Mechanical Modeling And Simulation Of Mobile System For Underwater Hexapod Robot

With the development of human exploration of the ocean,the movement ability of underwater detection equipment in the marine has become one of the key technologies that restrict the development of deep sea exploration and work.The propeller of the traditional underwater equipment will disturb the surrounding environment and influence the observation field.The equipment could not work normally and fixed-point operation when it meets the subsea current,but the underwater legged robot can effectively solve the problem.In this paper,based on the research of the current underwater equipment and the legged robot,a kind of submarine detection legged robot scheme is proposed,and the hydrodynamic forces on the underwater legged robot while moving on the sea floor are analyzed in detail.Firstly,in the view of the underwater environment,this paper analyzes traditional underwater remote control robot and the hexapod robot,determines the basic technical indexes of the underwater hexapod robot,designs the mobile system configuration,and determines the overall scheme of the underwater hexapod robot,including the structure form of leg joints,body and leg size,mass distribution,etc.Secondly,according to the configuration of mobile system,this paper builds the forward kinematics model and the inverse kinematics model of the leg.Also,the relationship between the velocity and acceleration of the joint coordinate system and the terminal coordinate system is analyzed.The leg dynamics model,including the viscous water resistance and the inertia water resistance,is set up.The analytic expression of the calculation of the leg joint torque is obtained,and the general expression of the leg dynamics is given.And the kinematics model of body is given.Thirdly,this paper analyzes the hydrodynamic term in leg dynamics model in detail,and establishes the integral formula of the leg hydrodynamic model and the body dynamic model,and the integral method of integral formula is given.Considering the characteristics of seabed mud,the paper builds a kind of contact force model between foot and sea mud,based on the terramechanics and the shape of the foot.Finally,the paper compares the results of the hydrodynamic forces of joints between the analytical formula and the CFD simulation software,which proves the validity of the model.The paper develops a kind of simulation environment of underwater hexapod robot,including hydrodynamic model and foot contact mechanics model,and then analyzes the forces of the joints under different conditions.