Robotic heron foot for locomotion in paddy fields

Benedict Fletcher
PhD student
University of Sussex, UK

The diversity of birds is extraordinary, as is the environments they inhabit, and the challenges they face to thrive. Locomotion in wetland environments is extremely difficult due to the thick and deep waterlogged mud. This makes the ease that wetland birds walk in these environments even more remarkable, and a valuable opportunity to learn how they do it. This is due, in part, to their iconic long skinny toes that distribute their weight and provides a stable contact with the ground. The joints in the toes can rotate backwards, allowing the foot greater conformity to uneven or obscured surfaces. Conformity at the joint level is key to achieving greater contact area, this is an area that passively compliant robots excel in. We are using a bio inspired, passively compliant heron foot to aid in wetland locomotion for walking robots. Therefore, our research explores the effect that changing the internal structure of a silicone joint has on the stiffness of the joint. Therefore, reducing the waste because only one batch of silicone is needed to achieve different stiffnesses. We experimented with two different types of silicone joint for the bio-inspired heron foot, one with no holes and one with 13 holes. We confirmed that the 0 holes joint was stiffer, 2.7Nm-1, than the joint with 13 holes, 2.2Nm-1. We found that it is possible to change the stiffness of the same batch of silicone by altering the internal structure of a joint in a bioinspired foot.

Benedict Fletcher graduated from the University of Plymouth with a BEng in robotics. He is currently in his second year of a PhD at the University of Sussex, researching bio-inspired robots to improve the lives of rural rice farmers. He made a robotic quadrupedal walker as his undergraduate dissertation that was designed for the remote rescue of victims in extreme situations, such as after a natural disaster.