DJI Wookong Parameter Adjustments and EffectsWritten by Jonathan Malory
When you change any of the parameters it is important to test your multirotor under safe conditions:
1. Make sure your multirotor is mechanically set up properly, ensuring there are no loose connections, bad solder joints anywhere (including the flight battery connectors), propellers are undamaged and not cracked and that your motors move freely and smoothly. If there are any mechanical shortcomings in your setup you will not be able to make an accurate observation of the effects of your parameter alterations. For example, your multi rotor may flip of act erratically, at which point many people will instantly assume that the Wookong flight controller is at fault - but flips are very rarely caused by the DJI Wookong (I've never had this happen) and are frequently caused by a loose prop, a bad ESC connection or a faulty motor. If you record your test flights and your multi rotor flips it will be easier to figure out which side of the multirotor had problems. For instance, if it flips up and over from the right it is likely that something on the left is failing and you can start your investigations in that area.
2. Be sure that your multirotor is properly connected to the Wookong and that all wires go to the correct places according to the manual.
3. Conduct test with new parameters outside with zero wind if possible, or in a large indoor space. It is easier to tell how effective your adjustments have been if there is no interference from excessive winds initially.
4. Make sure you have plenty of space for your test flight, with no people near to you and enough space to safely crash land if something goes wrong or something unexpected happens.
5. It is recommended that you lift off in Atti mode to begin with as Manual mode can be unpredictable, especially if you've just altered the parameters. Besides, a lot of the parameters pertain to Atti mode anyway, so it makes sense to test the flight characteristics in this mode.
In many cases you will not need to adjust any of the autopilot parameters, especially if you're flying an average sized mulitirotor frame size - say like the Flamewheel quads and hexas, or the xAircraft quad or hexa.
However, if you're flying something larger and heavier it can be helpful to tweak the parameters a little.
It is best if you set all the parameters to 100% as a starting point. It is also incredibly useful to have a laptop or netbook or tablet you can take to the field with you so you can adjust the parameters in situ. However, you can assign some of the parameters to a dial or slider (poti (potentiometer) on your radio.
It is recommended that you start with the DJI Wookong Basic Parameters, because if you don't have these setup nicely in the first place it won't help at all if you adjust the other Advanced Parameters.
In the AutoPilot of your DJI Assistant Software in the Basic Parameters section you will see the heading for Pitch - Roll - Yaw - Vertical, which pretty much describes all the directions a multirotor is able to move in.
Pitch and Roll
Pitch is forward/backwards movement and roll is left/right movement. It is these planes you will most want to get right to achieve stability, especially for camera work. While testing your pitch and roll parameter alterations it is essential that you do so in a place where there is no wind disturbance, otherwise you will not be able to tell if your multirotor is reacting to the wind or your settings. Also, make sure you are conducting tests in Atti mode as Manual mode is not really effected and GPS Position Hold mode will confuse your visual findings.
The best way to test the Pitch and Roll settings live is to assign them to a dial or slider on your radio - in your DJI Assistant Software you will find in the AutoPilot section that there are drop down menus below Pitch - Roll - Yaw - Vertical that say INH. If you change Pitch to x2 and Roll to x3 you can run a lead from x2 and x3 on the Wookong Controller to spare channels on your receiver then assign those channels to a variable control on your radio. If you don't have enough channels you can adjust one at a time, or keep stopping and plugging your multirotor into a PC and manually adjust the settings.
It's best to start at 100% on everything. If your multirotor oscillates a lot, wobbling like a UFO from an old movie, you probably need to adjust your Pitch and/or Roll settings down a bit, say to 85% and see how she flies then. In most cases 100% will be pretty nice.
Assuming you have 100% on all your settings and your craft does not oscillate wildly in no wind, you can lift off from the ground in Atti mode to about two meters or just over six feet then push the elevator stick forward and release it to see how your multirotor reacts. If you feel that your multirotor is too slow to return to a level flying position you can turn the Pitch dial on your radio up a bit (or alter the settings via a computer up by 10 to 15%) and see how she reacts then. Eventually, if you dial up high enough, your multirotor may wobble around the centre, level spot. You want it set so that it does not wobble around centre, so adjust your setting back down a touch until your multirotor does not oscillate on its pitch axis when performing this manoeuvre.
Repeat the above for aileron movements, that is left to right.
Yaw or Tail Movement
In most cases your multirotor will not have a tail, though perhaps a tricopter or Y-6 has that kind of feel, but the principles of this and that of an rc helicopter's heading hold tail gyro are pretty much the same. When not touching the rudder stick you want your multrotor to keep pointing in the same direction. So upping the Yaw parameters will make your multirotor more adamant about trying to stay pointing the same way.
However, a multirotor yaws by altering the speed of opposite spinning propellers to increase the torque in one direction or the other so you won't be able to get it to wobble like a helicopter does with its tail rotor fighting the main rotor, but you may notice that the starts and stops are more abrupt as you get the settings higher - so this setting is more about your personal choices, for instance you may want the yaw to be a little soft on stopping if your filming from your multirotor, or you may want it to be sharper if you're stunt flying. Furthermore, if you find that your multirotor yaws more keenly one way that the other it could be that not all your motors are pointing directly upwards, say if you bent a boom slightly or have it inserted slightly off centre.
There are two aspects to your DJI Wookong's ability to maintain altitude. The first is keeping to the same height when hovering on the spot, and the second is maintaining the same height when flying in a straight line.
With this setting you can test it in Atti Mode by hovering a couple of meters (six feet) off the ground and see how well your multirotor keeps its position, then pushing up a couple more meters and setting the throttle stick back to centre and see how keenly it goes back to hovering at the same height. Chances are it will be just fine at 100%. However you can adjust the parameters up and see how you feel.
Attitude, not to be confused with Altitude, is concerned with your multirotor's flight level or angle, and how quickly it moves off level and back to self-leveling. These settings only effects Pitch and Roll, which is why they are positioned beneath the Pitch and Roll settings in the DJI Assistant. Furthermore, there is no point messing with this if you don't have your Pitch and Roll set up nicely to begin with. Most of the time a setting of 100% will be perhaps be a tiny bit too low, so you can up them to 110% if you wish and see if it feels better.
However, everyone has different tastes and needs, so you can up the Attitude settings if you want your multi rotor to Pitch and/or Roll and self-level more quickly, or adjust them below 100% if you want reactions to stick inputs to be slower. Be aware though that if you set these too low your Wookong will have very little control over Attitude and you may lose control of your multirotor. Setting this too high will make the movements too violent. DJI recommend that you do not set these parameters below 80% or above 150%.
To be honest I have never touched the advanced parameters and DJI recommend that most people simply leave them alone.
note: Advanced Parameters only affect GPS Mode
I: The 'I' setting is meant to be used for forward flight when there are head winds and tail winds, increasing the parameters for strong head winds and decreasing them for strong tail wind. Personally I do not recommend flying multirotors in strong winds of any kind, so for me this setting is redundant.
V-Damping: Velocity damping concerns how quickly or slowly the brakes are applied when you stop descending or ascending. You increase the value if you want your multirotor to stop more quickly or sharply.
Disturbed Gain: This supposedly increases the aggressiveness of Position Hold when increased.
NB: Again, I never touch any of these advanced settings, and even the basic settings will be good for most at the default setting. If all else fails and you feel you've got lost with your own settings, reset everything to default and start again. To be honest, for most people you will not notice much difference between default settings and your own tweaks, unless you tweak your multirotor out of control. :)