First robot

[jannas_gutiere]

Ok, Im designing my first robot which is nothing too complicated I hope but Ive come across a problem already and I figure the experts will know what to do

Ok, situation is: Im building a robot which has 2 wheels on an axle, bosch 750s on both blah blah blah but... The weapon, Im thinking a weapon along the lines of Stingers, a large arm whic pertrudes out of the back persay. The question is, how do they make the arm swing over in a controlled manner and how dont they blunt the weapon dragging it across an area after it is swung?

Thanks for any help in advance
Jannas G.

[typhoon_driver]

arm swing over in a controlled manner

They would drive forward, then stop and go into full reverse. This caused the arm to fly forward.

blunt the weapon dragging it across an area after it is swung

The floor is make from wood so it shouldnt affect it too much if at all. If you make the arm steel then it can be sharpened easily enough with an angle grinder

[jannas_gutiere]

Ah, I see. This uncomplicates things alot. I did try and look up this information myself but the stinger webpage seems to refuse to work for me.

So I would just have a castor or something to support the arm in its neutral position? What would you recommend?

Thanks for understanding though,
Jannas Gutiere

p.s. Sorry if my english isnt up to scratch, its my second language

[grant_ploughbot]

Hi there, we use have a very similar design in some of our pay-to-drive machines. Its actually very simple, but the one thing to make it work better is to try and make the robot as balanced as you can over the wheels. The closer you can get to making it balanced, the easier the lance will throw itself over the top.
The very end of the lance can be as sharp as you like, but i would recommend using something very smooth (a castor would break too easily) on the underside/topside of the lance to help with turning.

[woody]

I believe Im correct in this ...

Stingers weapon arm is clamped to the axle.. a bit like a conrod .. with a brake lining material replacing the bearing .....this allowed them to set a drag and limit the force transmitted from the axle to the weapon and visa versa.

Have a look here .....http://web.archive.org/web/*/http://www.robot-stinger.co.ukhttp://web.archive.org/web/*/http://...-stinger.co.uk

[jannas_gutiere]

Any ideas how long the arm would need to be to obtain the appropriate lever force? The weight, I could balence near centre with a large weight. Lastly, will 2 Bosch 750s, one on each wheel, be enough for such a burden?

Thanks,
JG.

[typhoon_driver]

stinger was powered by 2 bosch 750s.

Any ideas how long the arm would need to be to obtain the appropriate lever force

If you balance the lever on one side with a heavy weight then you could in theory have it as long as you want.

I suggest you do a few experiments and see what works with your design.

[jannas_gutiere]

Ok, Ill leave you all alone while I experiment.

Thanks for all your help, I knew you would pull through for me

Jannas Gutiere

[terry]

Toxic uses 2 x bosch 750s 1 on each wheel,
I have no problems with power and its nippy,
about 16mph i think,the ratio is 10 to 1 and the
wheels are 260mm.

[woody]

@ 24V you should be getting 12mph with that wheel size and gear ratio.