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.
If you can design a robot that consumes meat and vegetables to recharge its power then you will really have something! 

There are so many different robot concepts and designs that it is not a productive discussion to lump them into a single category of being designed to mimic the human body. I can think of many robots that are not like this. A great example is the Odex 1 from the mid-80's, seen [here.](http://www.theoldrobots.com/odex.html)

However, if you think about the tasks that many robots are asked to perform, you will find that most of those tasks were designed to accommodate the human body. Any assembly line that grows from manual, low-volume, production, into a high-speed automation line would be a great example. Since the tools and tasks started as human-capable chores, it is natural that we would design robots that can accomplish the same chores. 

Additionally, many robotic implementations are able to restructure the tools and tasks such that they greatly outperform any human capability. A simple example is a tool-changing end effector. I don't know of any humans who are born with a tool turret at the end of their arm! 

I also question your statements about human inefficiencies. For some tasks you are 100% correct. Running a long distance fast, as you mention, is a good example. But we can also climb mountains, jump chasms, and ride motorcycles. *Inefficient* in one thing might be a consequence of superb adaptability for many things. 

The objective way of looking at this question is to first ask, *what is the robot being designed to do?* Starting with real requirements is the first step to designing a robotic (or other) system to meet those requirements. Overly general statements about whether or not the design is anthropomorphic do nothing to lead a robot designer toward a proper solution for the tasks that the device is intended to accomplish.