Vehicle Control Device for Automated Driving Stability
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Solution Overview
Problem
Existing automated driving systems face issues with engine and transmission synchronization due to time degradation, leading to engine racing and stalling, as they do not adequately account for changes in power characteristics and clutch slipping, especially in automated driving scenarios.
Innovation Solution
A vehicle control device that includes a target drive torque determination unit, a performance change information acquisition unit, and a target gear ratio correction unit, which senses changes in vehicle components and adjusts drive instructions to stabilize vehicle behavior by determining and correcting the target gear ratio based on acquired performance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automated driving control is implemented without correcting for transmission-side time degradation, then automation is achieved, but engine racing and stalling occur due to synchronization deviation
Solution Approach 1:
The system implements feedback control by continuously monitoring actual vehicle acceleration and comparing it with target acceleration. The acceleration deviation is used to calculate correction amounts that are applied to gear ratio commands, enabling the system to automatically compensate for transmission-side time degradation and maintain synchronization between engine and transmission during automated driving.
Solution Approach 2:
The system performs preliminary correction by calculating and applying gear ratio correction amounts before synchronization issues manifest. The correction is based on pre-stored acceleration characteristics and real-time deviation detection, allowing the system to proactively adjust gear timing and prevent engine racing or stalling before they occur.
2Reliability
If drive torque monitoring is performed at the motor-side only, then torque level difference is suppressed, but transmission-side time degradation is not detected
Solution Approach 1:
The system uses vehicle acceleration information, which is already being measured for automated driving control, for a dual purpose: both for position control and for detecting transmission-side time degradation. This multi-functional use of existing sensors allows the system to monitor transmission performance without adding dedicated sensors, while still capturing the degradation information needed for correction.
3Device complexity
If gear change control is performed without correcting for power characteristics change, then control simplicity is maintained, but vehicle behavior becomes unstable over time
Solution Approach 1:
The system dynamically adjusts gear ratio parameters based on detected transmission degradation. By changing the gear ratio command values according to the calculated correction amounts, the system compensates for power characteristics changes in the engine and transmission, maintaining stable vehicle behavior over time without requiring complete redesign of the control architecture.
Data Source
AI summary
The present invention realizes a vehicle control device that, even when power characteristics of a power generation device and a power transmission device changes, senses degradation of vehicle components, corrects a drive instruction to the power transmission device, and is thereby capable of stabilizing vehicle behavior over a long term. The present invention, in a predetermined vehicle environment state, measures fluctuation in drive power and acceleration in a transient region by using vehicle behavior sensors 4, performs comparison with a reference fluctuation, and thereby senses degradation of vehicle components. The drive instruction to the transmission 16-side is corrected in accordance with the degradation of vehicle components that is sensed. Thus, it is possible to stabilize vehicle behavior (performance) over a long term even when, during automated driving, the power characteristics of the drive power source and the transmission 16 change due to factors such as time degradation of vehicle components.