Synchronous feedrate scheduling for the dual-robot machining of complex surface parts with varying wall thickness

• Published in: International journal of advanced manufacturing technology Vol. 119; no. 3-4; pp. 2653 - 2667
• Main Authors: Sun, Yuwen, Shi, Zhenfei, Xu, Jinting
• Format: Journal Article
• Language: English
• Published: London Springer London 01.03.2022; Springer Nature B.V
• Subjects: Aerospace industry; Algorithms; CAE) and Design; Computer-Aided Engineering (CAD; Constraint modelling; Engineering; Industrial and Production Engineering; Industrial robots; Linear programming; Machining; Mechanical Engineering; Media Management; Original Article; Robots; Scheduling; Synchronism; Variable thickness; Varying wall thickness; Synchronous machining; Dual-robot milling; Feedrate optimization
• ISSN: 0268-3768; 1433-3015
• DOI: 10.1007/s00170-021-08512-2

Industrial robots have been gradually applied to the machining of large thin-walled parts in the fields of aerospace and industrial manufacturing. In order to ensure the machining accuracy and improve the machining efficiency, a synchronous feedrate scheduling strategy of dual robots is presented in this paper for the mirror machining of complex surface parts with varying wall thickness. In this method, the toolpaths located, respectively, on the inner and outer profiles of a given complex surface part (IOPCSP) are first expressed as quintic NURBS curves, and then the synchronous mapping relationship between the corresponding points on the dual toolpaths is established to obtain the constraint condition for guaranteeing the synchronous movement of the two cutters. Afterward, a time-optimal synchronous feedrate scheduling model with constraints of jerk and synchronization is built, by which the kinematic performance of the robots can be fully utilized and the cutting performance of the cutter can be fully maintained. For further accelerating the process of solving the nonlinear model, the linear relations of constraints with respect to the square of feedrate are constructed and thus a linear programming algorithm is used to achieve the exact expression of the feedrate profiles. Finally, validation experiments are conducted with a six-axis industrial robot, by moving along the geometrically complex toolpaths on a sculptured surface part with variable thickness according to the scheduled feedrates. The results of simulations and experiments indicate that the proposed method is effectiveness and has potential to be used in the accurate synchronization of dual robots.