Improvement of travel distance at the outdoor environment by using IMU and encoder

This paper proposes a new algorithm for improving the estimation accuracy of travel distance of a mobile robot at the outdoor environment by estimating the slanted angle of road. When a mobile robot is movement on the flat surface, the travel distance can be estimated by the encoder values directly even though it includes some errors caused by the slippage and the disturbances. However, when the mobile robot is traveling on the irregular topography, the real travel distance of the mobile robot becomes less than the distance provided by the encoders. Using the gyroscopic sensor, the slope of the traveling road is estimated and that is utilized to estimate the planar distance from the origin which is a very important factor for the localization of the mobile robot on the a priori provided map, while the travel distance is measured by the encoders. The absolute motion of the mobile robot is recorded based upon the encoder data which is compensated for the slope angle which is measured by the IMU (Inertial Measurement Unit) sensor.