Rhythmic control method of a worm robot based on neural CPG

Abstract

In this study, a motion control method is designed for software bionic robot based on peristaltic mechanism and central pattern generator (CPG). The earthworm, as a representative animal of Annelida, is chosen as the prototype of bionics. By making biological analysis of red earthworm and taking a lot of observations of the creep in the soil, the deformation mode and peristaltic mode of the robot are determined, then a continuous flexible deformation worm robot is designed and made which consists of a variable parallelogram array based on Similar Design Principle. The robot is made up of six modular telescoping units, and we call the unit “a segment”, which is the same as that of earthworms. The robot is controlled by CPG, which is specially designed according to the rhythmic motion of invertebrate; the differences between CPG and normal control were compared, and the simulation showed that CPG is more suitable for such rhythm control. By referring to relevant document literature and experiments, the intensity and rigidity of connecting rod in different positions in each telescopic unit are determined, and the key structures such as quadrilateral node connecting piece, driving motor base and bidirectional retracting wheel are designed. And one-dimensional shrinkage and expansion was achieved by one motor, too. The robot will be miniaturized, which will be widely used in special operations, medical fields and micro-pipe testing.