Vehicle Speed Control Deceleration Comfort via Preceding Vehicle Speed Feedback
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Solution Overview
Problem
Conventional speed control systems for vehicles often cause discomfort to drivers during deceleration due to mismatched deceleration control with the driver's feeling, particularly when controlling inter-vehicle distance and relative speed.
Innovation Solution
A speed control system that detects the distance and relative speed to a preceding vehicle, computes a corrected distance condition evaluation index, sets a threshold, and adjusts deceleration control to match the driver's comfort by using a formula that accounts for the speed of the preceding vehicle and offsets the target relative speed at zero distance, ensuring smooth deceleration without an inflection point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deceleration control is implemented using conventional distance condition evaluation index, then inter-vehicle distance control is achieved, but driver comfort deteriorates due to inflection points in deceleration output
Solution Approach 1:
The patent modifies the distance condition evaluation index by introducing a correction term that accounts for the speed of the preceding vehicle. This parameter change eliminates the inflection point in the deceleration output by adjusting how the evaluation index scales with distance and speed, resulting in smoother deceleration that matches driver expectations while maintaining effective inter-vehicle distance control.
Solution Approach 2:
The system incorporates feedback from the preceding vehicle's speed into the deceleration control calculation. By continuously monitoring and adjusting the distance condition evaluation index based on the preceding vehicle's speed, the system achieves smooth deceleration profiles that eliminate abrupt changes and inflection points, thereby improving driver comfort without sacrificing control reliability.
2Device complexity
If acceleration/deceleration control is determined without considering preceding vehicle speed, then control simplicity is maintained, but driver comfort deteriorates due to mismatched acceleration feeling
Solution Approach 1:
The patent introduces a correction term that incorporates the preceding vehicle's speed into the distance condition evaluation index. This parameter change adds only one additional variable to the control calculation, maintaining relative simplicity while significantly improving acceleration/deceleration smoothness and driver comfort by eliminating inflection points in the control output.
3Reliability
If target relative speed is set to zero at zero distance, then collision avoidance is maximized, but driver comfort deteriorates due to unnatural deceleration profiles
Solution Approach 1:
The patent modifies the relationship between distance and target relative speed by introducing a correction term that accounts for the preceding vehicle's speed. This parameter change ensures that the target relative speed approaches zero asymptotically as distance approaches zero, rather than forcing an abrupt zero value, thereby maintaining collision avoidance while creating natural, smooth deceleration profiles that match driver expectations.
Data Source
AI summary
In a vehicle speed control system, a preset offset distance is taken as a zero value of an inter-vehicle distance in a brake discriminant. When the current value of a corrected distance condition evaluation index is higher than the brake discriminant, a value on the brake discriminant is set as a target value of the corrected distance condition evaluation index. Deceleration control is started to decelerate the subject vehicle so that the deceleration of the subject vehicle becomes equal to the target deceleration of the subject vehicle computed based on the target relative speed corresponding to the set target value and the actual relative speed.