Abstract Summary
The delivery of medical products by drone is potentially game-changing and promises shorter delivery times, particularly when trying to service hard to reach rural areas, and reduced carbon emissions. However, this raises a number of technical challenges, one of which being what is the vibration signature of drone platforms given that some medical products can become unstable and lose their efficacy when exposed to vibration. Medicines are transported in standard packaging containers which have been designed principally for thermal insulation performance and containment of spillages, not vibration isolation. The aim of this study was to design and experimentally evaluate a medical goods package capable of mitigating the vibration experienced specifically during transportation by drone. Two similar designs have been developed that feature coil spring and wire rope isolators respectively. Transmission of vibration by these prototype packages was bench tested on a shaker in the laboratory. Transportation trials were also conducted for a multicopter drone and a conventional road vehicle. In flight tests, the predominant excitation occurred at the blade passing frequency in the 63 Hz octave band, significantly above the fundamental suspension modes. The prototype packages reduced overall vibration levels by a factor of six compared with standard commercially available packaging. Isolation performance was slightly worse when transported by car since road inputs occur at characteristically lower frequencies. The prototypes are significantly heavier than the standard product when empty but this is partly off-set by a reduction in the number of cool packs facilitated by the use of high performance vacuum insulation panels for thermal insulation. Future work will seek to establish acceptable vibration thresholds for medical products through vibration and pharmaceutical laboratory testing to inform the design of medical packaging and its securement within the cargo hold.
