Steering Power Backup Control Before Vehicle Travel Enable

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Solution Overview

Problem

In steer-by-wire steering systems, the challenge is ensuring reliable electric power supply to steering actuators when the vehicle battery is not sufficiently charged, which can lead to inadequate power transmission and potential vehicle operation failures.

Innovation Solution

A steering control device that incorporates an auxiliary power source to back up the main power source, with a controller that ensures the auxiliary power source is charged to a sufficient level before allowing vehicle travel, and includes a monitoring circuit to determine the charge state of the auxiliary power source, thereby preventing vehicle operation when the backup is insufficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the vehicle is permitted to travel immediately after activation, then the ease of operation is improved, but the reliability deteriorates because the auxiliary power source may not be charged sufficiently to back up the main power source

Engineering Contradiction:
Improveease of operationVSAvoidreliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary charging of the auxiliary power source before permitting vehicle travel. The controller monitors the charge state and only allows travel when the auxiliary power source reaches a predetermined charge level, ensuring backup capability is established in advance.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the auxiliary power source is charged before permitting travel, then the reliability is improved, but the loss of time increases due to waiting for sufficient charge accumulation

Engineering Contradiction:
ImprovereliabilityVSAvoidloss of time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system uses periodic charging cycles during vehicle operation to accumulate energy in the auxiliary power source. The controller manages charge/discharge cycles based on main power source availability, allowing the system to prepare backup capacity during normal operation without delaying initial vehicle startup.

Inventive Principle:
Principle #19Periodic action

3Reliability

If the main power source is used to charge the auxiliary power source, then the reliability is improved, but the use of energy by the main power source increases

Engineering Contradiction:
ImprovereliabilityVSAvoiduse of energy by main power source
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system maintains continuous operation of the main power source to simultaneously supply vehicle loads and charge the auxiliary power source. This continuous useful action ensures the main power source remains active and the auxiliary source accumulates backup capacity without interrupting vehicle operation.

Inventive Principle:
Principle #20Continuity of useful action

4Reliability

If the vehicle is prevented from traveling when auxiliary power source charge is insufficient, then the reliability is improved, but the productivity deteriorates due to delayed vehicle operation

Engineering Contradiction:
ImprovereliabilityVSAvoidproductivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary charging during vehicle activation and idle periods before travel is required. By establishing backup capacity in advance during non-productive periods, the system ensures rapid response capability when travel is needed without compromising productivity.

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

Ensures reliable operation of the steering system by preventing vehicle travel until the auxiliary power source can support the main power source, reducing power consumption and maintaining system reliability.

Implementation Method 1

an auxiliary power source that backs up the main power source

Methodology Applied
Scientific EffectBattery (electricity): Battery (electricity)

Implementation Method 2

the main power source is configured to be charged with electric power generated by an in-vehicle generator

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4173868B1Steering control device, vehicle power source system, and vehicle
Publication Date: 2025.10.15 JTEKT CORP
  • EP4173868B1 patent drawingFigure 1
  • EP4173868B1 patent drawingFigure 2
  • EP4173868B1 patent drawingFigure 3

AI summary

The present invention relates to a steering control device (50) including a controller configured to control driving of a motor (41) that generates a torque. The torque is a torque applied to a steering mechanism (12, 14) of a vehicle using electric power from at least any one of an in-vehicle main power source (71) and an auxiliary power source (70A) that backs up the main power source (71). The controller is configured to wait (S302) for the auxiliary power source (70A) to be charged to an extent that the main power source (71) is able to be backed up and to permit (S103) the vehicle to travel when the controller is activated with an activation operation for the vehicle as a trigger and transitions to a state where control of the motor is executable. The invention further relates to a corresponding power source system and vehicle.