Research in the CBNT
The world's best propellers are said to be something like 60-70% efficient in terms of driveshaft power conversion to forward thrust. Fish on that same scale (obviously muscle power to thrust) are said to be more like 95% efficient. The numbers are hard to quantify exactly, but it is obvious that there is a lot to be gained if we can work out how fish manage to do what they do. In the Biomimetics Laboratory we focus on two aspects of efficient propulsion: improving the drive mechanism to convert continuous rotary input power to oscillatory linear ouput thrust; and on integrating advanced sensory information into the fine motor control of the flexible propulsor to optimise the fluid flow and maximise thrust at whatever speed.
Flow Sensing, Visualisation, and CFD
Fish are good at what they do because they can sense, literally feel, the flow over their bodies, and then do something about it. They have a sense called the lateral line which consists of two systems: one which measures pressure, and the other which tracks the direction and speed of the flow over the fish's body. Our sensors - developed in collaboration with partners in Italy - mimic the latter. We are now working on deploying the sensors, which work well in the laboratory, into real-world devices to track flow and improve thrust production.
The bottom of a river or the ocean is a busy place, where fluid dynamics, geology and biology all interact. The dynamics of the interaction result in a constantly changing environment. The natural world doesn't mind, but modern transportation and ecological conservation requirements are restricted to very specific locations, and too much local change can be a major issue. Our research is looking at the role of kelp beds and seagrass meadows in reducing local erosion in the coastal environment for inspiration on the design of new tools for erosion control in nearshore and riverine environments.
At the completely biological end of the bionics spectrum, the Biomimetics Laboratory is also involved in behavioural ecology research on the most charismatic of the local aquatic fauna, the European beaver, which was reintroduced into neighbouring areas and has migrated into the Cleves district over the last few years. Our work is documenting how many animals there are, what they are eating, and what impact their presence is having (and will likely have) on the heavily modified, mostly agricultural, ecosystem of the lower Rhine river. A recent addition to the project is the evaluation of the interactions between beavers and nutria, an invasive species introduced to the area during the fur trade.
The ocean is a big place. To monitor what's going on, we need sensors that can operate remotely and send us back data on the local state of play. Working with collaborators all over the world, we are developing new sensor technologies and deployments to monitor ocean currents and animal movements. The focus right now is on dolphin distribution in the Philippines and seagrass in the Mediterranean. A whole new project is coming on line soon to study the interaction between local and global scale currents in areas where renewable energy harvesting might be developed.
Biomechanics and Orthotics
The lab's origins are in Biomimetics and Comparative Biomechanics. It is a small step from developing flexible biomimetic robots and the actuators needed to power those to designing and building assistive devices that can directly help people with their every day tasks. As with everything in robotics, power is nothing without control, so our research also focusses on monitoring the health of the patients or operators using the assistive devices or intelligent clothing. Our people are working on smart textiles, soft robotics, pneumatics and artificial muscles to develop new demonstrator technologies.
Autonomous Surface Vehicles
The lab has recently been provided with a 5m robo-boat to support its research on autonomous surface vehicles. We will be restoring the vessel and upgrading its systems to modern standards, then looking to develop and test autonomous control algorithms using commercial gps, radar, sonar and lidar, combined with our own sensors, first for use in still water and eventually in rivers and the ocean. The eventual goal is to send our robotic vessel out to sea to collect data on the abundance, distribution and movements of whales and dolphins in the North Sea.
Over the years, to support our research, we have acquired and developed a fair few machines and processes to manufacture experimental equipment. That has now developed into an area of research all of its own. Along with the ENSPIRE teams and the HSRW FabLabs, we have begun working on new digital manufacturing techniques and on CNC automation of measurement equipment.