April 23, 2017, 07:31:08 pm
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Author Topic: Steering help on Viper Kit  (Read 182 times)

CaptainXJ

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Steering help on Viper Kit
« on: March 15, 2017, 05:42:17 pm »
My GF and I are just starting out and we bought the Viper kit with the flipper attachment. We have everything together exactly by the book, and everything works except steering. As per instructions the right motor is plugged into CH1 and the left in CH2. When pushing up and down on the stick the left wheel turns and pushing left and right turns the right wheel. I am assuming I need to program my transmitter for single stick driving but have had no luck locating any instructions on how to do so.


Silver Spark 33.3:1 Motors
tinyESC v2.4.1
Radiolink R7EH-S receiver
Radiolink T6EHP-E transmitter

Coboxite

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Re: Steering help on Viper Kit
« Reply #1 on: March 15, 2017, 09:00:19 pm »
You need to enable "elevon" mixing. I have no idea how your radio works, but it should be under the "MIX" option if it exists.


Alternatively, you can use a standalone mixer.

RevRobots

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Re: Steering help on Viper Kit
« Reply #2 on: March 16, 2017, 10:47:06 am »
Quote
When pushing up and down on the stick the left wheel turns and pushing left and right turns the right wheel.

Am I assuming correctly that the controls on the Transmitter are flipped 90 degrees? i.e. forward is turning and side to side on the joystick is forward and backward? If so, you just need to flip the polarity of one the motors by switching the solder joints.

Adam
Revelation Robotics

CaptainXJ

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Re: Steering help on Viper Kit
« Reply #3 on: March 16, 2017, 10:27:40 pm »
After some research based on your lead Coboxite, it seems my transmitter does not have the mix option, so it looks like I will be going the route of the stand alone mixer. Seems weight is going to be my biggest enemy on this robot.

Thanks Adam but that is not the problem, Coboxite hit on it.

AmbientChaos

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Re: Steering help on Viper Kit
« Reply #4 on: March 17, 2017, 07:52:08 am »
The issue here is that you have two separate channels on the transmitter (left-right/aileron and forward-back/elevator) that you need to act as two combined channels for controlling your drive motors.  As Coboxite said, the two ways to do this are to mix the signals at the transmitter end or to mix the signals at the receiver end.  For the transmitter end I think that most people have transmitters that are intended for planes or planes/helicopters, but it seems that you have a transmitter that is intended solely for helicopters.  I have much less experience with setting up controls for that type of control scheme, but I think that it may be do-able if more difficult than with a transmitter meant for planes.

For plane transmitters, elevon mixing is convenient because pushing one direction on the stick can give you an equal output on on two channels.  For a helicopter transmitter (and anyone that has actually tried this can feel free to jump in and correct me), I think that you would want to set your swashplate type to 3-S (this being a type of mixing for helicopter inputs), and then I think that you would want to change the AFR to set the aileron and elevator channels to +/- 100%.  I think that this could give you something that is functionally similar to elevon mixing, but I could be entirely wrong. 

If it does seem to work at least as far as motor direction goes, (assuming you have fingertech tinyESCs to go with the silver sparks) you can run the calibration on each ESC so that the maximum input it sees from each direction on the stick gets translated to maximum output for the wheels.

If it turns out that this idea doesn't work, I think that your options would be either to get a different transmitter that allows you to do elevon mixing or to add a receiver-side attachment to do the mixing for you as Coboxite said.  If you're sure that you're getting into this hobby for the long-term it might make more sense to invest in a transmitter with elevon mixing, otherwise it might mean having to add a standalone mixer into every bot you build/drive in the future.

RevRobots

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Re: Steering help on Viper Kit
« Reply #5 on: March 17, 2017, 10:31:58 am »
Ok man, no problem :)

rcjunky

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Re: Steering help on Viper Kit
« Reply #6 on: March 17, 2017, 01:15:09 pm »
Shouldn't have weight issues with just the viper kit with the lifter add on, did ya change anything else?
Andrew Burghgraef
Canadian Carnage Robotics

Great Hobbies- Canada's leading retailer of radio controlled models and related hobby supplies

CaptainXJ

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Re: Steering help on Viper Kit
« Reply #7 on: March 18, 2017, 12:45:26 pm »
AmbientChaos- This fix does work, thank you. I had played with it some but had no luck. Revisiting it with your advice I managed to get the steering (mostly) working. I appreciate it. I still ordered a separate mixer to see if it gives me more precise steering.

rcjunky- Yeah I have a custom flipper and some armor panels I plan on using. Just going to get a postal scale so I can tweak everything.

Camo5

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Re: Steering help on Viper Kit
« Reply #8 on: April 11, 2017, 11:36:47 pm »
an alternative method, is drive normally, where top left or top right is full forward - basically, the controls are rotated 45 degrees on the controller.