Distributed adaptive formation tracking using quantized feedback communication for networked mobile robots with unknown wheel slippage

In this study, we consider a quantized-feedback-communication-based control design problem for the distributed adaptive formation tracking of multiple nonholonomic mobile robots with unknown slippage constraints under capacity-limited network control environments. Uniform-hysteretic quantizers are employed to quantize all the inputs and states of robots and the quantized position information of each robot is only transmitted to neighboring robots through directed networks. Compared with existing literature related to the robot formation, the primary contribution of this paper lies in establishing a novel local adaptive control design methodology to deal with the discontinuity problem caused by using the quantized states of each follower and the quantized position communication of neighboring robots. In the proposed strategy, the communication of the orientations and velocities of neighboring robots is not required for the local control design of follower robots. Moreover, quantized-states-based adaptive compensation schemes are constructed for the effects of signal quantization and wheel slippage. Based on the analysis of quantization errors, the practical stability strategy of the overall closed-loop formation system is derived with the convergence of local tracking errors. Simulation results clarify the proposed formation strategy.     

Large Hexadecametallic {MnIII–LnIII} Wheels: Synthesis,Structural, Magnetic,and Theoretical Characterization

The synthesis, gas sorption studies, magnetic properties, and theoretical studies of new molecular wheels of core type {Mn^III₈Ln^III₈} (Ln=Dy, Ho, Er, Y and Yb), using the ligand mdeaH₂, in the presence of ortho‐toluic or benzoic acid are reported. From the seven wheels studied the {Mn₈Dy₈} and {Mn₈Y₈} analogues exhibit SMM behavior as determined from ac susceptibility experiments in a zero static magnetic field. From DFT calculations a S=16 ground state was determined for the {Mn₈Y₈} complex due to weak ferromagnetic Mn^III–Mn^III interactions. Ab initio CASSCF+RASSI‐SO calculations on the {Mn₈Dy₈} wheel estimated the Mn^III–Dy^III exchange interaction as ?0.1 cm^?1. This weak exchange along with unfavorable single‐ion anisotropy of Dy^III/Mn^III ions, however, led to the observation of SMM behavior with fast magnetic relaxation. The orientation of the g‐anisotropy of the Dy^III ions is found to be perpendicular to the plane of the wheel and this suggests the possibility of toroidal magnetic moments in the cluster. The {Mn₈Ln₈} clusters reported here are the largest heterometallic Mn^IIILn^III wheels and the largest {3d–4f} wheels to exhibit SMM behavior reported to date.     

在线电解修整磨削的电解磨削液研制

为了对金属结合剂砂轮电解修整 ,研究并配制了电解磨削液。根据电解磨削液的性能要求 ,分析确定了电解磨削液中具有电解、钝化、防锈和润滑等性能的各组元 ,并通过静态实验确认了各组元对电解磨削液性能的影响。确定最佳电解磨削液在实际系统中对金属结合剂砂轮进行电解修整得到了较为满意的修整结果。所研制的电解磨削液具有实用价值 ,可用于生产。     

关于轮网络的一簇猜想

轮网络是由Cayley图模型设计出来的一种新型互连网络模型.星网络、冒泡排序网络、修正冒泡排序网络可嵌入轮网络.为了揭示它的整体结构,对轮网络提出如下一簇猜想:轮网络是边不交的i个Hamilton圈及2(n-i)-2个完美匹配的并,其中1≤i≤(n-1);并证明了当n=4,5,6,1≤i≤3时,猜想成立.     

Equitable total coloring of <Emphasis Type="Italic">F</Emphasis><Subscript><Emphasis Type="Italic">n</Emphasis></Subscript> ⋁ <Emphasis Type="Italic">W</Emphasis><Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>

The minimum number of total independent partition sets of V ∪ E of graph G(V,E) is called the total chromatic number of G denoted by χ _t (G). If the difference of the numbers of any two total independent partition sets of V ∪ E is no more than one, then the minimum number of total independent partition sets of V ∪ E is called the equitable total chromatic number of G, denoted by χ _et (G). In this paper, we obtain the equitable total chromatic number of the join graph of fan and wheel with the same order. Supported by the National Natural Science Foundation of China (No. 10771091).     

关于一些图类的L(1,2)-边标号

For a graph G and two positive integers j and k, an m-L(j, k)-edge-labeling of G is an assignment on the edges to the set {0,..., m}, such that adjacent edges receive labels differing by at least j, and edges which are distance two apart receive labels differing by at least k. The λ′j,k-number of G is the minimum m of an m-L(j, k)-edge-labeling admitted by G.In this article, we study the L(1, 2)-edge-labeling for paths, cycles, complete graphs, complete multipartite graphs, infinite ?-regular trees and wheels.     

MG转轮收集探测系统的检验实验

利用SFC提供的束流对新建的转轮系统进行了检验实验,得到了相关的实验结果.实验证明了该装置的可靠性,为进一步开展超重核的研究完成了预实验.A new set up was built in IMP. The reaction 24Mg+232Th was performed as a test experiment for this set up. The decay chains of 252No and 253No have been observecl in this reaction. The results show that this set up is efficient for the rear events and it is possible to use this set up in the future experiment.     

S_n+W_n的邻点强可区别全色数

设G(V,E)是阶数不小于3的简单连通图,k是自然数,f是从V(G)∪E(G)到1,2,…,k的映射,满足:对任意的uv∈E(G),f(u)≠f(v),f(u)≠f(uv)≠f(v);对任意的uv,uw∈E(G)(v≠w),f(uv)≠f(uw);对任意的uv∈E(G),C(u)≠C(v),其中C(u)={f(u)}∪{f(v)uv∈E(G)}∪{f(uv)uv∈E(G)},则称f是图G的一个邻点强可区别的全染色法,简记作k-AVSDTC,且称χast(G)=min{k G的所有k-AVSDTC}为G的邻点强可区别的全色数.得到了星与轮联图的邻点强可区别的全色数.     

超声辅助磨削杯形砂轮变幅器设计与试验

超声辅助磨削在硬脆材料的加工中应用广泛。为研制以杯形砂轮为加工工具的超声辅助磨削主轴附件式工具系统,建立了杯形砂轮变幅器的理论模型,推导了其频率方程,并通过Matlab开发了杯形砂轮变幅器设计软件。利用该软件结合有限元分析对杯形砂轮变幅器进行了设计。将研制的杯形砂轮变幅器与BT40刀柄一体化外套筒、导电滑环装配组成了杯形砂轮超声辅助磨削主轴附件式工具系统。对该超声振动系统进行了阻抗分析试验及超声谐振试验,结果表明,该超声振动系统阻抗性能较好,能够使杯形砂轮产生稳定的超声振动,验证了所提出的设计方法的正确性,为主轴附件式超声磨削装置的设计提供了理论参考。     

Synthesis,structure, EPR,and DFT calculation on dinuclear paddle wheel Cu(II) complexes with bis-chelate rings

A series of diester-dicarboxylic acids, L¹H₂, L²H₂, L³H₂, L⁴H₂, and L⁵H₂ and their dinuclear Cu₂ complexes [Cu(L¹)CH₃CN]₂ (1), [Cu(L²)H₂O]₂ (2), [Cu(L³)CH₃CN]₂ (3), [Cu(L⁴)EtOH]₂ (4), and [Cu(L⁵)CH₃CN]₂ (5), were synthesized. The crystal structures obtained for 1, 2, and 4 and the density functional theory optimized structures for 2, 3, and 5 illustrated the formation of tetracarboxylate “paddle wheel” complexes. The phthalyl and diphenyl head groups and the spacer moieties were appropriately altered and the size of the chelate ring expanded from 15-membered in 1 to 21-membered in 5. The dinuclear units have strong Cu–Cu interaction with EPR spectra exploring spin coupled features.