Robot Foundations 05, beginner
Where Am I?
Teach the robot to estimate where it is.
Your robot has a map. It has sensors. It can move. But there is one problem: the robot doesn't know exactly where it is on the map. Figure out how it can keep track of its position while moving.
- 01 The robot learned to move.
- 02 It learned to sense.
- 03 It used movement and sensing to reach a goal.
- 04 It built a map of its environment.
- 05 Now it needs to know where it is inside that map.
- Move
- Sense
- Map
- Localize
- Plan
- Control
Stages
Key ideas
Pose
(x, y, θ): where the robot is and which way it faces.
Odometry
Adding up wheel motion, step by step, to estimate the pose.
Drift
Slip and measurement errors are small, but they accumulate, so the estimate wanders away from the truth.
Predict and correct
Motion predicts how the estimate changes; an independent observation, such as a known landmark, corrects it.
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true pose and path (solid) estimated pose and path (dashed) landmark