| Amphibious robot,as a kind of robot with good mobility in water,land and transitional environment,can be used in marine resources exploration,military strategic investigation,disaster rescue and so on,and its application range is very wide.Based on research projects of amphibious robots and crawler robots at home and abroad,this paper summarizes the analysis of research status,completes the robot structure design,studied the analysis of hydrodynamics and land kinematics,develop control strategies for robot movement on land and underwater,and develops the display control system of the robot by Lab VIEW software.First of all,this paper summarizes the development status of amphibious robots at home and abroad,analyzes the structure and motion mode of existing amphibious robots and crawler robots,and defines the design indexes of amphibious robots.Then the structure of the robot is designed.According to the operation requirements,the strength of the control cabin is verified,the land motion mechanism of the robot is designed and calculated,and the selection of related mechanisms is completed.In addition,the stability of the robot’s underwater movement is analyzed,and the adjustment formula for the relationship between gravity and buoyancy is put forward.According to the measured data of buoyancy and gravity center,the stability of the robot is adjusted.Secondly,considering the nonlinear and strong coupling characteristics of the robot underwater movement,the hydrodynamics of the robot is analyzed by using the potential energy theory and viscous fluid theory,and the mathematical models of the robot direct navigation,pitching and heading movement are established.Using Fluent module,three underwater motion states are simulated,and the resistance of the robot at different speeds and postures is obtained.By solving the least square method,the hydrodynamic coefficient is obtained,and then the propulsive force required by the robot underwater movement is obtained,and the appropriate thruster is selected.Thirdly,the movement model of robot’s land walking mechanism is established,and the stress of the crawler unit is analyzed.The steering motion model of the walking mechanism is established to analyze the speed relationship and force of the track on both sides during the steering motion and verify the rationality of the design.According to the position of the center of mass of the robot,the stability of the robot motion in different situations is analyzed.Recurdyn simulation software is used to simulate the movement of the robot such as turning,climbing and obstacle crossing.The simulation results are compared with the theoretical analysis to verify the stability of the robot’s movement and the adaptability to different environments.Fourthly,the transfer function of the control system can be obtained according to the selected motor and propeller.The corresponding control system simulation model is established by software,and the control system model with traditional PID control and fuzzy adaptive PID control is simulated and analyzed.According to the obtained response characteristics and error tracking curve,the control effects of the two control schemes are compared,and then the control mode that is more suitable for the scheme is selected.Finally,the human-computer interaction interface of the amphibious robot is created by Lab VIEW,and the amphibious motion experiment of the robot is carried out by the experimental platform.The control effect of the robot control system is analyzed through direct navigation,diving and heading turning experiments under water.Through the experiments of driving in a straight line,turning and surmounting obstacles on land,the land movement ability and stability of the robot are studied. |
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