Vehicle Travel Assist Device for Difference-in-Level Stopping
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Solution Overview
Problem
Existing vehicle travel assist systems fail to prevent a vehicle from going beyond a target stop position when a wheel encounters a difference-in-level, as they do not adequately account for the relationship between the target stop position and the position of the difference-in-level.
Innovation Solution
A vehicle travel assist device that includes a travel state acquisition device, a difference-in-level position estimation device, and a vehicle travel control device, which determines if the vehicle will go beyond the target stop position when a wheel passes a difference-in-level and adjusts the target stop position or generates a braking force to prevent this, by estimating the position of the difference-in-level and predicting the vehicle's position at the time the wheel passes it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle travel control device controls the vehicle to travel toward a target stop position without considering the difference-in-level position, then the control system is simple, but the vehicle may go beyond the target stop position when a wheel passes the difference-in-level
Solution Approach 1:
The vehicle travel control device performs preliminary determination of whether the vehicle will go beyond the target stop position when a wheel passes the difference-in-level, before actually reaching that point. This allows the system to proactively adjust the target stop position or generate braking force to prevent overshooting, thereby improving stopping precision without requiring complex real-time reaction mechanisms
Solution Approach 2:
The control system segments the stopping process into distinct phases: normal travel control, difference-in-level detection and prediction, and corrective action (target position adjustment or braking). This segmentation allows each phase to be handled with appropriate control strategies, improving overall reliability while keeping individual control modules relatively simple
2Speed
If the vehicle increases driving force to climb over the difference-in-level, then the wheel can pass the difference-in-level, but the vehicle speed decreases causing the vehicle to go beyond the target stop position
Solution Approach 1:
The vehicle travel control device uses feedback from wheel position information and difference-in-level position information to determine whether the vehicle will overshoot the target stop position. Based on this feedback, the system dynamically adjusts the target stop position or applies braking force to compensate for speed variations caused by climbing the difference-in-level, thereby maintaining accurate stopping precision
Solution Approach 2:
The system changes the target stop position parameter dynamically based on the detected relationship between wheel position, difference-in-level position, and target stop position. When a wheel is determined to pass the difference-in-level, the target stop position is adjusted to prevent overshooting, allowing the vehicle to maintain appropriate speed while ensuring accurate final positioning
Data Source
AI summary
A vehicle travel control device controls travel of a vehicle toward a target stop position. Travel state information indicates a travel state of the vehicle and includes vehicle position information indicating positions the vehicle and each wheel. Difference-in-level position information indicates a position of a difference-in-level on a travel path. The vehicle travel control device determines whether the vehicle goes beyond the target stop position when a subject wheel of the vehicle passes the difference-in-level, based on the difference-in-level position information and the vehicle position information. When determining that the vehicle goes beyond the target stop position, the vehicle travel control device changes the target stop position so as to prevent the subject wheel from passing the difference-in-level, or generates a braking force to stop the vehicle before the subject wheel passes the difference-in-level.