Vehicle Torque Control Friction-Based Limiting

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Solution Overview

Problem

Existing vehicle stabilization control systems, such as traction control and anti-lock braking systems, often react too late and with high intensity, leading to increased load on the vehicle's electrical system and reduced driver comfort due to excessive control interventions.

Innovation Solution

A method and device that determine a coefficient of friction using internal vehicle variables and additional sensors, allowing for precontrol of torque limitations within the control loop to reduce the intensity of control interventions by setting a limit value based on the coefficient of friction, thereby enabling earlier and more gentle system activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the control system reacts only when stability limits are exceeded, then the control system activates only when necessary, but the control intervention occurs too late with high intensity

Engineering Contradiction:
Improvecontrol response timeVSAvoiddriver comfort
Core Design Contradiction:
Loss of timeVSEase of operation

Solution Approach 1:

The control system performs preliminary action by determining a coefficient of friction and setting a limit value for torque before the stability limit is exceeded. This precontrol enables the system to intervene earlier and more gently, avoiding late high-intensity corrections that compromise driver comfort.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the control system uses high intensity interventions to stabilize the vehicle, then vehicle stability is achieved, but the load on the electrical system and components increases

Engineering Contradiction:
Improvevehicle stabilityVSAvoidelectrical system load
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control system changes parameters by determining a coefficient of friction and using it to set a dynamic limit value for torque. This parameter-based precontrol allows the system to apply gentler, more appropriate torque limitations that maintain vehicle stability while reducing the load on the electrical system and components.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the control system intervenes frequently to maintain stability, then vehicle stability is maintained, but driver comfort is reduced due to excessive interventions

Engineering Contradiction:
Improvevehicle stabilityVSAvoiddriver comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

By determining the coefficient of friction and setting the limit value in advance, the control system prevents the need for frequent high-intensity interventions. The precontrol creates a buffer that allows the vehicle to operate closer to stability limits without requiring constant corrective action, thereby maintaining stability while improving driver comfort.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2327596B1Limitation of the torque of a friction coefficient based vehicle control loop
Publication Date: 2016.04.27 BAYERISCHE MOTOREN WERKE AG
  • EP2327596B1 patent drawingFigure 1~3
  • EP2327596B1 patent drawingFigure 2
  • EP2327596B1 patent drawingFigure 4

AI summary

One aspect of the invention relates to a method for limiting a torque or a characteristic parameter thereof in a control loop used to stabilize a vehicle. According to the method, a coefficient of friction is determined. Preferably, the coefficient of friction is estimated using vehicle-internal parameters. Depending on the coefficient of friction, a limit value for the torque or characteristic parameter thereof is determined. The torque or characteristic parameter thereof is then limited to this limit value.