Method and circuit configuration for determining a frictional value

US5513907A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Uwe Kiencke · Ludwigsburg, DE
• Armin Daiss · Wenzenbach, DE
• Gregor Probst · Landshut, DE

Key dates

• Filing date: Jun 22, 1994
• Grant date: May 7, 1996
• Expiry date: Jun 22, 2014

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B60T2210/12
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A frictional value between a motor vehicle tire and a road surface is determined for use in an ABS system or a traction control system. Various sensors at the automobile ascertain the vehicle speed and the brake pressure at individual wheels. The angular acceleration of the wheel is calculated from the angular velocity thereof. A wheel slip is calculated from the vehicle speed and from the angular acceleration. The dependency of the coefficient of friction is approximated from the wheel slip with a non-linear approximation equation. The current estimation value for the coefficient of friction is estimated with a recursive estimation algorithm from measurement values previously ascertained during a preceding measuring instant.