Project ROBOMAG – Robotic magnet placement development speeds up magnet posting
Magnomatics have successfully designed, manufactured and tested a 500kW wind generator based on the PDD motors and generators technology. The technology has been shown to be especially well-suited to offshore wind, where leading efficiency, low mass and size and low operation and maintenance cost lead to a significant reduction in levelized costs of energy compared to both state-of-the-art geared and direct drive options offered by industry leaders. To develop a more cost effective and safer production method to build the permanent magnet rotor, a major component of the PDD generator, Magnomatics embarked on the ROBOMAG project using robotic technologies to optimise the manufacturing process and drive big and safe productivity improvements.
One of the major components of any direct drive motor is the permanent magnet rotor which provides flux to the machine. Specifically, magnets are attached to a large steel rotor hub which rotates at the heart of the generator. Construction, magnetisation and safety aspects of these rotors has been the subject of much attention in the offshore wind industry in the last 10 years and methods of reducing the manufacturing costs to remain competitive have been explored.
With previous builds, magnets were loaded onto the rotor manually using bespoke tooling. This involved human labour and the associated risks of handling very large magnets (trapped fingers, hands etc). An alternative method of loading magnetised magnets onto rotors that has resulted in cost-savings in the automotive industry uses robots to pick, place and bond the magnets in position. Magnets used are typically large and exert high magnetic forces. A single magnet pole of a generator may exert forces of up to 3,000N and this can change rapidly according to the position of the magnet relative to the steel hub and neighbouring magnets.
Hence, a robotic magnet placement system must be capable of rapidly picking, placing and bonding live magnets to a hub in a controlled way such that a high level of spatial repeatability and bond-line quality is achieved. Supported by OWGP, Magnomatics worked with AMRC in Sheffield to actualise a solution.
For the first step in this process, using 2D and 3D finite element electromagnetic software, Magnomatics computed magnet placement forces and torques for a six metre diameter magnet rotor for numerous magnet placement combinations. This provided AMRC the maximum force and torque the robot arm would see and informed the design of an end-effector for the robot.
AMRC designed and made an end-effector to meet the requirement and using one of their automated cells, programmed a robot to demonstrate a solution that met the and reduced the time to pick and place a magnet on the rotor from 55 mins to 55 secs. This achievement not only reduces the time but it also provides a safer and flexible solution that lends itself to a wider range of magnet rotor diameters and massively reduced setup time with change rotor diameter.
Magnomatics is currently working with a large industrial development partner for the next stage of development looking at > 5MW generators with a goal of getting to 15MW generators.
ROBOMAG magnet pick and place demonstration
Download the case study below