Does it make any difference for robots with motors, to use a lever to pick up things compared to usual picking up? The force required for a human to pick up a box would be less if he uses a lever. Even though the total mechanical energy required is the same, one job is easier because human muscles operate more efficiently at low intensities for a long time.
Does this mean that for robots with motors, using a lever does not make any difference compared to the usual picking up, and the amount of energy spent is the same for both conditions?
Does force have any meaning for robots considering the fact that they do not feel labor and do not get tired? (If so, using a lever has no effect for robots in having the job done with less effort).
 A: If you're refering to fuel efficiency - no, it is not indifferent to engines (at to least internal combustion engnies as far as I can tell). Internal combustion engines have different efficiencies at different frequencies.
There are more factors: Internal combustion engines have a fairly bad Frequency-Torque characteristic. It looks like this:

On the horizontal axis is the frequency, on the vertical axis is the torque.
As you see outside a range of frequencies the internal combustion engine simply produces no power. On the upper and lower bound of frequencies the torque doesn't really just dissapear but drops off very quickly. Even in the active range you have a very bad curve, I've explained what curve we want and why in the section about electric engines, below.
Electric engines have an almost ideal Frequency-Torque characteristic:

This is what we want, because it virtually has the same power output at any frequency, "auto adjusting" to what the situation is. If we are at low speeds it has high torque and at sacrifices torque as the speed grows. This is perfect! Say you are climbing an incline, you're okay with lower speeds, as long as you actually make the climb. So the electric engine does this "naturally".
We want this on internal combustion engines aswell, so we've added the transmission. It allowes us to adjusts the frequency and torque to what we need, so it somewhat mimics the electric engine characteristic:

The separate black curves depict different settings of the transmission, in other words - your active gear.
In conclusion - no, the relation between speed and force that comprise the power output are not indifferent to machines. But electric engines come really close to it. On the other hand - internal combustion engines are very sensitive about it.
