Mechanical time constant method of identifying a bond axis in the two-inertia system

摘要

PURPOSE:To identify the mechanical time constant of a coupling shaft automatically by means of a simple software and an inexpensive hardware in a double inertia system wherein a motor and a load machine are coupled through a shaft. CONSTITUTION:A controller 100 delivers a torque command for a motor 4 so that a coupling shaft 7 vibrates and then the command is brought to zero thus bring about a free vibration state described by a motion formula represented by only the mechanical time constant and the rotational speed of the motor 4, a load machine 6 and the coupling shaft 7. A mechanical system 8 then performs predictive operation of model rotational speed corresponding to a rotational speed of motor detected at current sampling point under shaft vibration state based on a mechanical time constant of the coupling shaft 7 at the last sampling point identified according to the characteristic formula at that time and rotational speeds of motor detected at current, last and two times earlier sampling points. Mechanical time constant of the coupling shaft at current sampling point is then corrected and identified so that the difference between the model rotational speed and the detected rotational speed of motor will be zero.