# US 8,788,147 B2 · Method for determining a toothed rack force for a steering device in a vehicle

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- Number: US 8,788,147 B2
- Document ID: US8788147B2
- Status: Granted
- Kind: B2
- Application number: 13/317,281
- Filed: 2011-10-13
- Published: 2012-02-23
- Granted: 2014-07-22
- Earliest claimed: 2010-07-06
- Assignees: ZF Lenksysteme GmbH
- Applicants: Joerg Strecker; Thomas Werner
- Inventors: Joerg Strecker; Thomas Werner
- Web page: https://patentgrep.com/patent/US8788147B2

## CPC

- B62D 6/008: {Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications}
- B62D 5/0472: {for damping vibrations}
- G01L 5/221: {to steering wheels, e.g. for power assisted steering}
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)

## Abstract

Disclosed is a method for determining a toothed rack force on a steering device in a vehicle, wherein the toothed rack force (forZS) is determined as a function of a plurality of models, and wherein a component (forESM) of the toothed rack force (forZS) which relates to a driving process is generated by means of a first model, and a component of the toothed rack force (forZS) which relates to a parking process is generated by means of a second model.

## Claims

### Claim 1

A method for determining a toothed rack force representing force conditions at a front axle of a vehicle having a power steering system that includes a steering device and a control unit, the method comprising:
receiving at the control unit operating variables of the vehicle; and
determining by the control unit the toothed rack force (forZS) as a function of a plurality of models, wherein a component (forESM) of the toothed rack force (forZS) which relates to a driving process is generated by means of a first model, and a component of the toothed rack force (forZS) which relates to a parking process is generated by means of a second model; and
using the determined toothed rack force by the control unit in connection with a power steering system operation of the vehicle; and
wherein an adaptation is carried out as a function of at least one lateral force (fyADA), at least for the component (forESM) relating to a driving process; and
wherein the lateral force (fyADA) is found as a function of a modeled lateral force (fyMDL) that is found by means of a single-track model, an actual lateral force (fyFZG), and a slip angle (angSID).

### Claim 2 (depends on 1)

A method according to claim 1, wherein the actual lateral force (fyFZG) is determined by the control unit using the transverse vehicle acceleration (accLAT), the yaw velocity (anvYAW) and/or a yaw acceleration.