用于连续体的间隙非线性参数辨识方法

间隙在机械系统中是不可避免的,由间隙引起的接触非线性会严重影响系统的动态响应,使其偏离理想状态,进而降低机械系统的性能和使用寿命。若能利用系统的动态信息识别出间隙非线性参数,就能为机械系统的间隙控制提供依据。针对含间隙连续体系统,提出一种改进的恢复力-位移曲线和条件逆向路径法相结合的间隙非线性参数辨识方法。将哈密尔顿原理推导得到的微分方程简化为空间缩减模型,在获取系统输入和输出的基础上,使用改进的恢复力-位移曲线方法识别连续体系统的间隙值,再利用条件逆向路径法识别间隙接触刚度。整个识别过程在Matlab软件中进行仿真,并在设计的含间隙悬臂梁试验台上进行了参数辨识试验,仿真和试验结果均显示了较高的识别精度,验证了该方法的有效性。

Method for Nonlinear Parameter Identification of a Continuum Structure with Clearance

Clearance is unavoidable in the mechanical system. However,contact nonlinearitycaused by the clearancecan significantly affect the system, which leads to the result that the dynamic response deviates from the ideal state and the performance and service life of the mechanical systems will be reduced.Ifthe parameter of the clearance nonlinearity can be identified by taking advantage of dynamic characteristics, the clearance of mechanical systems can becontrolled in a reasonable range. Based on the continuum structure with clearance, a method of combining the modified restoring force surface (RFS) and the conditioned reverse path (CRP) is proposed toidentify the nonlinear parameters of the system. The space-reduced-order model can be simplified from the differential equation derived by the Hamilton principle.Based on the dynamic information, the clearance value of the continuum system can be identified by the modified RFS method. And then, the contact stiffness can beidentified by the CRP method.The entire identification process is simulated in the Matlab software, and the parameter identification experiments are conducted on the designed testbed with adjustable clearance. The results show that the precision of the identification method is high, and the effectiveness of the proposed method is verified.