Analysis of the Behaviour of Vertical Articulated Robots in Machining Operations

Abstract

The aim of this work is to improve the productivity of manufacturing cells by reallocating tasks between the machine tools and the robot. The true working capacity of the robot is established considering the process forces and taking into account the specified precision of the product to be manufactured by accurately modelling its behaviour. This modelling has been carried out using the multi-body method and considering a variable stiffness in the robot joints. The behaviour of the robot at different points in the work area is determined, determining where the best results are produced. This results in the possible reallocation of tasks, the positioning point and the orientation of the workpiece in the working area.The simulated or measured cutting force is fed into the model, modified according to variations in the machining parameters. These variations occur due to deviations of the robot during the machining path. A function is defined where the influence on the value of the force is recorded. This input information can be modified based on feedback from the estimated behaviour of the robot. The results of the modelling of the robot and its interaction with the cutting forces show the influence of the type of robot and the work area in which it is working, allowing the process to be characterised.