关键词: 缝合机器人, 服装生产, 服装裁片, 驱动力模型, 屈曲变形, 缝合质量

Abstract:

Objective To address the issues of crooked deformation and shear deformation in cut pieces caused by inadequate driving force and platen size, as well as the frequent need to replace the platen during the sewing process where the platen presses against the cut pieces, this study investigates the linear movement of the platen during this sewing process. The aim is to establish relationships between cut piece parameters, driving force size, and platen size, and to subsequently enhance the quality of cut piece sewing.

Method The study employed the energy conservation method to analyze the buckling deformation process of the cut piece, and established models for the minimum driving force and the critical buckling size of the cut piece, based on the nonlinear bending characteristics during buckling. The shear deformation of the cut piece on both sides of the platen was examined and a model was developed to calculate the maximum driving force under critical conditions on both sides. The models were validated through finite-element simulation analysis and experiments.

Results The minimum driving force model presented in this paper provides the minimum force required for the platen to press the cut piece during straight-line sewing without causing bending deformation. The factors influencing this minimum driving force included the initial sharp angle of the sewing needle α, the thickness of the cut piece Z, the proportionality coefficient K, the friction coefficient between the cut piece and the sewing table μ, and the weight of the cut piece m1, all of which were found positively correlated with the minimum driving force. The maximum driving force model offers the maximum driving force value to prevent shear deformation during sewing. It was found that the maximum driving force of the platen was mainly positively correlated with parameters such as the coefficient of friction between yarns μ₂, bending stiffness of the cut piece E_z, width of the yarns w, and the weight of the cut piece m₁. The maximum driving force was negatively correlated with parameters including the length of the yarns PY between two intersections of warp and weft yarns, the width of the single-cell model S, and the angle θ between the shear force F_s and the upward closing force F_l. The critical buckling size model provides a basis for selecting the appropriate platen size. The critical buckling size was mainly positively related to parameters such as the initial sharp angle of the sewing needle α, bending stiffness of the cut piece B, thickness of the cut piece Z, and the angle γ between the moving direction of the platen and the direction of the cut piece's buckling. The critical buckling size was proved to be negatively correlated with the forcing torque M₀, the total mass of the cut piece m₁, and the friction coefficient between the cut piece and the sewing table μ. Finally, by comparing the theoretical data with the data obtained from simulation and experimentation, the correctness of the theoretical data was confirmed, further validating the driving force model and the critical buckling model.

Conclusion The establishment of the driving force model provides a range of driving force values for the platen to press the cut piece during the sewing process, ensuring that the cut piece does not undergo bending deformation or shear deformation. This avoids the deformation issues that arise from inadequate driving force during sewing. The critical buckling size model offers a basis for selecting the appropriate platen size, mitigating problems such as bending deformation and frequent platen replacement due to improper platen size during the sewing process. Compared to traditional empirical methods for selecting driving force and platen size, the development of these models addresses issues related to cropping deformation, wrinkles, and platen size selection in mobile sewing, significantly improving the sewing quality and efficiency of cut pieces.

Key words: sewing robot, garment processing, cut piece for garment, driving force model, buckling deformation, sewing quality