Flexible Circuits and UAV Applications

Estimated reading time: 3 minutes

What is an UAV? UAV stands for Unmanned Aerial Vehicle which is any aircraft that is operated by remote control rather than a pilot; UAVs are also known as drones. People probably first started learning about drones from the military operations in the Middle East, where UAVs are used extensively in search and destroy operations. Military uses for drones are huge but there are a number of non-military applications that are emerging. The UAV market is likely to be one of the fastest growing segments of the electronics market during the next 5 years.

In addition to military uses, UAV applications are emerging in the following areas:

• Disaster Assistance:  Drones can quickly and efficiently cover areas struck by tornadoes, hurricanes, earthquakes, floods or forest fires. Drones are proving to be invaluable in surveying the scope of damage as well as pinpointing rescue needs.
• Search and Rescue:  Drones are used in rescue operations for locating lost hikers or stranded mountain climbers. Any rescue situation where a large area needs to be searched is a good application for a UAV.
• Agriculture:  Drones are ideal for surveying crop conditions over a large farm (1000 acres or more).
• Security:  Drones can be used at large outdoor events areas such as concerts, meetings or festivals where constant surveillance of the area and perimeter are needed to maintain security.
• Fishing Industry:  Drones can be used to quickly scan large bodies of water and pinpoint schools of tuna fish.
• Product Delivery:  Many shipping companies are already employing drones to deliver products in a conventional manner, but creative uses are also being employed. Amazon has a stated goal of delivering product right to a door step or shipping dock using a drone. One creative entrepreneur used a drone to deliver beer to thirsty ice fisherman on Mille Lacs Lake last winter. Unfortunately the FAA stopped that endeavor, at least for a while.

The ice fishing example highlights one of the issues with UAVs at this point. FAA regulations are either ill-defined or non-existent when it comes to drones. As a result, many uses or applications are on hold until the regulations can be fully developed and enforced.

Why Drones?

The military advantages for drones are pretty obvious; the pilot is hundreds or thousands of miles from the combat area. There is zero risk for from the pilot’s standpoint on even the most dangerous mission.   However there are many other compelling reasons that UAVs are more attractive than piloted aircraft.

• A UAV does not have to support the weight of a human nor the weight and equipment needed to sustain a human during flight. So there is no need for oxygen, pressure or temperature controls. No seats or windows are needed nor communication equipment. A significant amount of the electronic controls are with the ground pilot. This reduces the amount of weight on an aircraft, making it faster, more maneuverable and fuel efficient.  
• UAVs are significantly less expensive to build and maintain than aircraft flown by human pilots.   This makes a huge difference in uses in private industry where a small business can’t afford to acquire expensive manned aircraft.
• UAVs are not limited by human endurance, so undergoing significant G-force or rapid changes in pressure or temperature is not an issue.
• UAVs can fly for significantly long periods of time.  A typical commercial pilot is restricted to fly a maximum of 9 to 14 hours in a day. A drone can continuously fly for over 40 hours; the remote control pilot can change without disrupting the UAV operation.

Why Flexible Circuits in UAV?

A drone has servo motors, cameras, sensors and other equipment controlled by a central system. Wiring is needed to inter-connect these mechanisms which in some cases may span well over 25 feet.  Conventional wiring is time consuming, heavy and limited on types of terminations used.  Flexible circuits can be any odd shape desired and are much lighter. A significant amount of hand labor and weight is eliminated when replacing wiring with flex circuits. For high speed electronic controls, flexible circuits can be built with controlled impedance.  

In short summary, the utility offered by flexible circuits in UAVs mimics the advantages that make it popular in other portable electronic applications: lightweight, thin, highly reliable, flexible during use, and an ability to electrically connect across multiple layers as part of a complete packaging interconnect solution.

What to look for in a flex circuit supplier?

Here are a few things to look for:

• Capability for building large, odd shaped circuits.
• Quality and management systems in place that are needed to supply the Aerospace industry. Certification to AS9100 and ISO 9001:2008 come to mind.
• The ability to meet the systems requirement for military applications such as MIL-P-50884E qualified and ITAR registered.