Vehicle Headway Control via Accelerator Reaction Force
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Solution Overview
Problem
Conventional vehicle headway maintenance assist systems fail to effectively control deceleration when the driver operates the accelerator, leading to limitations in maintaining a prescribed headway distance from a preceding vehicle.
Innovation Solution
A vehicle headway maintenance assist system that includes a headway distance detection section, an accelerator actuation detection section, a deceleration control section, and a reaction force control section, which performs deceleration control when the accelerator is not operated and applies a reaction force to the accelerator when it is operated, using calculated steady-state and transient terms to set appropriate headway distance thresholds and target deceleration rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If deceleration control is performed only when the accelerator is not operated, then the control system is simple to operate, but the headway distance maintenance is unreliable when the driver operates the accelerator
Solution Approach 1:
The control system is segmented into two independent control paths: one for when the accelerator is not operated (deceleration control active) and one for when the accelerator is operated (reaction force control active). This segmentation allows each control mode to be optimized independently, resolving the contradiction between ease of operation and reliability.
Solution Approach 2:
The system dynamically switches between different control modes based on accelerator operation status. When the accelerator is not operated, deceleration control is applied; when the accelerator is operated, reaction force control is applied. This dynamic adaptation ensures both ease of operation and reliability under different driving conditions.
2Adaptability or versatility
If deceleration control is canceled when the accelerator is operated, then the accelerator operation is unrestricted, but the headway distance cannot be maintained when the driver accelerates
Solution Approach 1:
A reaction force is applied to the accelerator pedal as an intermediary mechanism. This reaction force gently pushes back on the accelerator when the driver operates it during critical headway situations, providing subtle guidance without completely restricting driver input. This allows the system to maintain headway distance reliably while still adapting to driver intentions.
Solution Approach 2:
The system applies a preliminary counteracting reaction force to the accelerator pedal before the headway distance becomes critically small. This preliminary anti-action prevents the harmful outcome (collision) by subtly influencing driver behavior in advance, rather than waiting for the problem to fully develop.
3Device complexity
If the headway distance threshold is fixed, then the control logic is simple, but the system cannot adapt to varying deceleration conditions of the preceding vehicle
Solution Approach 1:
The headway distance threshold is made dynamic rather than fixed. The threshold automatically adjusts based on the detected deceleration state of the preceding vehicle. When the preceding vehicle is decelerating, the threshold increases to account for the reduced speed gap, allowing the system to adapt to varying conditions without complex manual intervention.
Solution Approach 2:
The system continuously monitors the deceleration state of the preceding vehicle and uses this feedback to adjust the headway distance threshold in real-time. This feedback mechanism enables the control logic to adapt to changing traffic conditions while maintaining relatively simple overall system architecture.
Data Source
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AI summary
A vehicle headway maintenance assist system is configured to perform a haptic notification control of an accelerator to prompt the driver to release the accelerator when the accelerator is being operated and to perform a deceleration control of the vehicle based on headway distance when the accelerator is being operated as long as the headway distance from a preceding vehicle is less than a prescribed headway distance threshold.