Motorcycle Suspension Control During Automatic Braking

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Solution Overview

Problem

Existing straddled vehicle systems that automatically adjust braking based on inter-vehicle distance from a preceding vehicle often compromise riding comfort due to sudden changes in suspension stiffness before and after braking, leading to reduced comfort and increased pitching.

Innovation Solution

A straddled vehicle equipped with an electronically controlled suspension and a control device that adjusts damping forces and spring reaction forces of the front and rear suspensions in real-time based on detected inter-vehicle distance and braking force, minimizing stiffness changes and maintaining comfort during automatic braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If suspension characteristics are adjusted before brake actuation to suppress pitching, then vehicle posture stability is improved, but riding comfort is reduced

Engineering Contradiction:
Improvevehicle posture stabilityVSAvoidriding comfort
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The suspension characteristics are adjusted in advance before brake actuation occurs. The control device predicts or detects upcoming braking based on brake fluid pressure changes or other indicators, and proactively modifies suspension stiffness to prepare for the braking event, thereby suppressing pitching while maintaining comfort during normal riding

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The suspension system dynamically adjusts its characteristics in real-time based on the braking state. The control device continuously monitors brake fluid pressure and suspension position, and modulates damping forces and spring reaction forces to adapt suspension stiffness to the current operating condition, balancing comfort and stability

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If suspension characteristics are adjusted after brake actuation to suppress pitching, then vehicle posture stability is improved, but riding comfort is reduced

Engineering Contradiction:
Improvevehicle posture stabilityVSAvoidriding comfort
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The control device implements a feedback control mechanism that continuously monitors brake fluid pressure, suspension position, and vehicle posture. Based on this feedback, the suspension characteristics are adjusted in real-time during and after braking to suppress pitching while minimizing impact on riding comfort through precise, responsive control

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If damping force and spring reaction force are increased to suppress pitching, then vehicle posture stability is improved, but suspension stiffness increases reducing comfort

Engineering Contradiction:
Improvevehicle posture stabilityVSAvoidriding comfort
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The control device adjusts suspension characteristics differently for front and rear suspensions based on their specific roles. The front suspension damping force in contraction direction and spring reaction force are increased to suppress front-down posture, while the rear suspension damping force in expansion direction and spring reaction force are adjusted to coordinate with front suspension, creating localized optimization that balances overall vehicle stability with riding comfort

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4365040A1Straddled vehicle
Publication Date: 2024.05.08 YAMAHA MOTOR CO LTD
  • EP4365040A1 patent drawingFigure 1
  • EP4365040A1 patent drawingFigure 2
  • EP4365040A1 patent drawingFigure 3

AI summary

There is disclosed a straddle vehicle that automatically actuates a brake, based on an inter-vehicle distance from a preceding vehicle, reduction in riding comfort due to brake actuation is suppressed; wherein a control device (60) of a motorcycle (1) includes a brake controller (62) that controls a front wheel brake (8B) and a rear wheel brake 9B, based on an inter-vehicle distance from a preceding vehicle detected by a radar (22); the control device (60) including a suspension controller (63) that, after actuation of the front wheel brake (8B) and/or the rear wheel brake 9B is started by the brake controller (62), performs at least one of increasing a damping force of a front fork (20) in a contraction direction, increasing a spring reaction force of the front fork (20), increasing a damping force of a rear suspension (30) in an expansion direction, and reducing a spring reaction force of the rear suspension (30).