Week 15 System Integration

🔧 System Integration Week — Final Project: Robotic Manipulator Arm

The final project focuses on developing a robotic manipulator arm capable of articulated movement, actuator-assisted extension, and gesture-based control through a wearable glove interface. The inspiration for the project originated from cinematic robotic systems and industrial manipulators that combine exposed mechanical structures, layered actuators, responsive movement, and human-machine interaction. Instead of creating a fully autonomous robotic system, the project explores how human hand movement can directly control a fabricated robotic arm through embedded electronics, mechanical systems, and real-time actuator response.

The robotic arm is designed as a gesture-controlled manipulation system where the user wears a glove integrated with flex sensors. As the user bends their fingers or changes hand position, the flex sensors detect variations in resistance values. These signals are processed by a microcontroller and translated into servo motor movement, allowing the robotic arm to mimic the movement of the user’s hand and arm gestures in real time. The project therefore focuses on creating a physical interaction loop between human motion and robotic articulation.

The entire robotic arm is divided into four major sections: the gripper section, wrist and forearm section, upper arm section, and rotating base section. Each section is designed to perform a specific movement while maintaining structural rigidity and manageable weight distribution.

The gripper section uses a two-side parallel jaw mechanism inspired by industrial robotic manipulators instead of humanoid robotic fingers. This approach was chosen to simplify the mechanics while improving gripping reliability and structural stability. The jaws are fabricated using 3D printed components connected through pivot joints and linkage systems. Silicone molded grip pads are attached to the inner jaw surfaces to improve friction and grip performance while handling objects. A compact servo motor mounted inside the wrist assembly controls the opening and closing of the gripper.

The wrist and forearm section supports the gripper assembly and provides orientation control through wrist tilt movement. This section also contains part of the actuator-assisted extension mechanism which increases the reach capability of the robotic arm. Structural reinforcement plates are integrated along both sides of the forearm to reduce flexing during movement. Internal routing channels are incorporated within the structure to organize sensor wires and servo cables while maintaining a cleaner assembly.

The upper arm section contains the major load-bearing joints of the system including the shoulder and elbow mechanisms. High torque servos are integrated into these sections to generate sufficient lifting force while maintaining controlled articulation. The elbow and shoulder joints use double-supported bearing structures to reduce wobbling and prevent excessive load concentration on the servo shafts. The arm proportions were intentionally kept compact to reduce torque requirements and improve movement stability during operation.

The rotating base section acts as the primary support structure for the entire robotic arm. The base houses the main electronics system, power distribution system, custom PCB, and rotational mechanism. A large bearing is integrated into the rotating platform to support the arm weight and allow smoother horizontal rotation. The base dimensions are intentionally wider to improve overall stability and reduce tipping during extended arm movement.

The electronics architecture is centered around the Seeed Studio XIAO RP2040 which acts as the primary controller for the robotic arm system. The XIAO RP2040 is integrated into a custom PCB designed specifically for the project to create a compact and organized electronics assembly. The PCB handles signal routing, servo communication, sensor connections, and power distribution while minimizing loose wiring within the system.

The gesture-control glove acts as the main input interface for the robotic arm. Multiple flex sensors are integrated into the fingers of the glove to detect bending motion. As the user bends specific fingers, the corresponding movement is mapped to different robotic arm functions such as gripper actuation or arm articulation. Additional movement control may also be integrated through joystick modules or potentiometers depending on the final control strategy.

A PCA9685 servo driver module is integrated into the system to generate stable PWM signals for multiple servo motors simultaneously. High current servo operation is powered through an external regulated 5V power supply to avoid voltage instability and servo jitter. Capacitors are integrated into the power distribution system to smooth sudden current fluctuations generated during rapid arm movement.

The fabrication process combines multiple digital fabrication workflows. Structural arm sections, servo mounts, linkage systems, and electronic housings are designed using Autodesk Fusion and fabricated using 3D printing with PLA material. Structural reinforcement plates and support panels are fabricated through laser cutting using acrylic or MDF sheets. Silicone molding and casting processes are used to fabricate the soft gripping pads integrated into the gripper jaws.

The final robotic arm is expected to demonstrate gesture-controlled articulated movement, stable gripping, actuator-assisted extension, custom PCB integration, and multi-process fabrication workflows within a compact robotic manipulator platform. Beyond functioning as a robotic arm, the project explores the relationship between human motion, embedded electronics, mechanical systems, and digitally fabricated interaction devices.