Development of a Water Strider Inspired Robot

The family of insects known as water striders support themselves and move on the surface of water using surface tension. This unique type of movement is not typically utilized in robotics. In this study, we investigated the impacts of wire geometry, material type and surface coatings on the supporting forces achievable by surface tension and applied these results to design a small surface tension based robot. The effects of different contact angles on the supporting force were investigated, a relationship was determined experimentally between the total leg length and the supporting force, and the drop off of supporting force as two legs approach each other was characterized. The robot was developed to be capable of supporting a weight of approximately 12 grams and be capable of moving along the surface of the water utilizing piezoelectric actuated drive legs. While the physics of surface tension constrain them to a small size, surface tension based robots could be utilized in applications of water or other liquid monitoring where low disturbance to the liquid is desired while still maintaining the freedom of movement across the surface.