离心机刮铲装置刚度的建模及分析

对P25T/K全自动间隙离心机刮铲装置在制造、使用过程中出现的振动或抖动,以及刮刀损坏筛篮面网等问题进行理论分析;重点对刮铲装置刚度的建模进行分析和动态测试,通过现场测试的参数验证了所建模型的可靠性和对该装置进行改进设计的可行性。     

Sliding-induced non-uniform pre-tension governs robust and reversible adhesion: a revisit of adhesion mechanisms of geckos

Several mechanisms have been proposed in the literature to explain the robust attachment and rapid, controllable detachment of geckos'' feet on vertical walls or ceilings, yet, it is still debatable, which one is ultimately responsible for geckos'' extraordinary capabilities for robust and reversible adhesion. In this paper, we re-examine some of the key movements of geckos'' spatula pads and seta hairs during attachment and detachment, and propose a sequence of simple mechanical steps that would lead to the extraordinary properties of geckos observed in experiments. The central subject under study here is a linear distribution of pre-tension along the spatula pad induced by its sliding motion with respect to a surface. The resulting pre-tension, together with a control of setae''s pulling force and angle, not only allows for robust and strong attachment, but also enables rapid and controllable detachment. We perform computational modelling and simulations to validate the following key steps of geckos'' adhesion: (i) creation of a linear distribution of pre-tension in spatula through sliding, (ii) operation of an instability envelope controlled by setae''s pulling force and angle, (iii) triggering of an adhesion instability leading to partial decohesion along the interface, and (iv) complete detachment of spatula through post-instability peeling. The present work not only reveals novel insights into the adhesion mechanism of geckos, but also develops a powerful numerical simulation approach as well as additional guidelines for bioinspired materials and devices.     

铲斗粘附土体现象的浅析和拨叉排土装置的设计

浅析了铲斗粘附土体的粘附力主要由机械粘附力和物理粘附力所构成,并设计了可跟随斗形、结构简单的拨叉排土装置.     

基于调刀基准的定位误差计算

根据定位误差的产生及其定义,提出了一种基于调刀基准的定位误差计算方法,避免了计算前的分析与判断.该方法不仅易于理解,而且更简捷,同时也丰富了定位误差的计算方法.     

TBS全自动离心机刮铲卸料装置的动态特性分析

通过对TBS全自动间隙离心机刮铲装置在生产过程出现的问题进行分析;采用用户自定义矩阵单元来处理刮铲装置结合部的接触问题,在Pro/E软件上建立了刮铲装置＂Z＂轴的有限元模型,并对其进行了动态特性分析。运用该方法来进行结构的性能预测,并用于工厂对该装置的结构进行改进设计。     

精密镗削调刀器的设计与应用

通过对普通镗削敲刀的缺陷分析,结合刀块在镗刀杆刀槽孔中的滑移方式,详细叙述了设计并应用精密镗削调刀器的方法和注意事项。     

The optimum lift angle for the culinary spatula (turning shovel)

A culinary spatula (turning shovel) is one of the common cooking tools used in the Oriental kitchen. Since the use of a turning shovel may cause cumulative trauma to the wrist, the spatula angle for food frying, food turning, and food shovelling was investigated. The subjects were eight female students who were experienced cooks. Handle angle significantly affected both performance and subjective rating. The optimum angle is 25°.     

基于机器视觉的木制压舌板裂纹自动拣选系统

针对压舌板表面裂纹缺陷的在线检测及劣品剔除问题,提出一种基于机器视觉的自动化检测系统。 首先基于对压舌板 及其裂纹特征的分析,设计了包含两组视觉检测机构的硬件装置。 该装置以链齿型传送带为基底,作为压舌板基本传送机构; 设计了链齿型传送带与反射型光电接近开关的特定装配模式,用于产生脉冲、提供系统时序;建立了基于多级缓存机制的系统 控制架构,协同调配时序脉冲触发、调用及使能各个硬件部件。 裂纹检测算法方面,采用一种基于方向空间显著性的方法。 首 先经 OTSU 算法、面积筛选以及形态学运算等预处理定位压舌板区域;然后基于方向空间显著性提取裂纹特征点,进而基于双 阈值连接限制生成候选裂纹线条;最后基于延展角度、起始位置等多维条件约束精确识别裂纹。 在实际生产现场对本文系统性 能进行了测试,结果显示,在检测效率为 11 支/ 秒的前提下,误检率低至 4. 17%,漏检率为 2. 68%,与当前人工检测方法相比分 别降低 6. 66%和 5. 36%,表现出优越的性能,具有较强的实际应用价值。     

Pre-tension generates strongly reversible adhesion of a spatula pad on substrate

Motivated by recent studies on reversible adhesion mechanisms of geckos and insects, we investigate the effect of pre-tension on the orientation-dependent adhesion strength of an elastic tape adhering on a substrate. Our analysis shows that the pre-tension can significantly increase the peel-off force at small peeling angles while decreasing it at large peeling angles, leading to a strongly reversible adhesion. More interestingly, we find that there exists a critical value of pre-tension beyond which the peel-off force plunges to zero at a force-independent critical peeling angle. We further show that the level of pre-tension required for such force-independent detachment at a critical angle can be induced by simply dragging a spatula pad along a substrate at sufficiently low angles. These results provide a feasible explanation of relevant experimental observations on gecko adhesion and suggest possible strategies to design strongly reversible adhesives via pre-tension.     

Quantitative and Real-Time Evaluation of Pressure on Brain Spatula with Wireless and Compact Sensing System

The brain spatula has been an essential neurosurgical instrument since the early 20th century, when medical advancements enabled surgeons to operate deep intracranially for the first time. Monitoring the brain retraction pressure, especially at an early stage of the intradural procedure, is useful in preventing brain damage or postoperative cerebral swelling. Unfortunately, there is still a lack of effective methods that meet the demand for quantitative and real-time evaluation of applied pressure on brain tissue. In this study, a compact and wireless sensing system, encapsulated by soft biocompatible materials, for quantitatively assessing the pressure between brain tissue and a spatula, is proposed. The absence of physical tethers and the ion gel-based construction of the micro-structured sensor represent key defining features, resulting in high measurement accuracy of 1.0/N with reliable water-proof capabilities. Moreover, these sensors can be linked to a server network or mobile client for possible brain damage alerts as important safety addition. With our devices, detailed pressure data on retracting operations can be collected, analyzed, and stored for medical assistance as well as to improve surgery quality.