Fun, Learning, Friendship and Mutual Respect START  HERE


Unregistered
Go Back   HeliFreak > R/C Electronics Support > OpenTX Radios


OpenTX Radios OpenTX Radios Discussion and Support Forum


Like Tree1Likes
Reply
 
LinkBack Thread Tools Display Modes
Old 01-03-2018, 04:11 PM   #41 (permalink)
HF Support
 
Posts: 6,850
Thread Starter Thread Starter
 
My HF Map location
Join Date: Jan 2013
Default

Quote:
Originally Posted by teamdavey View Post
"Am I correct in assuming that in this newer version of openTX the weights are added in the swashplate section? SO, if I have to reverse something, do it there?"

If you asking about the files I posted, the swashplate section is not used at all.

Weights are in the inputs as normal.

To reverse a control (for example aileron) reverse the global variable - for aileron on companion go to flight modes and change the value from, say, 50% to -50 % - this emulates how many conventional transmitters handle swash mixing. On the Tx you can do this on the Global variables page directly.

To reverse individual servos and adjust servo neutrals use Outputs.

Jim Davey
Weights are in the heli-tab (swashplate section).

Adjust weights in the swashplate section. Alter CYC1, CYC2, CYC3 order to line up with servos. Reverse servos in the servo tab if servo reversals are needed (ie servos mounted inverted to expectation).

At all times collective alone should move swash plate up an down fairly evenly irrespective of angle of cyclic.

For heli oriented with nose North. Traditional CCPM arrangement in OpenTX is CYC1 is North servo, CYC 2 is South West servo and CYC3 is South East servo. (So counter clockwise from CYC1 to CYC3 when looking from the top. CYC1 always inline with nose-tail and not effected by aileron in 90, 120 or 140 configurations).
__________________
TRex 700E Pro DFC HV (BD3SX) - Gaui X5 (6S/BD3SX), Blade 130X, RealFlight, Heli-X, Taranis+DSMX
ArchmageAU is offline        Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 01-03-2018, 05:40 PM   #42 (permalink)
Registered Users
 

Join Date: Nov 2005
Default

"I believe so."

Interesting - I did not see it at a quick glance - will have to look again later, or is it somehow "under the hood"?
__________________
teamdavey
teamdavey is offline        Reply With Quote Quick reply to this message
Old 01-03-2018, 10:55 PM   #43 (permalink)
HF Support
 
Posts: 6,850
Thread Starter Thread Starter
 
My HF Map location
Join Date: Jan 2013
Default

Quote:
Originally Posted by teamdavey View Post
"I believe so."

Interesting - I did not see it at a quick glance - will have to look again later, or is it somehow "under the hood"?
Under the hood of the OpenTX is cosine multipliers to aileron, elevator and collective when using heli CCPM.

If you want full cosine based on swash angle and throw, then you would need to add metrics to know the length of the swash arms and the size of the swash plate. Considering the small angles usually involved, airfoil efficiency, rotor speed, flybar stabilisation, ground effect, clean/dirty air, air pressure at altitude, flap, lead/lag, etc.. linear is usually quite sufficient for the swash movement algorithm.

Even FBL systems do not worry about full cosine CCPM implementation. They rely on PID feedback loops from the gyro to do the finer adjustments.

This is a problem that can be seriously over-thought.
__________________
TRex 700E Pro DFC HV (BD3SX) - Gaui X5 (6S/BD3SX), Blade 130X, RealFlight, Heli-X, Taranis+DSMX
ArchmageAU is offline        Reply With Quote Quick reply to this message
Old 01-04-2018, 08:44 AM   #44 (permalink)
Registered Users
 

Join Date: Nov 2005
Default

Hmmmmm............without at least some approximating curve, there will be a "fight" with 4 servo CCPM when cyclic is applied toward hi and lo collective. All Txs that I am aware of have some compensation. That's why I put in the "tweak" curve.

You can get away with it on 3 servo since there is no fight, just some slight cross coupling at hi and lo which the pilot may or may not notice.

This issue is why I avoid 4 servo CCPM!
__________________
teamdavey
teamdavey is offline        Reply With Quote Quick reply to this message
Old 01-05-2018, 07:42 AM   #45 (permalink)
HF Support
 
Posts: 6,850
Thread Starter Thread Starter
 
My HF Map location
Join Date: Jan 2013
Default

Quote:
Originally Posted by teamdavey View Post
Hmmmmm............without at least some approximating curve, there will be a "fight" with 4 servo CCPM when cyclic is applied toward hi and lo collective. All Txs that I am aware of have some compensation. That's why I put in the "tweak" curve.

You can get away with it on 3 servo since there is no fight, just some slight cross coupling at hi and lo which the pilot may or may not notice.

This issue is why I avoid 4 servo CCPM!
I think I understand, but I need it clarified.

is the "fight" because the servos are rotational arms controlling a planar swash? At collective extremes you would operating entirely in the low or high portion of the servo sweep. The most extreme value would be moving at a different rate to the least extreme value.

In this case, as collective moves further from the centre, any moving servo would need to move through a compensation curve to map the "linear" movement onto a rotational base to reduce the "fight" to warp the swash.

Is the above correct?

In this case, you could add a single curve to match the 4 servos linear deflection from centre to a rotational deflection from centre.

This would not be a perfect solution as twisting the swash plate introduces other angles, but it should reduce the "fight".

Would be surprised if any FBL system ever got this 100% right either. I have not seen a FBL system that has parameters for servo arm length or servo degrees of arc in setup.

Maybe sound physical engineering (spreading the load), but an electrical programming nightmare (to ensure energy is not wasted trying to twist an inflexible swash).


Happy to be corrected on any of this as I have never seen a 4 servo CCPM physical setup for a heli (nor am fully aware of it's issues).
__________________
TRex 700E Pro DFC HV (BD3SX) - Gaui X5 (6S/BD3SX), Blade 130X, RealFlight, Heli-X, Taranis+DSMX
ArchmageAU is offline        Reply With Quote Quick reply to this message
Old 01-05-2018, 12:04 PM   #46 (permalink)
Registered Users
 

Join Date: Nov 2005
Default

Yes - you have it.

As you pointed out earlier, with three servo CCPM all that happens is a slight cross control effect at extreme cyclic/collective. On the 4 servo, at full collective, as the cyclic is introduced the differential movement results in trying to bend the swash plate (I love the "bend").

There is also some minor fighting just due to variation between servos - the IMAC guys go to some lengths to match servos to deal with this when they gang multiple servos.

I don't use 4 servo myself , but I came across the problem a few years ago when setting up and doing the initial no-bar test flying of a large (up to 120lb) UAV before the autopilot was integrated (Why, is another story:-)). It used 4 servo CCPM, 1/4 scale servos and very rigid linkages. The swash plate was properly designed with the input balls and Heim ball in the same plane so that was not an issue. The servos were close enough matched that collective movements alone were OK and we did not have to play with the individual ATV to match them. However, at high collective, the servo fight was obvious as cyclic was introduced. The JR 12X we were using has a selectable (on or off) linearizing function built into the swash mix page called EXP which pretty much cleaned it up. They likely assume you are using JR servos, but the big Hitecs we used have a pretty close transfer function (angle/micro sec) so it worked.

As you said, it is pretty strait forward in OpenTx to add a common mixer at the servo outputs to "linearize" their movement, which is plenty "good enough". I put that in the two quick files I ginned up earlier. The nice thing with OpenTx of course is that you have the full capability to tune this kind of stuff to perfection ------ if the weather is too bad to fly:-)

I am not sure what the story is with the FBL guys. As you say, the small interactions with 3 servo are going to be masked by the "I" in PID during maneuvers. I use MS Brain and 3 servo so the issue has never come up. Out of interest, I will dig around a bit.

Also - nice work generating the Heli tool in OpenTx - I used it to set up my only flybar helo to prove to a friend that Open Tx would support helos without having to design your own program! At the moment I don't know of anyone else in my area flying helos on Open Tx

Regards,

Jim Davey
__________________
teamdavey
teamdavey is offline        Reply With Quote Quick reply to this message
Old 01-05-2018, 08:24 PM   #47 (permalink)
Registered Users
 

Join Date: Jan 2018
Default

how different would the programming be for a 90* swash, compared to the 120*?
jacobault2001 is offline        Reply With Quote Quick reply to this message
Old 01-06-2018, 12:37 AM   #48 (permalink)
HF Support
 
Posts: 6,850
Thread Starter Thread Starter
 
My HF Map location
Join Date: Jan 2013
Default

Quote:
Originally Posted by jacobault2001 View Post
how different would the programming be for a 90* swash, compared to the 120*?
3 servo 90 degree swash is pretty easy. CYC1 is the elevator servo, CYC2 and CYC3 are the left and right aileron servos.

The OpenTX swash type supports this already (120, 120X, 140 and 90).

Most FBL units also support 90 degree swashes.

the 140 swash assumes the left and right connection points (CYC2 an CYC3) for the swash are the same distance forward as the elevator connection (CYC1) is back. A 140 swash works well for ensuring the speed of elevator and aileron tilt is consistent.

Most helis use 120 swashes just for convenience.
__________________
TRex 700E Pro DFC HV (BD3SX) - Gaui X5 (6S/BD3SX), Blade 130X, RealFlight, Heli-X, Taranis+DSMX
ArchmageAU is offline        Reply With Quote Quick reply to this message
Old 01-07-2018, 01:03 AM   #49 (permalink)
Registered Users
 

Join Date: Jan 2018
Default

ok thanks, but what would the differences be when programming the transmitter? no servo mixing?
jacobault2001 is offline        Reply With Quote Quick reply to this message
Old 01-07-2018, 05:33 AM   #50 (permalink)
HF Support
 
Posts: 6,850
Thread Starter Thread Starter
 
My HF Map location
Join Date: Jan 2013
Default

Quote:
Originally Posted by jacobault2001 View Post
ok thanks, but what would the differences be when programming the transmitter? no servo mixing?
CCPM in OpenTX means:
  • Making inputs for Aileron, Elevator and Collective
  • Programming the heli tab with swash type (120, 120X, 140 or 90) and weighting of horizontal, lateral and collective inputs. (Weighting can be negative).
  • Using CYC1, CYC2 and CYC3 in mixes instead of inputs for Aileron, Elevator and Collective.

On the model, use direct RX to Cyclic Servo connections (assuming FB model to do mechanical stabilisation).

That is pretty much all of it.
__________________
TRex 700E Pro DFC HV (BD3SX) - Gaui X5 (6S/BD3SX), Blade 130X, RealFlight, Heli-X, Taranis+DSMX
ArchmageAU is offline        Reply With Quote Quick reply to this message
Old 01-07-2018, 12:15 PM   #51 (permalink)
Registered Users
 

Join Date: Jan 2018
Default

ok, thank you. that makes sense.
jacobault2001 is offline        Reply With Quote Quick reply to this message
Old 11-22-2019, 11:19 AM   #52 (permalink)
Registered Users
 

Join Date: Nov 2019
Location: Gretton, UK
Question Trouble writing programme for ccpm helicopter

My brain is frazzled so I hope for a bit of advice on this subject.


I am using a Taranis X9D+ running OpenTx 2.1.9 with applicable Companion for Windows.


I'm transferring my helicopter flying from my old Futaba T9C and I have successfully generated a program on Companion/Tx for my Sceadu 50 Evo helicopter with conventional cyclic control. I now wish to generate a program via Companion/Tx for my other Sceadu 50 Evo which has a ccpm swash and flybar, therefore need ccpm mixing in the transmitter.


I like to use templates generated by others as the best way into complex programming so when I found this thread, near the beginning I found templates for ccpm programs which I have downloaded, read into Companion and worked on to provide a fairly straightforward listing. On reviewing the servo outputs I find that waggling the right hand stick is ineffective in moving any of channels 3, 4 and 6 from their current positions although they do move in response to the LH, throttle stick. I think that original eepe listing was generated for an earlier version of OpenTx but is converted appropriately by Companion on reading it in. So 2 questions:


- where am I going wrong?
- should I update to OpenTx 2.2.4


I think I do not want to go to 2.3.x as I'm using a lot of V8/7R type receivers.


Advice appreciated, maybe link to more appropriate template .eepe. ? Thanks.


Jerry
Scram is offline        Reply With Quote Quick reply to this message
Old 11-25-2019, 05:58 AM   #53 (permalink)
Registered Users
 

Join Date: Nov 2019
Location: Gretton, UK
Default Update - trouble writing program

The previous is not quite what I had written, somehow a fair bit got deleted (??).


In fact I posted the above message a few days ago on Openrcforums but got no response probably because there are few there fly this type of heli.


In fact I have now updated my X9D+ to OpenTX 2.2.4 but this has not solved my difficulty.


The heli .eepe file is now an .otx file. I cannot attach it here so if any will look at it, PM me your email address and I will send it.


Thanks, Jerry
Scram is offline        Reply With Quote Quick reply to this message
Old 11-28-2019, 10:34 AM   #54 (permalink)
Registered Users
 

Join Date: Nov 2019
Location: Gretton, UK
Default Found the answer

At last I have found the solution to my difficulty, of all places, probably the first place I should have looked - had I found it.


The solution I found in the Section 9 of the OpenTx 2.2 Manual, that is one of the How to sections. This covered programing for ccpm in the Tx.
Scram is offline        Reply With Quote Quick reply to this message
Old 12-28-2019, 07:22 PM   #55 (permalink)
Registered Users
 

Join Date: Jan 2014
Default Totally Confused...

I started flying helicopters back in 1990. I had 2 Concept .30s, a Schluter Superior .60, and a Miniature Aircraft X-Cell .60. I started with a JR HeliMax 6 and then moved to a JR X-347.

Life intervened and I had to sell every thing.

Fast forward. I got a simple 450 and a cheap radio. Kept the heli, bought a FlySky Th9x. Life was good. Built a semi scale Hughes MD-500. Went flybarless with Tarot ZYX S2 gyros. Life was still good.

Got into multirotors. Bought a Taranis X9e. Life was awesome. Upgraded the TH9x with an AR9x board running OpenTX. Also bought a QX7...and several multirotors....


Haven't flown the helis in a LONG time. Broke them out this week and ran into problems. Put the pod and boom back to a fly bar configuration.

Can't for the life of me figure out how to setup CPPM in OpenTX 2.3.4. I've read a bunch of stuff that just sounds like gobble dee gook that has no logical progression or even a complete step by step description.

Another thing I don't get is if OpenTX is so gawd awful powerful, why do I need to dig up some dark ages alchemist to get my radios to speak CPPM when my old TH9x did it out of the box?

Will some one please point me in the right direction?
Oldgazer is offline        Reply With Quote Quick reply to this message
Old 12-29-2019, 06:46 AM   #56 (permalink)
Registered Users
 

Join Date: Jan 2014
Default Problem Solved.

Flashed the radio with ErSkyTX.

Includes a template for a 450 Heli.

Many thanks to Mike Blandford.
Oldgazer is offline        Reply With Quote Quick reply to this message
Reply




Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the HeliFreak forums, you must first register.
Please enter your desired user name, your REAL and WORKING email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself. Use a real email address or you will not be granted access to the site. Thank you.
Email Address:
Location
Where do you live? ie: Country, State, City or General Geographic Location please.
Name and Lastname
Enter name and last name here. (This information is not shown to the general public. Optional)
Helicopter #1
Enter Helicopter #1 type and equipment.
Helicopter #2
Enter Helicopter #2 type and equipment.
Helicopter #3
Enter Helicopter #3 type and equipment.
Helicopter #4
Enter Helicopter #4 type and equipment.

Log-in


Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




Copyright © Website Acquisitions Inc. All rights reserved.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.

SEO by vBSEO 3.6.1