Self-reconfigurable Modular Robots: Structure Design And Study Of M~2SBot

Firstly, this paper presents a novel unit module of an autonomous mobileself-reconfigurable modular robot——M2SBot. It belongs to a three-dimension homogeneousand chain style self-reconfigurable modular robot. The unit module has a cube shape with asimple and symmetry structure. The center of mass of unit module is located near itsgeometric center. It has a joint degree of freedom, two driving wheels, four connectedsurfaces, many types of sensors and a special mechanical connecting mechanism. The unitmodule not only can independently accomplish crossing obstacles, investigation and rescuemissions, but also like most other self-reconfigurable modular robots, modules can bereconfigured into a variety of common configurations.Secondly, the kinematics and dynamics about the unit module are analyzed. In theprocess of the kinematics analysis, the kinematics model is established. Then the commonmotion types are analyzed such as the straight line motion, turning motion and self-rotationmotion. The kinematics simulation analysis about the self-rotation motion by Adams confirmsthat the unit module has the ability of zero radius rotation around its mass center. In theprocess of dynamics analysis, we establish the dynamical models for terrace obstacle anduphill obstacle. At the same time, Obstacle crossing simulations have been analyzed based onthe Adams.Next, the structure of connection mechanism is discussed in detail. This paper proposes aconnection mechanism of latch type which has four circumferential uniform distributiongrooved cams with sine acceleration curve, based on two straight tooth gears transmission.The connection mechanism is composed of a female connector and a male connector. Thedocking experiment with the physical prototype verifies that the mechanism is rational,reliable and practical. The supporting capacity experiment proves that the mechanism hasbetter connection strength.Lastly, the automatic docking method among modules has been studied preliminarily.This paper proposes a position offset correction strategy based on the method of minimizingthe energy function. Meanwhile, we have planed a scheme finishing the automatic dockingmission. Besides, the combination configuration of many modules also has been introduced.