浅谈住宅小区电气规划设计要点

本文阐述了住宅区的低压配电干线合理规划的原则和要点,建议把室外管线综合的工作放在建筑方案设计初期.并介绍了住宅区的电气规划的工作内容及常用方法,从而解决了施工后期经常出现的管线布置困难的问题.     

基于PLC和触摸屏的车身总装夹具控制系统设计

车身总装工艺是白车身生产的关键工艺,论文用程序自动控制代替手动气压控制,确保达到车身总装质量和生产效率的要求.该设备的控制系统是以PLC控制技术为核心,以触摸屏为人机操作界面,采用二者配合控制实现了车身总装夹具的控制要求.设备已经投入生产,运行结果表明:该系统在降低了设备成本的同时,有效的缩短了生产周期,对其它类产品设计有一定参考价值.     

Quaternion-based nonlinear trajectory tracking control of a quadrotor unmanned aerial vehicle

At present, most controllers of quadrotor unmanned aerial vehicles(UAVs) use Euler angles to express attitude. These controllers suffer a singularity problem when the pitch angle is near 90°C, which limits the maneuverability of the UAV. To overcome this problem, based on the quaternion attitude representation, a 6 degree of freedom(DOF) nonlinear controller of a quadrotor UAV is designed using the trajectory linearization control(TLC) method. The overall controller contains a position sub-controller and an attitude sub-controller. The two controllers regulate the translational and rotational motion of the UAV, respectively. The controller is improved by using the commanded value instead of the nominal value as the input of the inner control loop. The performance of controller is tested by simulation before and after the improvement, the results show that the improved controller is better. The proposed controller is also tested via numerical simulation and real flights and is compared with the traditional controller based on Euler angles. The test results confirm the feasibility and the robustness of the proposed nonlinear controller. The proposed controller can successfully solve the singularity problem that usually occurs in the current attitude control of UAV and it is easy to be realized.     

家庭洗涤中织物运动测量方法探讨

家庭洗涤中织物的运动过程与洗后性能直接相关。针对洗涤运动特点,围绕织物家庭洗涤时的受力分析、动作分解、速度监测和轨迹跟踪四个方面,得出织物温态性能测量技术、高速摄像技术、传感器技术和电子示踪技术在洗涤运动测量中的研究应用;同时指出未来可以从测量设备的适用性和稳定性、织物含水率的可控性、动作分解原则的可靠性等技术难点深入探索,为实现高效、环保、智能化的家庭洗涤提供更全面的理论依据和更有效的技术支持。     

支柱孔滚子加工工艺及工装的改进

针对支柱孔滚子加工难度大的问题,对工艺进行了改进,利用齿轮顶尖,确保支柱孔滚子的同轴度;利用双刃镗刀,确保支柱孔的粗糙度,解决了直径95mm以上、长度140mm以上支柱孔滚子加工的瓶颈问题。并且提高了产品的加工质量。     

卫生间硅酸钙板轻质隔墙上瓷砖饰面系统应用技术研究

对卫生间硅酸钙板轻质隔墙上采用瓷砖饰面系统进行了相关应用性研究，讨论了硅酸钙板厚度、界面处理、防水处理以及粘贴材料等对系统粘结力的影响，提出了在硅酸钙板轻质墙体上进行瓷砖饰面的可靠施工方案。     

Effect of wear behaviour of single mono- and poly-crystalline cBN grains on the grinding performance of Inconel 718

Polycrystalline cubic boron nitride (PcBN) grains were fabricated by combining the monocrystalline cBN (McBN) nanoparticles and inter-abrasive ceramic materials via high temperature and pressure techniques. Grinding performance of Inconel 718 with single McBN and PcBN grains, including grinding force, force ratio, ground surface quality was investigated. Characterization of the wear morphology evolution of worn grains and scratches of PcBN grains were discussed. In addition, the fracture behaviour of PcBN grains was evaluated as the varying of the undeformed chip thickness. Results show that PcBN grains have the smaller grinding force and force ratio, more stable grain wear rate in comparison to McBN grains. Additionally, the better wear-resistance and grinding performance owing to its multi-cutting edges structure in terms of the grain wear morphology evolution were achieved for PcBN grains regardless of the undeformed chip thickness.     

The effect of epoxy resin to reduce the compression set of polysulfide sealant

In this article, modified polysulfide sealants with lower compression set were prepared by a simple method of introducing the diglycidyl ether of bisphenol A resin (DGEBA epoxy resin) into sealants. The investigation on reactivity analysis and gel faction test verified that the incorporation of epoxy resin in sealants was just a blending process rather than copolyaddition with polysulfide resin. Stress–strain behavior during compression revealed that the epoxy resin could reduce the compression stress when the sealants were loaded to a certain strain, which effectively lessened crosslink breakages and benefited to compression resistance. Also the rigid phenyl structure in epoxy resin may retard incidental slide between polysulfide chains and prevent interchange reactions between disulfide linkages. The incorporation of 2 phr epoxy resin distinctly reduced compression set of polysulfide sealant from 28.3% to 11.2% after compressed 25% at 23°C for 1 day. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012