Robust speed control of a stepping motor drive using fuzzy logic

Originally, stepping motors were mainly used for simple point-to-point positioning tasks. Nowadays, thanks to advances made in power electronics and in data processing, they are widely used in robotics and in numerical control of machines where they have to perform high-precision synchronised movements. But the variations of the mechanical configuration of the drive which are common for these two applications can lead to step losses. Moreover an open loop speed control is insufficient and a closed loop control is required. In this paper, we propose to apply fuzzy logic theory to control the speed of a stepping motor drive. An advanced test bed is used in order to test the dynamical properties and the robustness capacities of,the fuzzy logic controller when variations of mechanical configuration occur.