Expressive Protection Covers for Lightweight Robot Arms

Abstract

This graduation report describes the research and development of a novel product, a weatherproof fabric based robot protection cover augmented with flexible LED displays. The product has a built-in power and data distribution system and is capable of being mounted onto an existing lightweight robot arm (LWA). The project was done with the European Space Agency Telerobotics and Haptics Laboratory to improve the usability and durability of LWAs in future usage scenarios. These scenarios include ones where autonomous or teleoperated robots need to operate in suboptimal conditions in the presence of humans. The proposed product acts as an “Expressive Robot Skin” that enables the robot, and if available its teleoperator to communicate with the person(s) co-present with the robot, as it operates in an environment, such as outdoors. This is achieved by showing graphical elements on the display augmented robot protection cover. The scope of the project consisted of the following: analysis of the state of the art and the users; conceptualization of the device and its graphical language; virtual and physical embodiment of the product, and the evaluation of the proposed product with multiple experiments. For the analysis phase, the state of the art was investigated by reviewing relevant publications, patents and similar devices on the market. Additionally, interviews and observations were done with LWA users in the host laboratory. The findings from this phase were used to create four device concepts with different display capabilities. One concept was selected to be developed further. To evaluate the product, the following studies were run with 28 first time users: (1) a graphical questionnaire, using the virtual model of the product to investigate the readability of the graphical elements, (2) a controlled human-robot interaction experiment using a KUKA Robotics LWA equipped with the product prototype to measure its impact on a user’s ability to identify the actions of the robot in a teleoperated robot-assisted unstowage task scenario, (3) a post-experiment questionnaire to evaluate the user’s overall experience with the product and the robot, (4) testing of the robot equipped with the prototype to calculate its impact on the operation performance of the robot. The results showed that: (1) the graphical language consisting of simple icons and color performed well, but some elements could be erroneously interpreted in multiple ways, (2) the product significantly improved the user’s ability to identify the contact forces on the LWA, but it had no effect on the ability to identify the robot states or motion, (3) the device did not affect the emotional experience of the users, but it was reported to be helpful for identifying the contact forces and the state of the LWA, (4) the robot was able to use its full workspace and preserved 93% of its payload capacity. However, the protection cover of the product required further detailing and testing before it could protect a LWA during outdoor operation. It was concluded that with continued development the product could be beneficial during teleoperated robot missions on-board ISS or on ground; in the automated manufacturing and food processing industry; and with medical robots. The novelty of the product justified the start of a patent application to enable the exploitation of the technology in these fields.