Deadband Help

[Ether]

Originally Posted by Ether

Let "J" be your joystick value, in the range -1 to +1.

Let "d" be your desired +/- deadband.

Let "out" be your modified joystick command (incorporating the deadband).


Then:

if (J>d) out = (J-d)/(1-d);

else if (J>-d) out = 0;

else out = (J+d)/(1-d);

"d" is the deadband tuning parameter in the range 0 <= d < 1

Attached is a graph of what the above code produces for d=0.2:

[garyk]

Another way to create deadzone-behaviour is to square the joystick X, Y, or Z value (and preserve the original sign, so a negative joystick value gives a negative result). For example, a js value of 0.5 gives a square of 0.25, but the maximum value of 1.0 still gives 1.0.

The way I learned this is an example of why I love to be a mentor. I'd written the algebra to implement a dead zone and with two slopes - it was complicated and when I tried to teach it at a WRRF programming workshop I confused most of the students. Afterwards a student (I think from FRC1700, Gatorbotics) told me about the square trick - it did what I wanted and was far easier to teach and implement.

[Ether]

Originally Posted by garyk

Another way to create deadzone-behaviour is to square the joystick X, Y, or Z value (and preserve the original sign, so a negative joystick value gives a negative result).

Or use a simple function as shown in the attachment and you can adjust the sensitivity to suit your taste.