Vehicle Dynamics Control via Front Axle Braking Gradient

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Solution Overview

Problem

Existing methods for regulating vehicle driving dynamics to correct understeer are complex, requiring numerous parameters and significant computing power, and can compromise driving stability, especially on low friction surfaces.

Innovation Solution

A method that compares measured lateral dynamics variables with calculated ones using a vehicle model to determine understeer, allowing driver-independent braking force buildup on the front wheels, with the time gradient of braking force selected based on the difference, simplifying the control algorithm and reducing the need for complex calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If complex control algorithms with numerous parameters are used to regulate driving dynamics, then understeer correction capability is improved, but device complexity and computing power requirements increase

Engineering Contradiction:

Improveundersteer correction capabilityVSAvoidcontrol algorithm complexity

Core Design Contradiction:

Extent of automationVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the intermediate step of calculating target deceleration from the control algorithm. By directly comparing measured transverse dynamics variables with model-calculated variables and applying braking force based on the difference, the system achieves understeer correction without the complex multi-parameter calculations of prior art, reducing computational requirements while maintaining effectiveness

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of calculating target deceleration first and then deriving braking forces (traditional approach), the patent inverts the logic by directly using the difference between measured and calculated transverse dynamics variables to determine braking force requirements. This inversion simplifies the control logic and reduces the number of parameters that must be adapted

Inventive Principle:

Principle #13The other way round (Inversion)

2Extent of automation

If complex control algorithms with numerous parameters are used to regulate driving dynamics, then understeer correction capability is improved, but computing power requirements increase

Engineering Contradiction:

Improveundersteer correction capabilityVSAvoidcomputing power consumption

Core Design Contradiction:

Extent of automationVSUse of energy by moving object

Solution Approach 1:

The patent removes the computationally intensive target deceleration calculation step from the control algorithm. By directly comparing transverse dynamics variables and applying proportional braking force, the system maintains understeer correction capability while significantly reducing the computing power required, allowing cheaper microcontrollers to be used

Inventive Principle:

Principle #2Taking out (Extraction)

3Extent of automation

If braking interventions are applied on the rear axle to correct understeer, then understeer correction is achieved, but driving stability is compromised on low friction surfaces

Engineering Contradiction:

Improveundersteer correction capabilityVSAvoiddriving stability

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

The patent applies braking force locally and selectively on the front axle wheels rather than distributing it to the rear axle. This localized intervention on the front axle achieves understeer correction while maintaining better driving stability on low friction surfaces, as front axle braking provides more predictable and controllable correction without compromising rear axle traction

Inventive Principle:

Principle #3Local quality

4Ease of manufacture

If target deceleration calculation is included in the control algorithm, then braking force distribution is optimized, but the number of parameters requiring adaptation increases

Engineering Contradiction:

Improvebraking force distribution optimizationVSAvoidparameter adaptation requirements

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent extracts and eliminates the target deceleration calculation from the control algorithm. By directly using the difference between measured and calculated transverse dynamics variables to determine braking force, the system achieves effective understeer correction with fewer parameters that require adaptation to different vehicle types, simplifying the application process

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the control parameter from target deceleration (which requires complex calculation and multiple adaptation parameters) to direct transverse dynamics variable difference. This parameter change simplifies the adaptation process while maintaining the ability to optimize braking force distribution for understeer correction

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP2928737B1Vehicle movement dynamics control method

Publication Date: 2019.01.09 CONTINENTAL TEVES AG & CO OHG

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AI summary

The invention relates to a method for controlling the movement dynamics of a motor vehicle, in which a measured transverse dynamics variable is compared with a transverse dynamics variable which is calculated on the basis of a vehicle model, wherein it is checked whether the vehicle is understeering, and in this case the difference between the measured and the calculated transverse dynamics variables is reduced by increasing braking forces at the wheels of at least the front axle independently of the driver. According to the invention, the time gradient of the braking force at each wheel at which a braking force is increased is selected in accordance with the difference between the measured and calculated transverse dynamics variables. In addition, the invention relates to a brake system for a motor vehicle.