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148 CHAPTER FIVE
To look at the power, we’ll need to look at weight, required activities, locomotion meth-
ods, operation time, energy storage schemes, automation, communications, and refuel-
ing (recharging).
Locomotion

We’ll get into the mechanics of the robot in another chapter, but we should mention it
now. We’ll need to look at the mechanics needed to move the robot, the power needed
to affect movement, the required speeds, and the requirement for reliability. We will
need to look at the degrees of freedom required. We can think of degrees of freedom
almost like joints in a human limb. The robot will have to bend various directions and
must have separate control over each axis.
With the requirements for movement and power estimates in hand, we have all the
basics roughed out. We know how heavy the robot is, how much it will have to move,
and what sort of power source we will use. This part of the HLD is akin to planning an
invasion in wartime, like the invasion of Germany in World War II. General Bradley
knew how many tanks were required and how far they had to travel. This allowed him
to quickly rough out preliminary plans for the fuel supply.

Automation

Next, with the basic logistics worked out, it’s time to look at the automation of the robot.
We can assume for the moment that the specifications have already been simplified, so
the HLD problems are straightforward. Further, we can assume that computerization is
already in the plan. During the HLD, we’ll look to simplify things further.
A computer can often take over tasks that might be performed in other ways. If we
can move some of the robot’s functions into software, we gain two advantages. First, we
can delay portions of the design until the software needs to be written. Second, we can
reduce costs. Software is free to the extent that software programs can be loaded into
robot after robot for free (once we own the software).
Here’s a specific example of what can be done in software. Suppose the robot has
rechargeable batteries. Further, suppose the specifications call for notifying the opera-
tor when the batteries are recharged. This can be handled in two ways: