基于制动试验台的虚拟仪器与变频技术外文文献翻译、中英文翻译

VIRTUAL INSTRUMENT AND FREQUENCY CONVERSIONTECHNOLOGY-BASED BRAKE TEST SYSTEMBrake is widely useful and very important safety assuring equipment. The aim of Brake test system， which is based on visual instrument and frequency changing technology， is to integrative measure and analyze the performance and quality of the brake.This paper mainly introduces the principle， composing，function and features of the brake test system. And from the point of view of the principle of Visual Instrument （VI） technology， a test system， based on the VI and frequency changing technologies and consist of frequency changing drive and control sub-system and measuring sub-one， is constructed. With the test system the performances and braking course could be auto controlled and measured to the brakes which includes disc and drum ones. And the measuring and control software is programmed with the LabVIEW published by American NI Corporation， USA.Then data real time acquisition， processing， displaying and recording will be realized. The test system also has the functions of voltage adjusting， rotating speed control， load regulating， JC value setting， temperature measuring， and braking route and time memorizing and analyzing. It will be very important for meaning and exciting boosting effect to advance quality and capabilities of the brakes and the security of equipments and system which have adopt the brakes.1 Operating principlesAccording to the principle of work and power， the change of kinetic energy in the moving of objects equals to the full power of the force act on the object in that process.The energy obtained by brake to be tested：Therefore， it is feasible to use combined inertial flywheels to simulate rotating inertia of crane hoist and its transmission components to test the performance and quality of the brake.According to the moment of momentum theorem：Tbt =Ji （1）When Tb is fixed， tb can be controlled through combinations between Ji and differently. Brake drum or plate， which will be measured， and combined inertial flywheels for loading on are driven to rotate by AC frequency conversion motor （or DC one， which will not bedealt with in this article carefully）. According to the principles shown in the formula （1） ， we can simulate actual processes of brakes fitted on lifting and transport machineries， engineering ones， mining ones and construction ones by changing the technical specification duty JC， the flywheels inertial moment Ji and motors rotational speed ni.When detected brakes work in simulation cycle and brake repeated， infrared thermoscopes and torque sensors， and other sensors will record braking shown in the heat， braking torque，braking time and brake speed parameters.2The composition and structure of the brake test systemThis test system is intended to achieve the performances of drum and disc brakes and has following functions：（1） Brake replacementAccording to different type of brakes the corresponding base will be chosen and brake position could be adjusted using electric slide test-bed；（2） Multi-level loadingWe can simulate the actual loading on brakes in a crane with different combined flywheels. The test system adopts manual hydraulic system composed by a three-position four-way hand-operated direction valve， a relief one and their accessories， and it is operation saving and convenient to replace flywheels.（3） Regulation the rotational speed n （or ）It can be realized by changing frequency supplied to the AC motor. When braking torque is very large， such as 10000Nm， it should be appropriate for regulating initial brake speed upward 1000r/min to minimize rotating inertia possibly.（4） Braking frequency adjustmentBased on actual needs braking frequency can be confined in a range of 14 times per minute.（5） Braking torque measurementThere are three methods：a） Direct measurement via torque sensors：Rotational speed and torque sensor will be installed between the detected brake drum or plate and inertial flywheel plates.Dynamic braking torque of detected brake will be directly measured， shown in Fig.1 and Fig.2. According to the scope of braking torque of detected brakes， two or three rotational speed and torque sensors should be prepared for testing torque to meet the accuracy requirements；b） Indirect parameter measurement：Based on the rotating inertia and braking time we can get brake torque using mathematical relationship between these parameters， as shown in Fig. 2.c） Indirect measurement by pedestal-force：The pressure sensors are installed under the base where detected brake are fixed to feel the forces given by brake， and then to obtain brake torque.The second approach has small investment， simple structure and no torque sensors which mean not considering related troubles of changing torque sensors. But the procedure tocalculate torque is complex， and accumulating total errors would be larger and then the result accuracy will be low.The third way has the advantage of the replacement of sensors is easier and no special requirements for sensors installing precision. It is still an indirect measurement but the procedure is less than that in the second method and that means the cumulative errors relatively is smaller. And visible shortcoming is poor dynamic response.（6） Automatic controlExcept to manual operation test system is also programmed control.（7） MonitoringBraking frequency， initial braking speed， the aggregate braking number， moment， time and so on will be shown automatically.（8） Automatically data acquisition and processingThe curve describing braking torque， time and speed could be drawn automatically by means of computer software while detected brake is measured in dutycycle operation. Therefore， in response to the way to test braking torque the system can be divided into three ones of that with torque sensor such as Fig.1 and 2 above， that without torque sensor such as shown in Fig.3 and that of pedestal-power measurement without torque sensor， as shown in Fig.4. The test system is mainly composed of AC frequency conversion transmission system， flywheels loading system， rotational speed and torque sensors， base which to fix drum or plate brakes， adjustable DC power supply， detected brakes and test and control system.In addition to the above functions， the system could test following performances of the brakes：a） Release performance：This is tested under the conditions of 85%Ve and rated load，adjusting voltage via booster devices；b） Close performance：This is tested under the conditions of rated voltage Ve and 50% of rated loading；Otherwise， the following performances could also be tested：1） Structural performances：a） Ability of brake shoes position following drum；b） Assembly for keeping gaps between drum and shoes equalling；c） Lubricating.2） Other items：a） Contact area；b） Spring testing；c） Braking linings and shoes gap；d） Pins hardness.3 AC frequency conversion adjusting speed systemCompared with DC motor， the AC motor has simple and compact structure， little maintenance workload， high efficiency， small rotating inertia and quick dynamic response，and it could be made of high-voltage， large capacity and high speed. Currently， AC motor has trend to replace DC one in the field of adjusting speed transmission.Generally speaking， there are many kinds of motors which could be applied to diverse types of converter-driven， and which are roughly divided into ordinary AC motor， special one and dedicated one. The frequency conversion adjusting speeding system is composed of frequency converter anddedicated lift motor. To the ordinary asynchronous motor， the following factors should be considered while to determine their capacity：（1） Chosen motor capability should be greater than the power load needed；（2） Compared with needed load pull-in torque the greatest torque that motor exports should have sufficiently surplus volume；（3） Even supply voltage is lower 10% than rated value， motors can export needed torque also； （4） Considering the life length of motor it should running in the specified temperature scope；（5） Because of transmission rate of the transmission system，efficiency and load fluctuation， the motor power should have enough surplus volume；（6） Against load nature， it is necessary to choice a suitablemotors operating modes such as continuous service system， short-term operation and duplication system. In the AC adjusting speed control system with frequency converter motors slowdown is achieved by reducing the output frequency of the converter. When motors need slow down faster than the rate of free deceleration， underspeed of converter output frequency might be ran-up and the speed which is corresponding to that frequency is lower than the actual rotational speed of motor， and motor will be regenerative braking. In such cases， asynchronous motor will be an asynchronous generator， and load mechanical energy will be converted to electrical energy and then feedback to the converter. However， when the back feed is overload， overvoltage protection circuit of converter will work to cut converters output and motors will be freely slowdown instead a rapid speed-down. To avoid above phenomenon， that is， to consume the energy in other parts of the DC circuit without causing voltage rise in the voltage-fed converter， regenerating braking circuits （braking resistors） are normally used and the energy fed back to the DC circuit will consumed in the form of heat. For the test system， it is apparently that braking resistances are not necessary because of the usage of brake for braking deceleration. It is necessary to define surplus capacity of motor or converter on the basis of practical situation. And on the case of ensuring to meet requirements of driving system performance， energy consumption or economic factors should be considered， and overall system has a smaller investment and maximum benefits.基于制动试验台的虚拟仪器与变频技术 制动器是广泛有益的和非常重要的安全保障设备。制动测试系统的目的是综合衡量和分析制动试验系统的性能和质量的刹车，组成，功能。从目视仪器理论的角度来看，基于VI和频率不断变化的技术和包括频率变化的驱动和控制子系统和测量分之一构成的。随着测试系统的性能和制动过程可自动测量，以控制和刹车，其中包括光盘和鼓的。和测量和控制软件的设计与LabVIEW的出版的美国公司-美国。然后数据实时采集，处理，显示和记录一定会实现。测试系统还具有功能的电压调整，转速控制，负荷调节，巴埃纳价值设定，温度测量，和制动路线和时间背诵和分析。这将是非常重要的意义和令人激动的推动作用，以推进素质和能力的刹车和安全的设备和系统已经采取刹车。1.工作原理根据工作原理和功率的变化动能在移动的物体等于全部力量采取行动，该部队的目标过程中取得的制动能量进行测试：因此，它是可行的使用相结合，模拟惯性飞轮转动惯量的起重机吊重机及其传动部件的性能测试和质量制动。根据动量矩定理：Tbt =Ji （1）当TB是固定的，TB是可以控制的，通过组合之间籍和不同，制动鼓或板，这将是衡量，并结合惯性飞轮装载的驱动旋转的交流变频电机。根据原则表现在公式（1），我们可以模拟实际过程中刹车安装在起吊和运输机械，工程的，采矿业和建筑业的是通过改变技术规范责任巴埃纳，飞轮的惯性时刻姬和电机转速镍。当工作中发现刹车和制动仿真周期重复，其他传感器将记录中显示的制动热，制动力矩，制动时间和制动的速度参数。2.刹车测试系统的组成和结构该测试系统是为了实现表演鼓和盘式制动器，并以下职能：（1）更换制动根据不同类型的刹车相应的基地将选择和刹车的位置可以调整使用电动滑试验台；（2）多层次载入中我们可以模拟实际负荷制动器在起重机不同组合飞轮。该测试系统采用手动液压系统组成，由一个三人立场四路手操作的方向阀，救济及其配件之一，它是操作方便，节约和替代飞轮。（3）规例转速n它可以实现通过改变频率提供给交流电动机。当制动力矩非常大，如10000Nm ，应该适当调节初始制动速度向上1000r/min尽量转动惯量可能。（4）制动频率调整根据实际需要制动频率可以限于在1 4倍，每分钟。（5）制动力矩测量，有三种方法：a) 直接测量通过扭矩传感器：转速和扭矩传感器将被安装与检测制动鼓或板和惯性飞轮板.动态制动力矩的检测制动将直接测量，显示在图1和图2 。根据范围的制动力矩的检测刹车，两个或三个转速和扭矩传感器应准备用于测试的扭矩，以满足精度要求；b) 间接参数测量： 基于转动惯量和制动时间，我们可以用数学制动力矩这些参数之间的关系，如图2所示c) 间接测量的基座力： 压力传感器安装在基地发现刹车固定感受到部队给予刹车，然后获得制动力矩。第二个办法投资少，结构简单，没有扭矩传感器，这意味着不考虑相关故障的改变扭矩传感器。但是程序计算扭矩是复杂的，并积累总额将是更大的错误，然后将结果准确性低。第三条道路的优点是更换传感器更容易，也没有特殊要求的传感器安装精度。它仍然是一种间接测量的程序，但低于第二方法和手段的累积误差相对较小。