Robot winch frame offers speed, no swaying

A team lead by Dr Andreas Pott, of the Fraunhofer Institute for Manufacturing, Engineering and Automation (IPA) has been busy creating a device that promises to fast-forward the work traditionally carried out by cranes. With the assistance of two PhD students, Pott and his team’s hard work may finally begin to bear fruit.

Their new device consists of a large, mobile framework, with a central lifting mechanism made from winches and cables emanating from the framework’s eight corners. This sounds simple-enough, but until recently, such technology has been precluded due to limitations in computer processing power. The quickly-calculated movements required to work the eight separate lifting mechanisms would not have been possible only a few years ago, when such a computer-dependant operation would have been restricted by slower, bulkier and more expensive technology.

But recent technological advances have allowed such a machine to exist. All of the lifting mechanisms can operate simultaneously, their speed tailored to the specific weight of the load. By lifting with eight separate pulleys, the new device practically eliminates swinging – the single biggest reason that cranes must operate slowly. And by removing swing issues from the equation, the robotic device, dubbed IPAnema, can transport loads at speeds previously unthinkable when using cranes.

Last year, armed with their new technology, the team approached the Desertec consortium, whose grand plan is the building of gigantic solar-thermal plants across the north African desert. 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. This would shatter Europe’s existing goal of using at least 20% renewable energy sources by 2020.

Pott believes that the device has enormous money and time-saving capabilities. 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 many territorial conundrums remain unsolved (and are exacerbated by the recent political upheaval in the Arab world), Desertec is thinking big. The plan’s initial phase would see 100,000,000 mirrors covering an area of 36,000 square kilometres (14,000 square miles). Employing traditional methods, an army of workers would have to labour for decades in order to build such an enormous structure. 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 time and costs, pleasing both accountants and investors alike.

The IPA has been building on kinematic, motor and drive research first attempted in the 1980s over the last three years. Andreas Pott, leader of the IPA team, explained: “Until now, the idea of combining the power of a crane with the speed and accuracy of a robot was something people had tried but failed to do, due to limitations in computer processing power. Our IPAnema robot actually consists almost entirely of cables and winches, controlled with the aid of a computer. We are able to give commands to the winches in a completely synchronised way. We’ve taken pure science and put it to work on industrial grade devices.”

The demonstrator robot Pott and his team built last year is five metres high and has a footprint of nine metres by seven metres. In reality, however, even this massive structure would not be large enough for Desertec. In fact, it is estimated that this robot would have to be the size of a football pitch. However, unlike cranes that must move slowly, due to swinging loads, IPAnema can accelerate quickly and 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.

IPAnema currently only exists in prototype form, having been very much a part-time project for Pott. Since work began, the team has been guided by a mantra of industrial applicability. As a result, only industrial components have been used, so that the robot’s inherent ruggedness could be tested. The robot’s interfaces have been designed to connect with standard production equipment. 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 the working model just over a year ago. The pioneering pick and place task was successfully accomplished in summer 2009.

“When designing a robot capable of disparate tasks, flexibility is the key issue”, said 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.”

It might not just be the world’s energy problems this robot could solve; entire industries could transform their processes with IPAnema. Ports like Rotterdam could look very different once cranes have been confined to only small scale projects. In short, IPAnema could change the face of industry. Until now, computer processing power has proved a limiting factor to real-time, safe movement. Now, it seems, that barrier is being broken as sophisticated robotic controllers are coupled with a new generation of smart, large-scale robots with simple mechanical parts.