The Project:

EFT Mobility designed a tethering system for heavy lifting UAV (Unmanned Aerial Vehicle) platforms.

The Idea: The UAV is attached to a long cable, which is used to provide power from a ground station. This way, the UAV is able to fly for unlimited time.

Tethering Concept

Step 1: System Architecture and Concept

EFT Mobility first assessed the overall performance specifications and the correlating requirements for sub-components. Identifying the core technologies available on the market, allowed us to build a system architecture and refined requisites sheet, which would enable the desired use case.

Electronic Design

Step 2: Component Design

Three individual sub-systems were designed with the following functionalities:

  1. Ground Power System
    1. Converts 3-Phase AC to HV DC
    2. Safe turn-on and shutdown procedure
    3. Communication Interface between Ground Station and UAV
  2. Tethering Cable System
    1. HV Power Transmission
    2. Communication Link
    3. Mechanical Tethering Spool System
    4. Mechanical Link at UAV
  3. UAV Power System
    1. DCDC (HV to LV)
    2. EMU (Energy Management Unit)
    3. Battery System (Buffering + Emergency Descend)
    4. Communication Translation
HCC Photo 55

Step 3: Integration & Validation

All the individual subsystems were integrated and validated as a full system on the benchtop.

A specific focus is set on the validation of the proper functionality of all safety features. Additionally the long term performance of the system was verified in detail.

Tether Shipping

Step 4: UAV Integration & Validation

At this point, the system was integrated into the target UAV. First, the functionality of the system was assessed on the ground.

After extensive ground testing, the system was mature enough to go into flight examination.

A detailed flight assessment campaign was executed which evaluated the system under real-world conditions.

Griff G60 Tether

Step 5: Breaking World Record

The developed powertrain breaks a world-record. The news announcement:

In a collaboration with Griff Aviation, EFT Mobility developed a powertrain for the Griff G60 Tether. The G60 Tether is a heavy lift UAV platform with an astonishing MTOW (maximum take-off weight) of 150kg, a PayloadCapacity of 60kg and a AltitudeCapability of 100m. The unique part about the system is that the UAV is attached to a cable that allows to supply the required power from the ground, enabling theoretically unlimited flight time.

The platform offers a unique advantage in scenarios where a bird’s-eye perspective is essential for comprehensive data collection and analysis, such as surveillance, Search and Rescue missions, communication relay, and environmental monitoring.

The recent successful test flights set a world record for the heaviest lift using a tethered UAV.

With safety and reliability always as a top priority, the G60 Tether is also equipped with backup batteries. In the event of a power failure, these ensure a controlled and safe landing, minimizing the risk of damage to the UAV and the surrounding environment.