Robot Coordinate System
All robot coordinate systems follow this convention:
- Positive X Axis: Forward
- Positive Y Axis: Left
- Positive Z Axis: Upwards
Leg Naming Convention
For quadruped robots, legs are named according to their position:
- FR: Front Right Leg
- FL: Front Left Leg
- HR: Hind Right Leg
- HL: Hind Left Leg
Degree of Freedom Naming Convention
Joint Types
- Hip AA: Hip Abduction Adduction
- Hip FE: Hip Flexion Extension
- Knee: Knee Flexion Extension
DOF Abbreviations
We use the following abbreviations to label the degrees of freedom:| DOF Abbreviation | DOF Name |
|---|---|
| FRHAA | Front Right Hip Abduction Adduction |
| FRHFE | Front Right Hip Flexion Extension |
| FRK | Front Right Knee |
| FLHAA | Front Left Hip Abduction Adduction |
| FLHFE | Front Left Hip Flexion Extension |
| FLK | Front Left Knee |
| HRHAA | Hind Right Hip Abduction Adduction |
| HRHFE | Hind Right Hip Flexion Extension |
| HRK | Hind Right Knee |
| HLHAA | Hind Left Hip Abduction Adduction |
| HLHFE | Hind Left Hip Flexion Extension |
| HLK | Hind Left Knee |
Direction of Rotation
Motor Rotation
The positive direction of rotation is counterclockwise when looking at the motor from the top.
Leg Rotation
The positive direction of rotation is clockwise when looking at the robot leg from the side.
Neutral Standing Height
We consider the leg to be at neutral standing height when:
- Hip FE angle is at 45 degrees
- Knee angle is at 90 degrees
- Segment length: 16cm
- Neutral standing height: 24cm
Mechanical Conventions
3D Printing Direction
The recommended printing direction is the positive z-axis direction of the STL files.
Mechanical Interface for Actuator Modules
We use the same mechanical output interface for all actuator modules.
Mechanical Interface for Segments
Electronics Conventions
Wiring Conventions
The wiring conventions for the actuator modules and the electronics are documented in the Details Wiring page.