Introduction to RoboticsLocalization and Mapping IMarch 1, 2010
Last week’s exerciseRobotStadiumIntroduction to SVN (versioning/collaboration tool)TasksLocomotion: need to get up and runPerception: need to orient itselfCommunicate: need to share informationLocalize: need to reason about spaceDeliberate: need to plan what to do nextShare the load: 1 or 2 tasks per studentPresent your plan in 2 weeks in class – be specific
Localization
LocalizationGyroscopeOdometryControl inputGPSLandmarksSensor input with different uncertainties. What is the overall uncertainty of the estimate?
Uncertainty Models: The Gaussian Distribution
Error PropagationIntuition: the more sensitive the estimated quantity is to perception error, the more this sensor should be weightedCovariance matrixRepresenting outputuncertaintiesFunction relating sensor inputto output quantitiesCovariance matrixrepresenting inputuncertainties
Differential Wheel Robot Odometry
Error propagationWheel-Slipf=
Error Propagation
Belief representationParametric, single hypothesisParametric, multi hypothesisNon-parametric, multi hypothesis(particle filter)
Environment RepresentationContinuousDiscreteTopologicalVectorsArrayGraph
Example: Google MapsContinuous, Discrete or Topological?
Belief representation in topological maps
Multi-Hypothesis Belief Representation
From Sensor Data to Topological MapsExact Decomposition
Voronoi DecompositionPoints on lines have the same distance to neighboring obstaclesVoronoi edges correspond to the safest path
Adaptive Cell-Size
Exercise: Navigation AlgorithmsFind the shortest path from A to BChoose the map representationDevise an algorithm to extract path
Reactive vs. Deliberative PlanningSo farMove randomlyUse heuristics (follow wall, spiral, …)Use landmarks (infrared beacons, magnet wire)Use gradients / feedback control (Exercise 2)TodayDeliberative planningReason on abstract representation
HomeworkSection 5.6 (pages 212-244)

Lecture 07: Localization and Mapping I