Integrated Design, Dynamic Modelling, and Structural Validation of a 14-DOF Lightweight Humanoid Robot

This paper presents a unified design-to-validation framework for a compact 14-degree-of-freedom (DOF) humanoid robot developed using additive manufacturing. The methodology integrates mechanical design, finite element structural verification, kinematic and dynamic modelling, trajectory generation, and simulation-based validation into a single coherent workflow. A complete CAD model is used to extract accurate geometric and inertial parameters, ensuring physically consistent modelling from the initial design stage. The structural integrity of the 3D-printed PLA components is evaluated under a conservative 1 kN load using finite element analysis (FEA). Forward kinematics are formulated using the Denavit-Hartenberg convention, and joint torque requirements are derived using Euler-Lagrange dynamic modelling. Smooth joint trajectories are generated using cubic polynomial interpolation, and gait stability is assessed using the Zero Moment Point (ZMP) criterion. Simulation results obtained from MATLAB and CoppeliaSim demonstrate accurate tracking of joint displacement, velocity, and torque profiles across all 14 DOF, confirming actuator feasibility and stable coordinated motion. The proposed framework ensures that structural feasibility, dynamic performance, and motion stability are verified prior to physical implementation.