嵌入拉格朗日元法估算某些水下装置吸收波浪能研究(英文)

A simple approach is described to estimate the wave power absorption potential of submerged devices known to cause wave focusing and flow enhancement.In particular,the presence of a flow-through power take-off(PTO)system,such as low-head turbines,can be accounted for.The wave radiation characteristics of an appropriately selected Lagrangian element(LE)in the fluid domain are first determined.In the limit of a vanishing mass,the LE reduces to a patch of distributed normal dipoles.The hydrodynamic coefficients of this virtual object are then input in a standard equation of motion where the effect of the PTO can be represented,for example,as a dashpot damping term.The process is illustrated for a class of devices recently proposed by Carter and Ertekin(2011),although in a simplified form.Favorable wave power absorption is shown for large ratios of the LE wave radiation coefficient over the LE added mass coefficient.Under optimal conditions,the relative flow reduction from the PTO theoretically lies between 0.50 and 1 2≈0.71,with lower values corresponding to better configurations.Wave power capture widths,the sensitivity of results to PTO damping and sample spectral calculations at a typical site in Hawaiian waters are proposed to further illustrate the versatility of the method.     

一种纯电动环卫车辆上装取力控制方法

纯电动环卫车辆在变速器上集成取力器可为上装工作提供动力,其取力器的控制策略及方法相对于传统燃油车又有大的变化。该文介绍一种纯电动轻卡气压取力器的控制策略,包含取力器结合策略、停车取力策略、行车取力策略以及关闭取力策略,对于纯电动环卫车辆的取力控制具有一定的指导意义。     

发动机及取力装置转速自动控制系统的研发

针对专用车发动机和底盘取力装置转速控制问题,提出了基于闭环反馈式自动控制方式的解决办法,该系统依据工作机转速信号与标准信号的比拟,在控制集成块中测算处理数字信号差,利用可编程控制器对步进电机的转速进行实时调整,从而驱动发动机转速控制系统实现二次调速功能。随着产品的进一步完善,可大大提高车载取力工作机的工作效率和工作质量,具有很高的实用价值。