While Quad-Copters remain one of the most popular and best value for money configurations when it comes to multi-copter builds they are also the most susceptible to “single point of failure” because currently no main-stream multi-copter flight controllers allow a quad-copter to fly on less than four propellers.
The redundancy features of a multi-copter aren’t such an issue for your hobbyist who is likely to be flying over a large empty field so the risk of injury or damage to property is very slim. However when it comes to commercial applications these craft will need proven fail-safes and redundancy to prevent members of the public being injured or their property being damaged.
A university in Zurich have been specialising in multi-copter research for some time now and decided this would be an interesting challenge to over-come: Recently they have been developing an algorithm that will allow a traditional quad-copter to maintain flight on three or even two propellers.
When our new software detects a propeller failure, it uses the remaining propellers to cause a continuous rotation of the vehicle,” explains Mark Mueller, doctorate student at the Institute of Dynamic Systems and Control of ETH Zurich. The failsafe algorithm then controls the vehicle’s movement by tilting this rotation, and varying the total produced thrust of the remaining propellers.
The exciting revelation is their system uses no special hard-ware, the motors, speed-controllers, IMU’s etc. all remain standard it is literally a software change so fingers-crossed these kind of amazing fail-safe features will filter their way down to hobbyist level flight-controllers such as the DJI Naza and the 3DR APM.
For ETH Zurich’s home-page please follow this link: http://www.ethz.ch/en.html