【作者】 葛新方；

【导师】 竺长安；

【作者基本信息】 中国科学技术大学 ， 精密机械与仪器， 2014， 博士

【摘要】 在工程研究分析中,为了对结构进行健康监测(Structural health monitoring, SHM)和结构控制(Structural Control, SC),需要频繁的测量结构的动态响应。在结构的动态响应中,动态位移可能包含有很多与结构行为相关的重要信息,而这些信息可以用来对工程结构进行健康监测和结构控制。在结构健康监测中,当一个建筑物经历了较为严重的地震后,我们需要根据结构的位移信息来判断该建筑受到结构损伤的可能性；同样地,对于结构控制来说,为了辨识系统的状态我们需要知道结构的实时或者近实时位移信息。传统的接触式传感器在测量结构的位移时需要固定的参考点。但是,对于大型结构来说,参考点的选取非常困难,而且所选参考点在地震过程中是变化的。因此,在这种情境中运用传统的接触式传感器直接进行位移测量几乎是不可能的。相比于位移,加速度的测量比较方便。在进行加速度测量时并不需要选取参考点,而且在市面上有很多可用于测量较宽动态频率的加速度装置。从这个角度上来说,相比于对工程结构进行直接的位移测量,利用测得的结构加速度来重构系统的位移,似乎是一个很好获取结构动态响应的方法。文中基于离散奇异卷积法对位移响应重构进行研究,包括精确控制方程和传递函数的导出、基于逆问题控制方程和传递函数的导出、精确传递函数以及基于逆问题控制方程的传递函数基本特性以及基于离散奇异卷积的位移响应重构方法。在基于离散奇异卷积的位移响应重构方法研究中,着重分析了滤波器窗口尺寸的选取以及不同滤波器尺寸下基于离散奇异卷积的有限脉冲响应滤波器的特性。最后,对提出的位移重构方法进行仿真验证和实验验证。仿真与实验结果表明,基于离散奇异卷积的位移响应重构方法能够有效的利用加速度数据重构位移,且对噪声具有较强的抑制能力。加工过程中产生的加工误差以及装配过程中产生的装配误差都会对工程中机械装置的机械性能产生影响,甚至会对机械装置产生毁灭性的损伤。因此,我们需要分析研究工程中机械装置在加工及装配过程中产生的误差,以最大限度的降低这些误差对工程中机械装置机械性能的影响。针对工程中由于加工误差及装配误差可能产生的共振,提出了在机械产品设计阶段或者结构重设计阶段,充分考虑加工误差及安装误差对机械产品性能影响的设计思想,使最终成型的机械产品具有较强的鲁棒性,并运用该方法对叉车方向盘结构进行优化,达到了抑制叉车方向盘怠速振动的目的；针对具有相同部件的平面连杆机构,提出了基于最小输出位移方差和的寻找杆件最优组合的方法,以最大限度的降低杆件加工误差对连杆机构输出的影响,提高产品的性能,并将该方法成功运用于八连杆机械压力机最优杆组的确定问题中,求解出了最优的八连杆杆组组合。更多还原

【Abstract】 In the engineering research, dynamic responses of structural systems are frequently measured for the purpose of structural health monitoring and structural control. Among the dynamic responses, the time history of the dynamic displacement may contain important information on structural behaviors. For example, in case a structure experiences severe events such as a strong earthquake or a typhoon, a quick decision on the possibility of structural damage could be made based on the maximum displacement of the structure. For structural control applications, information on displacement should be provided in real-time or at least in near real-time to identify the states of a structure. Unfortunately, it is very difficult to measure displacement directly in large-scale structures because fixed reference points are rarely found to install displacement transducers. Moreover, the reference points as well as a structure move together during severe events, and thus the direct measurement of displacement using contact displacement transducers becomes almost impossible.Unlike displacement, acceleration is easily measured without a fixed reference point, and various types of accelerometers are commercially available for a wide range of dynamic frequencies. From this perspective, the reconstruction of displacement from measured acceleration seems to be a better method than the direct displacement measurement.This paper presents a new displacement reconstruction scheme based on the discrete singular convolution finite impulse response (DSC-FIR) filter. In this study, the governing equation and transfer function of the exact and an inverse problem is derived and the selecting of filter size, the features of the DSC-FIR filter on different filter size are presented. Finally, simulation and experiment are implemented to verify the proposed displacement reconstruction scheme and the results indicate that the scheme not only can accurately reconstruct displacement from the measured acceleration, but also has the ability for noise suppression.In mechanical engineering, the processing and installation error will affect the machinery’s mechanical properties and even may cause devastating damage. Therefore, we need to study the treatment for these errors in order to maximum decrease the impact of these errors on mechanical properties of the device.For possible resonance caused by the processing and installation error, we propose a robust design idea that considers the influence of these error on mechanical properties in the design or re-design stage. With the robust design, the mechanical products possess strong robustness. Using this design idea, we successfully optimize the steering wheel idle vibration of the forklift truck. For planar linkage mechanisms with the same parts, we propose a minimum sum of displacement variance(MSDV) method to find the optimal combination and minimize the influence of processing error on planar linkage mechanisms. For an eight-link linkage mechanisms, we use the MSDV method to obtain the optimal combination and simulation result indicate that the proposed method can effectively reduces the influence of machining error.更多还原