Apparatus for controlling still position in air

An apparatus for controlling a still position in the air, the apparatus comprising:

• a miniature unmanned aerial vehicle equipped with a plurality of rotors, the miniature unmanned aerial vehicle including an acceleration sensor and an angular velocity sensor and being able to keep its airframe horizontal;
• a stationary plane from which and on which the miniature unmanned aerial vehicle takes off and lands;
• and
• a plurality of string-like members which link the miniature unmanned aerial vehicle with the stationary plane and which are disposed in spaced places on the stationary plane, the plurality of string-like members being stretched to a length for all the members to become tense when the miniature unmanned aerial vehicle has come to a specified position which is a given position in the air;
• a plurality of winding machines which are placed on the stationary plane for each of the string-like members and deliver and wind each of the string-like members;
• a winding controller which integrally manages operations of the plurality of winding machines;
• and
• a slack detecting device which detects slack of the plurality of string-like members, wherein:
• when the slack detecting device detects slack of any one of the plurality of string-like members, the winding controller causes all the winding machines to perform a winding operation until the slack string-like member becomes tense.