EEEeeeeeeeeeeeee-axis!

It’s like christmas every day when you’re an engineer. As I mentioned before The Mighty Max is beginning to become a reality. My C-axis and my A-axis parts just showed up today and I immediately put together whatever I could first. Check out some other posts to see issues I had.

Mighty Max C-Axis and Igus

I mentioned in Accelstepper that I had been working on a 5 Axis platform for a laser cutting project. Well I’ve sent the drawings in and parts are slowly starting to come! We’ve already ordered and have many of the smaller parts…motors, drivers, (not yet controller….that’ll be another post) and the rotary parts for our rotational axis Namely the C-axis…Remember the ABC are the ones the rotate around our XYZ.

EMAk v1

So I’ve been wanting to make a Go-kart for like…well since Mario kart probably. By the way, the guy in that link just wrecks it….Anyways, so while deciding a new project, I had the choice between a laser cutter and the gokart.

I guess you’ve figured out already what I decided to build.

So, like the last project, a person should write down the kind of things they want to do, or rather, what they want the machine to do, So here it goes:

1. Go fast
2. ….

Ok. maybe thats a little short. How about we think of some limitations I’ll artificially put on the machine

1. It should be small. Almost uncomfortably
2. It should be fast, no less than 60 Km/h
3. Under 1000 euros
4. others

Well, ok that’s not so bad. There some other things I’d like to throw in there, A power governer, one that a person actually has to manually switch in order to go to super speed mode (60km/h +), an LCD speedometre, and maybe a battery charger display.

A friend of mine and I talked about it to today just to see approximately what a person would need for motor size (in KW),

We can use the Energy conservation law and namely the right side of it;

$T_1+U_1 = T_2+U_2$

$T=\frac{1}{2}mv^{2}+ mg\Delta\mathrm{x}$ Delta X in height above the ground. Which is in our idealized system 0.

I weigh about ahmmmm…80Kg and the machine itself will weigh a max of 30Kg (we wanna go fast) so in total 110Kg

I wanna go 80Km/h for max speed.

So we get

$T=\frac{110Kg}{2} \times (\frac{80000\mathrm{m}}{3600\mathrm{s}})^{2}$ Which is equal to about 27 KJ. I want to get to about 80km/h within 5 seconds. So to find out how many Watts we need, we can use the Power equation:

Approx Watts required: $P = \frac{T}{t}\approx\frac{27KJ}{5\mathrm{s}}\approx5.4KW$

So people can see what happened;

Alright. So in an ideal frictionless world. I’m looking for either a single motor at 5.4KW, or two motors half of that each (which I’ll ideally be doing)

Thats a nice start.

$e^{\sqrt{2}}$

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Infuratiation

So I have a 3d printer I designed myself. It’s a machine I planned to use, to make a little cash here and there and help me with machine projects. It also helped me release other realities, namely how you’re never really an engineer unless you’ve built something….completely wrong. Anyways, thats a discussion for another day. 3d printing is a FDM (fused deposited material) process, or an additive process. You’re building something from the ground up to the geometry you want, not taking something and cutting it away until you have said geometry. In 3d printings case, I taking a PLA (a corn based plastic) and melt it like a gluegun and accurately move it around until my object is built. Unfortunately, melting things usually released particles and gases from within melted thing. Plastic of course is no different and these particulates bother me. Though some people on the internets seem to thing that it’s perfectly fine, No worse than breathing smoke from frying foods….buuuut those are internet people and as far as safety goes. as long as you feel safe, and I don’t feel safe just plainly breathing plastic particulates.

3d printed Encoder

A customer of mine at the University of Kassel namely the Electric Motors and Drives institute asked me to print them some parts to mount an encoder they needed to test with one of their dspace control boxes they were having issues with. They required a mount for the electronics onto a super high RPM motor they had lying around (10k rpm) and for the magnetic encoder ring onto the shaft.

Accelstepper

For work I’ve been designing a 5 axis laser cutter and since all machines deserve a name I deemed the machine to be called The Mighty Max Its from one of those shows I used to watch and buy toys from as a child where I’m not sure if the accompanying toys came before or after the show. Anyways. We’ve basically completely finished the C axis…which is the rotational axis around the Z axis in a Cartesian coordinate system like so:

And we’d like to start testing initial designs to ensure we’ve actually got something going on here. So I decided to break out the arduino and some other little hardware bits to see if I can get something going and here’s my experience doing it.

So like a good little science person, one should have an idea to follow.

What do we want to do?

• Test stepper motors
• Count steps
• be able to send requests for steps
• Adjust speed and or acceleration
• must be usable with any kind of step/dir driver

So the easiest way to do any of this is really using an arduino and someone elses stepper library. Which thankfully one exists! The Accelstepper library which supports all sorts of banana things, but most interestingly is that it right off the bat crosses off three things off the wanted list.

• Test stepper motors
• Count steps
• be able to send requests for steps
• Adjust speed and or acceleration
• must be usable with any kind of step/dir driver

The other two things I want are just arduino things. I have an arduino M0 at home, which is a 32bit Uno shape/style board

So those are gone to.

This is my code for the arduino m0…We include the Accelstepper library set it’s max speed, accel and set the serial speed aswell (since the m0 is so super fast, we can easily afford to bump the baudrate…

#include AccelStepper.h; // Define a stepper and the pins it will use AccelStepper stepper(1, 9, 8); long steps = 0; void setup() { stepper.setMaxSpeed(51200); //steps per second stepper.setAcceleration(8000); // stepper.setSpeed(9600); SerialUSB.begin(115200); } void loop() { if (SerialUSB.available() > 0) { steps = SerialUSB.parseInt(); SerialUSB.println(steps); stepper.moveTo(steps); while (stepper.distanceToGo() != 0) { // Serial.println(stepper.currentPosition()); stepper.run(); } } //Serial.write("hello"); }

This will let me with arduinos Serial monitor in the IDE send a command at how many steps I want to move in one direction or another, count them, move with accel in that direction and then let me go back to 0 and hopefully go back to its original position. (it does)

Here’s a video and some pictures on the breadboard

A Message from the Space Pope

I’m a huge fan of films…I’ve always wanted to work in the industry to produce films. Sorta like my all time man crush, Adam Savage. So When I found out about this project I was thrilled. Rather I should say film, because it’s already completed! It’s a fan fiction film of Futurama done in live action. Which is unfathomable really. I posted the links to the trailer, the film itself and a behind the scenes. Please enjoy! Continue reading “A Message from the Space Pope”

Merry Star Wars

I just watched the new Rogue One movie lastnight and subsequently like I always do after a movie I immediately wikipedia’d it, then read greater film watcher reviews to see if I missed out on something. An interesting review I came upon was Hulk smasher or something where one particular point I disagree with considerably. Apparently, as I read through the comments, I wasn’t the only one who disagreed.
— Spoiler– Continue reading “Merry Star Wars”

Math Monkey

φI study mechanical engineering, as anyone who knows me know. I’m pretty bad at it. Hence this website….One thing I’ve noticed, and discussed with others is the entire lack of…speciality in subjects, or specifically. explanations of things. Any Google-fu’er can tell you, the more indepth you get into a subject the harder it can be to find real answers. A Recent subject for me, while looking into/researching vibration engineering for a 5 axis laser cutter I’ve been working on was “reactionary forces“. Often described by Newtons impulsesatz as $$m\: \ddot{x} = \displaystyle\sum_{i=1}^{n}\,F_i + Z_i$$ Where $Z_i$ is the reactionary force. I’m the last person in the world…or well maybe second last who should be asked what its all about. But basically to conserve energy in a system, you need it…but it doesn’t really exist. ‘Cause it’s virtual or some bullshit.

Anyways, it’s something that I’ve only ever had to calculate once, for a single assignment, and never had to do again. So I figured I’d write a little about it. Mostly because it was frustrating, but interesting at the same time. This is math heavy post btw. Continue reading “Math Monkey”