- May 12, 2011
Robotic researchers from Germany believe they hold the key to future global electricity generation: Giant robot cranes that can build huge solar arrays in the desert.
May 12, 2011 - Robotic researchers from Germany believe they hold the key to future global electricity generation. The team from the Fraunhofer Institute for Manufacturing Engineering and Automation (IPA) approached Desertec, a consortium whose big idea is the building of gigantic solar-thermal plants in the desert, last year. Desertec has calculated that if just 1% of the Sahara was devoted to solar energy production, enough electricity would be generated for the entire world at current annual levels of consumption. The IPA has been building on kinematic and motor and drive research first begun in the 1980s over the last three years. Dr. Andreas Pott, leader of the IPA team, explained: “The idea of combining the power of a crane with the speed and accuracy of a robot is something other people have tried to do, but computer processing power was simply not advanced enough for cable robots to succeed until now. Our IPAnema robot actually consists almost entirely of cables and winches. The winches are fixed to movable square metal scaffolding. Held between the cables, which are controlled by the winches with the aid of a computer, is the tool, known as the end effector. In the past, it was hard to predict what the result would be when the actuators were moved, but now we are able to give commands to the winches in a completely synchronised way, thanks to computer modelling. We’ve taken pure science and put it to work on industrial grade devices.” The demonstrator robot Dr. Pott and his team built last year is five metres high and has footprint of nine metres by seven metres. In reality, even this massive structure would be much too small for the Desertec Project. It is estimated that this robot would have to be the size of a football pitch. However, unlike cranes that, owing to their swinging loads, must move slowly, IPAnema can accelerate quickly in full control of its load thanks to its automatically controlled winches. The actuator drum contained within the winch produces force that is transmitted through the cable over long distances. These high forces can be used for both heavy loads and for speed simply by changing the gear box between operations. Although IPAnema currently only exists in demonstrator form, having been very much a part-time project for Dr. Pott, assisted by just two PhD students; from the outset IPAnema has been aimed squarely at the needs of industry. Since the IPAnema project began in 2007, the team has been guided by a mantra of industrial applicability. As a result, only industrial components have been used, so the robot’s inherent ruggedness could be tested. The robot’s interfaces have been designed to connect with standard production equipment. When work began on the IPAnema’s controller architecture and NC control in 2008, the team deliberately set the robot kinematic challenges by attempting to integrate it with other IPA research projects. This focus on prosaic details such as bearings, motor and drive technology and software paid dividends when the team was able to quickly manufacture eight winches and assemble IPAnema just over a year ago. The first pick and place task was successfully accomplished in summer ‘09. “When designing a robot capable of disparate tasks, such as lifting the seven tonne collectors, consisting of dozens of parabolic mirrors, or laying cabling, flexibility is the key issue”, said Dr. Pott. “We have experimentally proved that we can reconfigure our robot by decreasing the payload by an half or a third and transfer that capacity into an increase in speed by the same factor. This breakthrough doesn’t just have application in solar energy installation, we believe our technology could have just as transformational an effect on shipbuilding, aerospace, wind turbines, the erection of electric transmission lines, or indeed, any large scale construction project previously reliant on cranes.” Dr. Pott believes that the IPAnema’s money saving potential when compared with cranes will soon be proved. Crucial to it is the load control IPAnema has compared with a crane where speed is sacrificed to control sway. Large scale cranes require teams of skilled people who significantly add costs to the movement of large objects, making plans like that envisioned by Desertec uneconomic. Although the Desertec project still leaves many political questions unanswered, the technical obstacles the mega project would create appear to have been potentially addressed by IPAnema. Desertec’s initial phase should see hundred million mirrors covering an area of 36,000 square kilometers (14,000 square miles). Using traditional techniques, an army of workers would need to labour for decades to build such a massive infrastructure. As a construction project it would dwarf any other previously attempted, requiring terrifying upfront capital costs with a long, as yet uncalculated payback period. IPAnema’s deployment would slash those costs, pleasing both accountants and investors alike. It might not just be the world’s energy problems this robot could solve; whole industries could transform their processes with IPAnema. We have all grown used to massive warehouses clustered at the junctions of motorways; the future might see truly enormous, lights out warehouses on a previously unimaginable scale. Ports like Rotterdam might also look very different once cranes have been confined to only small scale projects. The automatic, repeatable, accurate nature of robots has long been predicted to change the face of industry, but until now, computer processing power has proved a limiting factor to real-time, safe movement. Now, it seems, that barrier is being dismantled as sophisticated robotic controllers are married to a new generation of smart, scalable robots with simple mechanical parts.Learn More
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