Pengda Zhao

The frame of the six-row self-propelled packaging cotton picker serves as the primary load-bearing structure. During operation, the frame is subjected to multiple vibration signals, which are further intensified by coupling effects. These vibrations negatively impact the machine’s operational stability and overall performance. In this study, vibration source tests were designed to collect dynamic response data, enabling systematic analysis of excitation mechanisms and vibration characteristics. Furthermore, a comprehensive analytical approach integrating finite element simulation with experimental analysis was employed to optimize the layout of the vibration sources on the frame. Finally, the frame was validated through modal testing, with multiple measurement points arranged at the interfaces between the frame and the vibration source for vibration tests and time–frequency domain analysis. The results indicate that the final optimized dimensional parameters of the frame were determined as follows: X1 = 1575 mm, X2 = 805 mm, and X3 = 275 mm. Furthermore, time–frequency domain analysis reveals that the natural frequency of the rack designed in this study is effectively separated from the dominant excitation frequency band. This design feature successfully mitigates the risk of resonance, thereby fulfilling the intended performance objectives.

The frame of the cotton picker is exposed to complex and varying loads during its operation. Therefore, conducting research on the vibration characteristics of the frame is crucial. In this study, vibration tests were conducted on the main vibration sources in a cotton picker at several measuring points on the frame. An accelerometer sensor was utilized to collect the signals. Fourier analysis was applied to analyze the vibration sources, encompassing the excitation frequency and the vibration source-coupled excitation frequency. Modal tests were also conducted to validate the finite element model and determine the natural frequencies of the frame. The results showed that the natural frequencies of the frame, specifically the third-order, fourth-order, and sixth-order frequencies, were comparable to the vibration source-coupled excitation frequencies. To prevent frame resonance, the response surface method was used to optimize the frame. Based on the MOGA algorithm, scheme 4 was identified as the optimal design. Furthermore, fatigue life calculations were carried out to optimize the parts with short lifespans on the frame, thereby enhancing the working performance.