Unmanned aerial vehicle mission types are now capable of civil and military uses not previously possible due to platform technology advancements. The design and implementation processes is based on mission and environment while remaining requirements driven. As applications for UAS missions increase the design and implementation challenges grow exponentially.
A potential UAS civil mission type that would provide a distinct advantage over current methods would be infrastructure inspection such as bridges and power lines. Currently such inspections are carried out using humans as the inspector either by climbing the structure to be inspected or using a helicopter to drop the person off on the infrastructure requiring inspection. Both methods are extre3mly costly and dangerous. The use of an unmanned aerial system would eliminate the unsafe human factor allowing a more detailed inspection as well as photos and videos that could be analyzed at a later time determining if actual repair work is required.
The mission type would require a platform with hover capability in order to inspect structure at various heights and environments. Platforms that would allow the hover capability would be a quadcotper/multi rotor, co-axial rotor, and a ducted fan which would allow for more leniency when bumping into objects or structure (CALTRANS, 2008). The most effective design would be the quad copter or co-axial rotor due to simplicity and size of the design as well as the potential for using lightweight electric motors for propulsion which helps reduce cost (Unmanned Aerial, 2015). The electric motors would have an electronic speed controller allowing for precise algorithms to be used in flight maneuverability, stability, and control. Wind and weather would be a concern as well due to flying near water over bridges and higher altitudes necessary to inspect high power transmission lines without making contact or colliding. Lightweight design coupled with a precise autopilot controller would be necessary as well as weather proofing the entire vehicle.
The UAS would require various sensors for precise collision avoidance as to not collide with structure being inspected. This could be accomplished with ultrasonic sensors or lasers. The main payload sensor would be the camera equipment for inspection which would also send a live video feed back to the operator/pilot. All data would be recorded for later analysis. The system would also require the ability to hold position via GPS but also an inertial navigational system utilizing an IMU if signal is lost when structure obstructs or reduces signal strength. Another option for more difficult inspection mission types would be to have two UAV’s. One for the actual inspection and one that flies at a specified distance away but trails behind to allow for the signal strength to remain strong regardless of location or position. Basically a flying antennae. The two UAV design and implementation option would be more costly but utilized in more specialized inspection mission types where signal relay is critical.
Line of sight requirements would be a challenge due to needing to inspect beneath structure that could be over water. Also the times at which this inspection would take place would be a challenge if inclement weather were to persist or if high winds are common in an area requiring inspection. Also making sure not to distract passersby’s or bridge traffic during inspection.
As mission types grow utilizing UAS’s obstacles will need to be overcome. However there are many applications for UAV’s currently that either reduce or eliminate the human factor risk making UAS mission types more valuable than ever.
References
Unmanned Aerial, 2015. State DOT: How Can UAV’s Aid in Bridge Inspections. Retrieved from http://unmanned-aerial.com/state-dot-how-can-uavs-aid-in-bridge-inspections/
Mennesota DOT, 2015. Unmanned Aerial Vehicle Bridge Inspection Demonstration Project. Retrieved from http://www.dot.state.mn.us/research/TS/2015/201540.pdf
CALTRANS, 2008. Bridge Inspection Aerial Robot Final Report. Retrieved from http://www.dot.ca.gov/newtech/researchreports/reports/2008/08-0182.pdf
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