Structure design and coordinated motion analysis of bionic crocodile robot

Crocodiles, one of the oldest and most resilient species on Earth, have demonstrated remarkable locomotor abilities both on land and in water, evolving over millennia to adapt to diverse environments. In this study, we draw inspiration from crocodiles and design a highly biomimetic crocodile robot equipped with multiple degrees of freedom and articulated trunk joints. This design is based on comprehensive analysis of the structural and motion characteristics of real crocodiles. The bionic crocodile robot has a problem of limb-torso incoordination during movement. To solve this problem, we used the D-H method for both forward and inverse kinematics analysis of the robot's legs and spine. Through a series of simulation experiments, we investigated the robot's motion stability, fault tolerance, and adaptability to environments in two motor patterns: with and without spine and tail movements. The experimental results show that the bionic crocodile robot exhibits superior motion performance when the spine and tail cooperate with the extremities. This study not only demonstrates the potential of biomimicry in robotics but also underscores the significance of understanding how nature's designs can inform and enhance technological innovations.