Power and Green Energy for Robotics

The Law of Conservation of Matter and Energy:

Neither energy nor matter can be created or destroyed, they can only be converted into other forms. Energy can be converted into matter and matter into energy only when traveling at speeds nearing that of light (3.00x106 m/s).

Energy is without a doubt, one of the most valuable things in the universe. Humans purchase, hoard and steal energy in various forms and without it, life itself would not be possible. Anything that breaths, moves or exists does so in a state that stores and converts energy.

One of the greatest limitations to date for robotic engineers is finding a maintainable source of energy to power the many electronic and mechanical systems that are needed to allow even the most basic robots to function.

Energy in its simplest definition is a just a state of matter, it exists in either potential or kinetic forms. Potential energy is energy that is stored in a system or by a body and it becomes kinetic energy once it is released. Kinetic energy is the energy that is possessed by a system due to motion.

OK, so if energy is so plentiful, why is it so difficult to get enough? The answer is simple; just as matter exists in different states, so does energy, and just like matter, some forms of energy are more useful than others. In order to use some forms of energy we must first convert them into another form. Unfortunately, this process can never be completed without consuming energy itself and it cannot be 100% efficient which means that some energy will be wasted. Before we can convert less-useful types of energy into more usable types, we need to gain a better understanding of every state that energy can be found in.

Potential Energy Sources:

Nuclear energy Nuclear energy is powerful. Nuclear power plants produce large amounts of power and do not release any pollutants into the air, however, a nuclear meltdown is catastrophic and leaves the surrounding area uninhabitable. Nuclear waist is also a problem it will remain radioactive for millions of years and is difficult to store.

Gravitational energy: Taking advantage of gravity would be an excalent power source for any non-interplanetary device since it would gain energy from mass. Gravity as a usable energy source could be used to get shuttles into space since the larger a planet was the more energy you would have to counteract its gravitational pull. Although the actual cause of gravity has not been discovered yet, we currently classify gravity as an attractive force between particles.

When Einstein wrote his general theory of relativity in 1915, he found a new way to describe gravity. It was not an attractive force between bodies, as Sir Isaac Newton had theorized, but a consequence of the distortion of space and time which he called 'space-time'. Any object distorts the fabric of space-time and the bigger it is, the greater the effect. Just as a bowling ball placed on a trampoline stretches the fabric and causes it to sag, so planets and stars warp space-time – a phenomenon known as the 'geodetic effect'. A marble moving along the trampoline will be drawn inexorably towards the larger ball. Thus the planets orbiting the Sun are not being pulled by the Sun; they are following the curved space-time deformation caused by the Sun. The reason the planets never fall into the Sun is because of the speed at which they are travelling. According to the theory, matter and energy distort space-time, curving it around themselves. 'Frame dragging' occurs when the rotation of a large body ‘twists’ nearby space and time. Gravity is not the force of mass attracting other mass. When an apple falls it is not gravity pulling it down it is actually the force of space pushing it down. A European satellite has accurately charted the variations in the strength of gravity across the surface of the planet earth. The map is featured bellow. The areas marked in red have a slightly increased gravitational pull, while the blue areas have a slightly decreased pull. What is very interesting is that when compared to a topographical map there are matching lines. This means that elevation effects the force of gravity. This effect would occur because features that run bellow the average elevation of an area are subjected to a lessened amount of force of gravity pressing down on them.

Elastic energy is the potential energy that is stored in rubber bands and springs when under pressure. This force even acts on planets and stars as they are pushed together into dense forms by the force of space pushing back on their mass.

Chemical energy is energy that is stored in the chemical bonds of molecules. Chemical energy can be released from matter when burned such as Oil, coal, petroleum, natural gas, and gasoline (fossil fuels). Chemical energy also exists within any chemical reaction in which molecular bonds are broken.

Electrical energy is the energy of moving electrons. Static electricity is different from the electricity that we normally use and can often be dangerous for electronic devices and is not useful as a power source because it is unstable.

Thermal energy: Just as solar panels convert sunlight into electricity, what if thermal panels could be designed that convert heat into electricity. This technology would be incredibly versatile. Imagine if all of the heat from parking lots could be used to power buildings. What if when you put your cell phone in your pocket it charger itself from your body heat? The force of hot air rising and cool air sinking causes currents of air. The force of moving air currents is a good source for energy. Wind turbines are currently used to harness wind and convert its motion into electrical energy.

Light energy Solar panels can be used to harness available light energy from the sun and convert it into electricity.

Sound energy is the energy produced by sound vibrations as they move through a specified medium. Sound vibrations cause pressure waves which lead to compression and rarefaction in the mediums which the sound waves travel through. Piezoelectric materials are substances that produce electricity when put under pressure. Piezoelectric disks are often used as inexpensive speakers because they will actually convert electricity into sound and sound into electricity.

Now that we have become familiar with all the various energy types available it will be easier to determine a way to gather them, convert them into one usable type and then store it. The reason for converting energy into one usable type is so that all of the energy that we gather can be stored in one single location and used when needed. The most useful form of energy for robotic applications is arguably electricity and the best way for us to store the electrical energy that we gather is in a rechargeable battery. The battery will allow the energy to be stored until it is needed. Rechargeable batteries store electricity by keeping electrons built up between metal plates set in a corrosive substance. The battery is an excellent way for our robot to have a supply of electricity even when some forms of energy are not immediately available.