Labview and programming gradual start/stop

[crollison]

How do you program so that the robot has to gradually start/stop. We are a little top heavy and need to reduce inertia. Looking at the examples and I don't think that the Joystick Response Curve is the right thing? Thanks for any help.

[pastelpony]

What do you mean "gradually start/stop" ? Do you want to throttle the speed of your drivetrain?

[crollison]

So that when you jam the joystick forward, it doesn't immediately go full speed.

[pastelpony]

Originally Posted by crollison

So that when you jam the joystick forward, it doesn't immediately go full speed.

Multiply your joystck inputs by their absolute value. This squares the inputs, only allowing full speed at a full push. For example, what would normally be 0.5 would be 0.25 and -0.9 would be -8.1 etc.

[wt200999]

Originally Posted by pastelpony

Multiply your joystck inputs by their absolute value. This squares the inputs, only allowing full speed at a full push. For example, what would normally be 0.5 would be 0.25 and -0.9 would be -8.1 etc.

If you look closely at the Tank Drive and Arcade Drive VIs, this is already done for you by default. Though this will not accomplish what was asked. If you jam the joysticks forward with the squared inputs, you will still go full speed immediately.

What you are asking is described fairly well here starting at post #8: http://www.chiefdelphi.com/forums/sh...d.php?t=125439

I attached a LabVIEW example at the end in post #10. If you search for the VI "PID Output Rate Limiter" you will get a VI that works well for this, and you can adjust the ramp time.

[Nyxyxylyth]

If you're using CANTalons, consider letting them do the heavy lifting by using Set Voltage Ramp. See 6.1 in the TALON SRX Software Reference Manual. Consider something like 0.33 (1 second for 0-33%; 3 second ramp from 0-100%).

[Chris Hibner]

Use the PID rate limit VI which can be found in the control & simulation -> PID palette.

See attached image.