Method and apparatus for detecting friction coefficient of road surface, and method and system for four-wheel steering of vehicles using the detected friction coefficient of road surface
US5365439A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 5, 1991 |
| Grant date | Nov 15, 1994 |
| Priority date | — |
| Expiry date | Jul 5, 2011 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T2210/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for detecting a friction coefficient of the road surface includes a detection step of detecting an operating angle of the steering wheel of the vehicle, a vehicle speed and an operating pressure of the hydraulic power steering unit for the front wheels, and a calculation step of calculating the friction coefficient of the road surface on turning of the vehicle by considering relationships among a slip angle of the front wheel, the friction coefficient of the road surface and a cornering force of the front wheels. The method further includes a step of prohibiting the execution of the calculation step when the steering wheel is turned back, whereby the calculation step is executed only when the direction of the operating pressure of power steering unit is in the equiphase with the operating direction of the steering wheel. Also, a four-wheel steering system includes has a rear steering actuator for steering the rear wheels so as to increase the steering angle of the rear wheels as the friction coefficient of the road surface calculated by the above-described method decreases.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.