Positioning control system for a fluid powered cylinder
US4804913A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1987 |
| Grant date | Feb 14, 1989 |
| Priority date | — |
| Expiry date | Oct 29, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/43115
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
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 t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.