LKA Torque Integration with Electric Power Steering

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Solution Overview

Problem

Existing Lane Keeping Assist (LKA) systems for motor vehicles face safety concerns due to the lack of integration with electric power steering systems, leading to inadequate verification of torque values and potential steering anomalies, which can endanger passengers.

Innovation Solution

A method for correcting a motor vehicle's trajectory by detecting road markings, involving an inverse conversion step to process the correction actuator torque through the electric power-assisted steering system, ensuring safety barriers are maintained and allowing the LKA torque to predominate over driver torque during lack of vigilance, using a known torque conversion curve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the LKA system implements torque correction independently of the electric power steering system, then the LKA function can be activated, but safety barriers are compromised and additional verification steps are required

Engineering Contradiction:
ImproveLKA automationVSAvoidsteering safety
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The LKA torque correction is merged with the electric power steering system by integrating the torque conversion process. The LKA correction torque undergoes the same conversion process as driver torque, using the Boost Curve function and verification step, thereby combining two previously separate systems into one unified steering control system that maintains safety barriers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electric power steering control unit is given universal functionality to handle both driver torque and LKA correction torque through a single conversion process. The same Boost Curve function and verification step serve multiple purposes: amplifying driver torque, converting LKA correction torque, and verifying safety for both torque sources, eliminating the need for separate safety mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If the LKA correction torque is added to driver torque after conversion, then trajectory correction is achieved, but the system complexity increases and safety verification becomes more difficult

Engineering Contradiction:
Improvetrajectory correction efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The LKA correction torque undergoes conversion and safety verification in advance, before being combined with the driver torque. By applying the Boost Curve function and verification step to the LKA correction torque beforehand, the system simplifies the final combination process and ensures safety requirements are met before the torques are summed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of adding LKA correction to already-converted driver torque and then verifying safety, the system inverts the approach by converting and verifying the LKA correction torque separately first, then adding it to the driver torque. This reversal of the operation sequence simplifies the overall control logic and maintains safety barriers more effectively.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3458339B1Method for correcting the direction of travel of a motor vehicle by detecting road markings on the ground
Publication Date: 2020.08.19 RENAULT SA
  • EP3458339B1 patent drawingFigure 1~3
  • EP3458339B1 patent drawingFigure 4

AI summary

The invention concerns a method for correcting (1) the direction of travel of a motor vehicle by detecting road markings on the ground, comprising a reverse conversion step (12), converting a corrective actuator torque (Treq_machine) into a steering correction instruction (T LKA_Final), a step of providing (17) said steering correction instruction (T LKA_Fina l) to a control member (3) of the electric power steering system, and a processing step carried out by the power steering device, passing through the conversion step (14).