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One of the most important steps is of course the proper tuning of the gimbal. However, it is also, unfortunately, the least straight-forward and most debatable step. No unique or universal tuning recipe seems to have yet appeared, and tuning remains an experimental process of trial-and-error. The following can hence only attempt to give some ideas. It is also necessarily very subjective, i.e. based on indivudal experiences for particular gimbals. If your experience has led you to different tuning rules please feel free to share them.
<span style="font-size:88%">''by OlliW, is somewhat outdated</span>''


== Tuning the PID controller of one axis ==
One of the most important steps is of course the proper tuning of the gimbal. However, it is also - unfortunately - the least straight-forward and most debatable step. No unique or universal tuning recipe seems to have emerged yet, and tuning remains an experimental process of trial-and-error. The following can hence only attempt to give some ideas. It is also necessarily very subjective, i.e. based on individual experiences on specific gimbals. Furthermore, a basic understanding by the operator is unavoidable, and the following is accordingly explanatory in parts.
 
If your experience has led you to different tuning rules please feel free to share them (the [http://www.olliw.eu/storm32bgc-wiki/index.php5/Talk:Tunning_Guide Discussion] page could be a good place for that).
 
== Tuning the PID Controller of one Axis ==


=== Preliminaries ===
=== Preliminaries ===
The PID controller is the part of the firmware which controls the orientation (attitude) of the camera by taking the measured attitude and driving the motors such that the camera stays put. It is assumed that the reader understands the basics of PID controllers; many introductions are available on the web. At this point the first, and maybe most important comment is at place:
The PID controller is the part of the firmware which controls the orientation (attitude) of the camera by using the measured attitude for driving the motors such that the camera stays put. It is assumed that the reader understands the basics of PID controllers; many introductions are available on the web. At this point the first, and maybe most important comment is at place:


  '''The PID tuning rules given in (essentially) all texts on PID controllers do NOT apply to brushless direct-drive gimbals!'''
  '''The PID tuning rules given in (essentially) all texts on PID controllers do NOT apply to brushless direct-drive gimbals!'''


So, the situation for the brushless gimbals is somwehat different than for the "usual" systems, and this obviously affects the tuning practice. Furthermore, although maybe termed PID in all cases it seems that the implemented PID controllers differ in their working, one probably should distinguish as follows:
So, the situation for brushless gimbals is somewhat different to that for the "usual" systems, and this obviously affects the tuning practice. Furthermore, although maybe termed PID in all cases it seems that the implemented PID controllers differ somewhat in their working; one probably should distinguish as follows:


* AlexMos 2.3 and below, [http://www.rcgroups.com/forums/showthread.php?t=1978860 EvvGC]: these firmwares implement basically PD controllers, with a "weak" I term
* AlexMos 2.3 and below, [http://www.rcgroups.com/forums/showthread.php?t=1978860 EvvGC]: These firmwares implement basically PD controllers, with a "weak" I term.
* [http://sourceforge.net/projects/brushless-gimbal-brugi/ BruGi], [http://www.rcgroups.com/forums/showthread.php?t=2059364 BGC32], AlexMos 2.4, o323bgc/STorM32bgc: these firmwares implement "full" PID controllers
* [http://sourceforge.net/projects/brushless-gimbal-brugi/ BruGi], [http://www.rcgroups.com/forums/showthread.php?t=2059364 BGC32], AlexMos 2.4, o323bgc/STorM32bgc: These firmwares implement "full" PID controllers.


'''''Comment:''' The AlexMos codes are of course not available, one can hence only speculate, however the various available descriptions/tutorials are telling.''
{{COMMENT|The AlexMos codes are of course not available, one can hence only speculate, however the various available descriptions/tutorials are telling.}}


The good message is that the PID controllers in the second category of firmwares work by the very same basic principles, which means that the tuning recipes given for any of them may be used to tune STorM32-BGC gimbals. The less good message is that there seem to be two different general tuning strategies, which may be called "low-PWM" and "high-PWM" tuning, and neither of them avoids experimenting. The "low-PWM" tunning has emerged as a result of experience for Gopro and larger gimbals; the "high-PWM" tuning has been described for small or micro gimbals. At this point it's not clear though which one is generally better, or if any is the best at all.  
The good message is that the PID controllers in the second category of firmwares work by the very same basic principles, which means that the tuning recipes given for any of them may be used to tune STorM32-BGC gimbals (be aware however that this doesn't mean that PID values can be carried over; the units generally are different!). The less good message is that there seem to be two different tuning strategies, which may be called "low-PWM" and "high-PWM" tuning, and neither of them avoids experimenting. The "low-PWM" tuning resulted from experience for Gopro and larger gimbals; the "high-PWM" tuning has been described for micro gimbals. At this point it's not clear which one is generally better, or if any is the best at all.  


As a general tuning rule, consider:
As a general tuning rule, consider:


  Don't overdue it. Better be a bit conservative.
  Don't overdo it. Better be a bit conservative.


The first sentence is supposed to mean that while it's true that a proper tuning can lead to enormous performance gains and is mandatory for optimal operation it's also true that it is meaningless to adjust the parameters to their last digit. The second sentence reflects the fact that a PID controller which is aggresively tuned for a certain condition (e.g. battery voltage) is also very sensitive to changes in these conditions, i.e., is less robust.
The first sentence is supposed to mean that while it's true that a proper tuning can lead to enormous performance gains and is mandatory for optimal operation it's also true that it is meaningless to adjust the parameters to their last digit. The second sentence reflects the fact that a PID controller which is aggressively tuned for a certain condition (e.g. battery voltage) is also very sensitive to changes in these conditions, i.e., is less robust.


Finally, although it may be obvious and may appear a bit smart ass, it cannot be over emphasized that:
Finally, although it may be obvious and may appear a bit smart ass, it cannot be over emphasized that:
Line 29: Line 33:
Inspection of the various threads immediately confirms this point.
Inspection of the various threads immediately confirms this point.


=== Basic PID parameters ===
=== Basic PID Parameters ===
  The basic PID controller parameters are [P], [I], [D], and [Vmax].  
  The basic PID controller parameters are {{GUI|P}}, {{GUI|I}}, {{GUI|D}}, and {{GUI|Vmax}}.  
The parameter [Vmax] is known in other firmwares as e.g. the motor PWM or motor power.
The parameter {{GUI|Vmax}} is known in other firmwares as the motor PWM or motor power.
 
The o323bgc firmware provides also the parameters {{GUI|Pan}}, {{GUI|Voltage Correction}}, and {{GUI|Hold To Pan Transition Time}}. These are however not relevant for the basic tuning, and {{GUI|Pan}} should in fact be deactivated for tuning.


The o323bgc firmware provides also the parameters [Pan], [Voltage Correction], and somewhat hidden [Hold To Pan Transition Time]. The later are however not relevant for the basic tuning, and should in fact be deactivated for tuning.
[[File:1main.png|480px]]


=== Coarse tunning settings ===
=== Coarse Tuning Settings ===
For basic tuning, the advanced tunning parameters should be deactivated.  
For the basic tuning, the advanced tuning parameters should be deactivated.  


* [Pan] MUST be set to zero (or the hold mode ensured by other means, such as via the [AUX Kex Modes])
* {{GUI|Pan}} MUST be set to zero (or the hold mode ensured by other means, such as via the {{GUI|Pan Mode Control}} settings)
* [Voltage Correction] should be set to 0%
* {{GUI|Voltage Correction}} should be set to 0%
* the battery should neither be fully charged nor nearly discharged (i.e. have a voltage of around 3.7 V per cell)
* the battery should neither be fully charged nor nearly discharged (i.e. have a voltage of around 3.7 V per cell)


The first step is to obtain a basic, working tuning (coarse tuning) of all axes. One should tune first the pitch axis, then roll, and only then yaw. Ideally one would block the roll and yaw axes while tuning the pitch axes, and the yaw axis while tuning the roll axis. In any case make use of the [Roll Usage], and [Yaw Usage] parameters to avoid uncontrolled motion or even damage to the gimbal.  
The first step is to obtain a basic, working tuning of all axes (coarse tuning). One should tune first the pitch axis, then roll, and then yaw. Ideally one would block the roll and yaw axes while tuning the pitch axis, and the yaw axis while tuning the roll axis. In any case make use of the {{GUI|Roll Usage}} and {{GUI|Yaw Usage}} parameters to avoid uncontrolled motion or even damage to the gimbal.  


Once the gimbal is coarsely tuned, one may proceed to the fine tunning. Here the Data Display is most useful.
Once the gimbal is coarsely tuned, one may proceed with fine tuning, which is entirely trial-and-error and no tuning recipe exists at all. Here the Data Display is most useful.


=== "Low-PWM" tuning ===
=== "Low-PWM" Tuning ===
  The "low-PWM" tuning strategy starts from the recommendation to set [Vmax], or motor power or PWM, as small as possible.
  The "low-PWM" tuning strategy starts from the recommendation to set {{GUI|Vmax}}, or motor power or PWM, as small as possible.


The motor power should of course be also as large as needed, to overcome the motor's cogging torque, friction or imperfections in the balance, which sets the lower bound. Typical tuning guides are
The motor power should of course also be as large as needed to overcome the motor's cogging torque, friction or imperfections in the balance. This sets a lower limit to {{GUI|Vmax}}. Typical tuning guides are


* [http://sourceforge.net/p/brushless-gimbal-brugi/wiki/PIDtuningguide/ http://sourceforge.net/p/brushless-gimbal-brugi/wiki/PIDtuningguide/]
* [http://sourceforge.net/p/brushless-gimbal-brugi/wiki/PIDtuningguide/ http://sourceforge.net/p/brushless-gimbal-brugi/wiki/PIDtuningguide/]
* [https://bradatech.com/xPedRobo/shop/download/uploading_software_martinez_board.pdf https://bradatech.com/xPedRobo/shop/download/uploading_software_martinez_board.pdf], page 10
* [http://www.multi-rotor.co.uk/index.php?topic=2945.0 Quick how to tune guide for BRUGI/martinez brushless gimbals]
* [http://blgwiki.com/index.php?title=A_Tuning_Guide A Tuning Guide - Brushless Gimbal Wiki]
* PLEASE ADD HERE
* PLEASE ADD HERE


As said before, this recipe has emerged from the experience by several authors on Gopro and larger gimbals, and in this sense maybe considered as "proven". Generally, the value of Vmax must not be too small:  
As said before, this recipe has emerged from the experience by several authors on Gopro and larger gimbals, and in this sense may be considered as "proven". Generally, the motor power must not be too small:  
 
The value of [Vmax], or motor power or PWM, should not be below 65 or 25%.
 
Lowering the [Vmax] value also diminishes the available angle resolution, and if it's too small the gimbal can't correct smoothly anymore.


=== "High-PWM" tuning ===
  The value of {{GUI|Vmax}}, or motor power or PWM, should not be below 65 or 25%.
  The "high-PWM" tuning strategy starts from the recommendation to set [Vmax], or motor power or PWM, as large as possible.


The rational in this tunning is that a larger motor power makes the system react faster (allowing in principle a faster correction and hence smaller error angles) and be more robust against disturbancs such as cogging torque, frictions, wind gusts and so on.
Lowering the {{GUI|Vmax}} value also diminishes the available angle resolution, and if it's too small the gimbal can't correct smoothly anymore.


The upper limit for [Vmax] is mainly determined by the heat produced in the motors. Obviously, the motors should not get too hot. In practical terms, one should be able to touch the motors for several seconds (10 sec or more). The motor heat is however not the only factor which determines the proper [Vmax] value. As with the other parameters, one needs to experiment. It may e.g. happen that with a too large [Vmax] one may never achieve a vibration free, good tuning, and a somewhat lower [Vmax] is much better.
=== "High-PWM" Tuning ===
The "high-PWM" tuning strategy starts from the recommendation to set {{GUI|Vmax}}, or motor power or PWM, as large as possible.


As regards [P], [I], [D], these two procedures seem to work:
The rational in this tuning is that a larger motor power makes the system react faster (allowing in principle a faster correction and hence smaller error angles) and be more robust against disturbances such as cogging torque, frictions, wind gusts and so on.
*'''Procedure A:''' Set [I] to a small value (might be worth to try even zero). Increase [D] and [P} alternatingly, and step by step. The gimbal should not start to oscillate. Since it are only two paramters one will quickly find the best balance of large [D] and large [P]. Now turn up the [I] value until the gimbal starts to oscillate (watch the accelerometer data in the Data Display), and back off by some 10 %. Finally, experiment with all three values. The general goal should be to get a large [I] value.


*'''Procedure B:''' Set [P] to zero, and first adjust [I] and [D]. That is, increase I until the gimbal oscillates, then increase [D] to damp the oscillation. Repeat until neither increasing [I] nor [D] stops gimbal oscillations. Now also use [P], and experiment with all three values until the result is satisfying. The general goal should be to get a large [I] value.
The upper limit for {{GUI|Vmax}} is mainly determined by the heat produced in the motors. Obviously, the motors should not get too hot. In practical terms, one should be able to touch the motors for several seconds (10 sec or more). The motor heat is however not the only factor which determines the proper {{GUI|Vmax}} value. As with the other parameters, one needs to experiment. It may e.g. happen that with a too large {{GUI|Vmax}} one can't achieve a vibration free, good tuning, and a somewhat lower {{GUI|Vmax}} is much better.


== Voltage correction ==
As regards {{GUI|P}}, {{GUI|I}}, {{GUI|D}}, these two procedures seem to work:
The voltage correction mechanism in 0323bgc attempts to compensate the effects by a varying battery voltage on the PID controller tuning. It does it by modifying the actual motor power. i.e. [Vmax] values proportionally to the voltage change. The proportionality factor is given by the parameter [Voltage Correction].
*'''Procedure A:''' Set {{GUI|I}} to a small value. Increase {{GUI|D}} and {{GUI|P}} alternately, step by step. The gimbal should not start to oscillate. Since it are only two parameters one will quickly find the best balance of large {{GUI|D}} and large {{GUI|P}}. Now turn up the {{GUI|I}} value until the gimbal starts to oscillate, and back off by some 10 %. Finally, experiment with all three values. The general goal should be to get a large {{GUI|I}} value.


For instance, with a [Voltage Correction] of 100%, a drop in the battery voltage by 25% leads to an increase of the actually used Vmax value by 25%. With a [Voltage Correction] of 50%, a voltage drop by 25% leads to a 12.5% increase in Vmax, and so on.
*'''Procedure B:''' Set {{GUI|P}} to zero or avery small value, and first adjust {{GUI|I}} and {{GUI|D}}. That is, increase {{GUI|I}} until the gimbal oscillates, then increase {{GUI|D}} to damp the oscillation. Repeat until neither increasing {{GUI|I}} nor {{GUI|D}} stops gimbal oscillations. Now also use {{GUI|P}}, and experiment with all three values until the result is satisfying. The general goal should be to get a large {{GUI|I}} value.


The mechanism can significantly reduce the dependence of the gimbal performance on the battery voltage. It can however not accomplish what could be achieved with a truely constant (regulated) voltage.
'''''Tip:''' Vibrations or oscillations of the gimbal can be nicely seen in the DataDisplay's accelerometer panel.''


== Tuning the pan mode ==
== Voltage Correction ==
In o323bgc the pan mode, also known as follow mode, is in some ways independent on the PID controller tuning. Thus, the PID controller tuning must be done with the pan mode deactivated. However, on the other hand, once the PID controller is tuned, the pan mode can be adjusted easily without having to touch the PID controller in any ways. (this is probably one of the apealing features of 0323bgc)
The voltage correction mechanism in o323bgc attempts to compensate the effects by a varying battery voltage on the PID controller tuning. It does it by modifying the actual motor power. i.e. {{GUI|Vmax}} values proportionally to the voltage change. The proportionality factor is given by the parameter {{GUI|Voltage Correction}}.


The pan mode is controlled by the parameters [Pitch Pan], [Roll Pan], and [Yaw Pan].
For instance, with a {{GUI|Voltage Correction}} of 100%, a drop in the battery voltage by 25% leads to an increase of the actually used Vmax value by 25%. With a {{GUI|Voltage Correction}} of 50%, a voltage drop by 25% leads to a 12.5% increase in Vmax, and so on.


These parameters determine the pan speeds for each of the three axes. A zero means that the pan mode is deactivated, i.e., that the axis is in hold mode (also known as locked mode). There is little more to say here.
The mechanism can significantly reduce the dependence of the gimbal performance on the battery voltage. It can however not accomplish what could be achieved with a truly constant (regulated) voltage.


The transitions from hold to pan and pan to hold modes, which are possible via e.g. the external keys, present a challenge, since the abrupt accelerations on the camera which may occur in these situations cannot be handled well by the brushless gimbal technique. The acceleration after having switched from hold to pan can be limited or smoothened using the [Hold To Pan Transition Time] parameter.
== Tuning the Pan Speed ==
For the STorM32-BGC the pan (follow) mode is in some ways independent on the PID controller. The PID tuning must thus be done with the pan mode deactivated. However, on the other hand, once the PID controller is tuned, the pan speed can be easily adjusted without having to touch the PID controller any further. This is probably one of the appealing features of the STorM32-BGC. Accordingly, the discussion of the hold and pan modes is deferred to a later chapter.  


== Tuning the IMU/AHRS/MARG ==
== Understanding the Parameters ==
PLEASE ADD


== Understanding the parameters ==
Maybe useful references (from the German FPVC forum):
Maybe usefull references (from the German FPVC forum):
* http://fpv-community.de/showthread.php?20795-Brushless-Gimbal-Controller-SOFTWARE&p=382163&viewfull=1#post382163
* http://fpv-community.de/showthread.php?20795-Brushless-Gimbal-Controller-SOFTWARE&p=382163&viewfull=1#post382163
* http://fpv-community.de/showthread.php?20795-Brushless-Gimbal-Controller-SOFTWARE&p=381584&viewfull=1#post381584
* http://fpv-community.de/showthread.php?20795-Brushless-Gimbal-Controller-SOFTWARE&p=381584&viewfull=1#post381584
* http://fpv-community.de/showthread.php?20795-Brushless-Gimbal-Controller-SOFTWARE&p=381513&viewfull=1#post381513
* http://fpv-community.de/showthread.php?20795-Brushless-Gimbal-Controller-SOFTWARE&p=381513&viewfull=1#post381513
== Next step - RC Inputs ==
With these settings we have a self leveling gimbal. No matter what movements the gimbal support is undergoing, the camera remains stable. While this might be perfectly sufficient for basic operation, normally the gimbal shall also be moved via a RC stick or, on a hand-held gimbal, via a joystick, or functions such as switching between hold and pan modes or releasing the shutter of the camera remotely are desired.
You can learn about these possibilities in the next chapters; continue with [[Configure the RC Input]].

Latest revision as of 01:04, 9 January 2015

by OlliW, is somewhat outdated

One of the most important steps is of course the proper tuning of the gimbal. However, it is also - unfortunately - the least straight-forward and most debatable step. No unique or universal tuning recipe seems to have emerged yet, and tuning remains an experimental process of trial-and-error. The following can hence only attempt to give some ideas. It is also necessarily very subjective, i.e. based on individual experiences on specific gimbals. Furthermore, a basic understanding by the operator is unavoidable, and the following is accordingly explanatory in parts.

If your experience has led you to different tuning rules please feel free to share them (the Discussion page could be a good place for that).

Tuning the PID Controller of one Axis

Preliminaries

The PID controller is the part of the firmware which controls the orientation (attitude) of the camera by using the measured attitude for driving the motors such that the camera stays put. It is assumed that the reader understands the basics of PID controllers; many introductions are available on the web. At this point the first, and maybe most important comment is at place: 

The PID tuning rules given in (essentially) all texts on PID controllers do NOT apply to brushless direct-drive gimbals!

So, the situation for brushless gimbals is somewhat different to that for the "usual" systems, and this obviously affects the tuning practice. Furthermore, although maybe termed PID in all cases it seems that the implemented PID controllers differ somewhat in their working; one probably should distinguish as follows:

  • AlexMos 2.3 and below, EvvGC: These firmwares implement basically PD controllers, with a "weak" I term.
  • BruGi, BGC32, AlexMos 2.4, o323bgc/STorM32bgc: These firmwares implement "full" PID controllers.

Comment: The AlexMos codes are of course not available, one can hence only speculate, however the various available descriptions/tutorials are telling.

The good message is that the PID controllers in the second category of firmwares work by the very same basic principles, which means that the tuning recipes given for any of them may be used to tune STorM32-BGC gimbals (be aware however that this doesn't mean that PID values can be carried over; the units generally are different!). The less good message is that there seem to be two different tuning strategies, which may be called "low-PWM" and "high-PWM" tuning, and neither of them avoids experimenting. The "low-PWM" tuning resulted from experience for Gopro and larger gimbals; the "high-PWM" tuning has been described for micro gimbals. At this point it's not clear which one is generally better, or if any is the best at all.

As a general tuning rule, consider: 

Don't overdo it. Better be a bit conservative.

The first sentence is supposed to mean that while it's true that a proper tuning can lead to enormous performance gains and is mandatory for optimal operation it's also true that it is meaningless to adjust the parameters to their last digit. The second sentence reflects the fact that a PID controller which is aggressively tuned for a certain condition (e.g. battery voltage) is also very sensitive to changes in these conditions, i.e., is less robust.

Finally, although it may be obvious and may appear a bit smart ass, it cannot be over emphasized that: 

The key to a good performance of the gimbal is a perfect mechanics and balance.

Inspection of the various threads immediately confirms this point.

Basic PID Parameters

The basic PID controller parameters are [GUI:P], [GUI:I], [GUI:D], and [GUI:Vmax].

The parameter [GUI:Vmax] is known in other firmwares as the motor PWM or motor power.

The o323bgc firmware provides also the parameters [GUI:Pan], [GUI:Voltage Correction], and [GUI:Hold To Pan Transition Time]. These are however not relevant for the basic tuning, and [GUI:Pan] should in fact be deactivated for tuning.

1main.png

Coarse Tuning Settings

For the basic tuning, the advanced tuning parameters should be deactivated.

  • [GUI:Pan] MUST be set to zero (or the hold mode ensured by other means, such as via the [GUI:Pan Mode Control] settings)
  • [GUI:Voltage Correction] should be set to 0%
  • the battery should neither be fully charged nor nearly discharged (i.e. have a voltage of around 3.7 V per cell)

The first step is to obtain a basic, working tuning of all axes (coarse tuning). One should tune first the pitch axis, then roll, and then yaw. Ideally one would block the roll and yaw axes while tuning the pitch axis, and the yaw axis while tuning the roll axis. In any case make use of the [GUI:Roll Usage] and [GUI:Yaw Usage] parameters to avoid uncontrolled motion or even damage to the gimbal.

Once the gimbal is coarsely tuned, one may proceed with fine tuning, which is entirely trial-and-error and no tuning recipe exists at all. Here the Data Display is most useful.

"Low-PWM" Tuning

The "low-PWM" tuning strategy starts from the recommendation to set [GUI:Vmax], or motor power or PWM, as small as possible.

The motor power should of course also be as large as needed to overcome the motor's cogging torque, friction or imperfections in the balance. This sets a lower limit to [GUI:Vmax]. Typical tuning guides are

As said before, this recipe has emerged from the experience by several authors on Gopro and larger gimbals, and in this sense may be considered as "proven". Generally, the motor power must not be too small: 

The value of [GUI:Vmax], or motor power or PWM, should not be below 65 or 25%.

Lowering the [GUI:Vmax] value also diminishes the available angle resolution, and if it's too small the gimbal can't correct smoothly anymore.

"High-PWM" Tuning

The "high-PWM" tuning strategy starts from the recommendation to set [GUI:Vmax], or motor power or PWM, as large as possible.

The rational in this tuning is that a larger motor power makes the system react faster (allowing in principle a faster correction and hence smaller error angles) and be more robust against disturbances such as cogging torque, frictions, wind gusts and so on.

The upper limit for [GUI:Vmax] is mainly determined by the heat produced in the motors. Obviously, the motors should not get too hot. In practical terms, one should be able to touch the motors for several seconds (10 sec or more). The motor heat is however not the only factor which determines the proper [GUI:Vmax] value. As with the other parameters, one needs to experiment. It may e.g. happen that with a too large [GUI:Vmax] one can't achieve a vibration free, good tuning, and a somewhat lower [GUI:Vmax] is much better.

As regards [GUI:P], [GUI:I], [GUI:D], these two procedures seem to work:

  • Procedure A: Set [GUI:I] to a small value. Increase [GUI:D] and [GUI:P] alternately, step by step. The gimbal should not start to oscillate. Since it are only two parameters one will quickly find the best balance of large [GUI:D] and large [GUI:P]. Now turn up the [GUI:I] value until the gimbal starts to oscillate, and back off by some 10 %. Finally, experiment with all three values. The general goal should be to get a large [GUI:I] value.
  • Procedure B: Set [GUI:P] to zero or avery small value, and first adjust [GUI:I] and [GUI:D]. That is, increase [GUI:I] until the gimbal oscillates, then increase [GUI:D] to damp the oscillation. Repeat until neither increasing [GUI:I] nor [GUI:D] stops gimbal oscillations. Now also use [GUI:P], and experiment with all three values until the result is satisfying. The general goal should be to get a large [GUI:I] value.

Tip: Vibrations or oscillations of the gimbal can be nicely seen in the DataDisplay's accelerometer panel.

Voltage Correction

The voltage correction mechanism in o323bgc attempts to compensate the effects by a varying battery voltage on the PID controller tuning. It does it by modifying the actual motor power. i.e. [GUI:Vmax] values proportionally to the voltage change. The proportionality factor is given by the parameter [GUI:Voltage Correction].

For instance, with a [GUI:Voltage Correction] of 100%, a drop in the battery voltage by 25% leads to an increase of the actually used Vmax value by 25%. With a [GUI:Voltage Correction] of 50%, a voltage drop by 25% leads to a 12.5% increase in Vmax, and so on.

The mechanism can significantly reduce the dependence of the gimbal performance on the battery voltage. It can however not accomplish what could be achieved with a truly constant (regulated) voltage.

Tuning the Pan Speed

For the STorM32-BGC the pan (follow) mode is in some ways independent on the PID controller. The PID tuning must thus be done with the pan mode deactivated. However, on the other hand, once the PID controller is tuned, the pan speed can be easily adjusted without having to touch the PID controller any further. This is probably one of the appealing features of the STorM32-BGC. Accordingly, the discussion of the hold and pan modes is deferred to a later chapter.

Understanding the Parameters

Maybe useful references (from the German FPVC forum):

Next step - RC Inputs

With these settings we have a self leveling gimbal. No matter what movements the gimbal support is undergoing, the camera remains stable. While this might be perfectly sufficient for basic operation, normally the gimbal shall also be moved via a RC stick or, on a hand-held gimbal, via a joystick, or functions such as switching between hold and pan modes or releasing the shutter of the camera remotely are desired.

You can learn about these possibilities in the next chapters; continue with Configure the RC Input.

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