«This is a more energy - efficient and reliable solution since stationary hovering is difficult for quadrotors in the presence of even mild wind — which is common for construction sites. (sciencedaily.com)
The compliant wings of a bat - like flapping robot flapping at lower frequencies (7 - 10 Hz vs. 100 - 300 Hz of quadrotors) are inherently safe: because their wings comprise primarily flexible materials and are able to collide with one another, or with obstacles in their environment, with little or no damage.» (sciencedaily.com)
In a laboratory experiment, a 50 centimetre by 50 centimetre quadrotor craft equipped with the navigation system was able to take off, travel through an obstacle - filled indoor space and land successfully on an elevated platform. (newscientist.com)