Team MedBots

[Max]

Re: Team MedBots

I am only using gimsons so I think I will go for rear hinged but I might make it so I can change it to either way and test both.
Also, if I wanted to make a dirt cheap heavyweight (I mean really really cheap and ineffective) could I use wiper motors for drive? I think on 150mm wheels they can shift 100kg wouldn't they? I could go for 4 wheel drive and that should help. Looking through old build diarys it looks like loads of people give up on their first heavy weight or 'put it off for a while' but I thought if I made it cheap and simple then I stand a better chance of finishing it? I was just thinking I wanted something to put in to the arena and didn't want to spend much money. What do you think?

[RogueTwoRobots]

Re: Team MedBots

I think wiper motors will probably be underpowered. I ran two in my Rex's Challenge machine on 178mm wheels and when I stood on it it struggled to move with my then 16-year-old weight (which would've been less than 100kg). One of the issues is the small size and fixing method on the shaft. It doesn't particularly lend itself to having large diameter or heavy loads bearing on it.

If you ran some form of gearing to your wheels, even if it's just 1:1 to remove a lot of stress from the wiper motor's shaft, it could help things but I'd still be dubious about their ability to shift 100kg of robot. If they do, on 150mm wheels it'll be pretty slow. Getting hold of a cheap pair of wheelchair motors seems to be the preferred option for building a heavyweight on a budget.

[Ellis]

Re: Team MedBots

20 Argos drills, anyone?

[PJ-27]

Re: Team MedBots

I've often thought about using Fan motors in a heavy.

4 of them, chain drive, small wheels, should be fine.

[plargen]

Re: Team MedBots

i think a robot called wild willy used them for its drive in the robot wars series it was quite quick

[Max]

Re: Team MedBots

i think a robot called wild willy used them for its drive in the robot wars series it was quite quick

Wiper motors or fan motors?
I've also thought of using fan motors for a heavy but wiper motors seem easier.

[Max]

Re: Team MedBots

After a google search I've found it was 4 20A fan motors and it had an axe powered by a starter motor. Sounds very 'bitza'

[plargen]

Re: Team MedBots

u should find a vid i think it was quite quick, and sorry should have said fan motor

[psycho_fling]

Re: Team MedBots

for a dirt cheap hw go for wheel chair motors as they often come with wheels and thereofre shafts along with fixing points. they will also move the weight and you can over volt them

then go for a servo board controller on / off / on

[Max]

Re: Team MedBots

First video I find of wild willy saw it fight with 'flip flop fly' which was powered by 4 wiper motors! Lol
But the an motors were much faster and more powerful than the wiper driven one.

[harry hills]

Re: Team MedBots

that was then and this is now.

wheelchair motors should see you fine, and be dirt cheap if you look hard enough.

you could spend say £150 on a wheel chair, and atach servos to the joystick, add some 10ah or so sla's and you are almost there

[Max]

Re: Team MedBots

what do the rules mean when they say a walking mechanism must have 2 axis of motion?

[craig_colliass]

Re: Team MedBots

I think in this case the interpretation would be

axis1 = UP & DOWN,

axis2 = FORWARDS & BACKWARDS,

In practice the walking gait (the path of the foot) should not track a circle,
The idea is to stop people putting feet on a wheel calling it a walker and claiming the extra weight!

So the mechanism should lift the foot, extend it forward, place the foot on the ground, support the weight of the robot, and then power backwards propelling the robot forward, the foot is then at the start position to do it all over again.

In combat few mechanisms have been able to do that well with this form of propulsion but I hope to do something in the next few years if funds permit!

[Max]

Re: Team MedBots

With electronize controllers should the relays click if I plug it into the receiver with a receiver battery and move the stick on the tx without the main battery being plugged in?

[psycho_fling]

Re: Team MedBots

yes im pretty sure thats supposed to happen