Backup Wheel Speed Detection for Vehicle Stability Control

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Solution Overview

Problem

Electronic stability control systems in vehicles are limited by the reliability of wheel speed sensors, which can malfunction or provide inaccurate signals, leading to degraded or lost control functions during wheel speed sensor failures.

Innovation Solution

Utilizing electric motor speed signals as a backup to maintain antilock braking, traction control, and stability control functions by integrating them into the vehicle control system via the vehicle communication bus, ensuring continuous operation even when wheel speed sensors fail or operate abnormally.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wheel speed sensors are used to detect wheel speed for electronic stability control, then measurement precision is improved, but reliability deteriorates due to sensor malfunctions and signal loss

Engineering Contradiction:

Improvewheel speed measurement precisionVSAvoidwheel speed signal reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary computational method that processes multiple signal sources (wheel speed sensor signals and motor speed sensor signals) to determine wheel speed. When the primary wheel speed sensor signal is unavailable or abnormal, the system uses motor speed sensor signals as an intermediary substitute, combined with vehicle dynamics models, to calculate and provide continuous wheel speed information for stability control functions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes the parameter source for wheel speed measurement based on signal availability. It switches between using direct wheel speed sensor measurements and using calculated values derived from motor speed sensor signals and vehicle dynamics parameters. This parameter substitution ensures continuous operation of stability control functions even when primary sensors fail.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the electronic stability control system relies on wheel speed sensor signals, then measurement accuracy is improved, but the system turns off or degrades when sensors malfunction

Engineering Contradiction:

Improvewheel speed information accuracyVSAvoidsystem operation continuity under sensor failure

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic signal selection and switching mechanism that adapts the measurement system's operation based on real-time sensor health status. The system continuously monitors wheel speed sensor signal quality and dynamically switches between primary wheel speed sensor inputs and alternative motor speed sensor-based calculations, ensuring continuous adaptability and operation of stability control functions under varying sensor conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system prepares backup measurement pathways in advance by having motor speed sensor signals and vehicle dynamics models ready as pre-configured alternatives. When wheel speed sensor failures occur, these pre-prepared alternative signal sources and computational methods immediately take over, providing cushioning against system shutdown or degradation and maintaining continuous stability control operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Measurement precision

If wheel speed sensors are used for stability control, then control precision is improved, but loss of information occurs when sensors fail to provide signals

Engineering Contradiction:

Improvewheel speed detection precisionVSAvoidwheel speed information availability

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces the mechanical wheel speed sensor measurement system with an alternative computational approach using motor speed sensor data and vehicle dynamics models. When the mechanical wheel speed sensors fail, the system substitutes this information loss by calculating wheel speed from motor speed signals through mathematical relationships and vehicle dynamics equations, maintaining continuous availability of wheel speed information for control functions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10913449B2Vehicle electronic stability control system including back-up wheel speed detection

Publication Date: 2021.02.09 ROBERT BOSCH GMBH

AI summary

A vehicle control system includes a powertrain electronic control unit and an electronic stability control unit that is connected to the powertrain electronic control unit via a vehicle communication bus. The vehicle powertrain includes a wheel, a wheel speed sensor that is configured to detect a speed of the wheel, an electric motor that is configured to drive the wheel, and an electric motor speed sensor that is configured to detect the speed of the electric motor. If the wheel speed sensor is operating normally, the electronic stability control unit controls the vehicle based on an output of the wheel speed sensor. However, if the wheel speed sensor is not operating normally, the electronic stability control unit controls the vehicle based on an output of the electric motor speed sensor.