Vehicle Lateral Acceleration Control for Autonomous Piloting

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Solution Overview

Problem

Current automatic piloting systems for vehicles do not adequately consider passenger comfort in terms of handling and physical interactions, particularly with regards to lateral acceleration, and often result in complex and costly solutions with drawbacks in terms of robustness and deviation from initial trajectories.

Innovation Solution

A method for automatically piloting a vehicle that calculates a steering angle setpoint and adjusts speed to maintain lateral acceleration below a maximum admissible value, using a sighting distance proportional to the vehicle's potential speed and adjusting this distance based on lateral acceleration and deviation from a reference trajectory, while ensuring passenger comfort and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a complex automatic piloting system with multiple sensors and algorithms is implemented, then the autonomous driving capability is improved, but the device complexity and cost increase

Engineering Contradiction:
Improveautonomous driving capabilityVSAvoidsystem complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent extracts and focuses on the essential function of lateral acceleration control for trajectory following, separating it from complex multi-sensor fusion systems. By using only steering angle and lateral acceleration measurements, the system achieves autonomous piloting with minimal sensors, directly resolving the contradiction between automation extent and device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The control system uses the vehicle's own lateral acceleration feedback to automatically adjust steering commands for trajectory following. The system serves itself by using its own dynamic response (lateral acceleration) as the primary control variable, eliminating the need for complex external sensor systems while maintaining autonomous capability

Inventive Principle:
Principle #25Self-service

2Productivity

If the vehicle speed is increased to improve productivity, then the travel time is reduced, but the lateral acceleration increases causing passenger discomfort

Engineering Contradiction:
Improvetravel timeVSAvoidpassenger comfort
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent implements dynamic speed adjustment based on real-time lateral acceleration feedback. The controller continuously adapts the speed setpoint to maintain lateral acceleration within comfortable limits while maximizing travel speed. This dynamic balancing act resolves the contradiction by making speed a variable rather than a fixed parameter

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses lateral acceleration feedback to continuously adjust the speed command. When lateral acceleration approaches uncomfortable levels, the system automatically reduces speed; when it's safe, the system increases speed. This closed-loop feedback mechanism directly resolves the contradiction between productivity and comfort

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If the sighting distance is increased to improve trajectory accuracy, then the trajectory following precision is improved, but the lateral acceleration increases beyond admissible values

Engineering Contradiction:
Improvetrajectory following precisionVSAvoidexcessive lateral acceleration
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent makes the sighting distance a dynamic parameter that adjusts based on current speed and lateral acceleration conditions. Rather than using a fixed long sighting distance, the system adaptively shortens or lengthens it to maintain both trajectory accuracy and comfortable lateral acceleration, resolving the contradiction between precision and comfort

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the sighting distance parameter in real-time based on operational conditions. By dynamically adjusting this key parameter along with speed, the controller achieves trajectory following precision without generating excessive lateral acceleration, directly resolving the identified contradiction

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3071461B1Method and device for automatically controlling a vehicle
Publication Date: 2017.12.06 RENAULT SA
  • EP3071461B1 patent drawingFigure 1
  • EP3071461B1 patent drawingFigure 2~3
  • EP3071461B1 patent drawingFigure 4

AI summary

A method for automatically controlling a vehicle includes giving a reference local path and a potential speed of the vehicle. The method also includes calculating a stirring angle automatic setpoint that makes it possible to calculate a lateral acceleration proportional to the square of the potential speed of the vehicle, making the vehicle describe an arc of a circle including a point of intersection with the reference local path at a distance from the vehicle. A speed setpoint is generated and set to a value equal to that of the potential speed when the lateral acceleration has a value lower than a maximum permissible lateral acceleration value and the value of the potential speed is decreased when the lateral acceleration has a value higher than or equal to the maximum permissible lateral acceleration value so as to calculate a reduced lateral acceleration by repeating the calculating.