Intelligent double-eccentric disc normal adjustment cell in robotic drilling

An intelligent verticality adjustment method named double-eccentric disc normal adjustment (DENA) is presented in precise robotic drilling for aerostructures. The DENA concept is conceived specifically to address the deviation of the spindle from the surface normal at the drilling point. Following the concept of intelligent and accurate normal adjustment, two precise eccentric discs (PEDs) with the identical eccentric radius are adopted. Indispensably, two high-resolution stepper motors are used to provide rotational power for the two PEDs. Once driven to rotate with appropriate angles respectively, two PEDs will carry the spindle to coincide with the surface normal, keeping the vertex of the drill bit still to avoid the repeated adjustment with the help of the spherical plain bearing. Since the center of the spherical plain bearing coincides with the vertex of the drill bit, successful implementation of DENA has been accomplished on an aeronautical drilling robot platform. The experimental results validate that DENA in robotic drilling is attainable in terms of intelligence and accuracy.