Minimizing electromechanical oscillations in the drives with resilient couplings by means of state and disturbance observers

The paper presents the principles of estimating nonmeasurable state variables and external torque load in drives with an elastic motor shaft (two mass system). In many drive systems, resilient couplings between the motor and processing machine, caused by elastic shafts and gears, are often unavoidable. General rules of state and disturbance observers design are given. They have been applied to a drive system with an elastic shaft. Only the possibility of electromechanic torque generated by the motor and the speed of motor shaft measurements are discussed. Schematic diagrams of a drive system with an elastic shaft and appropriate diagrams of state and disturbance (i.e. external torque load) observers are shown. The proposed observer could be used for correcting drive control to minimize electromechanical oscillations in a variable speed drive system, which are caused by the elasticity of a mechanical connection