Vehicle Speed Control for Mixed-Friction Road Deceleration
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Solution Overview
Problem
Existing driver assistance systems struggle to achieve appropriate vehicle speed control, particularly in conditions where the road surface frictional coefficient is low, such as when snow accumulates on the vehicle's traveling lane, making it difficult to control acceleration and deceleration effectively, especially before traffic lights or when navigating curves.
Innovation Solution
A driver assistance apparatus that includes a determiner to detect road surface frictional coefficients, an estimator to determine high frictional coefficient areas, and a rate setter to adjust acceleration or deceleration rates based on these conditions, ensuring optimal vehicle speed control by setting higher deceleration rates in high friction areas and lower acceleration rates when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle uses standard acceleration and deceleration control, then the control system is simple and responsive, but the vehicle slips on low-friction road surfaces
Solution Approach 1:
The system performs preliminary detection of road surface frictional coefficients and identifies high frictional coefficient areas before the vehicle reaches them. Based on this advance information, the control system pre-adjusts acceleration and deceleration rates to match the upcoming road conditions, preventing slips before they occur. This preliminary action allows the system to maintain reliability without requiring complex real-time response mechanisms.
Solution Approach 2:
The control system dynamically adjusts acceleration and deceleration rates based on detected road surface conditions. When high frictional coefficient areas are detected, the system automatically modifies control parameters to match the changed environment. This dynamic adaptation enables the vehicle to maintain optimal traction and control across varying road surfaces without manual intervention.
2Speed
If the vehicle increases deceleration rate in high friction areas, then stopping distance is reduced, but control precision must be higher
Solution Approach 1:
The system detects and identifies high frictional coefficient areas in advance using image recognition and frictional coefficient estimation. By knowing the upcoming road conditions before reaching them, the system can pre-calculate and prepare the appropriate deceleration rate adjustments. This preliminary detection and planning reduces the need for high-speed real-time control precision, as the control actions are already optimized based on advance knowledge of road conditions.
3Reliability
If the vehicle decreases acceleration rate on low friction surfaces, then slipping is prevented, but acceleration performance is reduced
Solution Approach 1:
The control system applies different acceleration rates to different road sections based on locally detected frictional coefficients. When high frictional coefficient areas are detected ahead, the system increases acceleration rate specifically for those sections. Conversely, on low-friction sections, the system reduces acceleration rate to prevent slips. This localized quality adjustment optimizes acceleration performance for each specific road condition rather than using a uniform conservative rate throughout.
Data Source
AI summary
A driver assistance apparatus for a vehicle includes a determiner, an estimator, a detector, and a deceleration rate setter. The determiner determines whether the vehicle is slipping in vehicle speed control involving acceleration or deceleration of the vehicle. The estimator estimates a road surface frictional coefficient at a location where the vehicle starts slipping as a first road surface frictional coefficient. The detector detects a high frictional coefficient area that has a second road surface frictional coefficient higher than the first road surface frictional coefficient and is located in front of the vehicle. The deceleration rate setter sets, in the vehicle speed control involving the deceleration, a target deceleration rate to be used when the vehicle travels in the high frictional coefficient area to a higher value than the target deceleration rate set for the first road surface frictional coefficient.