Design of Self‑Reconfigurable Multiarm Robot Mechanism Based on Deployable Kinematic Chains

As the structures of multiarm robots are serially arranged,the packaging and transportation of these robots are often inconvenient.The ability of these robots to operate objects must also be improved.Addressing this issue,this paper presents a type of multiarm robot that can be adequately folded into a designed area.The robot can achieve different operation modes by combining different arms and objects.First,deployable kinematic chains(DKCs)are designed,which can be folded into a designated area and be used as an arm structure in the multiarm robot mechanism.The strategy of a platform for storing DKCs is proposed.Based on the restrictions in the storage area and the characteristics of parallel mechanisms,a class of DKCs,called base assembly library,is obtained.Subsequently,an assembly method for the synthesis of the multiarm robot mechanism is proposed,which can be formed by the connection of a multiarm robot mechanism with an operation object based on a parallel mechanism structure.The formed parallel mechanism can achieve a reconfigurable characteristic when different DKCs connect to the operation object.Using this method,two types of multiarm robot mechanisms with four DKCs that can switch operation modes to perform different tasks through autonomous combination and release operation is proposed.The obtained mechanisms have observable advantages when compared with the traditional mechanisms,including optimizing the occupied volume during transportation and using parallel mechanism theory to analyze the switching of operation modes.

Similar Vertices and Isomorphism Detection for Planar Kinematic Chains Based on Ameliorated Multi-Order Adjacent Vertex Assignment Sequence

Isomorphism detection is fundamental to the synthesis and innovative design of kinematic chains(KCs).The detection can be performed accurately by using the similarity of KCs.However,there are very few works on isomorphism detection based on the properties of similar vertices.In this paper,an ameliorated multi-order adjacent vertex assignment sequence(AMAVS)method is proposed to seek out similar vertices and identify the isomorphism of the planar KCs.First,the specific definition of AMAVS is described.Through the calculation of the AMAVS,the adjacent vertex value sequence reflecting the uniqueness of the topology features is established.Based on the value sequence,all possible similar vertices,corresponding relations,and isomorphism discrimination can be realized.By checking the topological graph of KCs with a different number of links,the effectiveness and efficiency of the proposed method are verified.Finally,the method is employed to implement the similar vertices and isomorphism detection of all the 9-link 2-D0F(degree of freedom)planar KCs.

Rigid Subchain Detection Algorithm of Mechanism Kinematic Chain and Realization of Recursive Program

In the process of kinematic chain type synthesis,it is necessary to solve the problems of isomorphism identification and rigid subchain detection.The problem of rigid subchain detection can be reduced to subgraph isomorphism problem,which belongs to NPC problem.This paper introduces the properties,detection methods,algorithm time complexity and program code of rigid subchain of kinematic chain.The detection codes of rigid subchains with different number of links are different.It is necessary to modify the for-loop nesting times of program code according to the change of the link number,so the code reusability is very low.In view of this,the recursive pseudo code of rigid subchain detection algorithm is proposed for the first time,which makes the program can be directly used for rigid subchain detection of any number of links,improves the reusability of the code,and provides a certain reference for the realization and optimization of computer programs for NPC problems in other disciplines.A rigid subchain detection software of kinematic chain was developed,and the rigid subchain detection process of a 16-link kinematic chain was successfully realized in the software.