What Is Robot Made Of...
On the most basic level, human beings are made up of five major components:
- A body structure
- A muscle system to move the body structure
- A sensory system that receives information about the body and the surrounding environment
- A power source to activate the muscles and sensors
- A brain system that processes sensory information and tells the muscles what to do
Of
course, we also have some intangible attributes, such as intelligence
and morality, but on the sheer physical level, the list above about
covers it.
A robot is made up of the very same components. A typical robot has a movable physical structure, a motor of some sort, a sensor system, a power supply and a computer "brain" that controls all of these elements. Essentially, robots are man-made versions of animal life -- they are machines that replicate human and animal behavior.
Well robots can be made from a variety of materials too, including metals
and plastics and most robots usually have at least 3 main parts:
- The Controller also known as the "brain" which is run by a computer program.
- Mechanical parts - motors, pistons, grippers, wheels,
gears that make the robot move usually powered by air, water, or
electricity.
- Sensors - to tell the robot about its surroundings.
These parts working together control how the robot operates.
Without the controller or "brain", motors, and sensors, robots would not
be able to function.
The vast majority of robots
do have several qualities in common. First of all, almost all robots
have a movable body. Some only have motorized wheels, and others have
dozens of movable segments, typically made of metal or plastic. Like the
bones in your body, the individual segments are connected together with
joints.
Robots spin wheels and pivot jointed segments with some sort of actuator. Some robots use electrics motors and solenoids as actuators; some use a hydraulic system, and some use a pneumatic system (a system driven by compressed gases). Robots may use all these actuator types.
A robot needs a power source to drive these actuators. Most robots either have a battery
or they plug into the wall. Hydraulic robots also need a pump to
pressurize the hydraulic fluid, and pneumatic robots need an air
compressor or compressed air tanks.
The actuators are all wired to an electrical circuit. The circuit powers electrical motors and solenoids directly, and it activates the hydraulic system by manipulating electrical valves.
The valves determine the pressurized fluid's path through the machine.
To move a hydraulic leg, for example, the robot's controller would open
the valve leading from the fluid pump to a piston cylinder
attached to that leg. The pressurized fluid would extend the piston,
swiveling the leg forward. Typically, in order to move their segments in
two directions, robots use pistons that can push both ways.
The robot's computer controls everything attached to the circuit. To
move the robot, the computer switches on all the necessary motors and
valves. Most robots are reprogrammable -- to change the robot's behavior, you simply write a new program to its computer.
Not all robots
have sensory systems, and few have the ability to see, hear, smell or
taste. The most common robotic sense is the sense of movement -- the
robot's ability to monitor its own motion. A standard design uses
slotted wheels attached to the robot's joints.
An LED
on one side of the wheel shines a beam of light through the slots to a
light sensor on the other side of the wheel. When the robot moves a
particular joint, the slotted wheel turns. The slots break the light
beam as the wheel spins. The light sensor reads the pattern of the
flashing light and transmits the data to the computer. The computer can
tell exactly how far the joint has swiveled based on this pattern. This
is the same basic system used in computer mice.
These
are the basic nuts and bolts of robotics. Roboticists can combine these
elements in an infinite number of ways to create robots of unlimited
complexity. In the next section, we'll look at one of the most popular
designs, the robotic arm.
