Motor Control

I am trying to set our arm to break when we let go of the joystick instead of it dropping back down, does anybody know how to do that? I believe we used a TalonSRX.

using LabView

Is your TalonSRX set in brake mode? Should be a button that can be pushed on motor controller to set mode. Without knowing more about your bot, it is difficult to see if a programming solution will help. Can you described in more detail what is actually going on?

Honestly… No Idea lol, I figured it was a coding thing but we cant touch the bot until the competition so we’ll have to check it there.

Might be something that can be fixed with code. What exactly is happening?

when we use the arm to aim our launching mech it slams back down where we would like it to hold its position

Are you trying to set/aim the mechanism manually, i.e. using the joystick to control up/down until it is in the right position?

This may not be purely a LabVIEW/control issue. There may be mechanical/design work to do as well in order to get that to work properly. Setting the speed controller to brake mode will be a good first step, but that often doesn’t provide enough force on its own to keep an arm elevated.

Can you provide as much information as possible regarding the design of your arm? What motor are you using? What gear ratio? How long is your arm? How heavy is it? Do you have any sort of counter-balance?
A picture may actually do wonders here.

Beyond that, how are you controlling your arm? Are you using Motion Magic on the Talon SRX? In Motion Magic, you can get a “gravity compensator” that can help maintain elevation. You can also develop a PID controller in your code or using the Talon SRX to try and maintain position. Information regarding a lot of the “smart” features of the Talon SRX can be found on the CTRE website.
http://www.ctr-electronics.com/talon-srx.html#product_tabs_technical_resources


However, any programmatic solution to holding the arm position is going to rely on stalling the motor that powers your arm. Depending on the motor selection and gear reduction involved, that may end up being something that could damage your motor. You may want to examine ways to adjust your design to hold position with minimal motor power applied. Look at adding more reduction, adding some sort of counter-balance (surgical tubing, constant force spring, gas shock, etc), or using some sort of mechanical braking mechanism.

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It is pretty much free floating, it has the ability to flip from one side of the bot to the other… so forward is up and reverse is down.

If you can provide pics or video like Lil_Lavery suggested above, we might be able to offer some suggestions. I would hate to provide a suggestion without a better idea of your mechanism operation which would cause you to burn up motors.

I’m sure I have a video somewhere, or one of my team members has one.