Energy saving for industrial robots
Automated manufacturing saves time, ensures product quality and makes workplaces safer. But it also requires additional power. Grid architecture and tools from an EU-funded project could make robotised factories more energy-efficient, improving their competitiveness and environmental impact.
© KUKA AG
Many manufacturing processes now take place in intelligent factories, where processes that build a product – such as spot-welding, riveting and gluing – are carried out by robots. It’s an ever-growing trend that keeps Europe’s manufacturing sector competitive, while improving products, the work environment and safety.
The hidden challenge is how to reduce the massive amount of energy all these robots use. A 12-member consortium of researchers, manufacturers and technology providers addressed this in the AREUS project. They developed an energy-efficient factory grid system that adapts well to renewables, along with IT tools that optimise energy and resource use in production processes. Used separately or combined, these innovations can cut manufacturing costs and make factories greener.
“Manufacturers are very concerned about the sustainability of automatic assembly processes,” says project coordinator Marcello Pellicciari of Italy’s University of Modena & Reggio Emilia. “In particular, energy efficiency is strategically necessary to give European manufacturers a competitive edge. The factories of the future have to be smart and green.”
Novel grid and tools
AREUS focused on reducing energy losses and optimising resource use in robotised manufacturing. Its main outcome is a smart DC-based grid that saves both energy and materials.
In existing factories, high-voltage AC (alternating current) power enters the system from power plants. A series of copper or electronic transformers convert this first to standard AC voltage, then to and from DC (direct current) power to control electrical machines. In the AREUS factory grid system, the AC power is immediately converted to DC when it enters the system so fewer conversions are required. “Each time you convert AC to DC, you lose energy, “says Pellicciari. “The AREUS DC grid reduces conversion stage losses, allows factories to recover energy when a robot brakes to slow down or stop, and can also use a variable supply from renewables more easily and efficiently.”
The AREUS grid includes energy harvesters, storage and meters to optimise power use further. Overall, it can save 5-9% of a factory’s energy consumption and potentially up to 20%, says Pellicciari. Because the grid uses fewer transformers, it also needs less copper than conventional networks.
Three main energy-optimisation tools developed in AREUS support additional energy savings of up to 40 %:
AREUS Industry partners could generate up to €120 million in extra revenue per year from AREUS’ grid alone, says Pellicciari. The tools have been demonstrated at project partner Daimler on a four-robot working cell that includes spot welding, the most energy-intensive robot application. Results confirmed that AREUS’ technologies save energy and can be developed for industrial use.
Project partners are now developing the tools for industrial use, with different versions planned for large companies and for SMEs. Various partners are also investigating licencing opportunities for the simulation tools, adaptation of the smart grid to industrial standards and commercialisation of the sequence planner. The project has resulted in two spin-offs that aim to achieve some of these goals. In the academic world, AREUS project participants have published 24 peer-review papers in scientific publications – with further papers being accepted for publication – and given the keynote speech at several international conferences.
“We are starting a revolution,” says Pellicciari. “This is a disruptive change to the electrical power supply architecture of factories and to digital manufacturing simulation tools, I am proud to see that we are improving both the environmental and financial sustainability of the Factories of the Future.”