In order to improve the working performance of cassava harvester, structural bionic design for its digging shovel was conducted. Taking the oriental mole cricket's paws as bionic prototype, a new structural bionic design method for digging shovel was established, which considers the morphology-configuration-function coupling bionic. A comprehensive performance comparison method was proposed, which is used to select the bionic design schemes. The proposed bionic design method was used to improve digging shovel structure of a digging-pulling style cassava harvester, and nine bionic-type digging shovels were obtained with considering the impact of soil mechanics. After conducting mechanical properties comparative analysis for bionic-type digging shovels, the bionic design rules were summed up, and the optimal design scheme of digging shovel was obtained through combining the proposed comprehensive performance comparison method with Analytic Hierarchy Process (AHP). Studies have shown that bionic design method not only can improve the overall mechanical properties of digging shovel, but also can help to improve the harvesting effect of cassava harvester, which provides a new idea for crops harvesting machinery's structural optimization design.

In order to use mechanism model analysis instead of experimental test to control and adjust the temperature and oven temperature curve of each part of the integrated circuit board reflow oven to make it meet the process requirements, a fitting algorithm was used to establish a heat transfer model of the reflow soldering. The established reflow soldering heat transfer model was used to simulate and fit to obtain the integrated circuit board reflow soldering oven temperature curve, and compared it with the reflow soldering experiment curve to verify the reliability of the model’s simulation performance. The comparison results show that the reflow soldering oven temperature simulation curve is in good agreement with the experimental curve, and it can replace the experimental test to find the best. On this basis, the genetic algorithm was further used to optimize the temperature setting and oven temperature curve for integrated circuit boards. After optimization, the conveyor belt velocity of the integrated circuit board is preferably 1.4799cm/s, and the set temperature of temperature zones is 179 °C at small temperature zones 1~5, 185 °C at small temperature zone 6, 235 °C at small temperature zone 7, and 264 °C at small temperature zones 8~9; the area of the oven temperature curve that exceeds 217 °C decreases by $831.1611~^{\circ }\textrm {C}\cdot \text{s}$ , and its symmetry with respect to the peak is better, which is much closer to the ideal oven temperature curve. The research results provide a useful reference for the design of integrated circuit board reflow soldering process.

In order to improve the efficiency and effectiveness of the lightweight design of the gantry machine tool, a lightweight structural optimization design system for the gantry machine tool was constructed. Serialized gantry machine tools were parametrically modeled, and a load model with multiple operating conditions was established. A twice optimization design method integrating zero-order optimization, parameter rounding, and structural re-optimization was proposed. Using the proposed method, a lightweight structural optimization design system for gantry machine tool with parametric design, lightweight design, and other functions was developed. The developed gantry machine tool lightweight structural optimization design system was applied to complete the lightweight structural optimization design of gantry frame of a certain gantry machine tool, so the structural parameters of the gantry frame were optimized. Although the maximum stress and the maximum deformation of the gantry frame increases within the allowable range, the experimental comparison before and after the optimization shows that the mass of the whole gantry frame is reduced by 9.24%, which is beneficial to save the manufacturing cost. The research results show that the constructed lightweight structural optimization design system of the gantry machine tool has high engineering practicality.