Mechanical design

Group assignment: - Design a machine that includes mechanism+actuation+automation+application
- Build the mechanical parts and operate it manually
- Document the group project and your individual contribution

In this assignment we were working on the development of the robot arm for the group. For machine design, we built a 5-axis robotic arm which will be controlled using web interface control panel. Other team members handled the mechanical structure and electronics, I was in charge of writing the firmware and developing the interface to control the robot.
Group link

Assembling testing

My Role: Assisting in Mechanical Assembling & Control Interface Designing

• Mechanical Assembly:
  • Assisted in assembling robotic arm joints: base, shoulder, elbow, wrist, and gripper.
  • Mounted motors and ensured structural alignment for smooth movement.
  • Performed tuning and mechanical tests to verify joint performance.
  
  
  
  
  
• Control Interface Designing and firmware:
  Interface preview
  Firmware Code
  • Designed a manual control panel using Web serial communication.
  • Mapped controls to microcontroller I/O pins for each axis.
  • Labeled and tested the interface for usability and responsiveness.
  
  The Core Features we Implemented:
  • Multi-axis stepper control via serial interface
  • Angle-based motion mapping (0–180°) with step conversion
  • Session-based position memory with support for save and playback
  • Looped playback feature with adjustable timing between steps
  • Motor reset function to bring all motors to 0°
  
  Challenges
  • Serial Command Parsing: Since the interface was based on comma-separated strings, splitting and validating inputs reliably was critical to prevent misexecution.
  • Angle to Step Conversion: Each motor used a specific number of steps per revolution, requiring custom scaling (e.g., 1° ≈ 5.68 steps for 28BYJ-48 with gear ratio).
  • Position Memory: EEPROM was avoided to preserve lifespan, so all positions were stored in volatile memory during runtime and lost on power-off.
  • Looped Playback Timing: Introducing a custom delay between motor sequences helped simulate coordinated movement but required precise state tracking.
  • Safety Reset: A manual reset command was implemented to avoid mechanical overextension by returning motors to their safe base (0°) position.
  User Interface (UI) Overview

  The 4-Axis Stepper Motor Control System features a streamlined, web-based interface optimized for real-time motor control and precise position management. The interface is intuitive, responsive, and accessible via Wi-Fi, offering comprehensive control over each motor’s angle and speed.

  
  
  Main UI Sections 1. Connection Panel

  Select a serial port and baud rate, then connect. Real-time connection status is shown using clear visual indicators.

  2. Motor Controls

  Each of the four stepper motors includes:

  • Angle Adjustment: Set the desired motor angle using a slider.
  • Speed Control: Define movement speed in steps per second.
  • Move Command: A dedicated “Move Motor” button for each axis to execute commands.
  3. Saved Positions

  Quick-save and recall up to 10 preset motor positions. Custom labels such as “Left Turn,” “Right Turn,” and “Wave” help with easy identification and reuse.

  4. Console Output

  Displays real-time system feedback, including command logs and status messages for monitoring performance and troubleshooting.

  
• Collaboration & Documentation:
  • Worked with the electronics team to wire and test the control panel.
  • Participated in debugging and system integration.

What I have learned from this project.

Learning Outcomes 1. Mechanical Design & Fabrication

• Learned how to design a multi-joint robotic arm with degrees of freedom for pick-and-place tasks.
• Gained experience in using CAD tools like SolidWorks for 3D modeling and Assembly.
• Developed hands-on skills in digital fabrication (3D printing, assembly).
• Understood mechanical constraints like torque, joint limits, and structural integrity.

2. Actuation & Motor Control

• Learned to select suitable motors (stepper and servo) based on torque and precision requirements.
• Gained practical experience with stepper motor drivers.
• Understood the wiring and power requirements of a multi-motor system.
• Explored techniques for managing load and motor heat dissipation.

3. Automation & Embedded Programming

• Developed skills in embedded programming using Arduino/ESP32.
• Understood how to translate manual operations into automated sequences.
• Learned basic motion planning and joint coordination.

4. System Integration

• Experienced how to combine mechanical, electrical, and software components into a working system.
• Understood debugging practices across subsystems mechanical misalignment, electrical faults,load balancing and code errors.
• Gained project management skills: planning, documentation, testing, and iterative improvement.

5. Application & Real-world Relevance

• Understood how robotic arms are applied in real-life scenarios such as manufacturing and lab automation.
• Reflected on the limitations of the current model and ideated improvements.
• Learned to operate the arm manually and compare its performance with the automated mode.

6. Team Collaboration & Individual Growth

• Collaborated effectively in a multidisciplinary team by taking ownership of specific components.
• Practiced documenting work clearly for group reports and individual portfolios.

Files for codes Interface preview
Firmware Code