Magnexxica

[steelefist]

20170730_105007.jpg

I'm currently constructing a heavyweight robot.
The main design aims are:
Invertible.
Compact.
Very heavy armour.
Crushing weaponary.
Highly reliable.

The robot is split into 2 sections, the mobility part and the weapon part. This makes the weapon modular.

There are 9 (A4 sized) 10mm thick hardox500 armour plates which can be moved to different parts of the robot, depending on opponent (e.g. increased top armour for axe/hammer opponents).

The thickest armour at parts of the robot is 42.5mm thick, made of 4 layers of various materials.

The main weapon can exert approximately 75,000N - 100,000N of force. Equivalent to approximately 7500kg - 10,000kg. This is concentrated to two spike like structures.

I'm hoping for this to be completed in 8 to 10 weeks time.

Paul.

[Ocracoke]

Looks good so far, hope this one goes smoothly for you. What sort of drive system are you using on this one?

[Maxamuslead]

im no expert on this but to bend and pen hardox (heavyweight thicknesses at least) would you need more then 10 tonne ?

[steelefist]

In the past my biggest construction weaknesses have been with custom gearboxes and managing speed reduction in an efficient way. They always became the weakest link. So to simplify things, at least initially, I'm using three motors to power two 10 inch wheels (left and right).

The main drive motor is a full transaxle from a Kymco XL mobility scooter. I've used similar golf buggy transaxles before and they are impressively 'torquey' and reliable. Rated power is 850w, although it'll be running at around 2kw. Energy losses in the gearing are minimal, although I don't yet have a figure for this.

This big drive motor is aided by two geared Pride Go motors, one on each side. These will be running at around 800w each. These use the diffetential (in the transaxle) to be the turning/steering motors too.

A more complex set up than a single motor each side and a set up I've never tried before. Sort of like a hybrid system. It also brings in 2 levels or redundancy. If big drive motor control fails, the 2 smaller motors can keep control. If one of these fails, forward power is reduced but steering is maintained by second small motor.

Needless to say this is a brushed motor set up. I just need to work out the transmitter mixing.

The Kymco XL motor is rated to pull 330kg with a full load.

[steelefist]

I think so. I'm hoping to be able to bite the opponent and control the fight from there. But wheels and lighter armour should be vulnerable to the weapon.

[maddox10]

Very very ambitious.

My experiences with multiple motors for 1 purpose ain't to favorable.

Also, with that kind of armor you'll have to build very very tiny.

[steelefist]

The robot will be compact. A sort of T shape. About 65cm wide x 75cm long. 25cm high.

I know what you mean about the motors. If i do get trouble I plan on operating them totally independently. So the 2 smaller ones won't assist the larger drive motor. They will only steer.

The main weapon doesn't use hydraulics, which saves a lot of potential weight.

[Maxamuslead]

The main weapon doesn't use hydraulics, which saves a lot of potential weight.

How are going too achieve 9-10 tonnes of forces mechanically ?

Be interesting to see how you would achieve it

[typhoon_driver]

"About 65cm wide x 75cm long. 25cm high."

Not far off the dimensions of PP3D. I struggled to get 6mm hardox into the weight limit. Second time out most of it was 3mm.

[steelefist]

It uses a 3000lb winch motor. About 1400kg of pull on a flexible 5mm dyneema cord. This then has a pulley system multiplying the force by 4 times. The jaw is part of a lever which further multiplies the force by about 30%. The motor is running on a slightly higher voltage than normal too.

My first attempt used 2 ultra strong carbon steel crow bars to deliver the force to the 'teeth'. But the system was bending these bars at the same time. So I've had to beef up the thickness of the steel used. So the crow bars are no longer in use.
20170509_201059.jpg

[steelefist]

Pp3d had quite a heavy fly wheel on though I think. About 30kg.

[Ellis]

Cool build. Looking forward to more!

[TechAUmNu]

Triforce is 680x680x150mm with a 34kg weapon and still manages 6mm armour just fine. So I think that is doable as long as the weapon is light.

[steelefist]

I did a weapon test against 1mm thick stainless steel and against 4mm thick aluminium. I'll test different armour against different tooth designs to see what works best.

Here are the videos...

https://m.youtube.com/watch?v=1NmGJIi7QWw

https://m.youtube.com/watch?v=b5cw0dtsrAI

[TechAUmNu]

Try it against some 4mm hardoz and see if it makes a dent.