Lightweight Design of a Seat Module Assembly for a Robotic Arm Amusement Ride System Using Topology Optimization

This paper presents a methodology for the design of a lightweight seat module assembly (SMA) for an indoor robotic arm amusement ride. Typical SMA designs begin with a welded metal frame, and the exterior shell serves only as a non-structural cover, resulting in stress concentrations and excess weight. The proposed methodology introduces a bottom-up process that integrates topology optimization at the outset, enabling the outer shell to function as a primary load path and subsequently identifies the ideal configuration for internal secondary framing by utilizing manufacturing constraints. This approach is further enhanced by adopting fiber-reinforced polymers as the structural material, leveraging their high stiffness-to-weight ratio to replace conventional metallic designs. Multiple manufacturing-specific interpretations of the optimized design were explored to evaluate feasibility, including extrusion and tubing-based approaches. Finite element analysis of the final design under high intensity load cases verified that stress and displacement constraints were satisfied. This methodology achieved a 36% reduction in mass while increasing capacity from four to five seats, corresponding to a 49% reduction in mass per seat compared to the metallic baseline. The bottom-up process allowed for an integrated design approach, where the outer shell of the SMA was designed first, featuring a novel curved geometry which minimizes stress concentrations while contributing to the overall structural stiffness, followed by the integration of the internal structure. This methodology demonstrates a new direction for SMA design in the themed entertainment industry, where load path driven, composite-first approaches can reduce weight while increasing occupant capacity.