Research On The Motion Planning And Related Technology For Amphibious Multi-legged Robot

The research is supported by project of 'Biologically Inspired Crab-liked Amphibious Robot Study' which is funded by NSFC(National Natural Seience Foundation of China). After reviewing relative researchs at home and abroad, this dissertation focuses studies on motion planning of an amphibious multi-legged robot, including researches on mechanical design, kinematic model, analysis of forward and inverse kinematics, gait planning, design of control system and kinematic analysis based on simulation. The confirmation of the DOF of the robot is designed and is proved by the calculation of DOF. Then the mechanical parts are designed which compose the whole robot.Based on D-H coordinate system, the kinematic models of single leg and multi-legs of the robot are established, followed by kinematic analysis of swing legs which results in equations and jacobian matrix for inverse kinematics solution. Besides, by analyzing the cyclic approximation method for inverse kinematics solution, the improved algorithm is proposed to avoid the cyclic dead zone. Finally, the kinematic analysis based on the jacobian matrix for stance legs is performed.According to the duty of gait planning, the Plan Movement gait is created for the robot, for which the Motionless Trunk Method is suggested to plan the gait. Furthermore, an example of gait planning through such method is introduced, in which kinematics equations for leg ends are obtained. Based on multilevel hierarchical control theory, the scheme of control system is designed for the robot. The design is primarily focused on the hardware for joint servo drive module, the hardware and software for USB interface module and other modules.According to the result of gait planning, the joint driving variables are got in the inverse kinematic solution through simulation based on Simulink. Moreover, the analysis of cyclic approximation method is made through the simulation, the result of which is in accordance with the theory analysis made before. Meanwhile, in order to test the result of inverse solution, the kinematics of both single leg and multi-legs is analyzed based on the SimMechanics model. Finally, the simulation results proves the result of inverse kinematic solution and is in accordance with the result of gait planning.