Page 9 - Introduction to Autonomous Mobile Robots

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3.4 Mobile Robot Workspace Contents
74
3.4.1 Degrees of freedom 74
3.4.2 Holonomic robots 75
3.4.3 Path and trajectory considerations 77
3.5 Beyond Basic Kinematics 80
3.6 Motion Control (Kinematic Control) 81
3.6.1 Open loop control (trajectory-following) 81
3.6.2 Feedback control 82

4 Perception 89
4.1 Sensors for Mobile Robots 89
4.1.1 Sensor classification 89
4.1.2 Characterizing sensor performance 92
4.1.3 Wheel/motor sensors 97
4.1.4 Heading sensors 98
4.1.5 Ground-based beacons 101
4.1.6 Active ranging 104
4.1.7 Motion/speed sensors 115
4.1.8 Vision-based sensors 117
4.2 Representing Uncertainty 145
4.2.1 Statistical representation 145
4.2.2 Error propagation: combining uncertain measurements 149
4.3 Feature Extraction 151
4.3.1 Feature extraction based on range data (laser, ultrasonic, vision-based
ranging) 154
4.3.2 Visual appearance based feature extraction 163

5 Mobile Robot Localization 181
5.1 Introduction 181
5.2 The Challenge of Localization: Noise and Aliasing 182
5.2.1 Sensor noise 183
5.2.2 Sensor aliasing 184
5.2.3 Effector noise 185
5.2.4 An error model for odometric position estimation 186
5.3 To Localize or Not to Localize: Localization-Based Navigation versus
Programmed Solutions 191
5.4 Belief Representation 194
5.4.1 Single-hypothesis belief 194
5.4.2 Multiple-hypothesis belief 196