Abstract: Objective To address the issues of low walnut harvesting efficiency and low fruit removal rate, a flexible rocker-arm vibration-based walnut harvesting machine is designed, utilizing trunk vibration for harvesting. The study investigates the impact of different vibration parameters on vibration performance. By employing response surface methodology, the vibration acceleration responses under the two-way interaction of parameters are obtained, aiming to optimize the design structure and operational parameters.Method This paper conducts structural design and stress analysis of key components of the harvester to determine the optimal parameters. Simulation analysis and vibration operation tests are performed on the clamping area of the walnut tree and the trunk to assess the acceleration response. Using Design-Expert 13.0 software, vibration frequency, tree diameter, and vibration time are considered as the main factors, with vibration acceleration as the evaluation criterion. The response surface methodology is employed to study the influence of these three parameters on vibration acceleration.Result The ADAMS simulation software indicates that the optimal diameter of the flexible rocker arm is 15 cm, and the optimal clamping force is 2 800 N. By comparing the simulation results with the field harvesting test results, the vibration acceleration errors at the clamping area and trunk of the walnut tree, under different frequencies, are within 5%. The contribution rates of vibration frequency, tree diameter, and vibration time to the vibration acceleration evaluation index are 2.317 8, 1.649 2, and 1.489 4, respectively. When the vibration frequency is 14 Hz and the tree diameter is 15 cm, the vibration acceleration reaches its maximum value of 63.417 m·s^–2. The impact of the three factors on vibration acceleration, in decreasing order, is: vibration frequency, tree diameter, and vibration time.Conclusion This paper focuses on the designed flexible rocker-arm vibration-based walnut harvester, analyzing the structural features of the equipment and the impact of operational parameters on energy transfer. The study provides operational parameter guidelines for efficient walnut harvesting in large-scale standardized orchards, aiming to effectively improve walnut harvesting efficiency and fruit removal rate.

Key words: flexible arm, vibrating harvesting, structural design, vibration response