全动平尾带偏度载荷校准试验技术研究

飞机飞行载荷测量是飞行试验的一项必不可少的工作。针对全动平尾飞行载荷难以测量的问题,提出了带偏度载荷校准试验方法。共进行了五种带偏度载荷校准试验,并利用校准试验数据建立能测量平尾在任意操纵偏度下的载荷方程。通过飞行试验验证了该方法的正确性,为全动平尾飞行载荷测量提供了一种重要的技术途径。     

起落架载荷脱机校准试验技术研究

应变法是起落架载荷实测的主要方法,载荷校准试验是应变法测载的关键环节,直接决定了载荷实测结果的准确性。随着航空技术不断发展,常规的起落架联机校准方法已经无法满足校准试验要求。针对目前起落架载荷校准实际需求,提出了一套起落架脱机载荷校准试验方法,并将该方法用于某型飞机起落架载荷校准试验。通过与常规方法对比显示,该方法有效提升了试验加载能力、安全性、试验效率,更加精准的模拟了起落架的真实受载,提升了试验精度。     

导弹挂飞载荷的校准试验分析

为得到某型导弹的挂飞载荷,采用杆式内置六分量应变天平方法进行测量,详细介绍了该方法的基本原理,为飞行实测导弹挂飞载荷提供了一种思路。该方法的测量结果可用于风洞试验和计算流体力学仿真分析结果的对比。介绍了集成有应变天平的挂飞导弹的载荷校准试验,来验证应变天平的测量误差和测量能力。分析试验数据可知,该方法的测量精度满足飞行实测要求。     

基于多点协调加载试验的机翼飞行载荷模型研究

研究了基于多点协调加载试验的机翼飞行载荷测量技术。在某型飞机机翼载荷校准试验中,使用了自动液压加载系统,并研制出新的飞机约束装置,从而实现了多点协调加载试验,其中试验数据由机载测试系统进行采集。提出了建立机翼载荷模型的方法,最后通过地面检验试验和飞行试验验证了机翼载荷模型的合理可靠性。结果表明:该方法能够建立更高精度的机翼载荷模型。     

飞机载荷校准虚拟试验建模方法研究

载荷校准虚拟试验可以实现对真实试验的外推、预测以及模拟演练等。建模的优劣影响了载荷校准虚拟试验对真实试验的逼真度,决定了虚拟试验的成败。本文以某型飞机机翼为例,研究了载荷校准虚拟试验建模的各个环节,包括有限元建模、虚拟应变电桥建模、约束及载荷建模和模型修正等,形成了载荷校准虚拟试验的建模方法。     

基于实测载荷谱的板簧衬套载荷提取及台架疲劳试验

为快速且有效地对板簧橡胶衬套进行疲劳耐久验证,以在试验场测得的轮心六分力为输入,以后悬架多体模型为载体,采用虚拟迭代技术,提取了衬套的动态载荷。依据损伤等效原则,采用变载荷序列方法制定了衬套的台架疲劳试验规范,保证了台架试验与试验场道路的关联性,且缩短了台架试验时间,实现了5. 03倍的加速,衬套最终通过了台架疲劳试验的验证。     

基于工况组合的飞行载荷测量方法

在载荷校准试验中,可用应变电桥和独立载荷工况是建立载荷模型的关键参数,对于独立载荷工况数量不足的特殊结构进行载荷测量时,可采用工况组合的方式建立载荷模型,充分利用应变电桥和独立工况。采用工况组合法对翼尖结构进行载荷建模,使用飞行试验数据,与正校准的改进T值法载荷测量结果对比,一致性较高,可用于特定结构的飞行载荷实测或作为载荷应变法的对比验证方法。     

一种检测用可变刚度连续型机器人设计

设计一种新型结构的连续型机器人.该机器人以螺旋弹簧为主干,采用线驱动的方式,可实现平面内单自由度弯曲.通过建立机器人运动学模型,得到驱动线位移-柔性关节弯曲角度的对应关系.提出一种通过改变驱动线张力实现连续型机器人变刚度的方案,对柔性关节分别建立力学模型和Adams模型,进行理论和仿真分析,通过实验对所提出的运动学模型...     

基于台架试验的扭转梁后桥刚度研究

扭转梁后桥的线刚度和角刚度是影响汽车平顺性和操纵稳定性的两个重要因素。以某轿车扭转梁后桥AP35为例,在台架试验基础上,采用数学建模法分析扭转梁后桥的角刚度,为类似产品的改进设计提供参考。     

车身台架疲劳试验程序载荷谱研究

提出一种能简化加速车身台架疲劳试验的程序载荷谱编谱方法。基于试车场实测路谱准确获取车身连接点随机载荷谱,并简化为车身转矩载荷谱。应用雨流计数法和数理统计方法,得到均幅值载荷分布规律,其中均值服从正态分布,幅值服从威布尔分布;编制程序载荷谱并简化。应用有限元法和疲劳分析理论对车身疲劳寿命进行预测,从疲劳所用时间和行驶里程两个方面对危险部位寿命进行比较分析;结果表明,在车身连接点随机载荷谱和编制的程序载荷谱的作用下,车身的损伤分布及大小基本一致,验证程序载荷谱的有效性。所提出的编谱方法对其他车型的车身台架疲劳试验也有一定的应用和参考价值。     

基于视觉识别的互感器负荷箱全自动校准装置研制

目前互感器负荷箱校准采用的是“半自动化”装置,即负荷值测量自动化,档位切换人工操作。该文设计了一种基于视觉识别的负荷箱档位自动切换装置,该装置能通过视觉子系统识别负荷箱负载档位信息,上传到上位机形成校准方案,然后通过运动控制适配器将负荷箱的机械档位自动切换到方案上相对应的负载点进行校准,实现负荷箱校准的全自动化。     

一种免加载校准方法

本文针对工业现场大吨位料仓衡器无法用砝码加载进行校准的情况提出了一种免加载校准方法,可以大大减少校准费用和时间,保证校准精度,满足工业现场精度要求。     

Development of variable temperature instrument for sensor calibration

An experiment to calibrate temperature sensors at cryogenic temperature has been performed. The main objective of this study was to develop a precise instrument for calibrating the temperature sensors over a temperature range of 4 K to approximately room temperature without liquid helium. The instrument consists of radiation shields, a sensor block, an electric heater, a cryocooler and a vacuum chamber. In a vacuum chamber, the cold head of the cryocooler is thermally anchored to the sensor block to bring the apparatus to a desired temperature. An electric heater is placed at the second stage of the cryocooler to control the temperature of the sensor block. The entire apparatus is covered by radiation shields and wrapped in multi-layer insulation to minimize thermal radiation in a vacuum chamber. The dimensions of components including instrumental wires are optimized to reduce total heat invasion from room temperature into cryogenic temperature. The vacuum chamber is pumped down and cooled to cryogenic temperature by a cryocooler. The resistance of each temperature sensor is measured at steady state as well as cooling down and warming up cycles, and the performance of calibration is discussed with respect to the sensitivity and resolution.     

A two-dimensional test body for calibration of coordinate measuring machines

A two-dimensional test body having cross-aligned hollow cones has been developed for automatic calibration of coordinate measuring machines (CMMs). Two hours are sufficient for the measurement of translatory and rectangularity errors of a CMM by means of the test body. In this paper the principles of measurement of such erros using the test body are described These principles can be utilized on the assumption that one knows the exact values of the test body, so the calibration procedures for the test body are also described.     

高精度一维标定装置控制系统设计

为解决在科学测量中标定装置的精度、稳定性等问题,设计了基于At89s52单片机的高精度一维标定装置控制系统.该装置主要用于自动检测微距变化与位置标定.装置由单片机、步进电机、驱动器和滚珠丝杠组成,通过单片机来驱动步进电机,带动滚珠丝杠的运动而使平台移动.通过系统设置可以控制分辨率的大小.介绍了如何通过单片机实现控制的过程,以及对在控制系统设计的同时遇到的问题进行了解决.通过量块对于该装置的检定,精度达到10微米级.相比于一些大型高精度测量仪器,具有成本低,人机界面良好等优点.之后将进一步通过计算机通信技术来对数据的输入,实现更高的智能化.在沉降监测领域中,该装置可以用来模拟沉降量,进而对实验进行评估.     

随机变刚度支撑平台的研究

以电磁变刚度支撑为研究对象,分析了随机变刚度支撑系统,介绍了该系统的工作原理.在此基础上建立了较为合理的线性化数学模型,为电磁变刚度支撑的结构设计提供了理论依据.同时通过有限元分析软件对电磁结构的电磁场特征参数进行了分析,并得出磁感应强度的分布图,为电磁变刚度支撑平台数学模型的修正提供了指导.     

Torque sensor calibration using virtual load for a manipulator

Accurate load sensing of a manipulator becomes increasingly important in performing various tasks involving contact with an environment. Most of the research has been focused on improving the hardware of a force/torque sensor. The torque sensors for a manipulator suffer from crosstalk, which is difficult to compensate for even with sophisticated calibration. This research proposed a novel calibration method composed of two steps. Through the primary calibration, the torque sensor output can be related to the joint torques. The secondary calibration, which is based on a virtual load, is conducted to compensate for the crosstalk of a torque sensor. The virtual load is obtained from the sensed joint torques and manipulator configuration. Using the proposed calibration method, the external load acting on the end-effector of a manipulator can be accurately measured even with relatively low-quality torque sensors. The experimental results showed that the error in the load sensing was significantly reduced by the proposed calibration method.     

A variable stiffness mechanism for a movable magnet track of a linear motor stage

A movable magnet track for a linear motor stage changes the reaction force of a magnet track into vibration energy and reduces the stage base vibration. Although a movable magnet track can reduce the base vibration, the dynamic characteristic of the movable magnet track may be modified against the motion profile variation. This paper presents a variable stiffness mechanism for a movable magnet track of a linear motor stage. First, we introduce a passive Reaction force compensation (RFC) using a movable magnet track, and the Negative stiffness mechanism (NSM). Then, the variable stiffness mechanism using the NSM is used to reduce the stage base vibration. Lastly, simulations are performed using a linear motor motion stage with the NSM and the movable magnet track. The variable stiffness mechanism using the NSM not only reduces the reaction force but also adjusts the dynamic characteristic of the system.     

Force control compensation method with variable load stiffness and damping of the hydraulic drive unit force control system

Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit (HDU), and the contacting between the robot foot end and the ground is complex and variable, which increases the difficulty of force control inevitably. In the recent years, although many scholars researched some control methods such as disturbance rejection control, parameter self-adaptive control, impedance control and so on, to improve the force control performance of HDU, the robustness of the force control still needs improving. Therefore, how to simulate the complex and variable load characteristics of the environment structure and how to ensure HDU having excellent force control performance with the complex and variable load characteristics are key issues to be solved in this paper. The force control system mathematic model of HDU is established by the mechanism modeling method, and the theoretical models of a novel force control compensation method and a load characteristics simulation method under different environment structures are derived, considering the dynamic characteristics of the load stiffness and the load damping under different environment structures. Then, simulation effects of the variable load stiffness and load damping under the step and sinusoidal load force are analyzed experimentally on the HDU force control performance test platform, which provides the foundation for the force control compensation experiment research. In addition, the optimized PID control parameters are designed to make the HDU have better force control performance with suitable load stiffness and load damping, under which the force control compensation method is introduced, and the robustness of the force control system with several constant load characteristics and the variable load characteristics respectively are comparatively analyzed by experiment. The research results indicate that if the load characteristics are known, the force control compensation method presented in this paper has positive compensation effects on the load characteristics variation, i.e., this method decreases the effects of the load characteristics variation on the force control performance and enhances the force control system robustness with the constant PID parameters, thereby, the online PID parameters tuning control method which is complex needs not be adopted. All the above research provides theoretical and experimental foundation for the force control method of the quadruped robot joints with high robustness.