Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Radio Equipment => Topic started by: johnf on August 31, 2018, 01:44:40 pm
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Hi everyone,
Could anyone tell me how to programme my 2.4Ghz TX to provide separate control of 2 shafts with rudder off the standard 2 sticks to enhance a model's turning circle in harbour.
I understand the old idea of using a separate "mixer" to speed up or slow each motor according to rudder settings. However, with modern programmable TXs, surely it is possible to "mix" the rudder with the two ESCs to give such an important function. Indeed, I am pretty sure I have read corresponding articles in model boat magazines.
I have tried everything pushing countless buttons and looking through old magazines but have failed to date. I have an "all singing and dancing" HK Orange DRX Spectrum DSM2 compatible TX together with the popular FlySky FS i6 and the somewhat simpler Spectrum DX5i with aileron/elevator mix switch.
I am sure this will be of interest to numerous model tug skippers - so please help if you can. <:(
Dr John Fowler Leeds & Bradford MBC
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The basic idea of using a mixer, whether software in the transmitter or hardware in the boat, is that one stick (the throttle) provides speed information, the other (rudder) control provides distribution information to control the relative speeds and directions of the two motors. the rudder stick (certainly in the hardware type) can also work the rudder. A second throttle stick is not needed, unless a third motor is involved.
Going from automatic mixing to manual tank steering would probably involve a change of profile in mid sail. This might or might not be possible. I'm just guessing since I don't have that kind of transmitter, but two conflicting sets of logic in the same box rarely works.
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I think that one of the problems in using the internal mixing facilities in the TX can be that they are set up for aircraft use (V Tail I believe) and do not act on the channels needed for controlling a model boat. These complications are why people tend to buy dedicated mixers.
There is a cheap and cheerful solution which I use on my fishery cruiser model. Each motor has its own ESC and is controlled separately by the two vertical TX sticks which gives tank steering. I have then used the undercarriage toggle switch on the TX to trip a switch on the RX which cuts out the signal from the right hand TX stick and transfers it to the left hand stick so that both motors are controlled from the Left hand stick together. This means that for general sailing around the pond I can run the two motors together and just rely on the rudder for steering but at the flick of the undercarriage switch revert back to independent tank steering for close quarters manouevering.
It works fine.
Colin
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Sorry for the typos - was in a bit of a rush earlier!Colin
Typos corrected.
Peter.
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I think that one of the problems in using the internal mixing facilities in the TX can be that they are set up for aircraft use (V Tail I believe) and do not act on the channels needed for controlling a model boat. These complications are why people tend to buy dedicated mixers.
There is a cheap and cheerful solution which I use on my fishery cruiser model. Each motor has its own ESC and is controlled separately by the two vertical TX sticks which gives tank steering. I have then used the undercarriage toggle switch on the TX to trip a switch on the RX which cuts out the signal from the right hand TX stick and transfers it to the left habd stick so that both motors are controlled from the Left hand stick together. This means that for general sailing around the pond I can run the two motors together and just rely on the rudder for steering but at the flick of the undercarriage swaitc revert back to independent tanl steering for close quarters manouevering.
It works fine.
Colin
Hi Colin, have you got a wiring dia. For that tx mod please, I like the idea very much.
John
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John,
Not immediately available I'm afraid, I wired it some years ago, the baot had a long construction period!. I will try and sketch it out and put it up on here within a day or so.
Colin
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Bingo! I vaguely remembered that I might have done a rough diagram which I saved on my PC and here it is!
You just need a simple latching switch which mimics the action of the retract switch on the TX by switching the signal input wire to the right hand ESC from the RX right stick signal output to the left stick output. I think the diagram makes it clear.
There are lots of R/C switches available but you need one suitable for retract gear i.e. it stays where it is set until you change it back. Not all of them do that. I am not sure which would be the most suitable switch these days but no doubt someone on here can recommend one.
Colin
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you can do this with a servo and microswitch if you want, rough as, but it will work. an RC switch would be a tidier solution.
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Thanks guys, I get it, switching the signal wire from one esc to the signal wire of the other
Esc through a rc / mechanical switch creates a Y lead to the left stick.
Is that correct.
John
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Yup, that's it.
Colin
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I think that one of the problems in using the internal mixing facilities in the TX can be that they are set up for aircraft use (V Tail I believe) and do not act on the channels needed for controlling a model boat. These complications are why people tend to buy dedicated mixers.
Colin
If you buy one of the more advanced transmitters you can program the channels to whichever stick you want. e.g. vtail mixing is normally on rudder and elevator on planes, this is left hand stick for rudder and right hand stick for elevator on a mode2 set. this could be reprogrammed to give elevator on the left handstick, forward and reverse used for speed control and motor steering on the left stick, left to right. The vtail mix will then mix both channels together. The right stick , left to right can be used for the rudder for normal steering. Most transmitters will have programmable free mixing for more advanced setups.Of course if you just buy the cheapest set such as a Planet you lose any such ability.
Jim
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Yes Jim, not everyone wants to buy the more expensive sets for a relatively simple model boat setup. Horses for courses really. The arrangement in my fishery cruiser does all I need really with its handling combination.
Colin
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The method of using "Vitail" mixing in Mode 1 to give twin screw model conventional rudder/motor control with the option of motor steering, was fully described in the Feb issue of Model Boats.
If the transmitter has the mixing functions you need, it does seem unnecessary to buy extra bits. But there again you do have to read the instructions that ought to have come with the radio outfit.
Glynn Guest
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Apologies my previous post was missing the last paras, moderator please remove.
I have just purchased an FS-i6 for £34 post paid from a UK E-bay supplier. I already have the FS-i6s but wanted to have model names hence the new purchase. The radio has memory for 20 models and remembers all the settings for each model. First job is to name your model and save the setting. Press and hold the OK button select System Setup move to model name, choose a number then give it a name. You need to press and hold the cancel button until the screen changes or the settings will not be remembered!! Select the model you have named
I use Aero Mode2: channel 1 (right horiz stick, centre spring) for my rudder;
channel 3 (left vert stick, no spring) for the motors
I use receiver channel 1 for the rudder
Channel 3 for 1st ESC
Channel 6 for 2nd ESC
Mixing[]
Select Functions from the Menu then Mix
Select Mix1; Mix is On; Master Ch1; Slave Ch2; Pos-mix -20%; Neg-mix -20%; Offset 0%. Press and hold the cancel button until the screen changes
Select Mix2; Mix is On; Master Ch3; Slave Ch6; Pos-mix 100%; Neg-mix 100%; Offset 0%. Press and hold the cancel button until the screen changes
Select Mix3; Mix is On; Master Ch1; Slave Ch3; Pos-mix 20%; Neg-mix 20%; Offset 0%. Press and hold the cancel button until the screen changes.
Move back to Display and press OK.
The channel stick positions are displayed.
Moving Ch1 rudder shows full movement
Moving Ch3 ESCs shows Ch3 and Ch6 movement. Moving Ch1 at the same time shows Ch3 and Ch6 increasing or decreasing.
There is the adjustment movement on Ch3 and Ch6 when the ESC Ch3 is at neutral but this should not pose a problem as normal practice is to move ahead or astern before moving the rudder.
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hi there Colin
What speed controllers did you use when you were switching the signal on/off? because using modern day speed controllers - when you switch the signal off, and then back on, they sometimes reset themselves at Zero - wherever the throttle stick is positioned on the handset.
In other words, if you are running two speed controllers off one channel - and say you are running at half speed, you switch one of the speed controllers off (say, for arguments sake the portside speed controller) then switch it back on - where your transmitter throttle stick position is set - this will now become the midway position for the portside speed controller, if you follow what I mean :-)
so therefore when you bring your throttle stick back to neutral for the starboard speed controller, the port one will still be running at half speed - due to the fact that it has reset itself at a different position.
In 'olden days' when the very early ACTion speed controllers & Electronize you could switch on/off quite easily using the signal wire as they did not have the technology built into them for memorising the stick position.
John
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Hi John,
Yes, I do see what you mean. Not at home at the moment so can't check but they are quite old controllers and would be of the more simple type. Sometimes progress isn't progress I feel, having fitted a brushless/LiPo setup in latest model whch needs careful managing, cell balancing and the correct charging regime.
Just like computers really. Used to be just switch on and go!
These days I would use a mixer as they don't break the bank.
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Hi all, good point about switching signals and coming back to a new neutral.
I remember an old mixer I had that shared the full signal across two servos and you only got half the movement on each servo being mixed.
Have the new ones got a full movement of the mixed servos?
regards
Roy
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Thank you Dave for those settings.
I have the FS-10ch but hadn't reached your level of sophistication. Just using 2 mixes so far. Will try yours out before next launch.
Thanks
Gerrit
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Hi Gerrit
Glad to have helped. I should have mentioned you need to set your chosen second channel to none so that no other stick or switch interferes with the mix. Haven't tried it but if your motors are not matched using say VRB on ch6 allows you to make slight adjustments. The adjustment need to be small and works from the centre position of VRB.
Enjoy and please post your experience as this is very much in the early stages of development
Dave
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Hi Dave
Got it set up, only testing using the display for now.
Ch 6 doesn't change with movement of Ch 1 (rudder), only Ch 3 ESC moves a bit.
Not sure what you meant by 'setting second channel to none'?
I do have VrB as Trim for Ch6
They only draw back I see so far is that I loose using Sport/Normal mode switch to tone down my throttle. That switch only works on Ch 1,2 and 4 :-(
Gerrit
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Hi Gerrit
Sorry when I said second channel I was referring to the channel you had selected for the second ESC ie ch6. Any other control on Ch6 will overide the mix. As you have VrB also on Ch6 this needs to be in the central position or it will override the mixing. Slight movement of VrB either side of the central position will act as Trim, but it needs to be slight. I suggest you turn this off initially to see the mixing effect.
I agree you can't use Ch3 with the Sport/normal, but you can use Ch2 in place of Ch3 and that should work. All control is then on the right stick
OR Switch to MODE1 and Ch2 and Ch3 sticks reverse position(sides) and you just need to re program your settings, changing Ch3 to Ch2
Hope this helps
Dave
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Hi Everyone,
Many thanks for all the replies to my original post.
I have concluded that my 3 TXs do not have the "stick to channel" feature found on the best systems. Thus I cannot have the Throttle/Rudder or Aileron/Throttle mix I need.
I really cannot do "tank steering" with a separate rudder. However, I will try switching a TX from Mode 2 to Mode 1 and programming an existing V-Tail or Elevon mix to see if that does the job.
with best wishes John %%
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Hi Dave
Sorted:
I switched to Mode 1, Ch 4 RH side horizontal is now rudder. Ch 3 LH side vertical is throttle.
Mixes:
1- Master Ch4, Slave Ch6, -25%
2- Master Ch3, Slave Ch6, 100%
3- Master Ch4, Slave Ch 3, 25%
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Hi Gerrit
Glad to have helped. Please update on actual on water usage, thanks.
Hi John
In your original post you said "I have an 'all singing and dancing' HK Orange DRX Spectrum DSM2 compatible TX together with the popular FlySky i6 ..."
My solution was based on the FlySky i6 with firmware version 2.0 16-Aug-2017. If your FS-i6 has an earlier version it may need to be upgraded to at least this version.
I do not use the built in Elevon and V-Tail mixes as they restrict the channels you can use. I used the three Mix settings selected just above the Elevon and V-Tail on my Tx screen. This will allow you to choose which channels to mix unlike the Elevon and V-Tail settings.
Hope you can get your setup to work. As an ex flyer I can appreciate your problem with multiple controls but your i6 set is certainly capable of providing the solution and at fraction of the price of other named offerings.
I am no expert on the Spectrums but suspect they could also be made to do similar mixes.
Dave
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Okay, I have been reading this thread on and off, and my itty bitty brain says,
Put your throttles on the Elevator channel and mix, for Vtail, on the rudder.
So the elevator would be up(fwd) and down(rev) and rudder would then
control the rudder, and slow one motor in a turn.
Isn't this what needs to be done, or is it just not that simple. :((
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I agree this may work in some situations but requires a y-lead for the ESCs which means you lose the ability to reverse individual motor direction. I well remember using such a set up in my flying days with two servos for which this mix is designed. Using Elevon results in Ch1<=Ch2+Ch1 and Ch2<=Ch2-Ch1 so the rudder will also be affected by the other channel.
Using the mix function, one stick and channel control the rudder, whilst another stick controls the ESCs by two channels. The rudder also mixes its output with each ESC channel to increase or decrease the speed.
FlySky have developed their Tx to cover all forms of modelling and the Mix function certainly makes the Tx more model boat friendly. For simple setups it is comparable with some of the functions found on my Taranis but at a fraction of the cost.
Hopefully more people will develop their skillsets to take advantage of the new equipment and functions and share their experiences for all our benefit.
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Despite the warning this is an old topic, I think I'd be better to abandon this thread https://www.modelboatmayhem.co.uk/forum/index.php?topic=66150.new#new and resume here.
I will digest the previous posts w.r.t. my intention to run two motors on a tug with something like "tank" steering. I note that the "mixers" use two channels to integrate rudder with differential motor speed and direction. I'm thinking of keeping rudder separate on the RH Tx stick (I have a 9-channel plane/helicopter Tx) and using the left stick as up/down for motor power and left/right for left/right motor mix. But perhaps the mixers like these https://www.componentshop.co.uk/action-electronics/mixers-multifunction.html give a more practical result, and presumably the 2 channels could both be off the left stick. I'm thinking of a bow thruster as well and that could be on the right stick.
I admit this is my first boat project although I've good experience with RC electronics in aircraft and have programmed microprocessors (I had thought of doing my own mixer with Arduino but it seems unnecessary). I'd appreciate any feedback on the likely manouverability with these systems and in particular the merits of having separate vs integrated rudder channel.
Cheers
Nelson
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Looking further, My transmitter, JR DSX9, has mixing functions and also you can control ailerons with one stick throw using two channels and two servos, so that should be able to be hacked to produce differential throttle on 2 motors.
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Looking further, My transmitter, JR DSX9, has mixing functions and also you can control ailerons with one stick throw using two channels and two servos, so that should be able to be hacked to produce differential throttle on 2 motors.
And pricewise, there's not much difference between a P94 mixer with built in ESC's, and just 2 ESC's like this https://www.rchobbies.co.nz/dynamite-dyns2210-wp-60a-fwd-rev-brushed-esc/ with the mixing done in the TX.
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Looking further, My transmitter, JR DSX9, has mixing functions and also you can control ailerons with one stick throw using two channels and two servos, so that should be able to be hacked to produce differential throttle on 2 motors.
I think the answer is to change the "model" to Mode 1 (the Tx is assembled as Mode 2 with left stick for throttle un-sprung) then use V-tail mixing which would for aircraft put rudder and (two-channel) elevator on left stick, and wire the 2 motor ESC's to the 2 elevator channels on the Rx. Hopefully the various "elevator" and rudder parameters can be tweaked to get the steering required.
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Morning All
My input on this, I have a twin motor Aquarama in build. And started out with a Futaba 6EX. I wanted independent ESC control but also some mixing with the rudder. I achieved it by enabling V-Tail mixing on the TX, and switching my TX to Mode 1 got the sticks into the 'right' place. I created a test rig to figure it out and test, results are here:
https://youtu.be/wmmUGpZXJyA (https://youtu.be/wmmUGpZXJyA)
Since that I've run out of channels on the Futaba, so have taken the plunge with an FrSky QX7S TX and R8 Pro RX, as others have said, bit of a learning curve but once learnt the possibilities are many...
My current programming here:
https://youtu.be/MLLzn5WOcZI (https://youtu.be/MLLzn5WOcZI)
Similar basic control as the Futaba, but tweaks aimed at improving control.
So my aim is not exactly two motors from two sticks, but an approach where the TX takes the mixing strain and I use the TX in a more conventional way.
Best regards
David.
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Glad to hear that the TOM (Together Or Mixed) method of twin motor control works for others, previously published in the Feb 2018 issue of Model Boats.
As many might not have access to this issue, I could (time readily available courtesy of the latest "lock-down") write out a brief description of this method?
Glynn Guest
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Please do, always interesting!
I managed to program my radio so that I by flicking a switch can choose between no mix, combined motors, mixed motors, mixed motors and thruster and mix to have all things combined to crab/go sideways on one stick.
Don't ask how I did it {-) I did try to explain it in a thread here but don't think I succeeded.
Hama
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Please do, always interesting!
I managed to program my radio so that I by flicking a switch can choose between no mix, combined motors, mixed motors, mixed motors and thruster and mix to have all things combined to crab/go sideways on one stick.
Don't ask how I did it {-) I did try to explain it in a thread here but don't think I succeeded.
Hama
Edit: found the thread
https://www.modelboatmayhem.co.uk/forum/index.php/topic,49976.msg509345.html#msg509345 (https://www.modelboatmayhem.co.uk/forum/index.php/topic,49976.msg509345.html#msg509345)
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OK here goes, the TOM (Together Or Mixed) electric motor control method sailing using a transmitters internal mixing circuits.
Firstly, you need a transmitter with two dual axis stick units and the option to have "V-tail" mixing. This means that the functions of Rudder and Elevator are combined into to control the two separate surfaces on the "V-tail" of a model aircraft with two servos.
It also makes life a lot easier if the transmitter is in "Mode 1". This refers to the way our aeromodelling cousins fly their models, see attached figure.
With the transmitter in Mode 1, the rudder servo is plugged into what the flyboys would call the Aileron socket of the receiver and the ESC's are plugged into the Elevator and Rudder sockets, see figure.
Now the horizontal moment of the Right-Hand transmitter stick should operate the models rudder as normal. Also normal will the motors response to the vertical movement of the Left-Hand stick i,e. push the stick up and the model moves ahead, pull it down and the model goes astern.
But, the clever bit is that if the Left-Hand stick is moved horizontally then the motors will rotate in the opposite directions. Combinations of the vertical and horizontal movements of this stick can either tighten a models turn or allow it to rotate "on the spot" and anything inbetween.
It might not work exactly right at first but adjustments are easily made (usually swapping the motor wires or the receiver sockets the esc's are plugged into and maybe the servo reversing switches). I've often set the controls up out of the model using servos (easier to see when they move in the same or opposite directions).
I find this method of sailing such an equipped model is more natural and in emergencies my instinctive "rudder-throttle" control is safely reverted to. Plus, it's nice to use something I've already paid for in the transmitter....
Glynn Guest
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My JR DSX9 Tx allows twin motors with separate throttle curves (for twin-engined aircraft). I can add in mixing from the rudder that has it's own response curve. And with a switch the mixing can be turned off for synchronous motors plus rudder for normal cruise. All on the conventional (for here and the US) mode 2 with throttle and rudder on the left stick. Sorry - just saw the recent posts - I don't seem to be getting notifications.
Cheers
Nelson