Vehicle Control Device Acceleration Stability
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Solution Overview
Problem
Existing vehicle control systems face issues with sudden deceleration during brake loss and excessive acceleration changes when transitioning from normal driving mode to automatic driving mode, leading to unstable vehicle control.
Innovation Solution
A vehicle control device with an acceleration/deceleration control unit that estimates vehicle acceleration based on the driving state before transitioning, prohibits feedback control until the acceleration deviation meets a threshold, and adjusts the driving force and braking force to ensure smooth mode switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If brake control is suppressed for a predetermined period of time from the time of returning, then excessive acceleration change is suppressed, but sudden deceleration may occur due to brake losing
Solution Approach 1:
The system performs preliminary action by setting a reference target driving force to zero at the time point of returning and changing the target driving force at a predetermined change rate before feedback control is reactivated. This preliminary adjustment of driving force prevents sudden deceleration while the brake control is suppressed, resolving the contradiction between acceleration stability and brake control reliability.
2Speed
If feedback control is immediately reactivated after returning to automatic driving mode, then control responsiveness is improved, but excessive acceleration change occurs
Solution Approach 1:
The system performs preliminary action by adjusting the target driving force at a predetermined change rate before reactivating feedback control. This preliminary adjustment ensures that when feedback control is reactivated, the acceleration change is already within acceptable limits, thus maintaining both control responsiveness and acceleration stability.
Solution Approach 2:
The system applies dynamics by making the feedback control status changeable from prohibited to permitted based on the differential acceleration threshold. This dynamic adjustment allows the system to balance responsiveness and stability by reactivating feedback control only when acceleration stability is ensured.
3Productivity
If the target driving force is changed rapidly after returning, then control efficiency is improved, but excessive acceleration change occurs
Solution Approach 1:
The system applies parameter changes by controlling the rate of change of target driving force to a predetermined change rate. This controlled parameter adjustment ensures that productivity is maintained while preventing excessive acceleration change, resolving the contradiction between control efficiency and acceleration stability.
Data Source
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AI summary
A vehicle control device (20) is configured such that if, during an automatic driving mode in which a vehicle (M) is automatically driven regardless of operations by a driver, such automatic driving mode is temporarily stopped by a prescribed operation by the driver and a normal driving mode in which the vehicle (M) is driven in accordance with the operations of the driver is entered, and thereafter the automatic driving mode is returned to from the normal driving mode, specific control is implemented in the post-return automatic driving mode, such control being determined on the basis of the driving state of the vehicle (M) during the normal driving mode before the return.