ACC Deceleration Control for Smooth Heavy-Vehicle Stopping
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Solution Overview
Problem
Existing adaptive cruise control (ACC) systems do not effectively address the issue of jerking during vehicle stoppages, particularly in large vehicles, and the relationship between target deceleration speed and jerk has not been sufficiently examined.
Innovation Solution
A driving assistance apparatus that includes an inter-vehicle-distance detection section, relative-speed detection section, and a target-acceleration/deceleration-speed output section, which outputs a target acceleration/deceleration speed based on inter-vehicle distance and relative speed, and a cancel section that adjusts the deceleration speed to prevent jerking by canceling the deceleration that causes jerk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong brake force is applied to stop heavy vehicles in ACC, then stopping capability is improved, but jerk occurs during deceleration
Solution Approach 1:
The patent applies dynamics by making the deceleration speed variable rather than constant. The target deceleration speed is dynamically adjusted based on vehicle speed, allowing the system to optimize between stopping capability and jerk suppression at different operating conditions. This is achieved through equations that calculate different target deceleration speeds for different vehicle speed ranges.
Solution Approach 2:
The patent changes the parameter of deceleration speed based on vehicle speed conditions. When vehicle speed is high, a larger target deceleration speed is used for efficient stopping. When vehicle speed is low, a smaller target deceleration speed is used to prevent jerk. This parameter adaptation resolves the contradiction between stopping performance and comfort.
2Adaptability or versatility
If ACC is actuated at low speeds including stoppage, then ACC functionality is improved, but jerk risk increases due to heavy vehicle weight
Solution Approach 1:
The patent extends ACC functionality to low speeds and stoppage conditions by adapting the target deceleration speed parameter. The system calculates appropriate target deceleration speeds even at very low vehicle speeds, enabling ACC to operate across the full speed range while maintaining jerk suppression through speed-dependent deceleration control.
Solution Approach 2:
The system dynamically adjusts control parameters to accommodate ACC operation at low speeds and stoppage. By making the target deceleration speed a dynamic variable that responds to current vehicle speed conditions, the system enables versatile ACC functionality while preventing jerk during low-speed deceleration and stopping maneuvers.
Data Source
AI summary
A target acceleration/deceleration output unit includes an acceleration/deceleration output unit which outputs an acceleration/deceleration including a deceleration, on the basis of the vehicle-to-vehicle distance from a host vehicle to a preceding vehicle and the relative speed of the host vehicle and the preceding vehicle, and a canceling unit which cancels a deceleration that causes jerking from the deceleration output from the acceleration/deceleration output unit, wherein the acceleration output from the acceleration/deceleration output unit, and the deceleration obtained by the canceling unit are output as a target acceleration/deceleration.