Today the interaction of the new technologies with humans can offer a lot of advantages. On the other hand, in the last decades the focus was on the automation itself rather than on its fusion with human work. This alternative approach, which is also the key idea of Industry 4.0, provides a more relevant role to the human being. This interaction, in fact, can augment the human capabilities compensating the respective limitations and providing benefits in performance terms of the overall system.
For this purpose, the Hololens were implemented in the analysed project in such a way that the operator, during the grinding process is able to respect the fixed parameters as an automatic system.
For the human being, the understanding of the behaviour of a machine can be learned through adequate interfaces and the repetitive usage of the system.
Examples of HoloLens interfaces
The better hololens interface is chosen after a test campaign. For each interface, at the end of the tests, each operator reported his opinion on a questionnaire in terms of:
Understanding of the system;
Mental activity required;
Further implementations, comments or observations.
The questionnaires were useful to have an operators’ feedback on the use of the system in order to have their opinion on how the interface should change.
The better Hololens interface is chosen after a test campaign. The video below shows the performances that the operator reaches with the used of this technology:
From the video above can be seen as some parameters such as the tool inclinations, the applied load force and the tool feed speed are kept constant thank the used of the Hololens technology.
In the charts below are plotted both tool inclinations acquired during the grinding process; The first with the use of the hololens and the second ones without them.
As can be seen from the above chart, the operator, without any external help, if he is wrong, he continues to make the error. On the other hand, with the use of the Hololens the operator keeps a much constant azimuth and elevation.
In order to not overload the interface on the HoloLens for the operator, an audio system has been implemented to help him respect a process parameter as the tool’s feed speed.
The HoloLens has been also programmed in such a way that, when worn, through voice commands, it is possible to activate or deactivate some predefined functions.
Sample's thermal heating shown through HoloLens
In the “WORK MODE”, the operator sees the emoticons that guide his actions during the grinding process. If a predefined critical temperature threshold is reached, the video of the thermal heating, sent by the thermal camera in real time, will be projected above the sample.
It is evident, with this application, how the human capability can be increased using augmented reality technology.
This research project born within a collaboration between the Department of Industrial Engineering of University of Trento and Fly SpA.
The main purpose is to develop a robotised system for grinding of Titanium welded components for aeronautic application, with particular regard for the welding of titanium alloy outlet guide vanes.
The whole research work can be divided into two sections:
Firstly, carrying an experimental campaign with grinding operators for find an empirical or semi-empirical relationship between the process parameters and a suitable quality characteristic. Thanks to this study, the grinding process can be optimized and the found parameters can be used in an automated process.
The selected process parameters, analyzed after the development of a test bench, are:
Grinding tool inclinations: azimuth and elevation;
Tool feed speed;
Vertical load of the tool;
Tool torque (pressure);
After a statistical study of the test results, the process will be optimized in terms of time and material used.
The architecture of the system used for the acquisition of the process parameters can be seen in the following figure.
Acquisition system for the process parameters
The acquisition interface for the computer is designed with the QT library; For the load cell reading is used a national instruments board. For the communication with the laptop interface and with the Hololens are used respectively the ZeroMQ and MQTT libraries.
Moreover, to make robust the acquisition of the whole system’s architecture, some HTC tracker tests have been done with the vibrations of the tool and with sparks released during the grinding operation.
In a first analysis, the whole acquisition structure has been also useful to qualify the robotic grinding process, sensorizing the robotic grinding cell as it is done for the manual cell. This approach highlights the differences between the two ways of working and analysing the relative results, in order to test and validate the equipment and consumable used.
Manual process VS Robotized process
In the second section of the work a system for measuring the profile of the weldings with the aim of enabling an automated grinding process is developed to be implemented in the robotic cell.
In the second section of the work, a system for measuring the profile of the weldings with the aim of enabling an automated grinding process is developed.
The proposed instrument is a high-speed 2D/3D Laser profiler.
Furthermore, by using an optical prism the laser path is triangulated to gain access between the vanes.
3D printed support between Keyence sensor head and optical prism
After that the acquisition configuration components are chosen, they will be implemented and simulated on a robot arm.
Robot arm simulation with the designed system on the OGV’s vanes