Christmas is a time of good cheer (for humans and robots)

It was a very good Christmas party ... and my friend started talking about an aspect of his life of which I was completely unaware.  And, once again, I found myself in the company of an enthusiast, whose hobby raised some interesting questions about optimal design.
He said that he and his son had worked together on a battle robot which had been good enough to appear on the TV series "Robot Wars".  The series, and similar ones in other countries, features radio controlled robots whose aim is to incapacitate or destroy another one.  There are some "house robots" which are created with sophisticated weapons.  One of the house robots is "Shunt"

Shunt from "Robot Wars"

There are numerous sources of information about how to start designing such a device.  This blog entry is not about those sources.  It is simply a short reflection about the conflicting objectives faced by the designer.  The robot needs to have offensive and defensive equipment.  Offensive equipment will protrude from the body, and poses a weakness in the defensive shield.  (Medieval castles, wartime pillboxes, army tanks, navy ships - all have the same conflict - in order to be able to shoot arrows, firearms, tank missiles ... there must be an opening, which becomes a target for hostile fire.)  So you protect your offensive equipment especially well.  But the more weight you add to the armour, the more power you need, and the less manoeuvrable the robot.  
Another conflict arises between weight and abiliy to manoeuvre.  The heavier the robot, the harder it becomes to accelerate and turn, so to make it easier, you add more powerful engines  which adds to the weight.  
I could go on.  Suffice it to say that different people have solved these conflicting elements in many different ways.  Next time one of these programmes is on TV, just think - operational research has been used, unknowingly, to solve the problems of conflicting objectives.