Fury (combat robot) Build Log

Mr. Brightside

Mr. Brightside

Mr. Brightside

Associate
Joined
27 Apr 2004
Posts
2,377
I mentioned a while back in the Why isn't Robot Wars on TV anymore? thread that myself and a few friends would be building a combat robot. Thought I'd make a sort of build log type thing on here in case anyone's interested.

A few details:

Name: Fury
Weapon: Top hinged pneumatic flipper
Drive: Two wheel drive, differential steering
Motors: 2x DeWalt 24V drill motors and twin speed gearboxes
Peak power: 4HP

What will hopefully make Fury unique is the power supply; we're going to be using two YUASA 12V 17AH batteries in series for 24V main drive, and will have a third YUASA 12V 17AH battery that can be used in series with the main, to momentarily boost the drive voltage to 36V for extra speed and torque.

The dual voltage drive, direction, and speed will all be controlled by our own DIY motor controller I will be designing, which will provide continually variable speed control in both forward and reverse, at both 24V and 36V, all done with solid state components only (aswell as electronic braking and neutral).

We had hoped to complete the design and build this summer before we all go off to University, but we've all just been too busy to get that much done, so it's now going to be a longer term project - hopefully finished by this time next year.

A picture is worth a thousand words, so with the introduction and description done, here are a few:

19.jpg


10" Tungsten carbide tipped saw we bought for the project. Everything we've used so far (steel wise) was scrap - a few lengths of box section, and a pair of old car ramps will form the frame for bodywork.

26.jpg


Partially completed chassis. This was my first time welding.

35.jpg


Putting the side pieces on.

37.jpg


Putting the side pieces on (again).

33.jpg


Close up.

34.jpg


Close up (again).

43.jpg


Mock up of how it will go together. The bodywork will be welded to the red car ramps, which in turn will be bolted to the chassis so that the entire top can be lifted off for easy access for repairs and maintenance.

Competition wise, if/when we finish it, we hope to enter in Roaming Robots.

Hope this is of interest to some of you on here.
 
Last edited:
Yeah flippers where boring, axes, grinders, saws, whirling disks of doom, big pointy shooty outy things, and hydraulic crushers where the best parts (although they where never as effective)
 
Got to agree - flippers good but spinning flywheel causes maximum damage.

Just a thought - what's the outer skin going to be?

Considered an inner skin around key components to prevent damage from axe type weapons?
 
See these are the comments I get everytime I tell someone about Fury.

Problem is, the competition rules for Roaming Robots state that no spinning weapons are allowed at all. Or flame. Or projectiles. IF they were allowed we would almost certainly have gone for those.

So it was really a choice of flipper or crusher - and we thought hydraulics would probably be a little too ambitious, since none of us have particularly mechanical backgrounds - it's much more in electronics.
 
Looks awesome.

How much did the motors cost? Will you be going into more detail about the motor controller?

Oh, and you should mount that circular saw on the top of the robot.
 
Mr. Brightside said:
See these are the comments I get everytime I tell someone about Fury.

Problem is, the competition rules for Roaming Robots state that no spinning weapons are allowed at all. Or flame. Or projectiles. IF they were allowed we would almost certainly have gone for those.

So it was really a choice of flipper or crusher - and we thought hydraulics would probably be a little too ambitious, since none of us have particularly mechanical backgrounds - it's much more in electronics.
Click to expand...

That's as good a reason as any! Makes sense to go with the flipper then.
 
Badger2003 said:
Just a thought - what's the outer skin going to be?

Considered an inner skin around key components to prevent damage from axe type weapons?
Click to expand...
Probably whatever we can find in the way of scrap sheet steel. Colour scheme is going to be light ish green. And yeah, we'll almost definitely have an inner skin around the electronics, and ideally the batteries too. Weight limit is 100kg, so it will be fun trying to choose something thick enough to stop an axe while also staying under that limit.

p4radox said:
Looks awesome.

How much did the motors cost? Will you be going into more detail about the motor controller?

Oh, and you should mount that circular saw on the top of the robot.
Click to expand...

Thanks :D Yeah it would be pretty cool having the saw on the top, except we'd need to buy/build an AC inverter, and... spinning weapons are against the rules.

The motors were $57.99 each and the gearboxes $54.99 each.

I've got all sorts planned for the electronics; an LCD in a rear mounted service hatch for diagnostics and battery voltage read outs. At the moment I've only drawn up partial schematics for the motor controller - nothing of the rest of the control system (but I've got it all in my head).



The above may or may not make any sense without further explanation. It's just the power supply and motor controller stages. The terminals labelled 24VLS and 36VLS are for voltage sensing - the output from each of these potential dividers will be connected to an ADC pin on the main controlling PICmicro (probably an 18 series device); the voltage on these pins, divided by five, will be a percentage indication of the real level of the 24 and 36 volt rails. cm1g is charming main ground; the others should be self explanatory.

The motor controller sections themselves should be pretty self explanatory; the logic gates serve two purposes; firstly to protect against shoot through (switching on MOSFETs on the same side of the motor and causing a short) as a result of possible programming errors, and secondly to reduce the amount of outputs required on the controlling PICmicro.

lm is left motor and rm is right motor. s is source, d is duty, c is clockwise, and a is anticlockwise.

If s is low, power is taken from the 24V rail - if high, it's taken from the 36V rail. If d is high, power is applied to the motor - if low, no power is applied to the motor (this will be the pin driven by PWM signal from the PICmicro). If c is high current is allowed to flow driving the motor clockwise, and anticlockwise if a is high. If c and a are high, both motor terminals are shorted; electric braking. If c and a are low, the motor is not connected and is in 'neutral'.

We'll be using 2.4GHz RC equipment. I'll connect each channel to the controlling PICmicro and sample the PWM control signals from each channel using that. We hope to add an electronic accelerometer aswell so it always runs straight. Although the steering is, mechanically, differential style, I'll program things such that to the driver it's car style (i.e. one stick for speed and one for direction).

The motor controllers still need a bit of work. For each MOSFET in the schematic, we'll be using four MOSFETs each rated at 55A. The problem is with the upper four which are acting as current sources (or drains if you look at it the 'proper' way...), yet we'll be using N channel MOSFETs throughout; therefore we need to be driving the gates of these with a voltage at least 10V greater than whichever rail is being used to drive the motors (either 24V or 36V). Looking into voltage doubler circuits at the moment as a work around for this problem.
 
Last edited:
Mr. Brightside said:
See these are the comments I get everytime I tell someone about Fury.

Problem is, the competition rules for Roaming Robots state that no spinning weapons are allowed at all. Or flame. Or projectiles. IF they were allowed we would almost certainly have gone for those.

So it was really a choice of flipper or crusher - and we thought hydraulics would probably be a little too ambitious, since none of us have particularly mechanical backgrounds - it's much more in electronics.
Click to expand...

Where can the rules be read? (I cant find them on the website)

It really sucks that no spinning weapons are allowed.
 
Last edited:
Making it out of those car ramps, if robot wars WAS on TV, you wouldn't make the weight limit.

Been there, done that, didn't win the t-shirt. :p

Pneumatic axe for the win :p
 
You must log in or register to reply here.
Back
Top Bottom