具有柔性特性的机电伺服系统辨识

Identification of electromechanical servo systems with flexible characteristics

机电伺服系统中的柔性谐振特性是限制系统性能的关键要素,准确地描述柔性特性对于抑制谐振和提升伺服性能有重要意义.本文采用伪随机序列作为辨识激励,将脉冲响应相关性辨识和特征系统实现算法相结合,提出了一套集实验设计、模型计算、模型验证于一体的系统辨识方案;该辨识方案适用于机电伺服系统的辨识任务,且能够有效识别系统的柔性模态.本文以某大口径射电望远镜天线设备为应用实例,详细介绍了本文所述辨识方案的实施细节,得到了此天线伺服系统的模型.为了评价所得模型的质量,分别从频域和时域对比了本文方法、最小二乘和子空间方法所得模型与实测数据的拟合情况;结果表明,相比其他两种辨识方法,本文方法获取的模型对柔性谐振的辨识更加准确.

The flexible resonance characteristic in the electromechanical servo system is the key element that limits performances of the system.An accurate description of this characteristic is of great significance for suppressing resonance and improving the performance of the servo system.In this paper,adopting pseudo-random sequence as the identification input and combining impulse response correlation identification and eigen-system realization algorithm,an identification scheme which integrates experimental design,model calculation and model verification is proposed.This scheme can effectively identify the flexible modes,and hence is suitable for the identification of electromechanical servo systems.Using a large-aperture radio telescope antenna as the application example,the implementation of the identification scheme is detailed,and the models of the antenna servo system are obtained.The frequency-domain and time-domain fitting indexes indicate that,compared with the least square method and the subspace method,the model obtained by the method in this paper shows advantages in fitting flexible resonances.