Issue link: https://htpgraphics.uberflip.com/i/1385717
SUMMARY // In underwater exploration, umbilical cord or tether cables are used to provide data transfer, electrical power and control commands to underwater robots and surface vessels. In a limited-size environment such as nuclear inspections, multiple ROVs may be deployed and due to the density of various objects underwater, tangles and loops tend to form in low- tension zones due to residual tether torsion and flexure. Tangles and kinks could hinder the operation of the ROV, and attenuate signal transmission in fibre-optic cables. A novel robotics tether system is developed that can navigate in the water to prevent loops and tangles and avoid obstacles. The bio-inspired design mimics the motion of a snake in the water; the system consists of a custom micro- thrust system that is designed to be fitted on the tether with intelligent sensing capabilities. Three simulated use cases are considered; traditional tether, constant thrust tether and constant thrust with wave pattern. FUTURE ASPIRATIONS // Further work is required on the novel soft sensor design. Currently, we are developing a soft sensor that is elastic in material and can detect light stress forces. According to the occurred deformation in the elastic material, a detection is achieved between sensor layers. This stage is still under development and require more modifications. Once the soft sensor is successfully implemented, we will explore other deployment scenarios. This could include different robotic platforms and applications dependent upon the specifics of the challenge. The combination of the custom thrusters, AI control and soft sensor will provide us with a prototype system for user trials. Interest has already been expressed by Sellafield Ltd to collaborate on use-case tests. Practical on-site trials will help provide us with valuable operational data, user feedback and highlight further areas of development, research, and commercialisation options. Our project industry partner is SMD company who provided a large-scale tether sample to help us understand the bending characteristics and how much thrust force is needed for a large-scale system. RAIN PROGRESS // To mitigate traditional tether cable risks, such as loops and entanglement, a novel collision avoidance robotic tether prototype has been developed to achieve efficient locomotion in a nuclear inspection environment. To allow suitable control, a custom robotic micro- thrust system has been designed and manufactured to generate an axial micro thrust forces as required. The hydrodynamics of the tether system have been digitally trialled in a marine simulation environment; system functionality and performance were validated. The system was designed, fabricated, and tested experimentally using single and tri double micro-thrust units with cylindrical base tether grip. The experimental testing revealed that the system performed efficient locomotion and obstacle avoidance using manual commands. REMOTE INSPECTION 45 This study provided a proof-of-concept design and implementation of swimming tether performance that mimics snake locomotion. The research achieved provides a preliminary investigation of the effect of the tether motion with various micro-thrust PWM. It is valuable to note that to achieve the desired tether capabilities the system underwent iterative development and testing. To further enhance the performance of the initial CART-I model, additional control and sensing capabilities are being developed with artificial intelligence resources to achieve autonomous obstacle detection and collision avoidance. This will utilise a novel soft sensor design.