Industrial Robots

Modern industrial robots are true marvels of engineering. A robot the size of a person can easily carry a load over one hundred pounds and move it very quickly with a repeatability of +/-0.006 inches. Furthermore these robots can do that 24 hours a day for years on end with no failures whatsoever. Though they are reprogrammable, in many applications (particularly those in the auto industry) they are programmed once and then repeat that exact same task for years. A six-axis robot like the yellow one below costs about $60,000. What I find interesting is that deploying the robot costs another $200,000. Thus, the cost of the robot itself is just a fraction of the cost of the total system. The tools the robot uses combined with the cost of programming the robot form the major percentage of the cost. That's why robots in the auto industry are rarely reprogrammed. If they are going to go to the expense of deploying a robot for another task, then they may as well use a new robot.
	This is pretty much the typical machine people think of when they think of industrial robots. Fanuc makes this particular robot. Fanuc is the largest maker of these type of robots in the world and they are almost always yellow. This robot has six independent joints, also called six degrees of freedom. The reason for this is that arbitrarily placing a solid body in space requires six parameters; three to specify the location (x, y, z for example) and three to specify the orientation (roll, yaw, pitch for example). If you look closely you will see two cylindrical pistons on the side of the robot. These cylinders contain "anti-gravity" springs that are a big part of the reason robots like these can carry such heavy loads. These springs counter-balance against gravity similar to the way the springs on the garage door make it much easier for a person to lift. You will see robots like these welding, painting and handling materials.
The robot shown at right is made by an American company, Adept Technology. Adept is America's largest robot company and the world's leading producer of SCARA robots. This is actually the most common industrial robot. SCARA stands for Selective Compliance Articulated (though some folks use Assembly here) Robot Arm. The robot has three joints in the horizontal plane that give it x-y positioning and orientation parallel to the plane. There is one linear joint that supplies the z positioning. This is the typical "pick and place" robot. When combined with a vision system it can move product from conveyor belt to package at a very high rate of speed (think "Lucy and the candies" but way faster). The robot's joint structure allows it to be compliant (or soft) to forces in the horizontal plane. This is important for "peg in hole" type applications where the robot will actually flex to make up for inaccuracies and allow very tight part fits.
	The machine at left can be called a Cartesian robot, though calling this machine a robot is really stretching the definition of a robot. It is Cartesian because it allows x-y-z positioning. Three linear joints provide the three axes of motion and define the x, y and z planes. This robot is suited for pick and place applications where either there are no orientation requirements or the parts can be pre-oriented before the robot picks them up (such as surface mounted circuit board assembly)..

by
Rich Hooper
learnaboutrobots.com

Solar Photovoltaic

Basics of Solar Photovoltaic

Solar PV cells convert solar energy in to electricity that is used to charge batteries to provide lights during night. Solar energy has excellent potential in Pakistan that receives high levels of solar radiation throughout the year. Solar Energy is available at a rate of 1000 watts per square meter in Pakistan. This can be converted to DC electricity with the help of Solar Photovoltaic cells, which may be used to pump water, operate fans, TV and telecommunications directly during daytime. The electrical energy generated during the day time (5-8 hours of sunshine), can also be stored in deep cycle lead acid batteries which can be used at night to provide power for lighting, radio, Television and fans. The system will be user-friendly and designed as a stand-alone system for each household, who will be trained to operate and maintain it. The user will only be required to switch on/off the system, as is done in normal home lighting systems. In addition, Solar Photovoltaic Panels can generate enough electricity to pump water from depth of 350 ft, 700 ft and up to 1000 ft.
The system design caters for placement of solar panels on the rooftop or in open un-shaded areas in each house. The panels will charge batteries during daylight hours and the stored energy will be used to provide light to homes/streets and operate fans/TV during day and night.
Solar PV Brackish Water Pumps can be installed for pumping enough water to meet the demand of the dwellers in each village. According to the World Health Organization WHO standards the daily requirement of water for each individual is 25 liters per day. The Solar Pump operated in the daily sunshine hours, pumps water to be stored in the overhead storage tank in each village which can be further distributed to each household.
Solar refrigeration units can be provided to each village dispensary where various medicines including the anti venom injections are provided. Water purification plants and Water Desalination units provide supply of clean portable drinking water to the users.
Solar energy is a potentially available renewable energy source in this region. This source can be utilized as an excellent alternative to fossil fuels for these areas. Solar energy resource is planned to successfully utilize for household applications and electrification of remotest villages of these areas. The outcomes of this program are social uplift, betterment and provision of basic amenities of life.
Resource Potential of Solar Photovoltaic Project
Pakistan covers 796,095 square kilometers of land between latitudes 24° and 36°north and longitudes 61° and 76° east. At present, it faces serious energy problems: 95 per cent of its electricity generation comes from hydropower, which becomes less productive during the driest, hottest months of the year and cannot keep pace with the sharp rise in energy demand. Also, about 70 per cent of the population lives in some 50,000 villages dispersed around the country. Many of these villages are far from the main transmission lines of the national grid and, because of their relatively small populations; it is usually not economically viable to connect these villages to the grid. Solar energy, on the other hand, has excellent potential in areas of Pakistan that receive high levels of solar radiation throughout the year. Every day, for example, the country receives an average of about 19 Mega Joules per square metre of solar energy
Annual Direct Normal Solar Radiation Map of Pakistan:

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