Performance Tests for Wireless Real-time Localization Systems to Improve Mobile Robot Navigation in Various Indoor Environments

This research introduces a research effort at the Peter Kiewit Institute in Omaha, Nebraska by investigating the performances of current wireless real-time localization technologies. Futhermore, the research shows how localization technologies can be applied to sensoraided intelligent mobile robots for high-level navigation functions for indoor construction security and material delivery. Sensor-based exploration enables a robot to explore an environment and to build a map of the explored environment. A critical component of sensor-based exploration is robot’s ability to ascertain its location in a partially explored map or to determine that it has entered a new territory. Theoretically, one can determine the (x, y) coordinates of the robot using dead-reckoning – a process that determines the robot’s location by integrating data from wheel encoders that count the number of wheel rotations. However, dead-reckoning often fails to accurately position the robot for many reasons, including differential of wheel rotation rate and wheel slippage. Especially when the robot slips, the wheel rotation does not correspond to its movement, and thus encoder data, which reflects the state of the wheel rotation, does not reflect the robot’s net motion, thereby causing positioning errors. A global positioning system (GPS) offers an alternative to dead-reckoning, but it is limited to outdoor applications. Tracking mobile assets in indoor environments is a challenging task, especially for large open spaces such as airport terminals and museums. Among the emerging technologies, mobile devices and wireless technologies are widely recognized as solutions for identifying locations of mobile assets in such areas. However, the integration of these technologies into indoor building space has been limited. For example, one type of building space in which the integration has been particularly slow is a highly congested area with room partitions, metal structures, furnitures, and high traffic of people. Location tracking in such environment often has low valuation attributes, including reliability, security, and performance. In turn, the lack of these attributes has prevented high performance wireless networks from replacing traditional IT systems in critical applications. Critical applications