Fully automated drone powered by solar energy

XSun designs and manufactures a drone that is both energy-independent and can make its own decisions, for fully-automated missions. The company needed reliable, high-performance sub-assemblies to design it’s SolarXOne. The start-up approached maxon for the propulsion system.

Adapting space technologies for use at lower altitude was the idea behind creating a fully automated solar powered drone. Benjamin David started his company XSun, and with a decade of experience at Airbus Defense & Space his idea produced SolarXOne: A solar-powered, electrical, self-contained drone with a tandem wing design.

SolarXOne, with its dragonfly-like design, has excellent aerodynamic performance and a large surface area of solar panels, to collect as much solar energy as possible. This is all within a very high-performance, fully-electric environment.

“We firmly believe that a combination of new technologies and renewable energy sources will best meet current environmental, economic and societal challenges,” says Benjamin David. He also points out that solar power increases the on-board battery life by a factor of 3.

Just like a satellite, SolarXOne is packed with technologies. Half airplane, half drone, this UAV weighs 25 kgs and has a 4.50 metre wingspan. With a daily flight range of 600 km it can fly over thousands of acres, producing image resolution within centimetres of accuracy. Many industries could benefit from the drone for a wide variety of missions:

• Mapping and topography of large areas on land or at sea, such as natural bush reserves
• Very high-resolution photographic surveys for large-scale linear infrastructure (pipelines, electricity lines, roads, rivers, etc.)
• Photographic surveys for precision agriculture, for example forest mapping
• Monitoring and inspection missions.

maxon motors are “definitely the best”

The guiding principles of the SolarXOne design was a DC motor system that was efficient, top quality, reliable and durable. “Because of the fully electric design, we had to strive for cost and energy efficiency in every assembly. This is why it was essential to work only with the best, and that means maxon for the propulsion system,” said David. For propulsion, the challenge was to find the most reliable, highest performance, and smallest systems possible, with virtually the same requirements as in the aerospace sector. “In those three areas, maxon is definitely the best. There are very good reasons why they supply NASA with its robot motors! We were delighted to see maxon enter the drone market, and our collaboration was set up very quickly,” adds  David.

Every aspect of the technology had to be pushed right to the limit for the drone to be able to fly independently for more than 12 hours. XSun took advantage of maxon’s expertise in controllers, DC motors and propulsion.

“From an energy point of view, the aim was to keep consumption as low as possible while remaining as light as possible: a genuine technological challenge”, recalls Michael Niemaz, Aerospace Project Engineer at maxon, who has been working with XSun since 2019. Back then, maxon had just released its first drone motor range. To meet XSun’s requirements, maxon adapted one of its brushless drone motors, the ECX 87 Flat DC motor.

Luise Löskow, Aeronautics Project Manager at maxon, says: “When we started working with XSun, the design of this type of DC motor only existed in its basic form. This is why we had to customise a product that was still under development, to which we had to incorporate new features such as sensors. Our experienced team (design engineers, test engineers, quality engineers, purchasers and production operatives), had in-depth discussions about the various technical requirements and problems, so as to find appropriate solutions. Finally, we increased the power of the ECX87 Flat DC motor and modified its winding for optimum propulsion. SolarXOne is now equipped with two adapted ECX87 Flat DC motors positioned at the front of the aircraft.”

“For SolarXOne to be able to fly over cities in total safety, XSun wanted to have its drone certified as far as possible. This where maxon’s expertise played an important role, because we provide a build quality that guarantees a sufficiently reliable DC motor to be certifiable in the future,” Michael Niemaz pointed out. The founder of XSun agrees with this, adding: “It would have been hard to achieve the same level of quality with a partner other than maxon. Very few companies would be able to provide a highly detailed 25-page test report!”

Ever since they met at the Paris Air Show in 2019, the maxon and XSun teams have been working in close collaboration. In July 2020, for its first long-range solar flight, the SolarXOne succeeded in flying silently for 12 hours without any CO2 emissions, and completely independently. Since then, it has completed operational assignments for various clients in France and other parts of Europe.

For more information, visit: XSun.fr

maxon motor Australia tel. +61 2 9457 7477.

Brushed DC motors for higher temperatures.

DC motors that withstand high temperatures up to 200⁰C were exclusively the domain of brushless DC motors. maxon has now changed that with the new HT (High Temperature) brushed DC motor.

Motors capable of operating at high ambient temperatures are nothing new to maxon. The HD (Heavy Duty) brushless DC motor range, developed to operate in ambient temperatures up to 200⁰C, has been on the market for over a decade. Until now, these temperatures were exclusively the domain of brushless motors; maxon has now changed that with the new HT (High Temperature) brushed DC motor.

A major oil and gas company approached maxon looking for a brushed DC motor capable of operating in ambient temperatures up to 180⁰C. Their established multi-imaging tool, utilised for pipework casing inspection, used a high temperature brushed DC motor. However, when new tools with higher seismic shock levels were added, the current DC motor system failed as it wasn’t robust enough. Unsurprisingly the company didn’t want to redesign the entire system as this would be expensive and time-consuming; instead, they turned to maxon to provide a solution. maxon’s engineers set about developing a tailored DC motor drive system based on the standard DCX 22mm brushed DC motor series for the downhole application.

The main fundamental parts of the DC motor, namely the winding and magnet, were the first to be dissected. Unlike the HD brushless DC motors that use Samarium Cobalt (SmCo) magnets for high temperatures, the engineers elected to use a new high-temperature grade Neodymium (NdFeB) magnet. The reason being: strength. Samarium Cobalt magnets capable of elevated temperatures have been available for several years, but they are not as strong as Neodymium magnets. As well as being slightly weaker, using Samarium Cobalt magnets would mean the size of the DC motor would have had to increase to meet the torque requirements.

High-temperature windings are not new to maxon. The maxon configurable DCX motor series using standard winding operates to a recommended maximum of 125⁰C. If the temperature increased above this level, the insulation in the winding would become soft and unstable and could collapse onto the magnet. So maxon’s engineers created a customised winding and produced some samples. Once this was validated, the electro-magnetic circuit was complete.

A DC motor is much more than just the magnet and winding, so once a viable design for these was complete, the engineers looked at the rest of the motor to ensure all the other elements were capable of enduring the temperatures. The standard polymer brush cover required a new design using high-temperature capable material.

maxon produced the first samples and then came the validation testing. maxon’s test laboratory facilitates extensive environmental testing. The motors were heated up to 180⁰C in the test chamber and then run. Also, the stability of the rotor was tested at 180⁰C and 200⁰C. Once the maxon engineers were happy that the solution would work in the application, they supplied the customer with samples for their testing. These passed with no issues, and the motors released to production standards.

The DCX22S HT DC motor works with the GPX22 and GPX26 gearbox ranges, including the high-efficiency gearbox GPX22UP. These can have extended temperature lubrication to match the motors ambient temperature capability. Your local maxon sales engineer will help you match the motor and gearbox combination to your application.

maxon Group Australia tel. +61 2 9457 7477.