RoboticsIntermediate
Field-Relative vs Robot-Relative Driving
The same joystick push means different things depending on whether commands are interpreted from the field or the robot.
Site connection
The robotics writing describes gyro-dependent swerve behavior and why orientation sensing matters.
Visual model
Command frame changes module vectors
A swerve command combines translation and rotation, but the frame of reference decides what forward means.
Interactive
Each module receives its own speed and wheel angle
Robot-Relative
Forward means the direction the robot is currently facing. If the robot turns, the same joystick input moves in a new field direction.
Field-Relative
Forward means the field's forward direction. The robot uses its gyro heading to rotate the driver command into robot coordinates.
Field-relative driving feels natural to drivers, but it depends on trustworthy heading estimation.
Common Pitfalls
- Using the wrong coordinate convention in kinematics.
- Not resetting gyro heading before a match.
- Failing gracefully when the gyro disconnects.
Quick check
Quiz
What sensor is usually essential for field-relative driving?
- Gyro
- Break beam
- LED controller
- Bumper switch
The robot needs heading to rotate field commands into robot-relative commands.