Lean Angle Determination via Axle Load for Motorcycle Stability

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Solution Overview

Problem

Existing methods for determining the lean angle of a two-wheeler, such as motorcycles, are not sufficiently accurate or simple, which hinders effective compensation of steering disturbance torques during braking, impacting driving safety.

Innovation Solution

The method calculates the lean angle based on the axle load of at least one wheel, using sensors to determine the axle load and incorporating additional factors like tire width, speed, and curve radius, allowing for precise determination and automatic adjustment of brake pressure to enhance driving stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a lean angle sensor is used to measure the lean angle directly, then the accuracy of lean angle measurement is improved, but the device complexity and cost increase

Engineering Contradiction:
Improvelean angle measurement accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/physical lean angle sensor with a calculation-based approach using acceleration sensors. The lean angle is derived from the relationship between lateral acceleration (ay) and vertical acceleration (az) according to the formula tan(α) = ay/az, eliminating the need for dedicated lean angle sensing hardware while maintaining measurement accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces acceleration sensors as intermediary devices that measure dynamic parameters (accelerations) which can then be processed to derive the lean angle. This intermediary approach allows indirect measurement of lean angle through readily available sensor data from the vehicle's dynamic response.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If existing methods calculate lean angle based on lateral and vertical acceleration, then the device complexity is reduced, but the measurement precision deteriorates due to insufficient accuracy

Engineering Contradiction:
Improvesensor system simplicityVSAvoidlean angle calculation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent incorporates feedback mechanisms by continuously monitoring acceleration data and dynamically calculating the lean angle in real-time. The system uses the relationship tan(α) = ay/az with continuous feedback from acceleration sensors to maintain accurate lean angle measurement throughout vehicle operation, adapting to changing driving conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the approach from direct physical measurement to mathematical parameter transformation. By utilizing the trigonometric relationship between acceleration components (tan(α) = ay/az), the system transforms readily measurable acceleration parameters into accurate lean angle information through parameter transformation rather than direct sensing.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If brake pressure is adjusted to compensate for steering disturbance torques during cornering braking, then driving safety is improved, but the control system complexity increases

Engineering Contradiction:
Improvedriving safety during cornering brakingVSAvoidbrake control system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic brake pressure adjustment based on real-time lean angle calculation. The brake control system dynamically modulates brake pressure on the front and/or rear wheel as a function of the calculated lean angle, allowing adaptive compensation for steering disturbance torques without requiring a complex pre-programmed control system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes brake control parameters (brake pressure) based on the calculated lean angle parameter. By using the lean angle as a control parameter to modulate brake pressure, the system achieves safety improvements through parameter-based control rather than complex mechanical or electronic control mechanisms.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides accurate lean angle measurement, enabling improved driving safety by reducing steering disturbances, detecting wheel slipping, and implementing load-dependent control strategies, including brake and traction control, and passive safety systems.

Implementation Method 1

The axle load is a force that acts as a result of centrifugal force and weight in the wheel plane

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

The axle load is a force that acts as a result of centrifugal force and weight in the wheel plane and is inclined by the lean angle relative to the vertical axis, which is directed parallel to the weight force vector

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP3253628B1Method for determining the roll angle of a two-wheeled vehicle
Publication Date: 2020.09.02 ROBERT BOSCH GMBH
  • EP3253628B1 patent drawingFigure 1~2
  • EP3253628B1 patent drawingFigure 3~4
  • EP3253628B1 patent drawing

AI summary

The invention relates to a method for determining the angle of inclination of a two-wheeled vehicle, wherein the axle load is determined at at least one wheel and the angle of inclination is calculated as a function of the axle load.