变频调速应用技术（三） 第二讲 了解功能调变频（上）

本文主要介绍变频器的若干种功能。它们是：操作方式的选择功能、频率给定功能、若干频率称谓的定义、升速和起动功能、降速和停机功能等。     

增量式光电旋转编码器及在角减速度测量中的应用

介绍了增量式光电旋转编码器的原理、结构，根据输出信号的特征提高测量精度的四倍频处理方法，在此基础上说明了常用的基于编码器的输出信号的测速原理、方法。最后给出了基于增量式光电旋转编码器进行角减速度测量的系统构成，实际应用精度要求采用的最小二乘拟合法的处理方法。     

推杆制动器在小功率下运带式输送机上的应用

分析了下运式输送机的制动技术,着重对推杆制动器在小功率下运带式输送机中的应用进行了分析,提出了选用推杆制动器的原则,以及合理制动加速度的确定方法。     

自由曲线实时插补的减速控制

本文提出了一种自由曲线实时插补过程中的减速控制方法。该方法计算量小,计算效率高,同时该方法减速时的加速度能根据当前插补点离插补终点的距离自动作一些相应的变化,使速度变化更趋平稳,且避免了越程、失步现象的发生,因此非常适合于实时插补的需要。文中给出了该方法的原理,阐明了该控制方法中的相关技术处理。     

A tree-structured crash surrogate measure for freeways

In this paper, we propose a novel methodology to define and estimate a surrogate measure. By imposing a hypothetical disturbance to the leading vehicle, the following vehicle’s action is represented as a probabilistic causal model. After that, a tree is built to describe the eight possible conflict types under the model. The surrogate measure, named Aggregated Crash Index (ACI), is thus proposed to measure the crash risk. This index reflects the accommodability of freeway traffic state to a traffic disturbance. We further apply this measure to evaluate the crash risks in a freeway section of Pacific Motorway, Australia. The results show that the proposed indicator outperforms the three traditional crash surrogate measures (i.e., Time to Collision, Proportion of Stopping Distance, and Crash Potential Index) in representing rear-end crash risks. The applications of this measure are also discussed.     

Simulator evaluation of drivers' speed, deceleration and lateral position at rural intersections in relation to different perceptual cues

Aim of the study was to investigate, by means of a driving simulator experiment, drivers’ behaviour in terms of speed, deceleration, and lateral position on major approaches of rural intersections in relation to different perceptual cues.In the experiment, ten different design conditions with and without speed-reducing treatments along the approach to the intersection were tested. Twenty-three drivers drove a test route two times and data from the second drive were used for comparison. The order of the ten design conditions was counterbalanced for all the drivers to minimize the presentation order effect. Three different data analysis techniques were used: (a) cluster analysis of speed and lateral position data, (b) statistical tests of speed and lateral position data, and (c) categorical analysis of deceleration behaviour patterns.The most effective treatments were the dragon teeth markings (based on the principle of optical road narrowing), the colored intersection area (based on the principle of intersection highlighting), and the raised median island (based on the principle of physical road narrowing). These measures, in comparison to the base intersection, produced: (1) a significant speed reduction starting from 250 m before the intersection in the range between 13 and 23 km/h, (2) a significant change in the deceleration behaviour with a reduction in the proportion of drivers which did not decelerate, and (3) a shift away from the intersection of the deceleration beginning. Given the significant effects on drivers’ behaviour, the dragon teeth markings, the colored intersection area, and the raised median island are strongly recommended for real world implementation.     

S曲线加减速算法研究

S曲线加减速是高档CNC系统中的一项重要功能。本文对S曲线加速度算法进行了深入的研究，给出了加加速度、加速度、速度、位移的计算通式，并对各种情况进行了讨论，通过一个计算实例表明，本文所给出的S曲线加减速算法克服了传统加减速算法中的缺点，速度在变化过程中十分平滑，是一种适合于高速切削的柔性加减速算法。     

Effects of in-vehicle warning information on drivers’ decelerating and accelerating behaviors near an arch-shaped intersection

This paper attempts to evaluate the effects of in-vehicle warning information on drivers’ decelerating and accelerating behavior when approaching an intersection near an arch-shaped bridge, where traffic accidents have often occurred due to poor visibility. The warning information was provided with images and/or voice, triggered by the actual presence of a stopped vehicle at the downhill road section of the intersection. An on-site driving experiment was conducted on a national highway in Hiroshima City, Japan, by involving 14 university students, and it was demonstrated that dynamic information seems more effective for drivers to avoid dangerous driving situations than static information. It was also found that having only the voice-based warning information may be as effective as having both the voice and image warning information.     

The use of a heel-mounted accelerometer as an adjunct measure of slip distance

A human-centered measure of floor slipperiness could be useful as an adjunct to conventional tribologic measures. This paper reports on the development and evaluation of a measure of slip distance based on variables derived from the signal of a heel-mounted accelerometer. Twenty-one participants walked on a laboratory runway under several surface slipperiness conditions at three walking speeds during a protocol designed to produce a wide range of slip distances at heel strike. Analysis of variance showed significant effects of slip distance (no-slip, micro-slip and slide), walking speed (1.52, 1.78 and 2.13 m/s) and their interactions on peak forward acceleration, peak vertical acceleration and deceleration time of the heel following heel strike in 704 trials. Regression analysis of slip distance and deceleration time showed the strongest relationship with R2=0.511. Large individual variation in the strength of this relationship was observed. The heel-mounted accelerometer may have utility as an adjunct measure in the evaluation of floor slipperiness, particularly for field applications where direct measurement may not be feasible.     

浮式竹格栅坝水力特性试验研究

在用于河道整治的建筑物中，浮式格栅坝是其中的一种，它具有结构简单，施工方便，造价低廉等诸多优点，通过直接影响格栅坝下游流速场变化的坝体透水系数ａ、坝体倾角θ、河道水深ｈ、减速率ψ等重要水力参数的试验研究；提供了在不同坝体透水程度、河道平均流速及水深、坝体倾角运行工况下的图表，为格栅坝的设计及运行管理提供了可靠的依据。