wheel positions

[psycho_fling]

hi

for my new axe bot the plan was to have the wheels in the middle of the bot with lower ground clearance

however the way i had designed the bulkheads would have meant the speed 900 axe motor would be in the way of one of the wheels

so im just wondering do people with 2wd systems think front wheel or rear wheel drive (in terms of positioning) is best??

i plan to try and keep the weight distributed evenly per left right sides and the drive is a fast timing pulley and belt setup

any help would be great

cheers alex

[mattsdragons]

Re: wheel positions

I'm basing this on cars but rear wheel drive is better as mire power goes down and they are usually faster. Think about it, would you rather push a load of weight or pull it behind you, for it I would rather push

[joey_picus]

Re: wheel positions

I would have said the front actually as it would make the axe easier to point at robots you wish to use it on.

[psycho_fling]

Re: wheel positions

that was my thinking @ Joey

[typhoon_driver]

Re: wheel positions

yeah i'd vote for front

[widow_twanky]

Re: wheel positions

front, middle or four wheel drive but I reckon having them at the rear makes it more difficult to be accurate when hitting something

[team_orr]

Re: wheel positions

Yeah having them at the front allows for smoother controll and better accuracy

[RogueTwoRobots]

Re: wheel positions

One thing to bear in mind with having the wheels at the front is that there is a possibility that the robot may veer or spin slightly when you try to go forwards. Quite often when you have drive wheels at the rear of a robot, going forward in a straight line is no problem but when trying to reverse in a straight line, the robot is prone to spinning round one of the wheel axis' (Drumroll was particularly bad for this - watch some old Youtube vids and you'll see it very rarely goes back in a straight line, I always had to sort of wiggle it backwards)

If you have the wheels at the front, you've effectively got a rear-wheel-drive robot going in reverse, so the robot could suffer from this issue, although the effect may be less if the weight is distributed evenly as you are planning to do. There is some physics-related explanation as to why a robot is generally easier to control when the wheels are at the back but I'm not even going to pretend that I remember what it is. It made sense though when I heard it.

Avenger (the Aussie axe) had its wheels at the front too when it was first built, with the idea that it was easier to point the axe at an opponent, but the builder moved them to the rear when it got rebuilt as he was struggling for good straight-line control.

Obviously each setup has its pros and cons but they're just some points to consider when deciding.