Design And Reconfiguration Strategy Of Series Reconfiguration Modular Robot

The reconfigurable modular robot system consists of a series of basic modules.These modules have low-level ability of motion,necessary sensors and simple functions.By the connection,disconnection and rotation,modules can form different configurations to adapt to the varied working environment and tasks.Compared with the traditional robots with fixed structure,reconfigurable robots have the advantages of wider versatility,stronger robustness and lower cost.In this paper,series modular robot with cube shape is developed.Each module unit has six interfaces and three degrees of freedom.Modules are docked by shaft and hole.Then driven by the moving cam mechanism,the pin locks the joint to achieve reliable connection.According to the structural characteristics of the module,the base is designed to support the module unit.The series modular robot can realize the reconfiguration of various configurations on the base.Each module unit is a small mechatronic product with an independent control system.In this paper,we design the hardware circuit for the module unit,compile the supporting software program,and build a master-slave centralized control system.The centralized control system makes it easy for the upper computer to get the global information of the whole system,so as to calculate a better reconfiguration strategy.We combine the position and attitude information and topological relationship of the module as eigenvector,which can fully reflect the state information of the module in the robot system.On this basis,the eigenvectors of all modules are orderly combined to establish a topological relationship matrix for chain reconfigurable modular robots,which reflects the structure of modular robots in detail.Module unit is cube shape,which determine that all of their motion forms can be summarized as attitude adjustment unit and L-shaped displacement unit.The L-shaped displacement unit is the only way to realize the displacement of the module.For this reason,a reconfiguration strategy based on auxiliary module group is proposed.The L-shaped displacement unit composed of auxiliary modules can move every module in the initial configuration to the target position one by one,and finally,reconfiguration will be realized.This reconfiguration strategy is simple,effective and universal,and can be used to reconstruct any series configuration.To drive the auxiliary module group move to the target position at the fastest speed,the fastest depth descent method is proposed.The feasibility of the reconfiguration algorithm is verified by visual simulation animation.Based on screw theory,the kinematics model of series modular robot is established,and the forward kinematics solution is automatically generated by exponential product method.Generally,there are many redundant degrees of freedom in modular robotic systems.According to the connection characteristics of modular units,we find a reduction method,which can simplify all kinds of series configurations into ladder shape,which has no redundant degrees.Then,by the sub-problem method,the inverse kinematics solution of series configurations,which can be simplified to 5 degrees of freedom or less,can be automatically solved.Through computer simulation and example calculation,the correctness of the above algorithm is verified by computer simulation and practical calculation.