Hybrid Structure Design of Lightweight Robotic Arms Based on Carbon Fiber Reinforced Plastic and Aluminum Alloy

Some light materials, such as hollow sphere composite (HSC), carbon fiber reinforced plastic (CFRP), and aluminum alloy (AA), are currently used in the design of lightweight robotic arms. However, the high cost limit the use of HSC, the CFRP has a relatively low cost but poor processing property, and the AA has good processing property but relatively high density. To make up respective shortcomings, this study focuses on the design issues of lightweight robotic arms by using two kinds of materials. Based on the CFRP and AA, a hybrid structure design approach is proposed to minimize the total mass of the lightweight robotic arms with CFRP/AA hybrid structure. To accomplish the objective, structural dimensions and layer parameters in hybrid structures are parameterized as design variables subject to the strength, stiffness, and dynamic constraints. Moreover, the bonding strength of the interaction surfaces between CFRP and AA parts is also considered on the basis of the cohesive zone model (CZM). In optimization design, the ABAQUS and elitist non-dominated sorting genetic algorithm (NSGA-II) in modeFRONTIER utilizing the Python script are respectively employed for the structural analyses and iteration calculation. Finally, a design example and an experimental prototype are provided to validate the proposed method and compare with the previous AA prototype in mass with a reduction of 24.32%.