[216] Full-contact and immediate-proximity airborne inspection with a hybrid crawler-multirotor vehicle
R Watson, T Zhao, D Zhang, G Dobie, C MacLeod and S G Pierce
University of Strathclyde, UK
Multirotor unmanned aerial vehicles (UAVs) now see significant adoption to in situ inspection processes across the civil and energy sectors. Their mobility provides flexible and inexpensive visual screening, informing subsequent repair activity and reducing operator hazard exposure. However, turbulent near-surface aerodynamic effects and sensor stability requirements often frustrate deployment of contact-based non-destructive evaluation (NDE). Conventional multirotors maintain significant stand-off relative to the target, placing sensors at a single static point of contact via long effector structures. This lever arm, and their slow dynamic responsiveness, limits sensor placement accuracy.
Herein, we thus examine a novel hybrid crawler-multirotor vehicle designed to operate in close multi-point contact with common industrial plant structures such as insulated pipe networks, storage tanks and pressure vessels. Multiple points of contact increase stabilisation by reactive support from the target object. Using a multidirectional array of reversible-thrust propellers, this vehicle may redirect and fully invert its thrust to provide support as it is driven around the asset outer surface, operating without magnetic or vacuum adhesion.
Characterising in situ condition monitoring performance, we consider immediate-proximity visual inspection of a welded section of 12.75 inch (324 mm) outer diameter schedule 80 steel pipe deploying a 5-megapixel machine vision camera at 55 mm stand-off. Laboratory trials evince successful manual and automated landing atop the pipe and full-contact circumnavigation. Further, active repositioning enables target seeking and contiguous surface scanning. In stationary poses at 45° intervals around the asset, the vehicle maintains a mean absolute position deviation of under 0.75 mm. Discussion of the results considers deployment of additional NDE sensor modes and expansion of the practical use of airborne systems.
Herein, we thus examine a novel hybrid crawler-multirotor vehicle designed to operate in close multi-point contact with common industrial plant structures such as insulated pipe networks, storage tanks and pressure vessels. Multiple points of contact increase stabilisation by reactive support from the target object. Using a multidirectional array of reversible-thrust propellers, this vehicle may redirect and fully invert its thrust to provide support as it is driven around the asset outer surface, operating without magnetic or vacuum adhesion.
Characterising in situ condition monitoring performance, we consider immediate-proximity visual inspection of a welded section of 12.75 inch (324 mm) outer diameter schedule 80 steel pipe deploying a 5-megapixel machine vision camera at 55 mm stand-off. Laboratory trials evince successful manual and automated landing atop the pipe and full-contact circumnavigation. Further, active repositioning enables target seeking and contiguous surface scanning. In stationary poses at 45° intervals around the asset, the vehicle maintains a mean absolute position deviation of under 0.75 mm. Discussion of the results considers deployment of additional NDE sensor modes and expansion of the practical use of airborne systems.
