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Calibration of Mobile Robotic Systems: A Pilot Study
1  Department of Research and Development, Tactile Robotics Ltd, 100-135 Innovation Dr., Winnipeg, Manitoba, Canada R3T 6A8


Wheeled mobile robots (WMRs) are very interested for different applications from in-house activities in assisting elderly people and patients to space exploration. While the design concept and the application of the WMRs determine the shape, dimension, and specifications of the prototype robot, the positional errors occur during the operation of the WMR. In order to reduce the effect of positional errors, the motion of WMRs is corrected using calibration techniques. Calibration is defined as a set of operations that establishes, under specified conditions, the relationship between the values of quantities indicated by a measuring instrument and the corresponding values realized by standards. Example of calibration techniques employed to correct the WMRs movement are odometry, 3D camera error detection, active beacons, gyroscope and magnetic compasses. Each technique requires a set of sensory systems to measure the position, orientation, velocity, and/or acceleration of the robot. Odometry provides better short-term accuracy than other methods that allows very high sampling rates with lower costs. In addition, in odometry approach, fewer landmarks are needed to localize the WMR over its trajectory. This paper explains how the odometry technique was employed to improve motions of this robotic platform, and then reports technical results of an attempt to reduce positioning errors of a small WMR with a two-wheeled structure. The technique and instrumented setup could be used to alleviate the errors originating from imperfections in design, prototype, and assembly.

Keywords: Calibration, Sensory system, Positional error, Performance analysis