ETD

• Collaborative robots
• Gage R&R
• Human Robot Interaction
• Industry 4.0
• Pulse-echo test
• Safety assessment

Collaborative robots are a new trend in the field of industrial and as an important part of the strategy Industry 4.0. The main goal of this new solution is to improve safety, ergonomic, productivity, and quality. This solution aims to fill the gap between manual manufacture and fully automated production, which means human shares the workspace with the robot where it helps operator with the non-ergonomic, repetitive, uncomfortable, and dangerous operation.

This work of thesis explains how a collaborative robotic cell in line with the principles of Industry 4.0 was introduced in the work environment of Esaote SpA, a leading medical company in non-invasive diagnostic imaging, to optimize tests of ultrasound probes.
The robotic cell was developed from a collaboration between the Institute of BioRobotics of the Scuola Superiore Sant'Anna, Prensilia Srl and Esaote SpA.
The collaborative robotic cell was developed to improve the repeatability and reproducibility of the Pulse-echo test for the Ultrasound imaging probes.
Pulse-echo testing is used to detect the presence of defects and test transducer performance. Pulse echo testing is an electroacoustic measurement that involves generating a short duration (ns) pulse that is injected into the probe cable and travels to a target located in a water tank. The ultrasonic pulse is reflected by the target and received by the transducer. The pulse-echo equipment PULSE ECHO 2.0 (adopted in Esaote SpA) is composed of an oscilloscope, a scanner that performs a large bandwidth analysis on every element of the probe under test. In this test, the alignment of the transducer is a crucial phase for the reliability of the test. Probe positioning is typically performed by an operator visually inspecting the echo signal displayed on the oscilloscope, and manually translating and orienting the probe through linear guides. Consequently, the performance, both in terms of operating cycle time and reproducibility, is scarce, especially when the measurement system is expected to work in a production environment (in-process quality control for probe large mass production). For this reason, the collaborative robotic cell (composed of a robotic arm UR3e) was implemented to helps the operator to align the transducer against the target. To validate the new measurement system Platform 4.0, composed of the Pulse-Echo 2.0 and the COBOT, a Gage R&R (Repeatability and Reproducibility) study was performed. The Gage R&R consists of several parts that are repeatedly measured by multiple appraisers. The repeated measurements are called replicates. In this way, the magnitude of the variation of the measurement system and the sources that cause this variation are assessed.
Incorporating the collaborative cell into a work environment requires that safety requirements for collaborative industrial robot systems and the work environment are met. In particular, this work has described the process for achieving the CE marking.
Finally, a questionnaire to assess the acceptability of the COBOT by workers of Esaote SpA was developed. The questionnaire is composed of different items and the subjects are asked to express their opinion on a numerical scale ranging from 1 to 7. The questionnaire allows to understand if sharing the work table with the robotic arm makes the operator uncomfortable, if the operator feels safe when the robot moves and when he interacts with the gripper, how difficult is learning and execute the task, if the system provides a condition for its users to perform the tasks safely, effectively, and efficiently while enjoying the experience.