The Method of Aiming towards the Normal Direction for Robotic Drilling

作者：Gao, Yuhao; Wu, Dan^*; Dong, Yunfei; Ma, Xinguo; Chen, Ken

来源：International Journal of Precision Engineering and Manufacturing, 2017, 18(6): 787-794.

DOI：10.1007/s12541-017-0094-4

• Robotic drilling
• Normal direction
• Laser displacement sensor
• Perpendicularity
• Accuracy

During the robotic drilling of an aircraft assembly, the normal directions of the workpieces are to be measured to guide the robot by aiming the spindle at the real normal directions of the curved surfaces. This paper describes the development of a method of using four laser displacement sensors to measure the normal direction and the implementation of the proposed method in a robotic drilling system to meet industrial application requirements. First, a novel mechanical structure is introduced to achieve a higher installation accuracy for the laser displacement sensors with a micro adjusting method. Next, the hardware structures and a convenient method of calibrating the sensors are introduced. To accommodate the complexity of the industrial circumstance, a procedure of measuring and adjusting is developed with consideration of both an angular deviation threshold and a limited adjusting iteration. Finally, the experiments of measuring and adjusting iteratively show that two iterations can achieve a satisfactory angular deviation of 0.1 degrees for planar workpieces and three iterations are required for curved workpieces, with the perpendicularity errors of the drilled holes being less than 0.3 degrees. The results can meet the required perpendicularity accuracy of 0.5 degrees.

• 出版日期2017-6
• 单位清华大学