Propulsion Mechanism And Experimental Research On Robotic Fin In Amphibious Environment

With the development of robot technology, the robot is no longer a single adapting to land or underwater environment, which can accommodate the special needs of complex transitional environment of riparian areas. It will have a very real sense to develop amphibious robot which possess the good performance of trafficability characteristic and the ability of passing obstacle, high-efficiency propulsion, maneuvering and good concealment, as well as the ability of relieving in the complex amphibious transitional environment. Therefore, it should be carried out urgently to improve the amphibious robot of the good performance of trafficability characteristic and adaptability in amphibious environment, as well as optimizating form amphibious robot the morphological parameters, structure parameters and motion parameters of propulsion mechanism. Transitional environment is mainly composed of soft media such as sand and mud moisture, amphibious robot would often appeare the phenomenon of slipping and subsidence in the transitional environment, which is attributable to the constitutive characteristics of environmental media, morphological and structural features of amphibious robot propulsion mechanism, and cupping with kinematic parameters of propulsion mechanism and other factors. Research on interaction of propulsion mechanism of amphibious robots and the transitional environment, which can improve the performance of trafficability characteristic of amphibious robots in the transitional environment, making the conversion of wanter and land of amphibious robot can really go practical.This thesis takes the perspective of bionics, surrounding the amphibious robot of the performance of trafficability characteristic and adaptability in amphibious environment, focusing on the propulsion mechanism of propulsion mechanism in amphibious environment, and we carry out an experimental study on amphibious biomimetic propulsion mechanism, which could provide a reference and bio-inspiration for the development of propulsion mechanism of amphibious robot. The main research contents and contributions of this thesis are presented as follows:(1) Taking the Kop Carp possessing maneuvering characteristic and the mudskipper exhibiting excellent ability of amphibious sports ability as a bionics research object, morphology and kinematics of the Kop Carp and mudskipper pectoral fin are detailed investigated, as well as the three-dimensional real-time high-speed camera system for kinematics experimental observation, coordinate transformation and the method of digital image processing technology are presented. Firstly, we investigate the morphological characteristics of Koi Carp pectoral fin rays in the hovering state. The kinematic observations of mudskippers in the water, the amphibious environment, terrestrial environment respectively are conducted to obtaine some related kinematic parameters of mudskippers including speed of the mudskipper and movement angle of pectoral fin under different experimental environment, we compare with morphology and movement characteristics of aquatic and amphibian pectoral fin pectoral, the results provides a reference to design and development an amphibious biomimetic pectoral fin. Finally, we analyze the forward speed of mudskippers at different ratio between amplitude and wavelength. It is found out that there is an optimal ratio between amplitude and wavelength under water and amphibious environment, which provides parameterized guidance for design and motion control of bionic multi-joint amphibious robot.(2) According to the morphological characteristics of mudskippers in amphibious environment, five different morphological parameters of the propulsion mechanism are designed. Based on RFT model and the method of micro-element analysis method to get interaction force conditions between propulsion mechanism and the media of mud, by using of the interaction force conditions and the stress, strain, intensity and time of of the transition medium, combined with intrinsic relationship of these four variables and specific morphological parameters of biomimetic propulsion mechanism, we calculate the mechanical properties of five different morphological parameters propulsion mechanism in amphibious environments, including the level of propulsion, vertical support force and torque variation in a movement cycle. Then we do comparative analysis of the properties of propulsion mechanism under different morphological parameters, the motion parameters and moisture content, interaction laws between the propulsion mechanism and amphibious environmental media has been gained, and intension-deformation theory of strength transitional environmental for the amphibious environment are also set up, which can rovide effective theoretical guidance for design and optimization of propulsion mechanism.(3) Based on morphological study on pectoral fin of mudskipper, combined with3D printing technology and similarity theory. We have designed and implemented amphibious biomimetic pectoral fin with five different levels of stiffness and the corresponding size and uniformly distributed form of biomimetic pectoral fins consistent with bionic object. An amphibious environmental solid experiment platform has been built, and the mechanical design, system hardware design and system software design of the amphibious environmental solid experiment platform are detailly introduced. The propulsive performance of amphibious biomimetic fin in different water content, different stiffness, different sports kinematic parameters is conducted, some motion characteristics including average propulsion, vertical displacement, maximum torque and average propulsion speed of the amphibious biomimetic fin in the movement cycle are measured, and compare with the experiments results of amphibious biomimetic fin and the results of propulsion mechanisms in amphibious environments to verify the feasibility of propulsion mechanisms, which provides a theoretical basis for the research of propulsion mechanisms in amphibious environment, meanwhile the results can provide general conclusions and design principles for the development of propulsion mechanisms when that can really go practical.