Design And Research Of Mobile Robot Based On Metamorphic Theory

Robotics has become a research hotspot in the face of complex accident scene environment and more arduous rescue missions.Where,in order to free human beings from a dangerous working environment,robotics has been widely studied and applied as a kind of intelligent technology.However,The traditional robot cannot satisfy the complicate and specific work tasks.Therefore,the metamorphic mechanism is applied to the leg structure of mobile robots.Based on the characteristics of variable structure and variable degree of freedom of the metamorphic mechanism,a metamorphic mobile robot is designed to adapt to various accident scene environments,complete more rescue tasks and meet the requirements of precision and diversification of robot work.In order to construct a reasonable metamorphic mechanism,an analysis method based on screw theory is adopted by combinations of the spatial structure transformation of the metamorphic mechanism with the motion characteristics.The kinematics analysis for constructing the mechanism screw matrix of the mechanism is developed.The space motion equation is established based on the D-H method,The spatial equation of motion and the dynamics model of the moving mechanism is established.Then the motion screw matrix is established based on the screw theory.Finally,the stability analysis of the configuration state transformation is carried out by the simulation software.The specific work content is as follows:(1)According to the specific task requirements,the topology diagram of the rescue mobile robot is designed based on the metamorphic theory,and the size of the component is determined according to the basic mechanism theory.The NX/UG software is used for 3D modeling,and the configuration of the mobile robot and its description method are analyzed..(2)The motion model of the travel mechanism is constructed based on the D-H parameter method.The forward motion equation of the mechanism is obtained by establishing the motion equation and solving the corresponding position of the mechanism.Then the further motion analysis of mechanism configuration based on the screw theory.The feasibility of the mechanism is reflected by the motion screw matrix and reciprocal screw system.The position of the connecting rod of the mobile robot with three configurations is simulated by MATLAB software.(3)The static model of a single moving leg branch is established,then the static characteristics,the variation of the internal stress between the connecting rods and the variation regularity of the motor driving torque are obtained.Meanwhile,dynamic modeling of mobile robots based on Lagrange method,According to the equivalent resistance gradient model of the mechanism,the randomness of the configuration is analyzed by changing different motion parameters.(4)ADAMS software is used to complete the kinematics simulation analysis of the robot.The simulation results show that the predetermined three configurations can be realized,which proves the feasibility of the mechanism.At the same time,the transformation configuration process of mobile robot is obtained.The results of displacement,velocity and acceleration show that the impact vibration is generated due to the contact of the rod in the transformation configuration,which is consistent with the random analysis based on the equivalent gradient resistance,and the correctness of the simulation results is verified.(5)Aiming at the impact during the movement of the mechanism,the combination of spring and vibration isolation between adjacent bars is adopted to avoid the random mechanism state.Finally the motion simulation is performed again to obtain a new force simulation curve,which demonstrates the effectiveness of the proposed solution.