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.

A New Topological Description Method of Kinematic Chain

This paper presents a novel method for the description of kinematic chains, namely the canonical description of kinematic chains including the synthetic degree-sequences and the canonical adjacency matrices sets of kinematic chains. The most important characteristic of this new description method is its uniqueness. Based on the new principle the isomorphism identification becomes easy and the structures of all kinds of kinematic chains can be stored in computer for the benefits of the realization of automation and intelligence of machine design.

ADJACENT MARTIX METHOD OF IDENTIFYING ISOMORPHISM TO PLANAR KINEMATIC CHAIN WITH MULTIPLE JOINTS AND HIGHER PAIRS

The adjacent matrix method for identifying isomorphism to planar kinematic chain with multiple joints and higher pairs is presented. The topological invariants of the planar kinematic chain can be calculated and compared by adjacent matrix. The quantity of calculation can be reduced effectively using the several divisions of bars and the reconfiguration of the adjacent matrix. As two structural characteristics of adjacent matrix, the number of division and division code are presented. It can be identified that two kinematic chains are isomorphic or not by comparing the structural characteristics of their adjacent matrixes using a method called matching row-to-row. This method may be applied to the planar linkage chain too. So, the methods of identifying isomorphism are unified in the planar kinematic chain that has or hasn＇t higher pairs with or without multiple joints. And it has some characters such as visual, simple and convenient for processing by computer, and so on.

AUTOMATIC DISPLACEMENT ANALYSIS OF PLANAR MECHANISMS WITH MATCHING BASIC KINEMATIC CHAINS METHOD

A simple, efficient, automatic and universal method to fulfill displacementanalysis of a great deal of mechanisms regenerated by Yan's mechanism creative theory has beendeveloped. For a regenerated mechanism, at first, the method identifies its type and structure andchanges it into a rigid structure by fixing the ground link and the input link. And then this rigidstructure is decomposed into a set of basic kinematic chains (BKCs). By matching the type of BKC,the displacement analysis equations can be set up, and all possible configurations, in whichpositions of all movable links are considered, can be given out.

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.

A New Complete Hierarchical Classification Approach to Kinematic Chains

Based on structural properties and genetic isomorphism-identification approach, this paper proposes a classification scheme of kinematic structures to categorize the kinematic chains into different families, thus facilitating the optimum selection of a basic structure of a mechanism. The kinematic chain is represented by a graph at first. The genetic adaptive model for the graph isomorphism identification is developed, which includes the construction of an effective method to decrease the problem's dimensions and applying an evolutionary searching strategy. From the various invariants of the genetic adaptive model, which charaterize the specific features of a kinematic chain or a family of kinematic chains, we obtain a six-step hierarchical classification scheme. This scheme classifies together the kinematic chains having similar sub-sets of structures forming isomorphic sub-chains. An example illustrates the theory, procedure and utitlity of the hierarchical classification. The scheme reduces computing time and effort in the optimum selection of a kinematic structure from a large family of kinematic chains.

KINEMATICS ANALYSIS OF GUIDED CHAIN DRIVE MECHANISM WITH LINKAGES

A method of analyzing the motion of guided chain drive mechanism with linkages is presented. The method studies the output motion of a point on connecting rod including motion track, velocity and acceleration.

STUDY ON ISOMORPHISM OF PLANAR KINEMATIC CHAINS

The isomorphism of planar kinematic chains is studied. The original methods for de- tecting isomorphism is discussed. A new matrix, the link -link path matrix, is presented to show the structures of planar kinematic chains. It is simple and reliable to detect isomorphism of planar kinematic chains by using the link-link path matrix.

Remanufacturing closed-loop supply chain network design based on genetic particle swarm optimization algorithm

As the huge computation and easily trapped local optimum in remanufacturing closed-loop supply chain network (RCSCN) design considered, a genetic particle swarm optimization algorithm was proposed. The total cost of closed-loop supply chain was selected as fitness function, and a unique and tidy coding mode was adopted in the proposed algorithm. Then, some mutation and crossover operators were introduced to achieve discrete optimization of RCSCN structure. The simulation results show that the proposed algorithm can gain global optimal solution with good convergent performance and rapidity. The computing speed is only 22.16 s, which is shorter than those of the other optimization algorithms.

Closed-loop supply chain network equilibrium strategy model with environmental protection objectives

With the increasing popularity of ecological civilization and sustainable development,enterprises should consider environmental protection measures in their operations in addition to pursue their economic interests.This paper establsihes a closed-loop supply chain network model composed of multiple suppliers,manufacturers,retailers,recyclers,and demand markets—regarding their dual goals of the profit maximization and the minimization of carbon emissions.The conditions necessary for establishing overall equilibrium and an equilibrium model of the entire closed-loop supply chain network are determined by applying variational inequality and dual theory.A modified projection contraction algorithm is used to design a model-solving program.Finally,using numerical examples,the paper conducts a comparative static analysis on important parameters such as the weight coefficients of environmental protection objectives and consumers'awareness of low-carbon environmental protection and attains some beneficial enlightenment on management.The results indicate that when the environmental protection objectives of a certain type of enterprise increases,both the economic benefits and environmental protection performance will improve;when the environmental protection objectives of all enterprises increases simultaneously,environmental protection performance improves significantly,but the changes in economic benefits of different enterprises are inconsistent and profit coordination is more complex.Although consumers’awareness of low-carbon preference could improve environmental performance,it reduces the overall profits of network members and the entire closed-loop supply chain network as a whole.The above conclusions can be used as a reference for the government in designing low-carbon environmental protection policy and in closed-loop supply chain research.

Pricing and decision of carbon emission reduction for closed-loop supply chain considering carbon trading mechanism

To determine the optimal pricing and carbon emission reduction decision, a closed-loop supply chain with a manufacturer and a retailer is investigated. In this system, the manufacturer manufactures new products and remanufactures used products while the retailer is responsible for selling new products and remanufactured products. The profit functions of the manufacturer and the retailer are developed, and the corresponding solution formulae for decision variables are given by the Stackelberg game model. Finally, a numerical example is given, and the optimal wholesale price, retail price, carbon emission reduction and others are obtained. Through the sensitivity of the unit carbon allowance price, some significant managerial insights are derived.

Improving the Performance of Urban Waste Management Systems in the Context of a Closed-Loop Supply Chain

The saving of non-renewable energies, as well as the reduction of emissions into the environment, are two crucial objectives of industrial production. The recovery of post-consumer products associated with the use of end-of-life products is part of a context of optimization of these objectives. This recovery maximizes the use of resources from end-of-life products in a circular logic while recording the environmental footprint. This study considers a recycling strategy adapted to the need and urgency to reduce greenhouse gas emissions caused by global warming. The proposed model aims to optimize the profits of the circular manufacturing strategies while minimizing operational costs (collection, sorting, recycling), transport, GHG emissions and recycling. In this paper, a compromise between the gains of CM and the costs associated with it was studied. The robustness of the designed model was tested using a case study based on real-world scenarios. A sensitivity analysis was carried out to study the impact of the emission cost on the overall objective, considering the two options currently offered to industries. The obtained results support companies to take the ecological aspect into account and integrate sustainable development into their strategic axes for their logistics supply chains.

Dynamic Pricing Model for the Operation of Closed-Loop Supply Chain System

A class of closed-loop supply chain system consisting of one manufacturer and one supplier is designed, in which re-distribution, remanufacturing and reuse are considered synthetically. The manufacturer is in charge of recollecting and re-disposal the used products. Demands of ultimate products and collecting quantity of used products are described as the function of prices and reference prices. A non-linear dynamic pricing model for this closed-loop supply chain is established. A numerical example is designed, and the results of this example verified the model’s validity to price for the operation of closed-loop supply chain system.

无寄生运动3-DOF 2T1R并联机构拓扑设计与分析

为充分研究少自由度并联机构所具备优势,拓宽其应用领域,设计并研究一种含冗余支链且无寄生运动三自由度两平移一转动(2T1R)并联机构,完成运动学和动力学分析。基于方位特征集(POC)的拓扑机构学理论方法,设计了一种含冗余支链且无寄生运动的两平移一转动并联机构,并进行拓扑分析,结果表明:该机构还具有部分运动解耦特性;根据基于拓扑特征运动学的建模方法,求得机构位置正反符号解;又基于位置反解分析了机构奇异性,基于位置正解给出了工作空间;基于虚功原理的序单开链法对机构进行动力学建模,求得了该机构移动副处的驱动力以及两个子运动链(SKC)连接处的支反力;概念设计了该机构的一种应用场景。

一种基于图论理论的大尺度连续变形机构构型综合分析方法

针对航空航天领域大尺度连续变形机构构型问题,提出了一种基于图论理论的大尺度连续变形机构构型综合分析方法。首先,分析了大尺度连续变形机构的组成与基本功能,获得了满足机构拓扑结构、约束条件的要求,对变形机构运动链进行了分析,得到了符合条件的运动链,并对其进行了数学描述;其次,选择并分析了运动链的拓扑对称性,利用特征数组的方法得到了判别矩阵,对运动链进行了同构判别,从而得到了可行的多种运动链形式;再次,建立了各运动链的拓扑图,通过筛选得到了最终的拓扑图,去掉该拓扑图的各个构件,得到了拓扑变换子图和相对应的邻接矩阵,对拓扑图进行了同构判别,再通过改变机架与移动副的位置得到了满足要求的12种构型,画出了其相应的机构拓扑图和机构简图;最后,考虑了大尺度连续变形机构的整体稳定性,避免了尺寸过大等因素,对大尺度变形机构进行了构型优选,得到了符合要求的多种新构型。研究结果表明:该方法能够将大尺度连续变形机构抽象为图形式,获得了22种构型,可根据机构变形要求的不同,改变优选依据,从而得到符合不同要求的构型。

Decision model for closed loop supply chain with uncertain demand and price-dependent returns

A single product closed-loop supply chain that satisfies an uncertain market demand with original and remanufactured products is considered.The yield of the recovery process is random and depends on the acquisition price offered for the end-of-life products.In such a stochastic setting,a firm needs to make production and procurement decisions so that the total expected profit is maximized.Both centralized and decentralized models are established depending on the party collecting the returns.The optimal acquisition price and production quantities of original and remanufactured products are determined for the firm.The contracts to coordinate the decentralized systems are chosen and the optimal contract parameters are determined.A computational experiment is given to show the effects of recovery parameters on the system performance.Results show that the recovery parameters have a high impact on the profitability of the manufacturer in the centralized model and on that of the collection agency in the decentralized model.

混联支路并联腿运动学分析与尺度综合

针对步行机器人在核环境下作业时,动力源分散,不便于防护的问题,提出一种动力源集中布置,可用于构建步行机器人的四自由度混联支路并联腿部机构。运用螺旋理论分析其自由度数目、性质及机构特性。建立了运动学反解模型,并分别推导出驱动空间和关节空间的速度雅克比矩阵。以两个雅克比矩阵条件数为基础,提出了一种带权重的混合条件数,用于综合评价机构的力传递与运动传递性能。以混合条件数最小为尺度综合目标,先通过单调性分析得到结构参数的取值区间,再应用粒子群优化算法获得一组最优结构参数,为样机加工和其他混联支路并联机构尺度综合提供参考。该新型腿部机构动力源统一后置,便于集中防护,驱动空间具有驱动置换功能和半解耦特性,便于实现位姿控制,在核辐射、高温等恶劣环境下有着良好的应用前景。

Decision and Coordination in a Closed-Loop Supply Chain with Product Recycling Under Different Low-Carbon Regulations

The implementation of recycling activity is of great significance to closed-loop supply chain operations.Consumers’environmental awareness and governmental subsidy are considered in the two-echelon closed-loop supply chain.Two types of decision-making structures are proposed under different carbon emission regulations.The subsidy sharing mechanism is designed to resolve the channel members’conflict caused by double marginalization.This paper provides insight into the effect of environmental awareness and government subsidy under different low-carbon regulations on the supply chain benefit and social welfare via the game theory.The analysis results display that the government subsidy and subsidy sharing mechanism are profitably beneficial to the whole supply chain and social welfare.Moreover,a noteworthy result reveals that social welfare is not always directly proportional to consumers’environmental awareness.Social welfare decreases slightly with the increase in consumers’environmental awareness when consumers’environmental awareness is weak.However,social welfare will be significantly improved when consumers’environmental awareness increases beyond a certain threshold.

Coordination for a Closed-loop Supply Chain with Recycling Platform Considering Dynamic Setting

This paper presents a dynamic closed-loop supply chain(CLSC)model,incorporating a manufacturer,a retailer,and an internet recycling platform(IRP),utilizing differential game theory while considering the forgetting effect of consumers.The model encompasses factors such as the quality level of used products and Big Data marketing(BDM),comparing optimal equilibriums under decentralized and cooperative decision scenarios.To effectively coordinate the dynamic CLSC at each time point,we propose a revenue-sharing and cost-sharing(RSCS)combined contract.In addition to ensuring reasonable sharing of revenues and costs,this contract allows the manufacturer to flexibly adjust wholesale prices for final products and transfer prices for used products in order to distribute profits appropriately and achieve Pareto optimality within the CLSC system.Furthermore,our results indicate that there exists a threshold for Big Data marketing efficiency;high-efficiency BDM not only facilitates increased recycling on Internet platforms but also reduces unit recycling costs for enterprises.Interestingly,when implementing the combined contract,Big Data marketing efficiency does not impact the transfer price paid by manufacturers to Internet recycling platforms.