James, Kurian; Saseendran Pillai, P R(December 8, 2008)
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Abstract:
This paper introduces a simple and efficient method
and its implementation in an FPGA for reducing the odometric
localization errors caused by over count readings of an
optical encoder based odometric system in a mobile robot
due to wheel-slippage and terrain irregularities. The detection
and correction is based on redundant encoder measurements.
The method suggested relies on the fact that the
wheel slippage or terrain irregularities cause more count
readings from the encoder than what corresponds to the
actual distance travelled by the vehicle. The standard quadrature
technique is used to obtain four counts in each encoder
period. In this work a three-wheeled mobile robot
vehicle with one driving-steering wheel and two-fixed rear
wheels in-axis, fitted with incremental optical encoders is
considered. The CORDIC algorithm has been used for the
computation of sine and cosine terms in the update equations.
The results presented demonstrate the effectiveness
of the technique
Description:
Journal of Automation, Mobile Robotics & Intelligent Systems VOLUME 3, No 3 2009