The Gait Planning And Motion Analysis Of An Amphibious Spherical Robot System

With the continuous progress of human society,the robotic technology has already established a close relationship with our life.As a kind of robot,the amphibious spherical robot has many excellent properties in environment adaptability and flexibility,because of its symmetrical structure.It has been applied in many kinds of fields.So the amphibious spherical robot has become a hot topic in the field of robotic research.In this paper,we proposed a novel amphibious spherical robot system.The robot has dynamic stability,small environmental disturbance and flexible movement due to the global symmetry.The driving unit of the mechanical leg with a DC jet propulsion system can not only complete the multiple DOF on land,but also realize the movement and operation under water.The amphibious robot can act as a multifunctional structure,investigation,communication and recovery device in the ground and under water by configuring GPS,gyroscope,accelerometer and obstacle avoidance sensor.It can also release some small underwater robot to complete the underwater task in a narrow or confined space.In order to analyze the kinematic and dynamic characteristics of the amphibious spherical robot on land,we use the D-H parameter method and Lagrange function to establish kinematic equation and dynamic equation.The Jacobian matrix,which can reflect the relationship between the velocity and angular velocity of the joint can be obtained.It provides the theoretical foundation for the following simulation analysis based on virtual prototype.Then,in order to verify the feasibility of the gait planning algorithm,we use 3D mechanical software Solidworks to establish the simplified model of the robot,and import it into simulation software ADAMS(Automatic Dynamic Analysis of Mechanical Systems)for kinematic and dynamic simulation.At last,some experiments are carried out to verify that the simulation results in ADAMS are accurate to describe the motion characteristics of the robot.The dynamics model of the amphibious spherical robot under the water is established by using the Euler equation,Meanwhile,the parameters of the model are calculated.Secondly,the experiments and theory analysis are used together in the modeling and identification of the water jet propulsion,and the relationship between the input voltage and the water jet propulsion is established.Lastly,in order to verify the reliability of the underwater motion function,a set of experiment are carried out and the experimental results are analyzed and summarized.