Sequential Brake Actuation for Motorcycle Pitching Control

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Solution Overview

Problem

Automatic brake devices for saddle riding vehicles, such as motorcycles, often cause unintended disturbances to the driver during automatic brake control, as they do not adequately consider the suppression of driver attitude and the independent control of front and rear brakes.

Innovation Solution

A saddle riding vehicle equipped with an automatic brake device featuring independently actuable front and rear brakes, a brake modulator that includes collision possibility determining means, automatic brake control means, and brake operation determining means, which prioritizes rear wheel braking initially and then engages front wheel braking to minimize vehicle pitching and maximize braking force, utilizing a braking force map and friction coefficient estimation for optimal control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If automatic brake control simultaneously actuates both front and rear brakes, then braking efficiency is improved, but vehicle pitching increases causing driver attitude disturbance

Engineering Contradiction:
Improvebraking efficiencyVSAvoiddriver attitude disturbance
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary action by first actuating the rear brake to generate rear wheel braking force before actuating the front brake. This sequential approach allows the vehicle to begin decelerating through rear brake application, establishing a controlled deceleration profile that minimizes sudden pitching motions that would disturb driver attitude.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The brake control system is segmented into distinct front and rear brake control channels with independent actuation timing. The control device separates the braking function into two phases: first rear brake only, then front brake addition, allowing optimized control of each brake component to achieve both efficiency and comfort.

Inventive Principle:
Principle #1Segmentation

2Force

If rear brake is actuated to lock limit, then maximum rear brake force is achieved, but risk of wheel lock and loss of control increases

Engineering Contradiction:
Improverear brake forceVSAvoidvehicle controllability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The control device continuously monitors wheel speed and braking force parameters to detect approaching wheel lock conditions. Based on this feedback, the system dynamically adjusts rear brake force to maintain optimal braking pressure without exceeding the threshold that would cause wheel lock, thereby preserving vehicle controllability while maximizing braking effectiveness.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The rear brake actuation is dynamically controlled rather than statically fixed at lock limit. The system adapts rear brake force in real-time based on vehicle speed, road conditions, and wheel rotation state, allowing the brake force to vary between maximum effective braking and controlled reduction to prevent wheel lock.

Inventive Principle:
Principle #15Dynamics

3Loss of time

If front brake is actuated first, then braking response time is reduced, but vehicle stability and driver comfort deteriorate

Engineering Contradiction:
Improvebraking response timeVSAvoidvehicle stability
Core Design Contradiction:
Loss of timeVSStability of the object's composition

Solution Approach 1:

The system performs preliminary deceleration action through rear brake actuation before engaging the front brake. This initial rear brake application establishes a controlled deceleration phase that maintains vehicle stability and driver comfort, with the front brake subsequently providing additional braking force without causing sudden pitching.

Inventive Principle:
Principle #10Preliminary action

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

The solution effectively suppresses driver attitude disturbances by prioritizing rear wheel braking at the start of automatic braking, reducing vehicle pitching and providing a clear deceleration feeling, while allowing for maximum utilization of rear brake force and easy control through a braking force map, and adapting to road surface friction conditions.

Implementation Method 1

first actuates only the rear brake (3) to generate a rear wheel braking force

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

then also actuates the front brake (2) to generate a front wheel braking force

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3124369B1Automatic brake device for saddle riding type vehicle
Publication Date: 2019.07.31 HONDA MOTOR CO LTD
  • EP3124369B1 patent drawingFigure 1
  • EP3124369B1 patent drawingFigure 2
  • EP3124369B1 patent drawingFigure 3~4

AI summary

Object To suppress an unintended disturbance of the attitude of a driver at a time of automatic brake control in an automatic brake device for a saddle riding type vehicle. Solving Means A brake modulator 10 that controls actuation of front and rear brakes 2 and 3 includes a collision possibility determining unit 19, an automatic brake control unit 21, and a brake operation determining unit 20. When the collision possibility determining unit 19 determines that there is a possibility of collision, and the brake operation determining unit 20 determines that brake operation by a driver is absent, the automatic brake control unit 21 first actuates only the rear brake 3 to generate a rear wheel braking force, and then also actuates the front brake 2 to generate a front wheel braking force.