Advanced Sensing Development to Support Robot Accuracy Assessment and Improvement

Abstract

Robots can perform various types of automated movements in the workspace. In recent years, robot applications have been expanded to a much wider scope, including robot machining, robot assembly, robot 3D printing, robot inspection, etc. Many of these applications require robots to have higher absolute accuracy compared with conventional robot part handling and welding. The capability to assess a robot’s accuracy, and further, improve accuracy becomes important. In this paper, an advanced sensor and an accompanying methodology are developed that enable manufacturers to perform accuracy assessment to improve their robot systems. A smart target (patent pending) is developed at the National Institute of Standards and Technology (NIST). This sensor is integrated with a vision-based measurement instrument to perform high accuracy measurements of six-dimensional (6-D) information (x, y, and z position, roll, pitch, and yaw orientation) for a moving robot arm. The smart target is motorized. It can constantly rotate toward the vision-based measurement instrument to maximize its line-of-sight. A use case is presented to demonstrate the accuracy degradation assessment by using the smart target on a Universal Robot.