Design And Control For A Novel Spherical Amphibious Robot System

As a typical representative of high-end manufacturing industry,robot can help mankind work in the heavy or high risk environment.Because of it have advantages of durability and high degree of flexibility.Amphibious robots can achieve movement in both water and land areas,so this type of robot has wide application prospect,including in life,industry,military and other fields.First of all,this paper puts forward a new kind of spherical amphibious robots.The robot has two movement patterns on land.One is a driving-wheel movement pattern which is used to speed up the movement of robot under the flat terrain;the other is a quadruped movement pattern which is available to climb over obstacles.Wheel movement is achieved by that DC motors drives the wheels.Nozzle,water-jet propeller and two waterproof servo motors make up the robot's legs.Quadruped movement is achieved by four legs.At the same time,by adjusting the deflection Angle of waterproof servo motors,the thrust of water-jet propeller and the spray direction,the robot can realize movement of multi DOFS(degrees of freedoms)in water.Secondly,to evaluate movement characteristics of the robot on land,this paper analyzes two kinds of motion mode and the corresponding gait of the spherical amphibious robot adopted on land.Experiments of wheel movement are conducted under the condition of different terrains and different loads on land.The relationship between speed and the PWM(Pulse Width Modulation)duty ratio is obtained.Experiments of quadruped crawling movement are conducted under the condition of different terrains and different loads on land.The relationship between speed and frequency of the robot's movement is obtained.Then GPS(Global Positioning System)positioning related experiments are introduced.Finally,in order to achieve accurate control of the robot in water,Simulation analysis of the water-jet propeller model is implemented by CFD(Computational Fluid Dynamics)code,Fluent.The relationship between actuating force of the water-jet propeller and the PWM duty ratio is obtained.And wireless control experiment of the robot is conducted.Wireless control experiment can switch freely movement modes of the robot in water.Movement modes include forward,backward,rotation,floating,diving,etc.Maximum forward speed,maximum rotation angular velocity and maximum dive speed of the robot in water are obtained.Experimental verification demonstrates the feasibility of this novel spherical amphibious robot system.