Contact of balls in screw nuts and bearings causes the nonlinearity of a ball screw feed system. The identification of nonlinear stiffness helps to understand and control the feed system. The axial vibration of the ball screw feed system can be descripted by a single-degree-of-freedom (SDOF) system with polynomial nonlinear terms. Since generalized frequency response functions (GFRFs) can be expressed in terms of linear and nonlinear system parameters, one can estimate these parameters based on the measured GFRFs. In this effort, both single-tone and multitone harmonic inputs are employed to measure GFRFs, and a simple search algorithm is proposed to find the suitable frequency set of the multitone input. Parameter identification based on these two methods has been compared by numerical simulation and experiment. Since the response spectrum measured from vibration experiment of a ball screw system has even and odd harmonics, it is suitable to simplify the restoring force with square and cubic nonlinearity form. Static experiment is also conducted to verify the identified parameters, and the results show that the method based on single-tone inputs performs effectively in identifying axial stiffness of a ball screw feed system, but the method based on multitone inputs gets the incorrect results in practical application

滚珠丝杠螺母和轴承中滚珠的接触会导致滚珠丝杠进给系统的非线性。非线性刚度的识别有助于理解和控制进给系统。滚珠丝杠进给系统的轴向振动可以通过具有多项式非线性项的单自由度（SDOF）系统来描述。由于广义频率响应函数（GFRF）可以用线性和非线性系统参数表示，因此可以根据测得的GFRF估算这些参数。为此，单音和多音谐波输入都被用于测量GFRF，并且提出了一种简单的搜索算法来找到多音输入的合适频率集。通过数值模拟和实验比较了基于这两种方法的参数识别。由于从滚珠丝杠系统的振动实验测得的响应谱具有偶次和奇次谐波，因此适合用方和立方非线性形式简化恢复力。进行了静态实验，验证了辨识出的参数，结果表明，基于单音输入的方法在识别滚珠丝杠进给系统的轴向刚度方面有效，但基于多音输入的方法在实际中得到了错误的结果。应用