When human operators control complex machines, haptic feedback on the control interfaces can reduce operator errors and workload and increase situational awareness. Such benefits have been demonstrated during control of vehicles, drones, remote-controlled robots, but the maritime industry has so far largely ignored the potential of haptic feedback on the control interface of vessels. This paper aims to illustrate such potential.
First, three vessel control schemes are provided to illustrate similarities and differences in: manual control, supervisory control of an autopilot, and manual control while assisted by haptic feedback. Second, the design of a maritime simulator with active control levers is described, that allows exploration of the potential of haptic feedback for ship propulsion and manoeuvring control. An actuated 2-DOF azimuth control lever was designed, that can not only command engine speed and thruster azimuth angle by providing a position input, but that can also provide haptic feedback by generating force feedback in both degrees of freedom. Two such levers were constructed and were programmed to communicate with a commercial ship simulation environment, in which a scenario of a harbour tug navigating towards the next waypoint was programmed. A haptics software module was designed to allow easy programming of various types of assistive haptic feedback: virtual hard stops, damping fields, vibrations and repulsive or attractive forces. A real-time visualisation of the operation and the relevant signals is presented on multiple computer screens.
Third, this paper describes the implementation of three different types of haptic feedback to support navigation towards a waypoint: vibrations when heading errors exceed a certain boundary; repulsive forces that assist in steering away from certain boundaries; and assistive forces to guide towards a waypoint.
It is concluded that the developed maritime haptic simulator allows for human-in-the-loop experiments to explore potential benefits of haptic feedback for maritime applications: we could stably and reliably implement various force feedback designs based on task-related information from the simulated environment. This work also paves the way for developing operator support systems for other, more complex tug operations, as well as support for remote control of (semi-)autonomous ships.