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Overview

This guide helps you diagnose and resolve common issues with the Open Robot Actuator Hardware. Issues are organized by category for quick reference.
Always power down the system before performing any mechanical adjustments or repairs.

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Calibration Issues

Possible Causes:
  • Calibration tool not fully seated during offset measurement
  • Encoder index position not detected correctly
  • Incorrect offset values saved
  • Actuator module replaced without recalibration
Solutions:
  1. Verify calibration tools are properly installed with no gaps
  2. Ensure pins are correctly inserted into screw heads
  3. Re-run the calibration procedure
  4. Check that offset values are saved correctly in configuration
  5. If actuator was replaced, measure and save new offsets
Prevention:
  • Use velcro straps to keep calibration tools firmly in place
  • Always recalibrate after replacing or modifying actuator modules
Possible Causes:
  • Encoder wiring issues
  • Encoder index signal not connected
  • Motor driver configuration incorrect
  • Encoder damaged
Solutions:
  1. Check encoder wiring according to wiring conventions
  2. Verify encoder index signal is connected
  3. Test encoder signals with oscilloscope if available
  4. Check motor driver configuration settings
  5. Replace encoder if damaged
Prevention:
  • Follow wiring conventions strictly during assembly
  • Secure all connectors properly
Possible Causes:
  • 3D printed part warping
  • Incorrect pin diameter or length
  • Pins not fully seated
  • Wrong calibration tool version
Solutions:
  1. Check you’re using the correct tool for your robot (8dof, 12dof, or 6dof)
  2. Verify pin diameters: 2mm and 2.5mm
  3. Re-drill holes if needed (1.9mm for 2mm pins, 2.4mm for 2.5mm pins)
  4. Ensure pins protrude correct distance (4mm or 5mm depending on version)
  5. Reprint tool if warped
Prevention:
  • Print with “sparse double dense” setting as specified
  • Store printed tools flat to prevent warping

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Mechanical Issues

Possible Causes:
  • Over-tightened fasteners
  • Misaligned mechanical interface
  • Debris in output interface
  • Bearing damage
Solutions:
  1. Loosen fasteners slightly and check for binding
  2. Verify output interface alignment
  3. Clean output interface surfaces
  4. Check bearings for damage
  5. Reassemble with correct torque specifications
Prevention:
  • Follow torque specifications for all fasteners
  • Keep work area clean during assembly
Possible Causes:
  • Incorrect printing orientation
  • Printer calibration issues
  • Wrong STL file version
  • Post-processing needed
Solutions:
  1. Verify printing direction: positive z-axis of STL files
  2. Check printer calibration (bed leveling, extrusion multiplier)
  3. Download latest STL files from repository
  4. Clean up edges and holes with appropriate tools
  5. Reprint if necessary
Prevention:
  • Always print in recommended orientation
  • Calibrate printer regularly
Possible Causes:
  • Mechanical interface not properly seated
  • Fasteners not tightened evenly
  • Damaged interface surfaces
  • Wrong segment version
Solutions:
  1. Disassemble and check all interface surfaces
  2. Ensure mechanical interfaces match (all actuators use same interface)
  3. Tighten fasteners in star pattern
  4. Check for damage on mating surfaces
  5. Verify using correct segment length (16cm for quadrupeds)
Prevention:
  • Handle parts carefully to avoid damage
  • Follow assembly sequence in build guides

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Electrical Issues

Possible Causes:
  • Wiring connection issues
  • Motor driver not powered
  • Incorrect motor driver configuration
  • Communication failure
  • Motor phase wires disconnected
Solutions:
  1. Check all power connections
  2. Verify motor phase wires are connected
  3. Check encoder wiring
  4. Verify motor driver configuration
  5. Test communication between controller and driver
  6. Check for error messages in software
Prevention:
  • Use strain relief on all cables
  • Follow wiring conventions documentation
Possible Causes:
  • Poor wire connections
  • Electromagnetic interference
  • Incorrect wiring
  • Damaged encoder
  • Ground loop issues
Solutions:
  1. Check encoder wiring according to conventions
  2. Ensure proper grounding
  3. Use shielded cables if available
  4. Keep encoder wires away from motor power wires
  5. Check for loose connections
  6. Replace encoder if damaged
Prevention:
  • Route encoder cables away from power cables
  • Use proper connectors and crimping
Possible Causes:
  • Overcurrent condition
  • Insufficient power supply rating
  • Short circuit
  • Too many actuators on single supply
Solutions:
  1. Check power supply current rating vs. total load
  2. Look for short circuits in wiring
  3. Reduce number of simultaneous actuator movements
  4. Use higher capacity power supply
  5. Add additional power supplies for more actuators
Prevention:
  • Calculate total power requirements before selection
  • Add 20-30% margin to power supply capacity

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Operational Issues

Possible Causes:
  • Incorrect calibration
  • Joint angle offsets wrong
  • Control software issues
  • Mechanical slippage
Solutions:
  1. Verify calibration is correct
  2. Check neutral standing height: Hip FE at 45°, Knee at 90°
  3. Measure actual standing height (should be 24cm for quadrupeds)
  4. Re-run calibration procedure
  5. Check for mechanical slippage in joints
Prevention:
  • Recalibrate after any mechanical changes
  • Verify calibration regularly
Possible Causes:
  • Direction of rotation convention incorrect
  • Encoder direction reversed
  • Calibration offset errors
  • Software coordinate system mismatch
Solutions:
  1. Verify motor rotation direction: counterclockwise from top
  2. Verify leg rotation direction: clockwise from side
  3. Check coordinate system: X=Forward, Y=Left, Z=Up
  4. Recalibrate joint offsets
  5. Check software configuration matches hardware
Prevention:
  • Follow conventions documentation strictly
  • Document any configuration changes
Possible Causes:
  • Control gains not tuned
  • Communication latency
  • Mechanical binding
  • Insufficient power supply
  • Encoder noise
Solutions:
  1. Check for mechanical binding in all joints
  2. Verify stable power supply
  3. Check encoder signal quality
  4. Tune control gains in software
  5. Reduce communication latency
  6. Check for loose connections
Prevention:
  • Perform regular mechanical maintenance
  • Use quality power supplies
  • Follow proper cable management

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Getting Help

If you can’t resolve your issue using this guide:
  1. Search the Forum: ODRI Discourse Group - Many issues have been discussed
  2. Check the Paper: ODRI Paper - Technical details and theory
  3. Watch Videos: ODRI YouTube Channel - Assembly and operation demonstrations
  4. Post Your Issue: Include:
    • Detailed description of the problem
    • Robot configuration (8dof, 12dof, etc.)
    • Photos or videos if applicable
    • What you’ve already tried
    • Error messages or logs

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Contributing Solutions

Help improve this guide by sharing your troubleshooting experiences:
  • Post successful solutions on the forum
  • Document unusual issues with photos
  • Share diagnostic techniques
  • Suggest additional troubleshooting topics

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