  Crocodiles, known as 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 paper, we
draw inspiration from crocodiles and introduce a highly biomimetic crocodile
robot equipped with multiple degrees of freedom and articulated trunk joints.
This design is based on a comprehensive analysis of the structural and motion
characteristics observed in real crocodiles. The bionic crocodile robot has the
problem of limb-torso incoordination during movement, in order to solve this
problem, we apply 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 investigate the robot's stability of motion, fault tolerance,
and adaptability to the environment in two motor pattern: with and without the
involvement of the spine and tail in its movements. Experiment results
demonstrate that the bionic crocodile robot exhibits superior motion
performance when the spine and tail cooperate with the extremities. This
research not only showcases the potential of biomimicry in robotics but also
underscores the significance of understanding how nature's designs can inform
and enhance our technological innovations.
