Method and apparatus for opening or closing a door by measuring the instantaneous voltage and current in an associated motor
US5838126A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 22, 1996 |
| Grant date | Nov 17, 1998 |
| Priority date | — |
| Expiry date | May 22, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B19/42
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A method of electronically controlling the opening and/or closing of a door by a DC motor. An instantaneous position of the door is determined. The voltage across the terminals of the DC motor or the current flowing through the windings of the motor is regulated as a function of the determined instantaneous position. The above two operating steps are repeated at a predetermined time intervals for controlling the displacement of the door. To determine the instantaneous position of the door, the instantaneous voltage across the terminals of the motor is measured, and the instantaneous current flowing through the windings of the motor is measured. The displacement of the door during the present time interval is computed as a function of the measured instantaneous voltage and current values and as a function of known and constant values for the back-emf and for the internal resistance of the motor. The computed displacement is added to the value of the instantaneous position as determined during the preceding time interval to obtain the determined instantaneous position of the door at the end of the present time interval.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.