KEY ISSUES IN GECKO-INSPIRED ROBOTICS
Over the past two decades, numerous attempts have been made to create artificial analogs of gecko microfibrillar adhesives with aim for using in various technical applications. Artificial geckoinspired materials and robotic devices using them are not yet comparable in functionality with the biological prototype. So far, the selfcleaning ability, which is a key feature of the gecko adhesives and without which practical usage of artificial geckoinspired adhesives for gripping and moving objects is impossible, has not been implemented yet. There is currently no satisfactory explanation for the self-cleaning effect. In addition, the design of geckoinspired adhesives assumes that in geckos a preload required to achieve reliable adhesion is significantly lower than the values of the adhesion. However, there are evidences that the preload in geckos could actually be much higher than the final adhesion. The high preload suggests that geckos have mechanisms by which animals are able to create the preload locally by controlling the adhesive toe pads while climbing inclined and vertical walls. Revealing and technical implementation of these mechanisms will make it possible to use in robotics the artificial adhesive materials with high adhesive abilities, which application was previously difficult due to the need to provide high preload