Pham, C.N.P. et al. 2026. A Comparative Analysis of Optimal LQR and Conventional PID Control Strategies for Trajectory Tracking in a 3-DOF Spherical Articulated Manipulator. EAI Endorsed Transactions on Sustainable Manufacturing and Renewable Energy. 2, 4 (Jan. 2026). DOI:https://doi.org/10.4108/eetsmre.11147.