Feedback limiter for closed loop motor controller
US5821724A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 6, 1995 |
| Grant date | Oct 13, 1998 |
| Priority date | — |
| Expiry date | Nov 6, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/43021
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An apparatus and method are disclosed for controlling the motion of a machine system so as to cut individual lengths from a web having graphics on predetermined web positions and which allows the use of an inexpensive AC induction motor. An AC induction motor has an output power shaft for imparting the motive force necessary to drive the machine system, such as a web feeding system. A sensor is operatively coupled to the AC motor for determining the position of the motor during system operation. A controller is operatively connected to the sensor and motor and forms a closed loop control circuit. The controller changes the feedback loop characteristics of the closed loop control circuit during a stop, hold or start condition of the motor. By adding an externally generated compensating signal to the input of the feedback loop, the controller also minimizes acceleration error. The controller also limits the value of a signal reaching the feedback loop of the control circuit to a given maximum value so as to eliminate any over-reaction of the system, while allowing a signal having less than a given threshold value to proceed unaffected to the feedback loop.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.