High speed positioning system considering unknown coulomb friction and windup phenomenon

In a conventional positioning system, when the position error becomes small, the motor cannot obtain enough deceleration torque. Hence, the position response becomes slow. There is also another positioning system that is to design a position reference from trapezoidal speed reference. This positioning system is valid when load torque and the final goal position are given. However, if the load torque and the final goal vary, its position response cannot have the desired response. In order to overcome these problems, this paper proposes a new high speed positioning system of AC servo motor considering unknown coulomb friction and windup phenomenon. The proposed always uses the maximum acceleration or deceleration torque and the maximum speed.