Haptic Support for Bi-manual Control of a Suspended Grab for Deep-Sea Excavation

Deep-sea mining is an envisioned solution to cope with the fast increasing demand for rare-earth metals and decreasing supplies from conventional mines. It could involve a hydraulically actuated suspended grab to excavate metal-rich minerals from the seabed. Due to environmental uncertainties such an operation cannot be automated and should therefore be controlled by teleoperation, which traditionally suffers from sub optimal performance and limited situation awareness. The current study proposes two methods of hap tic feedback, natural force feedback and hap tic shared control, to improve the control of a grab in deep-sea mining. Natural force feedback is offered to improve the transparency of the system, which is hypothesized to improve situation awareness of the operation. Secondly it is hypothesized to reduce control effort by guiding the operator when offering hap tic shared control. Besides the individual effect, combining both hap tic feedback methods should also improve the overall task performance of the operation. A deep-sea mining simulation experiment is conducted to investigate the effect of these two hap tic feedback methods and their combination on operator control behaviour. The results show improvement of situation awareness (i.e. control errors) when offering natural force feedback and a reduction of control effort (i.e. control inputs) when offering hap tic shared control. However the results do not show an increase of task performance (i.e. excavated rock production) for either method. Although reduction of control error and effort will result eventually in long-term performance benefits. Combining both methods is therefore the best hap tic feedback method for improving a deep-sea mining teleoperation using a grab.