A fuzzy obstacle avoidance controller using a lookup-table sharing method and its applications for mobile robots

A Lookup-Table (LUT) based design enhances the processing speed of a fuzzy obstacle avoidance controller by reducing the operation time. Also, a LUT sharing method provides efficient ways of reducing the LUT memory size. In order to share the LUT which is used for a fuzzy obstacle avoidance controller, an idea of using a basis function is developed. As applications of the shared LUT-based fuzzy controller, a laser-sensor-based fuzzy controller and an ultrasonic-sensor-based fuzzy controller are introduced in this paper. This paper suggests a LUT sharing method that reduces the LUT buffer size without a significant degradation of the performance. The LUT sharing method makes the buffer size independent of the fuzzy system's complexity. A simulation using MSRDS (Microsoft Robotics Developer Studio) is used to evaluate the proposed method. To investigate the performance of the controller, experiments are carried out using a Pioneer P3-DX with LabVIEW as an integration tool. Although the simulation and experiments show little difference between the fully valued LUT-based method and the LUT sharing method in terms of the operation time, the LUT sharing method reduces almost 95% of the full-valued LUT-based buffer size.