Research On Gait Planning And Control Method For Bionic Amphibious Robot

The bionic amphibious robot is a new concept robot that can move in water and on land,freely crossing between the two environments.Its design inspiration comes from the body structure and movement patterns of animals.It has high obstacle-overcoming abilities,strong maneuverability,quick land-water conversion capabilities,and environmental adaptability.It can perform a variety of combat and detection tasks on land,nearshore beaches,and complex underwater environments,and has broad application prospects in both military and civilian fields.Traditional underwater vehicles mostly use propeller propulsion,but they have shortcomings such as high noise,large environmental disturbance,poor maneuverability,and poor concealment.In order to compensate for the shortcomings of propeller propulsion,people are constantly exploring new propulsion modes.Fish through millions of years of natural evolution and selection,have superior underwater mobility,while snakes have extraordinary mobility on land,both based on the principle of wave motion for walking or propulsion.In this thesis,Gymnarchus niloticus was taken as the bionic object to design a bionic amphibious robot,focusing on the research of gait planning and control strategies for the bionic amphibious robot in different environments.The theoretical modeling,simulation analysis,and experimental verification were completed.The detailed work contents are as follows:(1)The flexible long dorsal fin of Gymnarchus niloticus was selected as the bionic research object.Through observation and morphological analysis,the morphology and movement characteristics were summarized,the propulsion mechanism and motion laws of the undulating fin were analyzed,and a kinematic model was established.The adaptability of the model was verified through simulation,providing a design basis and theoretical foundation for the study of bionic amphibious undulating fin robots.(2)Based on the undulating movement characteristics of the flexible long dorsal fin,a bionic amphibious undulating fin robot was designed and studied.The principle of its land movement was obtained through the analysis of the motion state of its propulsion device.The three-dimensional movement of the undulating fin was simplified into a two-dimensional form.For ground movement,the simplified form of the undulating fin was modeled and imported into the dynamic analysis software ADAMS for simulation analysis.(3)Based on the kinematics model of the bionic amphibious robot,the adjustable parameters for controlling the movement of the undulating fins on both sides are determined.Through the analysis of its moving modes such as forward,backward,turning,floating and diving,the gait and gait transformation schemes of the bionic amphibious robot in different environments are designed.Combining the characteristics of the robot such as time-varying,strong coupling and nonlinear,the CPG control system based on Hopf neural network is established.An improved CPG network model was proposed to generate rhythm signals of undulating fins with 9 fin rays to simulate the motion of a biomimetic amphibious undulating fin robot.The improved CPG network consists of 9 chain coupled oscillators with bidirectional disturbances,which can achieve motion control of biomimetic amphibious robots.(4)The robot’s underwater and land gait were tested through experiments,verifying the robot’s motion ability and performance in both underwater and land environments.The feasibility of gait planning was also verified,indicating that its biomimetic amphibious robot can adapt to amphibious environments.