Off Season Control Systems

[spacepenguine]

Hi Chief Delphi,

I'm a few years out of first, but I'm thinking about taking up a special project with some former FIRSTers. What is the current favorite set of parts to build an off season control system with?

I'm familiar with the options from Cross the Road electronics, but I'm not sure I need something as heavy duty as I/O over CAN bus. It would be nice to be able to run programs locally (as opposed to being purely being remote I/O). I'm capable of building up everything from the microcontroller level, but we'd like to not re-create libraries/hardware that exist already.

Thanks!

[RyanCahoon]

Can you disclosure any details about the project?

What kind of sensor and control devices do you need to interface with? How much processing power do you need? Does the processor need to be x86-compatible, ARM-based, or does it matter? How comfortable are you with electronics - do you need something that will just work out-of-box, or are you comfortable hacking on the hardware a bit? What's your budget?

[spacepenguine]

Hi Ryan,

I don't mean to keep any detail of the project a secret, we just haven't defined most of the parameters yet. We're playing with the idea of building a FRC-like robot for the 2015 challenge during the week of Build18. For those not from CMU (incidentally like Ryan and I), this is a 1 week HW/SW hackathon during the first week of spring semester classes. This week also happens to be right in the middle of the build season.

The constrains are that we will likely only have $250-500 of budget that isn't coming out of our pockets. This budget doesn't need to include computers, joysticks/input devices, or metal/wood stock but does include the control electronics, speed controllers, sensors, motors, etc. Processor architecture is not a concern given that we can set up the cross compiler for it. I'm thinking we want something that is more powerful than an Arduino, since that can't really run an ip stack, but it definitely doesn't need to be more powerful than the cRios were. The group is junior and senior electrical and computer engineers, so we are capable of building up the control system from individual processors.

However, we don't think this would be a good use of a single week. What I'm hoping for is a system that already handles the teleop wifi connection and joystick input like the FRC drivers station does. I'm honestly not sure what the market for non-roborio controllers looks like right now.

[RyanCahoon]

Oh hey Ian - Sorry, I didn't notice it was you. Cool idea for Build18. Here's a couple of ideas off the top of my head:

Even though you said you want something more than an Arduino, I'll point out the RobotOpen stuff: http://www.andymark.com/product-p/am-2316.htm which has driver station software that comes with it. I used the Sasquatch board (now out of production) on an FRC-scale robot last year and was happy with it. The RobotOpen stuff that's still available now unfortunately is somewhat awkward to build a control system with, since you need a digital sidecar to go along with it, and I'm not sure what the timeline is like for the release of the next board. Running an IP stack on an Arduino is possible if you get one of the ethernet-enabled boards.

Since you're hacking together something that doesn't necessarily need to survive long-term, one option would be to program all your logic on a PC and use USB interface boards to control the devices. If you're driving things open loop, this will probably work fine; getting a real-time control loop to work might be harder. Since you already have laptops, this is probably the most cost-effective, though you would have to write your own comm software if you want Wifi control - another option would be to use wireless joysticks, depending on the range you need.

Another option if you don't need Wifi would be to use a Vex controller.

Other than that, any board that can drive servos can control FRC speed controllers. I know there are several products available that breakout servo headers for the RPi, for instance.