Micro-miniature folding unmanned aerial vehicle

An undercarriage spring is arranged between each undercarriage and an arm, and an arm spring is arranged between an arm joint and the arm. And the unmanned aerial vehicle has enough tension in a working state through the springs, so that the unmanned aerial vehicle is stable in structure and is not damaged due to excessive tension. The optimized spring mounting position enables the deflection of the arm spring and the undercarriage spring in a folded state to be small, and the arm and the undercarriage cannot deviate from the folding position due to small tension; in the unfolding process, the distance increment of the spring mounting columns is smaller than the maximum deflection of the springs, and damage caused by excessive stretching is avoided; when the unmanned aerial vehicle is in a flying state, the torque of tension generated by the springs to the arm rotating shafts is larger than the maximum reaction torque generated by the motors and the rotors during flying due to the distance between the spring