Handling constant and changing latency with graphical user interfaces: a study with remote crane operators

Nowadays, there are newer container cranes that can be operated remotely from a control room. However, the data transmission between operators in the control room and their cranes could introduce high latency that may affect operators’ ability to work safely and productively. We evaluated two types of graphical user interfaces (GUIs) that could support operators to remotely control their container cranes in the presence of latency. The first GUI predicted how the crane would move based on the operator’s real-time input, while the second GUI visualizes which prior input made by the operator is currently executed by the crane system. We involved seven remote crane operators in two experiments, where the first one compared both GUIs against the condition without additional visual support in constant latency rates and the second one compared both GUIs against the condition without additional visual support in continuously changing latency. Due to the small number of participants, it was not possible to confidently conclude that one GUI was significantly better based on the performance data of the crane operators. However, based on the feedback given by the crane operators, both GUIs were perceived less useful by the crane operators whether the latency rates were constant or continuously changing.