Structural Design and Performance Analysis of a Carbon Fiber Composite Robot Upper Arm Based on Multi‐Process Integration

ABSTRACT This study proposes a hat‐stiffened carbon fiber composite industrial robot upper arm (hereafter referred to as the composite upper arm) to address the excessive weight, insufficient stiffness and limited modal performance of conventional metal robot upper arms. By integrating the good machinability of metallic materials with the high specific stiffness of carbon fiber composites, an integrated forming method for a metal‐composite hybrid structure is proposed. Three‐dimensional carbon fiber braiding is introduced into the fabrication of the composite upper arm. A braiding‐layering‐winding composite preforming process is employed to enhance the delamination resistance, bending performance, and fiber volume fraction of the composite upper arm. A braided model of the composite upper arm is established. The braiding trajectories are determined by numerical calculation and mapped into the composite finite element model to analyze the stiffness and modal characteristics of the composite upper arm. Experimental results show that, compared to the metal upper arm, the composite upper arm achieves a weight reduction of 31% and an increase of 13% in the first natural frequency. After adopting the composite upper arm, the overall stiffness of the robot is improved by 13%.