  The traditional multicopter design method usually requires a long iterative
process to find the optimal design based on given performance requirements. The
method is uneconomical and inefficient. In this paper, a practical method is
proposed to automatically calculate the optimal multicopter design according to
the given design requirements including flight time, altitude, payload
capacity, and maneuverability. The proposed method contains two algorithms: an
offline algorithm and an online algorithm. The offline algorithm finds the
optimal components (propeller and electronic speed controller) for each motor
to establish its component combination, and subsequently, these component
combinations and their key performance parameters are stored in a combination
database. The online algorithm obtains the multicopter design results that
satisfy the given requirements by searching through the component combinations
in the database and calculating the optimal parameters for the battery and
airframe. Subsequently, these requirement-satisfied multicopter design results
are obtained and sorted according to an objective function that contains
evaluation indexes including size, weight, performance, and practicability. The
proposed method has the advantages of high precision and quick calculating
speed because parameter calibrations and time-consuming calculations are
completed offline. Experiments are performed to validate the effectiveness and
practicality of the proposed method. Comparisons with the brutal search method
and other design methods demonstrate the efficiency of the proposed method.
