Design of Quadruped Robot Torso Structure Based on Stress Analysis of Cross-Sections

Abstract

This research presents a structural design study of the torso frame of a quadruped robot، focusing on identifying the optimal shapes and dimensions of link rod cross-sections under tensile، compressive، bending، and torsional stresses. The objective is to achieve the minimum possible torso weight while maximizing payload capacity and thereby enhancing energy efficiency، using PLA material for 3D printing. The assumptions include analyzing individual cross-sections (circular، square، rectangular) without lateral supports. Finite Element Analysis (FEA) was conducted using SolidWorks software to simulate stress conditions، incorporating the effect of hollowing to reduce weight while increasing structural stiffness. The results indicate that circular sections are more susceptible to deformation under tensile and compressive loads، whereas rectangular sections (Position 1) perform better under bending، and circular sections demonstrate good resistance to tensile stress. The hollowing effect improves stress distribution without increasing material volume. The torso design was validated under a 400-gram load، showing good performance with cross-bracing supports Even after being hollowed out using the cavitation effect, a material saving of 1/8 of the cross-link size was achieved. This research contributes to the development of cost-effective quadruped robots for industrial and educational applications.