Vehicle Acceleration Control with Dynamic Threshold Adjustment

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Solution Overview

Problem

Existing vehicle control systems face issues with inaccurate acceleration measurement due to sensor abnormalities, leading to potential deterioration of drivability and excessive or insufficient acceleration, which can cause driver anxiety and safety concerns.

Innovation Solution

The system adjusts the output reduction process by using detected values from acceleration and vehicle speed sensors, with a higher threshold during sensor abnormalities to prevent unnecessary acceleration limits and optimize output reduction based on road gradients, ensuring sufficient acceleration and improved drivability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the system uses acceleration sensor values to control output reduction, then acceleration control precision is improved, but measurement reliability deteriorates when sensor abnormalities occur

Engineering Contradiction:
Improveacceleration control precisionVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The threshold value for acceleration limitation is made dynamic rather than fixed. When sensor abnormalities are detected, the threshold value is automatically increased to a higher predetermined value. This dynamic adjustment allows the system to maintain accurate acceleration control under normal conditions while ensuring measurement reliability when sensor abnormalities occur.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter (threshold value) based on the operational state. Under normal conditions, a lower threshold value is used for precise acceleration control. When sensor abnormalities are detected, the threshold value is changed to a higher predetermined value, preventing inappropriate output reduction and ensuring reliable operation.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the threshold value is kept low for precise acceleration control, then acceleration precision is improved, but drivability deteriorates when sensor abnormalities cause false readings

Engineering Contradiction:
Improveacceleration precisionVSAvoiddrivability
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The threshold value is dynamically adjusted based on sensor status. During normal operation, a lower threshold provides precise acceleration control. When sensor abnormalities are detected, the threshold automatically increases to a higher predetermined value, preventing false acceleration limitations that would deteriorate drivability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system takes preliminary action by detecting sensor abnormalities and preemptively increasing the threshold value before false readings can cause drivability issues. This prevents the problem of insufficient acceleration due to false sensor readings rather than merely reacting to it.

Inventive Principle:
Principle #9Preliminary anti-action

3Measurement precision

If the system limits acceleration based on sensor readings, then acceleration control is improved, but drivability deteriorates when sensor abnormalities cause excessive limitation

Engineering Contradiction:
Improveacceleration controlVSAvoiddrivability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system changes the threshold parameter from a fixed low value to a higher predetermined value when sensor abnormalities are detected. This parameter change prevents excessive acceleration limitation that would occur with false sensor readings, thereby maintaining drivability reliability while preserving acceleration control precision during normal operation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2796696B1Apparatus for controlling vehicle
Publication Date: 2020.02.12 TOYOTA JIDOSHA KK
  • EP2796696B1 patent drawingFigure 1~2
  • EP2796696B1 patent drawingFigure 3~4
  • EP2796696B1 patent drawingFigure 5~6

AI summary

An electronic control unit (1) reduces output of an engine (6) using a detection value of an acceleration sensor (21) such that acceleration of a vehicle does not exceed a predetermined threshold value. In a case where there is an abnormality in the acceleration sensor (21), the electronic control unit (1) sets the acceleration threshold value to be greater than that in a case where there is no abnormality, and the electronic control unit limits the vehicle speed to a predetermined value or slower.