Design and Prototyping of a 3DOF Worm-drive Robot Arm

Many designs for robot arms exist. Here we present an affordable revolute arm, capable of executing simple pick-and-place tasks. The arm employs a double parallelogram structure, which ensures its endpoint angle in the plane of the upper arm remains fixed without the need for additional actuation. Its limbs are fabricated from circular tubes made from bonded carbon fiber, to ensure low moving mass while maintaining high rigidity. All custom structural elements of the arm are produced via 3D printing. We employ worm-drive DC motor actuation to ensure that stationary configurations are maintained without the necessity of continuous motor power. Our discussion encompasses an analysis of the arm's kinematics. A simulation of the arm's operation was carried out in MATLAB, revealing key operational metrics. In conclusion, we achieved extrinsic endpoint position tracking by implementing its inverse kinematics and PID control using a microcontroller. We also demonstrate the arm's functionality through simple movement tracking and object manipulation tasks.