Sub-step Infrared Range Estimation For A Mobile Robot
Yusuke Fujii, David K. Wehe, Terry E. Weymouth · 2005
The infrared (IR) range sensors currently mounted on a mobile pllatform in the Mobile Robot Laboratory at the University of Michigan have a limited range resolution due to their 4 bit analog-to- digital converter (ADC). However, it is possible to obtain better resolution without changing the current hardware configuration by using knowledge about the robot's motion. This paper presents the algorithm for IR range estimation with sub-step accuracy. As the robot moves, a transition monitor detects the instance that a trimmed mean of the IR sensor outputs changes from one ADC step to another and evaluates the importance of the data depending on the type of transition. The information from the transition monitor is integrated recursively in time with the displacement information from an encoder to give the qub-step accuracy in the range estimates. Our algorithm also provides an improved range estimate error bound which is useful in sensor fusion and other applications. Details of the transition monitor are described in this paper, and experimental results which demonstrated a successful implementation of the algorithm are presented. The idea behind the algorithm can be applied to other sensor modalities having resolution primarily limited by a digitization device.