Compact and Lightweight Cable Attitude Measurement Device for Aerial Transportation Applications

Small-scale Unmanned Aerial Vehicles (UAVs) such as quadrotors and helicopters are popular nowadays in various applications like surveillance, aerial photography, air logistics, mapping, etc. In some applications, it is required to transport the payload by suspending it using cable or rope. Cable suspension of the payload provides the advantage of picking and placing the payload from a certain height. However, while transporting such cable-suspended payload, the payload is likely to oscillate. Sometimes its oscillations become severe and destabilize the UAVs, leading to an accident. To stabilize the oscillations of the payload, the control architecture of the UAVs has to be modified. Most of the recently developed control architectures require real-time feedback of the payload oscillations in terms of the cable's angular position. In this regard, we designed a Cable Attitude Measurement device to measure the cable attitude in this letter. The device's design is compact and capable of measuring cable attitude in real-time at 740 Hz by establishing communication between UAVs onboard autopilot. Indoor experiments using a motion capture system are carried out to validate the CAM device and identify its accuracy.