The larger problems with this and anything like this is simple economy of action and energy.
The first giant problem you have is energy. You need a power source that is robust enough to installed in the unit, and powerful enough to move the unit. This is a problem. They power levels required to operate the system, dictate the over all size..
Next, you have to consider the mechanical forces involved, and the energy requirements to move them. And this is a double whammy. Lets look at a few servos and motor control assemblies.
The energy required to move a 3psi butterfly valve is .10 amps on average. (if you have an automated sprinkler system for you lawn, you have 3psi butterfly valves, as this is the general valve system used in 90% of those systems. Of course, this means is can ONLY move up to 3 pounds of force.... about the strength of a newborn baby.... The amount of power required for a servo to move an 800 pound object runs roughly 30 to 50 amps....
And that's for a single servo, now multiply that by the number of servos in the system.. And lets assume an incredibly simple system, 2 servos per arm and leg, and 2 servos in the torso... that 10 servos at 40amps (avg).. that's 400 amps of power! (about twice the pull of a 2000sq/ft home).
Of course, you could do it with a less power intensive system, a hydraulic fluid system... The amount of mechanical/electrical energy required to push fluid is much less, thus allowing for savings in energy. (roughly 3 amps per servo) But, the system is much slower to respond, and you have to have a storage tank to hold and recycle the hydro fluid....
And, we have not even touched on the mechanical stresses, the weight of the system (which must be accounted)..... In short, to get more "performance", you need to increase weight, when you increase weight, you increase the energy requirements to move, which means a more robust power system, which means more weight, which means a more robust power system, which means more weight, which means you need a more robust power system...... (And on and on it goes)
So what could power such a system? Sort answer; Not much.... your choices for power are limited...... battery, engine, or reactor.
A battery capable of providing 10hours of power at 400amps would be MASSIVE (as in battery bank weighing in the THOUSANDS of kilograms), and that only provides power for our simple system for 10 hours.
Now, the same system could be powered by a 15hp diesel or gas motor. (assuming 24vdc) but you now have to worry about fuel....
A reactor could work, but you also need a turbine and water to generate the power. (a reactor creates heat, the heat turns water to steam, steam turns a turbine and generates your electricity). Not to mention a containment and shielding system for said heat and radiation.....
There has been several attempts to create a "walker" style tank for a number of years...And even a few prototypes though out history... all with the same result.... Too expensive, reduced battlefield performance, high maintenance costs, and limited armor protection.
**(Adamo1618 is an electrical engineer, and should have even more knowledge then I do on power systems, so we might be lucky enough for him to weigh in too)
