Control systems
US4257311A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 29, 1979 |
| Grant date | Mar 24, 1981 |
| Priority date | — |
| Expiry date | May 29, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05D1/0077
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A hydraulic control system has two fluid supply circuits which control fluid pressure supplied to respective chambers of a fluid-controlled actuator, each chamber having an individual piston mounted on a common actuator rod. In normal operation, a major part of the pressure is supplied to the actuator by the first circuit in accordance with control signals derived from an external source. The second circuit supplies pressure to its respective chamber at a lower level in accordance with control signals derived from the differential pressure across the piston in that chamber, the pressure supplied by the second circuit acting to reduce the differential pressure across the piston. The system also includes a control unit that responds to malfunction of the first circuit or error in the control signals supplied to the first circuit, by disconnecting the first control circuit from control of the actuator, such as by equalizing pressure across the piston in the first chamber. Upon detection of a malfunction or error, the control unit also supplies to the second circuit, instead of the signals derived from the differential pressure, control signals nominally-identical to the control signal…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.