Building a Six-Axis Robot Arm

Introduction

• Building a six-axis robot: affordable and accessible.
• AR4-MK3 features:
  • 600mm reach
  • 2kg payload capacity
  • Fully programmable software
  • Interfaces for custom tools and inputs/outputs

Required Parts and Tools

• 3D Printed Parts:
  • Used Peopoly Magneto X for printing
  • Features of Magneto X:
    • Large build volume
    • High-speed printing with brushless motors
    • High-flow wear-resistant hotend
  • Klipper firmware
  • Available with discounts
• Robot Kit from Chris Annin:
  • Electronics and mechanical parts
  • Includes Teensy control board, switches, connectors, cables
  • Aluminum parts for mechanical structure
• Servo Gripper Kit: Basic kit for initial testing and learning
• Motors and Drivers:
  • Stepper motors with planetary gearboxes from Stepperonline
  • Motors include encoders to detect movement accuracy

Assembly Process

• Base Assembly:
  • Drilling and tapping 3D printed parts
  • Almost all parts are metric
  • USB-C connectors
• Turret Bearings and Motors:
  • Large bearings for main turret, require possible Loctite
  • Motor and pulley assembly with tensioned belts
• Wiring:
  • Extensive wiring needed: soldering, splicing, sleeving
  • Recommendation against using tinned wires for terminals

Challenges and Solutions

• Motor Gearbox Issues:
  • Misalignment in gearbox causing rough operation
  • Reassembly smoothed the operation when tightened
• Wiring Length Concerns:
  • Hardwired connections; potential for improvement with correct wire lengths in future revisions

Initial Testing and Calibration

• Check motor functions, encoders, and endstops
• Calibrate endstop offsets
• Basic programming to operate movements and routines
• Software capabilities: loops, conditional checks, camera-based object recognition

Performance and Limitations

• Observations of wobble and inaccuracy
• Claims of 0.2mm repeatability questionable due to endstop calibration variance
• Belts inducing elasticity; motor backlash measured at 0.5° or more
• Structural design elements causing additional elasticity

Potential Applications and Future Improvements

• Initial use case: smooth camera movements for filming
• Interest in developing a camera-specific arm focusing on smoothness over strength
• Audience feedback requested for potential projects

Conclusion

• Praise for Chris Annin's solo effort in developing the AR4
• Encouragement to check out linked resources for more detailed guidance

Final Remarks

• Addressed delays due to personal health
• Acknowledgment of support from the community
• Sign-off and teaser for future content