DEVELOPMENT OF A 4-DOF LOW-COST ROBOTIC ARM WITH INTEGRATED CONTROL SYSTEMS AND 3D-PRINTED MECHANICAL DESIGN FOR EDUCATIONAL PURPOSES

Abstract

This study presents the design and development of a compact, low-cost 4-degree-of-freedom (4-DOF) robotic arm that integrates 3D-printed mechanical structures, a custom PCB-based control system, and Denavit–Hartenberg (D–H) kinematic modeling. The system achieves precise multi-joint motion using stepper-servo actuation and real-time analog joystick control. MATLAB-based simulations with Robotics Toolbox, Simscape, and Inverse Kinematics Designer validated the arm’s kinematic accuracy and workspace performance. A custom-designed planetary gearbox enables each joint motor to deliver up to 3.8 N·m of torque, enhancing the arm’s lifting capability and motion stability. The final prototype achieved a positioning accuracy of ±2.5 mm, a workspace volume of 1.13 m3, and a total build cost below $100 USD. The entire system was fabricated using FDM 3D printing and open-source electronics, enabling full reproducibility for educational and research purposes. Compared with existing open-source arms, the proposed design provides an improved torque-to-cost ratio and modular structure, making it suitable for instructional use in mechatronics and robotics courses.