Few questions about robots

I have a few questions about robots:
- I've seen robots that are pretty big, like the ones on the battlebots or junkbots. Are they strong enough to carry one person or maybe two?
- What are the most powerful/efficient motors for a robot that can tow about 200 kg?
- How much do these big robots usually cost? (excluding labor)

Thanx

electroniks said:

I have a few questions about robots:
- I've seen robots that are pretty big, like the ones on the battlebots or junkbots. Are they strong enough to carry one person or maybe two?
- What are the most powerful/efficient motors for a robot that can tow about 200 kg?
- How much do these big robots usually cost? (excluding labor)

Thanx

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1. They can be
2. There are like hundreds or thousands of good options here. Depends on what you can get. Obviously electric wheelchair (Rascal) motors are suitable.

Now you mention towing though, rather than carrying the weight on top. This can be a serious traction issue. The motor may be powerful, but without a lot of weight on the wheels the amount of force it can pull without slipping the tires is limited.

3. Anywhere between $50 and $1,000,000.

big robots cost a lot. starting from 100$ to 10,000$.
at first you must choose good motors. i suggest take 4 wheelchair motors (but bare in mind, those are slow). if you need more speed, then take bike engine and drive it with servos. then make the bot's body. use aluminum for minimum weight or iron or steel for maximum strenght. then find a biig battery or somekind of a gas tank (when using petrol motor). for a battery i suggest the one used on jahts (biig, expencive boats). those are like 70+Ah.

Wheelchair motors aren't that slow, and a lot of torque. I used a pair with a frame made from aluminum angle stock. The motors are 24 volts, but used 12 gel-cells. I had to make it start out slow to keep the frame from twisting and slipping the chain drive. The drive chain would still slip off the sprockets sometimes when changing direction, almost always when it smacked into the wall. Its been sitting gathering dust for years, as I need to build a much stronger frame, and better speed control.

I weigh about 230 LBS, could sit on top, and it still moved quite fast.

could you give me an idea, where to get a hold of some? and also how fast did it go. Also what sprocets did you use? what ratio that is. 1:1? 2:1? 1:2?