Locomotion Mechanics Of A Locust's Take-off And The Bionic Jumping Robot

Locusts have extraordinary jumping ability.The researches on the movement patterns and mechanical changes of locust jumping do not only deepen our understanding of the mechanism of insect jumping in nature,but also further stimulate the research and development of jumping mechanisms to improve the obstacle-crossing ability of bionic robots.Previous researches mainly focused on the kinematics of locusts hopping on a single surface.There was no mechanism for locust hopping to be extracted from the objective factors such as the surface.There also lacked of dynamic engineering applications.The purpose of this paper is to research the locust biology and establishes related models to reveal the mechanism of body and leg mechanics changes during locusts jumping.Therefore,the experiments were designed to imitate grasshopper jumping mechanism,which makes locusts take off from different ground and jump from water into air.Through experiments,we got the kinematics and mechanics data of the take-off moment of locusts.Based on the comparative analysis of rough surface and smooth surface take-off data,the effects of take-off surface on the mechanism of locust jumping and the synergistic effects of the claw and foot pad are discussed by the claw model.At the same time,ground jumping was interpreted by multi-body dynamics.The results show that the maximum normal force on the rough surface of locusts increased with the smooth surface,the maximum force of axial force and lateral force decreased when locusts take off.Different surface has influenced on the co-action time,lateral force declination and elevation angle of the aphid joints.Based on the experimental data of locust jumping in water,the similarities and differences between the moment in water and on ground were studied.The corresponding hydrodynamic model was established to analyze the instantaneous stress state.We explained how locusts get power from the water surface at the moment of take-off,break through the water's viscous resistance and complete the take-off action.The results show,the resistance of locusts' jumping from water is proportional to their own weight.When locusts jump from water,two hind legs pop-up step by step,the first pop-up hind legs make the locust get the water elevation angle,the other hind leg pop-up allows the locust to get the maximum speed,and the left and right direction is impacted by the second pop-up hind legs.The joints do not move at the same time when the locust jump from water,and the angles are significantly different from that of the ground joint angle.It is found by calculation that the tarsus motion in water is a piecewise curve.A new type of mechanism which can achieve continuous jumping was developed by simulating the way of locust-kick jump.On the basis of researching the energy conversion mechanism during jumping process,the torsion spring bounce mechanism was designed.The torsion spring completes the continuous leg contraction and take-off process under the combined action of the geared motor and the fuselage track,which means the robot can achieve stable landing to ensure multiple jumps.In order to enhance the ability of the jumping mechanism to jump on different surfaces,we studied the role of pat and claw by establishing the grasping model,and designed the bionic jumping base structure which was integrated by adhesive pat and claws.