Apr 07, 2013, 09:31 PM
Registered User
Joined Mar 2011
6 Posts
Discussion
Motor Mixing Problem

Hi Guys,
Can any help me with a motor mixing problem.
Our task is to design an ROV, but it must have vectored thrusters as shown in picture.
The picture also shows what motors must turn depending on the direction of the joystick.
Can anyone advise me on how I would mix the 5 ESC to achieve this.

Much apprecaited
Yorkie.

# Images

 Apr 09, 2013, 05:47 AM Metallica Londonderry UK Joined Nov 2004 415 Posts Hi Yorkie I replied to your PM, just for others info Yorkie is going to use servocommander for control so if anyone has experience with this chip in. Mmmm shame they dont do a demo of the software that had no output/limited time use or something like that so I could play about with some cross channel mixing.. Last edited by robe_uk; Apr 09, 2013 at 06:00 AM.
Apr 09, 2013, 06:38 AM
Metallica
Londonderry UK
Joined Nov 2004
415 Posts
Try this just to see what the servocommander software does, just working with Joystick B to start with.
Lets begin by defining what channels the esc are actually are connected to,

motor 1 = channel 11
motor 2 = channel 12
motor 3 = channel 13
motor 4 = channel 14

Now assign the joystick axis to a channel

Axis 1 (forward/backward) = channel 1
Axis 2 (left/right) = channel 2

Right here things get a bit messy, as some mixing is required and the motors are required to rotate in opposite directions depending on position of the joystick, so we will have to use and addition channel that has been inverted to aid in mixing, I will use channel 3, see picture where to invert.

So to move forward/backward

channel 1 mix channels 11+12+13+14

now the left/right

channel 3 mix channels 12+13

channel 2 mix channels 3+11+14 (because the channel 3 is inverted motors 2 and 3, remember we assigned them to channels 12 and 13, will spin the opposite way to 1 and 4)

Well try that and let us know how the software behaves, hopefully it will SUM the mixes to the esc's and give smooth control, if this works I may be tempted to change direction on my own project.

Good Luck
Rob