Measurements of Transient Driving Forces Generated by a Linear Motor and a Ball Screw Mechanism, and Comparisons to Those Static Characteristics

Abstract

Transient driving forces generated by a linear motor and a ball screw mechanism including a rotational servomotor were measured and compared to those static characteristics. The static relationships between the motor currents and the output force (torque) were linear. In the linear motor drive system, the step response of the driving force was 1/10 slower than that of the motor current. In the rotational servomotor, the torque response was oscillatory with 800Hz frequency and 0.01 damping ratio. In the ball screw drive mechanism, the driving force response was deeply depended to the preload force and was 1/100 slower than that the motor current. It is noted that the ball screw mechanism generated the driving force after the servomotor rotated. These dynamics should be considered in a usual position control design.