Aircraft Brake System Backup Mode Slip Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Aircraft brake systems face challenges in conserving energy stored in hydraulic accumulators during backup mode operations, as excessive use of antiskid control can deplete the limited energy reserves, while omitting antiskid control may lead to skidding issues on slippery surfaces.

Innovation Solution

A brake system that includes an energy storage device, processors, and a memory to determine when it's operating in backup mode, applying a first brake pressure command to an observer wheel, monitoring wheel speed, and adjusting brake pressure based on a target slip value offset from the ideal slip value to reduce braking efficiency and conserve energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If antiskid control is provided during backup mode operation, then skid protection is improved, but energy consumption from the accumulator increases

Engineering Contradiction:

Improveskid protectionVSAvoidenergy consumption from accumulator

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system applies partial antiskid control during backup mode by using a target slip value offset from the ideal slip value. This provides limited skid protection when needed while avoiding excessive brake pressure applications that would deplete the accumulator energy reserves too quickly.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system changes the slip control parameter from the ideal slip value to a target slip value that is offset during backup mode operation. This parameter adjustment reduces the braking efficiency slightly but conserves energy in the accumulator while still providing skid protection.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If antiskid control is omitted during backup mode operation, then energy consumption from the accumulator is reduced, but skid protection capability deteriorates

Engineering Contradiction:

Improveenergy consumption from accumulatorVSAvoidskid protection

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

Rather than completely omitting antiskid control, the system provides partial antiskid control by using an offset target slip value. This maintains some skid protection capability while significantly reducing energy consumption compared to full antiskid control operation.

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If full braking efficiency is maintained during backup mode, then stopping performance is improved, but accumulator energy is depleted faster

Engineering Contradiction:

Improvestopping performanceVSAvoidaccumulator operational capacity

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

The system changes the slip control parameter from ideal to offset target slip value during backup mode, which reduces braking efficiency slightly but extends the duration of accumulator operation by conserving energy reserves.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system accepts partial reduction in braking efficiency during backup mode to preserve accumulator energy, ensuring the system can continue to operate for more brake applications rather than depleting energy reserves quickly.

Inventive Principle:

Principle #16Partial or excessive 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 system effectively conserves energy by reducing braking efficiency on remaining wheels, ensuring safe stopping while minimizing energy consumption from the accumulator, thus extending its operational capacity.

Implementation Method 1

Hydraulic aircraft brake systems include an accumulator that stores hydraulic braking fluid under pressure

Methodology Applied

Scientific EffectHydraulic pressure storage: Hydraulic Accumulator

Implementation Method 2

Aircraft brakes are used to slow the aircraft down during landing roll along a runway

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS11505311B2Brake system providing limited antiskid control during a backup mode of operation

Publication Date: 2022.11.22 THE BOEING CO

AI summary

A brake system for a vehicle is disclosed and includes an energy storage device configured to store and discharge energy, a plurality of wheels having an observer wheel, one or more processors operatively coupled to the energy storage device, and a memory coupled to the one or more processors. The memory stores data comprising a database and program code that, when executed by the one or more processors, causes the brake system to determine the brake system is operating in a backup mode of operation. In response to determining the brake system is operating in the backup mode of operation, the brake system is caused to apply a first brake pressure command to the observer wheel. In response to determining the observer wheel is starting the skid condition, the brake system is caused to determine a second brake pressure command based on a target slip value.