Parking Assist Braking Switch for Accurate Stop Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing parking assist devices inaccurately recognize vehicle speed using wheel speed pulses, leading to premature stopping in front of the target position due to long input intervals, especially when there are no wheel speed pulse detections between certain distances.
Innovation Solution
A parking assist device that switches control from feedback to feedforward braking force control when the remaining distance to the target stop position becomes a predetermined value, using the traveling distance calculation unit and braking/driving force calculation unit to determine the appropriate braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If feedback control is used for braking force control based on wheel speed pulse detection, then the control system is simple and easy to implement, but the vehicle stop position accuracy deteriorates due to long input intervals of wheel speed pulse causing erroneous high vehicle speed recognition
Solution Approach 1:
The system performs preliminary action by calculating the actual vehicle speed using the relationship between traveling distance and traveling time before the stop position is reached. This preliminary speed calculation compensates for the delayed wheel speed pulse detection and enables accurate braking force control in the final approach to the target stop position, preventing premature stopping.
Solution Approach 2:
The invention introduces an intermediary calculation method that uses traveling distance and traveling time as intermediate parameters to derive actual vehicle speed. This intermediary approach bridges the gap between the discrete wheel speed pulse detections and the continuous speed control requirement, enabling smooth and accurate braking force adjustment near the target position.
2Device complexity
If wheel speed pulse detection is used for vehicle speed measurement, then the measurement method is simple and cost-effective, but the measurement precision deteriorates due to long input intervals causing difficulty in updating vehicle speed detection
Solution Approach 1:
The system performs preliminary action by continuously calculating actual vehicle speed using the relationship between traveling distance and traveling time before the stop position is reached. This preliminary speed calculation compensates for the delayed wheel speed pulse detection and enables accurate braking force control in the final approach to the target stop position, preventing premature stopping.
Solution Approach 2:
The invention substitutes the mechanical wheel speed pulse detection system with a computational approach that uses traveling distance and traveling time to calculate actual vehicle speed. This substitution replaces the discrete mechanical sensing method with a continuous mathematical calculation, thereby improving speed measurement precision without adding complex hardware.
Data Source
AI summary
The vehicle stop position accuracy is improved. A parking assist device, which assists parking of a vehicle at a target stop position, includes: a traveling distance calculation unit that calculates a traveling distance of the vehicle based on a wheel speed pulse; and a braking/driving force calculation unit that determines a remaining distance to the target stop position based on the traveling distance, and switches control of the braking force of the vehicle from feedback control to feedforward control when the remaining distance becomes a value equal to or less than a predetermined value.