Feedback and servo control for electric power steering system with hydraulic transmission
US6152254A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 26, 1998 |
| Grant date | Nov 28, 2000 |
| Priority date | — |
| Expiry date | Oct 26, 2018 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB62D5/065
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A vehicle power steering system 10 achieves a substantially linear control relationship between an applied steering torque input T.sub.s and a resulting steering force output, that is, a powered assist to vehicle steering. The system 10 includes a reversible fluid pump 24 driven by an electric motor 26. A pair of fluid lines 20 and 22 supply pressurized fluid from the pump 24 and to the left and right ports 56 and 58 of a power cylinder 18. A pair of pressure transducers 54 and 55 sense the fluid pressures LP.sub.p and RP.sub.p in the lines 20 and 22. The pressure transducers 54 and 55 are connected to an electronic control 32 which establishes an internal closed servo control loop 322 or 342 over the powered assist to vehicle steering provided by the power cylinder 18, for example, over actuation of the motor 26. The system 10 is preferably regenerative and includes a variety of safety features which prevent system runaway and allow unencumbered manual steering in case of failure of the system. The system 10 is also arranged for continuous rejuvenation of its hydraulic fluid, and the structure providing such rejuvenation can be employed in a wide variety of other systems. The elec…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.