Structural form and parameter optimization of manipulator grasping fragile workpieces to improve the impact characteristics based on the signal-to-noise ratio

The contact impact stress (CIS) between a manipulator finger and a fragile workpiece has a significant effect on clamping stability. The CIS is affected by various factors, for example, the structural form and parameters of the manipulator finger. In this paper, an optimization method combining Taguchi’s method with signal-to-noise ratio (SNR) theory is proposed to reduce the CIS by optimizing the structural form and parameters of the fingers of an internally supported manipulator. The process consists of three stages. In the first stage, finite element models are built using SolidWorks, HyperMesh, and LS-DYNA software to simulate the CIS of the manipulator when gripping fragile workpieces. In the second stage, the SNR theory is applied to evaluate the effect of CIS and its fluctuations on CIS by treating the CIS and its fluctuations as signals, and changes in the structural forms and parameters of the fingers as noise. In the third stage, the optimal combination corresponding to the maximum SNR is obtained, and the degree of influence and significance level of each factor on the impact force was obtained by calculating the SNR response and variance. The simulation results indicate that the optimized structural parameters reduce the CIS by 26.85% compared to the original design. The experimental results verify the correctness of the simulation results and the effectiveness of the proposed method in reducing CIS.