A Four-legged Wall-climbing Robot with Spines and Miniature Setae Array Inspired by Longicorn and Gecko

In industrial applications,climbing robots are widely used for climbing and detection of rough or smooth pipe surfaces.Inspired by the special claws of longicorn is that can crawl on rough surfaces and the array of tiny bristles of geckos that can crawl on smooth surfaces,a new type of wall-climbing robot for rough or smooth surfaces is proposed in this paper.The bionic palms of the robot are suggested with special bionic hooks inspired by the longicorn and bionic adhesive materials inspired by the gecko with a good performance on adhering on the surfaces.The special bionic hooks are manufactured by the 3D printing method and the bionic adhesive materials are made by the polymer print lithography technology.These two different bionic adhere accessory are used on the robot’s palm to achieve climbing on the different surfaces.This foldable climbing robot can not only bend its own body to accommodate the cylindrical contact surfaces of different diameters,but also crawl on vertical rough and smooth surfaces using their bionic palms.

Noise Reduction of UAV Using Biomimetic Propellers with Varied Morphologies Leading-edge Serration

The Leading-Edge(LE)serrations on owls'wings are known to be responsible for silent flight.However,this design has rarely been applied to reduce the noise of rotational rotor propellers and the morphologies of the existing serration designs are diverse.Here,we present a comparative study ofLE serrations with different morphologies in terms of the effectiveness in suppressing noise and promoting thrust forces.The performances of biomimetic propellers are investigated by Computational Fluid Dynamics(CFD)simulations and rotation experiments.The simulation results reveal that LE serrations could reduce velocity fluctuations and change the lamina-turbulent transition and turbulence distribution on the suction surface of propeller,but the morphology of the serrations influences its effectiveness.Rotation testing results indicate that the sawtooth propeller has the best performance on noise reduction(on average 2.43 dB and in maximum 4.18 dB)and simultaneously enhancing the thrust forces(3.53%).The largest practical noise reductions(4.73 dB and 3.79 rdB)using the sawtooth propeller are observed when the quad-rotor Unmanned-Aerial Vehicle(UAV)is hovering at heights of 5 m and 8 m,respectively.Our results indicate the robustness and usefulness of owl-inspired biomimetic serration devices for aero-acoustic control and aerodynamic performance promotion on propeller designs.This finding is expected to con^bute to suppressing the sound of propeller and the rotor-based aircraft.