Abstract: Due to its advantages of low cost, high efficiency and high flexibility, the robotic drilling system has been widely used in aircraft panel assembly. As an important part of the robotic drilling system for aircraft panel, the robotic automatic tool changing system greatly affects the efficiency and the flexibility of drilling. In this paper, the robotic automatic tool changing system is analyzed, focusing on the steady clamping force, the resistance during the process of tool changing, and the double-loop layout of cutter clamp assemblies of the disc-type cutter library. The steady clamping force of the cutter is calculated by analyzing the structure of two finger clips and the clamping principle. The theoretical resistance of the tool changing period is calculated by establishing the geometric relationship between the cutter profile and the clamp profile of the tool changing period and adopting the force analysis. Through simplifying the outline of the cutter assembly and the inertia calculation, researching into four double-loop layout plans, and aiming at minimizing the total inertia of circular cutterhead, the optimal layout plan of cutter clamp assemblies is obtained. Finally, following the project requirements, a design example of the disc-type cutter library with 24 cutters is given.

Key words: automatic tool changing system, disc-type cutter library, steady clamping force, tool changing resistance, double-loop layout