Simulation of compensated tool path through virtual robot machining model

Abstract

Nowadays, industrial robots could be a successful alternative to machine tools for milling of large parts with complex geometry. As it is known, poor accuracy which is most influenced by the stiffness of robot structure is recognized as a limiting factor for successful use of robots in milling tasks. Since there are different sources of error in robots, virtual manufacturing systems provide a useful means for products to be manufactured without the need of physical testing on the shop floor. This paper presents the developed virtual robot machining model, as a part of digital twin, for the simulation of a modified tool path generated by the compensation algorithm for the errors induced by cutting forces due to robot compliance. This part of digital twin includes the robot kinematic model, the Cartesian space robot compliance model, the model of cutting forces and the developed program based on off-line compensation algorithm. Development of such virtual robot machining model is important for the validation of modified tool path before the machining on a real robot. The developed virtual robot machining model is verified via several experiments, where the simulated surfaces are compared with the real machined surfaces generated by tool movement through a modified, i.e., corrected, trajectory on an available industrial robot programmed in G-code.