Tank Drive

[Idaman323]

We need help with using two joysticks with a tank drive system. I do believe the default code is only one joystick. If there is code somewhere, documentation, or even your help, it would help greatly, thank you!

[AIBob]

Tank drive is very simple to program, and I believe that it is included in the default code, as an option. but here is what you would use as the code:

pwm01 = p1_y;   //change 01 and 1 to appropriate joystick and pwm output
pwm02 = p2_y;   //change 02 and 2 to appropriate joystick and pwm output

Thats basically it...
You put that in the function 'User_Driver' in place of whtever code you used, and its tank drive.

[Goobergunch]

In the version of the default code that we use (not sure which one it is), the above code is included under Default PWM Mappings.

[Idaman323]

I got the default code off of innovation first's documentation part on their website.


Where is the User_Driver function within the code?

[AIBob]

Originally Posted by Idaman323

Where is the User_Driver function within the code?

It is located within "user_routines.c".

[Idaman323]

AHHH I cant find it anywhere in the thing

there isnt any function it...

[Orborde]

Er...it's in Default_Routine, not User_Driver

[AIBob]

OK... my team renamed that too, I just do not remember what we changed from the default code from last year, sorry.
It should be 'Default_Routine()'

[russell]

It is part of a long list which maps the joystick inputs to pwm outputs. Its about ten lines long, they all look about the same (number=number, and its about half or 3/4 the way down user_routines.c

[Idaman323]

So as long as I hav ethat included it should work?

[probizzle]

Originally Posted by Idaman323

So as long as I hav ethat included it should work?

Depends.

On our bot last year, the motors were placed such that we had to reverse motor output to one side.

So,

pwm01 = p1_y; //put the joystick input to motor output directly
pwm02 = 255-p2_y; //reverse this motor

worked. You might need this depending on how your gearboxes/motors are put in. I'm guessing you'll have to reverse one (try which one) of the motors.

And this is, of course, assuming you are using one motor for left drive and one motor for right drive (no more no less).

[Goobergunch]

Originally Posted by probizzle

And this is, of course, assuming you are using one motor for left drive and one motor for right drive (no more no less).

Or if you have two motors for each drive (four total) and the two motors on each side are connected via the yellow-red-black PWM cables to one PWM Output on the RC, like we did this year.

[Idaman323]

Should I comment/delete (not sure what would be better) out the stuff i don't need, like p1_x and p2_x, or does that need to be there for the bot to run?


And Ive only had a little of coding experience but wouldn't making the one motor go backwards be pwm02 = p2_y-255; not pwm02 = 255-p2_y; or did he have it right before?

And one more thing, in Deafault_Routine, there is a section titled, 1 Joystick Drive, and it combines the x, y on one joystick port.. Should i take this out?

[AIBob]

Originally Posted by Idaman323

Should I comment/delete (not sure what would be better) out the stuff i don't need, like p1_x and p2_x, or does that need to be there for the bot to run?


And Ive only had a little of coding experience but wouldn't making the one motor go backwards be pwm02 = p2_y-255; not pwm02 = 255-p2_y; or did he have it right before?

And one more thing, in Deafault_Routine, there is a section titled, 1 Joystick Drive, and it combines the x, y on one joystick port.. Should i take this out?

No.... you should leave them, as long as you do not send them to the pwms
No.... if you put in 0, it would leave you with -255, which is not an unsigned char and will give you an error.
Maybe.... You should comment this section out for later use

[Idaman323]

Okay I think I got it. Thanks for all of your help.