Kebab

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Trying to achieve rolls/flips at zero throttle
« on: June 14, 2017, 04:25:41 am »
I was watching this video: https://youtu.be/EbAwSQF0Ks0?t=3m53s

They explain how different rolls and flips can be performed with and without throttle. 

When I attempt to control the roll or pitch at zero throttle, my quad is basically out of my control.  Without throttle, I cannot maneuver.  Am I missing a key piece of information here?  I can't seem to find the setting or combination of settings in LibrePilot.

My stabilization mode is as follows:
Roll: Rattitude
Pitch: Rattitude
Yaw: Rate
Thrust: Manual

All 3 sliders in the Basic mode are around the middle of insane.

Any help or information would be greatly appreciated.  Let me know if you need more FC settings from me.

Thanks!

Re: Trying to achieve rolls/flips at zero throttle
« Reply #1 on: June 14, 2017, 05:44:38 pm »
If you pull the throttle stick all the way back to zero, that generally means to stop the motors in LP.  That is a safety feature.  You don't want to have to think "Now how do I stop the motors?" or "Where is that switch?" if your quad is about to hit someone.

First of all, you need to have your motor neutrals and ESC calibration set correctly, but I assume you already have that.

There are four ways I can think of to reduce the throttle when inverted when doing flips:
- Manually move the throttle to a little above zero.  Difficult because sometimes you might set zero (and motors will stop) and other times you might set more throttle than you want which can pull down to the ground more than you want.
- Adjust the transmitter throttle trim so that zero throttle stick still moves the motors.  LP does the rest.  It will automatically greatly increase the motor speeds when stabilization or command asks for it; as long as the motors are still being commanded to spin.  Adjust the trim after arming for each flight where you want this feature.  Adjust the trim back to allow stopping the motors and disarming.  Trim must be reset back to neutral or you can't arm it.
- Set the "Motors always spin / always stabilize when armed" setting in the output page.  You really need a disarming switch for emergencies when you set this up.
- Use CruiseControl on throttle and leave the throttle stick set to mid to high throttle during flips.  The default for this is to reduce the motors to 5% when inverted (actually once the quad is past 90 degree bank (105 actually)).  The default for CruiseControl is also to increase power automatically when you bank the quad; to increase it the correct amount to maintain altitude in a turn.  This boost can be disabled if all you want is to automatically reduce to 5% when inverted.  Zero throttle stick stops the motors as expected.  Settings are in Stabilization->Expert IIRC.

CruiseControl with Rattitude is the recommended way to learn flips.

I regularly do flips using CruiseControl starting from about 1m, giving full throttle and leaving it there for the whole flip, and doing the flip at about 3m with the initial upward speed.  It really couldn't be simpler.  This is on a medium powerful quad (not high powered) with flip rate set to 360 degrees per second.

Back off of insane configuration for your flips when you are learning.  I like 360 for rate (one flip per second) to start with because most people can keep up with it while it flips and you can mentally imagine what a 1 second flip would be like, count by seconds and imagine 1 smooth continuous flip per second.  This 360 flip rate avoids you doing a flip and a half when you only wanted one flip, but you do need to have a little more altitude or upward speed when you start the flip.

f5soh

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Re: Trying to achieve rolls/flips at zero throttle
« Reply #2 on: June 14, 2017, 06:13:36 pm »
Hi,

Regardless of stabilization mode selected (Rate, Rattitude, Acro+, Attitude...), if you want to still have control while Throttle is low you simply need to use ASWA (Always stabilized While Armed) enabled.
Better use a switch for arming.

Take a look here:
https://librepilot.atlassian.net/wiki/display/LPDOC/Always+Stabilized+When+Armed+mode+setup



Kebab

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Re: Trying to achieve rolls/flips at zero throttle
« Reply #3 on: June 14, 2017, 07:36:34 pm »
Hi,

Regardless of stabilization mode selected (Rate, Rattitude, Acro+, Attitude...), if you want to still have control while Throttle is low you simply need to use ASWA (Always stabilized While Armed) enabled.
Better use a switch for arming.

Take a look here:
https://librepilot.atlassian.net/wiki/display/LPDOC/Always+Stabilized+When+Armed+mode+setup

Thanks for helping me understand the purpose of this help page.  I already have an arm switch configured which is Accessory 0 on Channel 10 (S. Bus).  I also have 3 FlightModes set on Channel 5.  The portion near the bottom of the article where it says to set my Arming toggle and FlightMode both to Channel 5.  I guess that only matters if, for example, flightmode 1 is full stable and does not allow flips.  So, ASWA will be off for FlightMode 1.  Makes sense. 

For motor neutral:
Min: 1000
Neutral: 1032 for all motors
Max: 2000

So in AWSA, 0 throttle on my remote will actually mean Neutral (1032) for motors?  If this is the case, does that mean I have full operation for pitch/roll?  For example, throttle up to get in air, move throttle to 0 on remote, full right roll.  Will the motors increase their speed appropriately based on pitch/roll to perform the full flip/roll since the motors are in neutral, not 0?
« Last Edit: June 14, 2017, 07:45:31 pm by Kebab »

Kebab

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Re: Trying to achieve rolls/flips at zero throttle
« Reply #4 on: June 14, 2017, 07:43:26 pm »
If you pull the throttle stick all the way back to zero, that generally means to stop the motors in LP.  That is a safety feature.  You don't want to have to think "Now how do I stop the motors?" or "Where is that switch?" if your quad is about to hit someone.

First of all, you need to have your motor neutrals and ESC calibration set correctly, but I assume you already have that.

There are four ways I can think of to reduce the throttle when inverted when doing flips:
- Manually move the throttle to a little above zero.  Difficult because sometimes you might set zero (and motors will stop) and other times you might set more throttle than you want which can pull down to the ground more than you want.
- Adjust the transmitter throttle trim so that zero throttle stick still moves the motors.  LP does the rest.  It will automatically greatly increase the motor speeds when stabilization or command asks for it; as long as the motors are still being commanded to spin.  Adjust the trim after arming for each flight where you want this feature.  Adjust the trim back to allow stopping the motors and disarming.  Trim must be reset back to neutral or you can't arm it.
- Set the "Motors always spin / always stabilize when armed" setting in the output page.  You really need a disarming switch for emergencies when you set this up.
- Use CruiseControl on throttle and leave the throttle stick set to mid to high throttle during flips.  The default for this is to reduce the motors to 5% when inverted (actually once the quad is past 90 degree bank (105 actually)).  The default for CruiseControl is also to increase power automatically when you bank the quad; to increase it the correct amount to maintain altitude in a turn.  This boost can be disabled if all you want is to automatically reduce to 5% when inverted.  Zero throttle stick stops the motors as expected.  Settings are in Stabilization->Expert IIRC.

CruiseControl with Rattitude is the recommended way to learn flips.

I regularly do flips using CruiseControl starting from about 1m, giving full throttle and leaving it there for the whole flip, and doing the flip at about 3m with the initial upward speed.  It really couldn't be simpler.  This is on a medium powerful quad (not high powered) with flip rate set to 360 degrees per second.

Back off of insane configuration for your flips when you are learning.  I like 360 for rate (one flip per second) to start with because most people can keep up with it while it flips and you can mentally imagine what a 1 second flip would be like, count by seconds and imagine 1 smooth continuous flip per second.  This 360 flip rate avoids you doing a flip and a half when you only wanted one flip, but you do need to have a little more altitude or upward speed when you start the flip.

Thanks for the response!  I think your third bullet is what I am looking for.  I like the idea of the trim setting also.  I have the two potentiometer knobs on my remote, which I could utilize to adjust the trim on the fly.  It will definitely give me more options when I am testing configurations.  The insane setting has given me to ability to perform fast-ish flips, but there is probably a better way to achieve this motion without having it set so high.  I will have to continue reviewing and testing some of the configurations you suggested!

f5soh

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Re: Trying to achieve rolls/flips at zero throttle
« Reply #5 on: June 14, 2017, 08:00:18 pm »
Quote
So in AWSA, 0 throttle on my remote will actually mean Neutral (1032) for motors?  If this is the case, does that mean I have full operation for pitch/roll?  For example, throttle up to get in air, move throttle to 0 on remote, full right roll.  Will the motors increase their speed appropriately based on pitch/roll to perform the full flip/roll since the motors are in neutral, not 0?

Yes
At low throttle (0) the motors are spinning at neutral to tell you there is a danger.
At this point moving the quad by hand can cause issues to your body and/or fingers.
All sticks movements cause motor response as expected because the quad is Always Stabilized