Structural analysis of hybrid composite arms for light weight robots

Abstract

Robot structures made of steel or aluminum tend to be heavy and can undergo significant deformation, which leads to increased power consumption and a higher risk of failure under load conditions. Therefore, it is essential to create lighter-weight structures without compromising the performance of the robot. Taguchi methods can be employed to design these lightweight robot structures and optimize their performance. Additionally, finite element analysis and machine learning can provide valuable insights into the behavior of these structures. A series of experiments have been designed and analyzed for hybrid composite tubes used in robotic arm applications, particularly focusing on fiber-reinforced polymer (FRP) materials wrapped around aluminum tubes. Filament winding is a well-known technique for applying FRP to tubes, and the primary approach in this investigation was analyzed using ANSYS Composite Pre/Postprocessor (ACP). The study investigates three models of hybrid composite pipes, varying the number of layers and the winding angle. Each model was subjected to cantilever loading at various node points, while keeping the wall thickness of the tube constant at 3 mm. The model with a CFRP winding angle of 45° and a layer thickness of 1.5 produced the best results compared to the others. It was observed that both the bending moment and shear stress of the tube increased with a rising winding angle, whereas the strain energy of the tube decreased with an increasing winding angle. The optimal winding angle was determined to be 45°. Additionally, the stresses on the filament-wound tubes under different load conditions were optimized, and a statistical analysis was conducted using Mini-Tab. The research further focused on identifying the maximum failure loading conditions for optimal parameters through composite failure analysis. The failure conditions of the composite tube under maximum sustainable parameters were compared with those of standard aluminum and CFRP tubes. The hybrid tube demonstrated less deformation and stress compared to the other models.