Kabushiki Kaisha Sg

Yuuji Matsuki

Yasuhiro Yuasa

Wataru Shimizu

A coil assembly including primary coils disposed at predetermined locations axially spaced from one another and secondary coils provided in association with these primary coils is fixed at one end of a fluid powered cyliner. A piston rod is slidably disposed through a space in the primary and secondary coils. Rings made of magnetic substance are provided on the piston rod with a predetermined axial interval therebetween. Each of the primary coils is excited with one of reference AC signals which are out of phase with one another and an output signal which is electrically phase-shifted in accordance with the position of the piston rod is obtained as a sum of output signals from the secondary coils. Piston rod position data is obtained by measuring the amount of the phase-shifting and is utilized for positioning control of the cylinder. The velocity and acceleration of the movement of the piston rod are detected on the basis of the detected position data and the amount of overrun is estimated in accordance with the detected velocity and acceleration to effect the most accurate positioning control. Each time the positioning is completed, the amount of overrun is corrected to improve the accuracy of a next positioning control.

Growing community of inventors

Tokyo, Japan

Yuuji Matsuki