evo IX, Opel Ascona 400, DS3 R5).




Here we have high locking percentages to make the car more tail-happy and to have lots of traction.
If you are suffering from oversteer you should reduce these values.

Only values in the first row ("0% Throttle", "0% Brake") apply.
All other values, including the "Speed" mapping, are ignored by the NGP plugin.

Throttle:
Here you specify the locking of the differential as a percentage when applying power (=throttle, acceleration).
Specifying 0% here means to have an open differential.
The less the locking percentage, the less traction, but the more controllable the axle.

Brake:
Here you specify the locking of the differential as a percentage when coasting (applying brakes, deceleration).
Specifying 0% here means to have an open differential.

Speed:
Ignored.

These values' limits - just as an example here, different vehicles will have different values - are taken from the following file entries:

Code:

CenterDiffMapLockPctMin_NGP      0    CenterDiffMapLockPctMax_NGP      100    FrontDiffMapLockPctMin_NGP       0    FrontDiffMapLockPctMax_NGP       50    RearDiffMapLockPctMin_NGP        0    RearDiffMapLockPctMax_NGP        75

If you specify invalid or out-of-range values, these values will be checked and reset to the maximum value before you are starting the stage.


* mechanical front diff locking

The following figure shows the setup of the locking of a mechanical front differential (eg. Lancer Evo IX, DS3 R3).




* mechanical rear diff torque setting (of a rear wheel drive or AWD car)

The following figure shows the diff torque settings of an RWD car:




Center and front diff are disabled, you can deduce this from the "0.000000" presets.

The rear diff torque specifies the absolute preload locking torque.
Usually you do not need much preload, as this would only apply e.g. when stuck in a ditch and one wheel spins, with only one wheel having grip.
The higher the preload value, the less smooth the axle will behave.


Suspension Settings

Helper Spring

When setting up the suspension you should be aware of a nasty RBR peculiarity, which is related to the helper spring.

The built-in setup editor only allows for editing the length of the helper spring, but not the helper spring's block length (also called minimum spring length).

And even worse, the actual value of the helper spring's block length is not shown, so you have to guess.
You might think, well no problem, WorkerBee comes to the rescue ... yes, correct, but this is only half of the story.

The following figure shows what I am talking (writing?) about:



You see a screenshot of RBR in windowed mode, with RBR's built-in setup editor to the left and my SetupManager as overlay to the right.

The front left marked up in blue, the rear left in green. Note that you only see the block length in the SetupManager's window.

The trap with these settings is that RBR's setup editor uses 40% of the helper spring length as the block length, and this block length, in addition to the main spring length and helper spring length of course, is being used to calculate the suspension geometry.
So the values shown for camber, toe, caster and ride height are only valid for this exact helper spring block length.

But, RBR uses the actual, configured value from the LSP setup file when calculating the suspension geometry while driving.

So, unless you accidentially have configured the block length to be 40% of the helper spring length, you for sure will not get the correct toe, camber etc. values while driving.

The only solution to this issue is to manually edit the LSP setup files, calculating the block length yourself and put it into the right places in the file.
Or you could use my SetupManager, which automagically calculates and sets the helper spring's block length accordingly.
So you actually have the same suspension geometry while editing and driving.

Important change in NGP 3.0:
The plugin now automatically sets the helper spring minimum length to 40% of the configured helper spring length before starting the stage!
Hence no need to set the helper spring length anymore by yourself.


Dampers

One important setting of the damper setup is the fast bump threshold ("F Bump Threshold" in RBR's built-in setup editor), as is shown in the following figure:




The fast bump threshold is the damper piston velocity (in m/s) at which the damping value changes from "Bump" to "Fast Bump".

Simple explanation:
The low speed bump value is mainly responsible for controlling the unsprung weight of the vehicle, i.e. the wheels.
The rebound value controls the transitional roll of the car body on turn-in and turn-out of a corner.
The fast bump value is responsible for handling the bigger impacts like bumps and potholes, and the landing after a jump.
As the main goal of the suspension is to keep the car controllable, one usually sets a lower fast bump value than low speed bump value, because then the suspension will settle faster.

If you are not satisfied with this explanation read a good book or one of those magic setup guides out there on the net.
If you know better: why do you actually read this SetupGuide ?

Reasonable values for the fast bump threshold are in the range from 0.05 m/s to 0.30 m/s.
Yes, this seems to be very low, but the leading damper manufacturers can't be all wrong, and in fact the velocity of the body shell in transient maneuvers is quite low.

The following figure shows an exerpt of the telemetry recording of the Ascona on Harwood Forest with the damper piston velocity in m/s at the y-axis (the x-axis is just the time step):




Note that there is always some movement, and the peaks are located roughly at -0.25 to +0.25.

At step ~5800 you can see that the damper is fully depressed, comes to rest (velocity ~0) and then compressed at a very high speed of -2 m/s.

This matches the corresponding spring deflection, which you can see in the following figure (x: time step, y: spring deflection in m):




The normal deflection of this left rear spring is 0.291m, so at step 5800 we have an expanded spring at ~0.390m, which is then compressed very fast to about 0.220, and the damping prevents it from depressing too fast.

The following figures shows the details from steps 5750 to 6000 (spring and damper forces, damper piston velocity):





Enhanced Suspension

Some types of cars do support enhanced suspension settings. This includes 4-way damping and bump stop settings.
If the car you are setting up supports this feature, you will see the following dialog:




Note that the standard "Dampers" is greyed out, but a new "Dampers (Enhanced)" menu item is shown.
Another new menu item is "Bump Stop Settings".

"Dampers (Enhanced)" opens the following menu page:




"Bump Stop Settings" opens the following menu page:




Here you specify whether to use linear or progressive bump stops.

"Bump Stops" opens the following menu page to edit the bump stop setup values:





Input Controller Settings

The NGP plugin allows for configuring input filters of the handbrake and the clutch, as you see in the following RBR menu (Options --> Controls --> Filter Settings):




After choosing "Handbrake" or "Clutch" you have to select the type of input device:




Usually such filter settings only make sense if you have a digital device (button, shift lever of G25 etc.).
Based on your controller type (analog or digital) RBR chooses the appropriate filter settings, so only one of these filter settings actually applies.

No matter the device type, the following filter settings menu looks the same:




This is a working example for the handbrake filter settings.
The more flat the curve, the less braking forces will apply initially after pulling the handbrake lever.
The higher the rise rate, the more time passes before the handbrake applies fully.
Usually it should be best to leave the fall rate at "Instant", otherwise your wheels may still lock up although you have already released the handbrake lever.

You have to try and play with these settings to suite your driving style.
For sure after setting the filter you have to adapt your handling of the handbrake, as the timing will be different in when and how long to actually pull the handbrake to make the car turn.


Additional Settings

To improve the perception of the car behaviour NGP provides some parameters in the "RichardburnsRally.ini" file.

In the section [NGP] you will find the following parameters:

Skid Sound

Code:

tarmacSkidSoundThreshold=100 skidSoundThreshold=100

These specify the slip percentage threshold to play the skid sound for tarmac and other surfaces, respectively.
Here standard RBR uses a value of 125, which is too high to actually help in feeling the tyre slip.
Simplified, this value is the percentage of the peak force the tyre is currently using.
If the peak relative slip percentage is less than 100%, you can still apply more forces (throttle, brake, steering).
If you exceed 100%, the available tyre forces will decrease.

RBR lets you "feel" the tyre slip by playing a so called skid sound.
This is where these settings apply.
If you e.g. set the value to 95, you hear the skid sound as soon as you reach 95% of the peak tyre force.
If you set it to 105, you hear the skid sound maybe too late to be able to react to a spinning vehicle.

Gear Change Indicator

Code:

gearChangeIndicatorDeltaRPM=200

This value specifies the delta RPM (engine revs) for changing the color of the gear shift indicator.
Colors are as follows:
white - white
green - white
green - green
yellow - green
yellow - yellow
red - yellow
red - red

Double red light appears above (upshift - 25) for all gears except the last, where (rpm limit - 25) applies.
You have to shift up to the next gear as soon as double red light appears.

The higher the configured value, the wider the total RPM band will be.

E.g. delta=200, upshift=7000:

Code:

6000          6200          6400          6600          6800         6975 --------------+-------------+-------------+-------------+-------------+------------+--------------  white-white    green-white   green-green  yellow-green  yellow-yellow  red-yellow    red-red

The indicator uses the "Gear«N»Upshift" values of the engaged gear from the "common.lsp" physics file to select the colors.
So you no longer have to worry when to shift, as this usually will be different for each car.
Standard RBR used to use a hard coded value of 5500 to show double red if above, white if below, which may have been accurate for those old WRC cars.

Looks like this:





... more to come.
_________________
NGP 6 - It Doesn’t Just Raise the Bar, It is the Bar!