Collaborative robots in manufacturing
Robots are steadily becoming more commonplace in manufacturing. Traditionally these are large robot manipulators that look daunting but are highly efficient at their task, and capable of repeating operations with extremely accurate precision. Due to their high weight capacity they are not safe to have humans near them so we have to partition the environment. We operate them safely by keeping people away.
Typically manufacturing robots exist within a safety cage, obvious through a steel barrier, or using a light barrier which halts movement if a safety zone is entered. At present we are seeing a new generation of robots being developed called Collaborative Robots or Cobots. This robot is designed to operate around humans working with them and sharing the same space.
The introduction of cobots will be especially important in the manufacturing sector, which is set to be transformed under Industry 4.0 by the deployment of collaborative robots in support of traditional manual roles. This will provide significant opportunities for increases in efficiency as workers can delegate simple, repetitive, or load-bearing tasks to their cobot and focus on higher-level elements. For example the cobot may hold a piece whilst they work on it, turning it as appropriate for the process element freeing the need to clamp and re-clamp. Alternatively the cobot may undertake a dangerous element of the process, such as welding or working in an environment which may be challenging for the worker.
Whilst it can make the environment more pleasant for the worker it is natural that, being human, they will have expectations about their interaction, and the nature and characteristics of the cobot. Should the experience of working with a cobot be primarily negative the clear benefits will not be turned increases in industry efficiency. This is especially true for understanding how unskilled workers with little experience with robots will be affected by the introduction of robots, and how to facilitate their transition from manual to semi-automated work processes. The attitude of the workforce towards the interaction will play a significant role in the uptake of the technology.
In the first study of its kind, we have investigated how static graphical signage can improve performance and reduce anxiety in participants physically collaborating with a semi-autonomous robot. This study involved 90 participants who were split among 3 groups: an experimental group were presented with graphical signage related to the task; an active control group were presented with irrelevant signage; and a control group were presented with no signage whatsoever.
Participants were instructed that they would be co-working with the KUKA iiwa robotic arm on an Human Robot Interaction task in a manufacturing-type scenario. The KUKA arm was stationed at a “workbench”, along with 18 narrow vertical tubes, six of which contained bolts. Participants were instructed that the bolts needed to be extracted from the tubes and placed in storage behind them. The bolts were inaccessible to the human (due to the depth and diameter of the tubes), and while the robotic arm could access each of the tubes, it needed to be directed to each of the bolts by the participant to the tubes containing bolts. The task could be completed only by participants collaborating with the robotic arm. Participants were not provided with further instructions on how to operate the robot.
Participants in both the experimental and active control groups showed higher emotional valence, compared to the control group, indicting the mere appearance of signs was sufficient to positively impact on user feelings. However, only in the experimental group were participants significantly more productive, showing that improved robot usability can be attributed to relevant instructional signage. Furthermore, only in the experimental group did the anxiety of participants correspond to their success rate (with greater task success leading to lower anxiety), suggesting a positive feedback loop between signage and successful actions leads to increased confidence.
At a time when workers are concerned about the threat posed by robots to jobs, and with advances in technology requiring upskilling of the workforce, it is important to provide intuitive and supportive information to users. Whilst increasingly sophisticated technical solutions are being sought to improve communication and confidence in human-robot co-working, our findings demonstrate how simple signage can still be used as an effective tool to reduce user anxiety and increase task performance.
*Story as featured in The Statesman