Question: I have to determine speed and torque suitable for my combat robot.
I've done some calculations and I need to know whether they're right or not (because they don't seem to be right).

Suppose I have 10kg robot, I want to push other 10kg robot to the arena walls. Let's first assume opposite robot is not opposing my push. Suppose I want it to move it with acceleration of 10cm/sec/sec (also lemme know if acceleration assumed is suitable for robowar or not).
Then force required will be,

F = (total mass to be moved) \* (acceleration) = (10+10)\*(10e-2) = 2 N.
Assume opposite robot is also pushing with me same force, in that case I will need another 2 N for opposing his push, Now taking into account frictional retardation, suppose I need another 2 N so total would be 6 N.

Assuming velocity = 10cm/sec, then Power required will be 6 \* velocity = 6\*10e-2 = 600mW. For 12V motor even with 20% efficiency it would cause current of 250mA only. Also output power = speed X torque.

Now I've heard that robowars usually require motor with high full load current otherwise they'll be damaged.

So it looks like I am somewhere wrong in my calculations. If so, lemme know where,am I wrong where I assumed that opposing robot will cause just 2 N, because generally they'd be fitted with more high torque motors. But is it the only thing which goes wrong in above calculations? If opposite bot had to just exert 2N on my bot, are calculations right?

PS: By side-shaft geared motors, it is meant that it is internally geared with horizontal shaft, right? Or "side-shaft" means something more?

Answer: 
From another point of view, bipeds(humanoids) are regardless of their use interesting since they are high dimensional nonlinear hybrid systems. Sure, there are more systems with those qualifications, but the special thing with bipeds is that we have a clear intuition of what is right and wrong even without any mathematical background. Furthermore, take a quadruped(4 legs), those robots are arguably more inherently stable, while with two legs, especially if you remove the feet, that is a different story. So in a way, those humanoids are perfect tools to center nonlinear control theory around.

I think you can cook up a similar argument from an AI point of view. However, I agree with you that for many practical problems a biped makes no sense.
A car is good at driving high speeds on flat ground. A car cannot use a drill. A car cannot climb stairs.

A dishwasher is good at cleaning dishes. A dishwasher also cannot use a drill. A dishwasher also cannot climb stairs. 

> 
> The human body is highly inefficient. 
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On the contrary, the human body is extremely efficient. 100 food calories (kcal) will power a person for about a mile (running). A 12oz can of Coke has 140 calories, and there are 128oz in a gallon. That means a person running gets about 15 miles per gallon. If you walk you can double that because walking a mile only burns about 50kcal. 

So, 15-30 miles per gallon on soda, to put it into a format that allows for better comparison to cars. 

> 
> We can't run for very long times
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We can run longer than just about any other animal. The earliest form of hunting was the [endurance hunt](https://en.wikipedia.org/wiki/Persistence_hunting) where you basically chase an animal until it collapses. 

> 
> May be it is time that we took a step away from getting "inspired" by Nature, and build a man-made, highly efficient body.
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Build a highly efficient body to do what, exactly? Can you make a list of all the things you want this "body" to do, and then explain how exactly that body is going to traverse sand, rocks, grass, and stairs?