Motorcycle Braking Torque Distribution for Lean Angle Stability

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Solution Overview

Problem

Two-wheeled vehicles, such as motorcycles, experience increased steering torque during braking when cornering or driving on an incline, which can lead to unstable driving conditions and reduced safety due to the uneven distribution of braking torque between the front and rear wheels.

Innovation Solution

A method to automatically adjust and distribute braking torques between the front and rear wheels to maintain a steering torque within predetermined limits, ensuring stability and safety by calculating and compensating for the steering torque based on the lean angle and tire contact point position, using sensors and control units to manage hydraulic brake pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the front wheel brake is actuated during cornering, then the desired braking torque is applied, but an unwanted steering torque arises that straightens the motorcycle and increases the curve radius

Engineering Contradiction:
Improvebraking torqueVSAvoidsteering stability
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The braking torque application is segmented between front and rear wheels. Instead of applying braking torque only at the front wheel, the system divides the braking action into front and rear components, allowing independent control of each wheel's braking contribution to achieve desired deceleration while minimizing unwanted steering effects.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically changes the distribution parameter of braking torque between front and rear wheels based on lean angle and steering conditions. By adjusting the proportion of braking torque applied at each wheel in real-time, the system optimizes the balance between achieving desired braking force and minimizing destabilizing steering torques.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the steering torque is reduced by adjusting brake distribution, then steering stability is improved, but the driver's desired braking torque may not be fully implemented

Engineering Contradiction:
Improvesteering stabilityVSAvoidbraking torque
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The system employs feedback control by continuously monitoring the actual steering torque generated during braking and comparing it against target values. Based on this feedback, the control unit adjusts the distribution of braking torque between front and rear wheels to maintain steering stability while ensuring the total braking torque meets the driver's demand.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system applies counteracting steering torques through strategic brake distribution. When front wheel braking generates unwanted straightening torque, the system compensates by adjusting rear wheel brake application to generate opposing torque, effectively canceling out the destabilizing effect while maintaining total braking force.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Adaptability or versatility

If the lateral distance between tire contact point and wheel vertical axis increases with lean angle, then cornering capability is improved, but the steering torque during braking increases

Engineering Contradiction:
Improvecornering capabilityVSAvoidsteering torque
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The braking torque distribution is made dynamic rather than fixed. The system continuously adapts the front-rear brake torque split based on real-time lean angle measurements, ensuring optimal performance across varying cornering conditions. This dynamic adjustment allows the system to maintain stability despite changing geometric relationships between tire contact point and wheel axis.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2616292B1Method for regulating braking torque in a two-wheeled vehicle when traveling at a lean angle
Publication Date: 2016.09.07 ROBERT BOSCH GMBH
  • EP2616292B1 patent drawingFigure 1~2
  • EP2616292B1 patent drawingFigure 3
  • EP2616292B1 patent drawing

AI summary

In a method for regulating braking torque in a two-wheeled vehicle when traveling at a lean angle, the rider sets a desired braking torque which is distributed to wheel braking torques on the front wheel and rear wheel respectively in such a way that a steering torque resulting from the wheel braking torques falls below a threshold value.