University Project - Electronics Aspect

[eaycrcr]

Firstly... hello! I'm new!

I have tried to search through the forums but my limited knowledge keeps getting in the way.

Basically I am working on Mechanical Engineering project that will recycle bottles and extrude them into filament. There is loads of electronic components and control required.

I have done a module in Mechatronics and have some experience of LabVIEW and NI's CompactRIO

Things I am confused about:

-Motor control, am aiming to use a DC Permanent Magnet motor which will be driven from the RIO and maintain a constant torque. I understand that I need a control board that interfaces the power supply, PWM control and current feedback. Is it possible to make these or do I need something specific?

-Motor control, turning an AC motor on and off. Would love to use a simple Digital Out signal to connect a motor to it's power supply, what sort of component or board is required for this?

-Heating Element, similar to above, would need to turn it on and off depending on temp feedback.

And many more problems! I understand how to use a computer to generate control signals etc. just don't understand the hardware past the compactRIO that is necessary. I'm getting confused and would love some simple step by step help from anyone who has a clue what I need to do!

Thank you kindly for reading!

Chris

 

[cr0sh]

Your first problem is likely to be how you plan to turn the bottles into something that can be extruded; in other words, expecting to melt the bottles whole probably won't work well - you would likely want to chip/shred them into particles, which could then be fed (perhaps by a screw auger) into the extrusion nozzle (look at how the reprap folks built such a thing for ideas - they basically have used a couple of power-resistors bolted to the nozzle to supply the heat). Much of what you ask about will depend on budget; as far as the AC motor control, you could use a solid-state relay (SSR) module.

 

[eaycrcr]

cheers cr0sh.

I've been all over the RepRap fellas and have got a rough design now, perhaps I should elaborate to give more depth.

bottles will be blended (sounds funny but give **broken link removed** a look.

This will use an AC brushed motor, mainly for its torque-speed characterisitc.

Would need to turn this motor on and off depending on various factors (taken care of in the programming) but do not know what actual phsyical component takes in a digital high and allows the current to flow between the supply and the device. Will look into SSR now though thanks!

Then the granules will be fed into an Auger (you're hot on your stuff mate) which will carry them through a heated tube where they will be pressurised and melted. The auger, or screw, will be powered by a permanent magnet DC motor (or other suggestion). the pressure exerted on the liquid polymer can be related to the drive torque and hence the current drawn. Meaning that the control loop could be closed by feeding back the current draw. Is this determinable from a driver board? can i make a driver board?

The heated melt will be hauled off by another DC motor maintaing the diameter by a sensor that will monitor the diameter and vary haul off speed accordingly. so will need another control board here.

So basically I have some of the theory in mind, just dont know how this is realised in actual circuits / boards beyond the control modules of the compact RIO.

thanks for your time!

 

[ronv]

You can either buy or build the things you mentioned. What is your preference?
You will need to know the power requirements and basic specs before going to far.
Maybe a block diagram would make a good start.

 

[eaycrcr]

ah I replied but it appears to still be moderating. cool feature

EDIT:
ok not sure if my other post will show up so should probably continue?

don't wanna break any rules...

 

[eaycrcr]

You can either buy or build the things you mentioned. What is your preference?
You will need to know the power requirements and basic specs before going to far.
Maybe a block diagram would make a good start.

Buying would be best for the report but I would also like to get to grips with all this stuff myself.

So is a block diagram just a simple "what i think is going on" or a much more complex thing that I've seen you guys firing about... don't think I could manage the later...

 

[ronv]

No, just the big picture of how you visulize it. Like 1/2 HP ac motor = grinder block. 1,000 watt 120 volt ac heater = melting block. Something like that.

 

[eaycrcr]

Attached is the diagram requested, sorry if it's not the right sort of thing.

EDIT:
Have also attached a diagram of how I imagine the controller boards look that interface the PWM control, power supply and motor. Please tell me if this is possible, and where to buy / how to make one (or two).

Thanks very much!

 

[eaycrcr]

Worried that being on the second page means people don't see the thread anymore.

Was just wondering if anyone can simply tell me the hardware I need to translate a PWM signal from a controller output into a percentage of a motors supply voltage. And also the hardware required to read the current draw from the motor and feed it back to an input module on the same controller (its a compact RIO)

Pictures on post above may help.

Many thanks, sorry if I'm being annoying. Just new to electronics and very lost with this...