Non-saturating airspeed/attitude controls
US4385356A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1981 |
| Grant date | May 24, 1983 |
| Priority date | — |
| Expiry date | Mar 30, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05D1/0858
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
In a helicopter automatic flight control system having both automatic pitch attitude retention (70, 71) and automatic airspeed hold (84) and responsive both to pitch attitude error (206) and integrated (241) airspeed error (230), saturation of either the attitude error or integrated airspeed error circuitry is avoided by sensing (171) integrated airspeed error buildup to a threshold magnitude (which may be a significant fraction of the instantaneous authority of the automatic flight control system), and causing (169, 167) automatic slewing of the pitch attitude reference signal toward the current pitch attitude and reduction of the integrated airspeed error. In a disclosed embodiment, the correction of attitude reference and reduction of airspeed error is effected by utilizing an equal effective time constant (220, 221; 258, 259) for both actions over the same period of time (170, 168, 175).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.