본문 바로가기

카테고리 없음

[S-hero] Multi Tethered Drone with Better Accessibility

Purpose

The aerial robot can be used in various areas, however, the drone can only fly short period of time due to battery usage. To fly longer time tethered drone is used but the wired system limits the drone movement. Multi tethered drone can be a solution because the winch placed not only the ground but also under the drone can have more freedom to move with longer flight time. 

 

 

The basic concept of a multi-tethered drone that solves the flight time problem is shown in the figure above. Hold the main drone with B, control the string, and connect several A drones to distribute the weight. It will also control the length of the wires between drones and ground power supplies and drones through a winch respectively. In this study, the purpose of the study was to play the role of the main drone and the sub-drone with two drones before connecting several drones.

 

 

For the purposes of detail, it is as follows.

- Winch: Cable Twist Protection Design, Cable Length Control
- Tethered Cable: Setting the Length and Thickness of the Cable for Power Supply and Lightening
- Power supplies: cable positioning, power supply method setting, power distribution

 

 

Energy Supply Method

 

Hardware

System

Drone autonomous flight algorithm

 

 

 

Ground & Drone winch system algorithm

GPS trajectory

1st experiment log data

Flight Distance 87.0m
Average Speed 3.3km/h
Max Speed 36.8 km/h
Max Speed Up 2.2km/h
Max Speed Down 1.7km/h
Average Current 3.5A
Max Current 10.1A
Flight Time 9min 22sec

2nd experiment log data

Flight Distance 112.3m
Average Speed 4km/h
Max Speed 20.1km/h
Max Speed Up 2.6km/h
Max Speed Down 1.7km/h
Average Current 4A
Max Current 8.7A
Flight Time 12min 30sec

 

Limitation

 

The magnetic field continues to occur at a certain level as shown in the figure below. It is presumed to be a magnetic field by a winch cable. Also, the initial calibration did not go well due to the surrounding magnetic field. Therefore, there was an inaccurate estimation of the Yaw axis.

In addition, a sharp drop in voltage occurred. The exact factors are not yet known, but the drone crashed from 24V to 16V.