Vehicle Trajectory Control with Held Speed Suppression
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Solution Overview
Problem
Existing vehicle control systems fail to effectively prevent and suppress deviations from a target trajectory during curve traveling due to unpredictable road surface frictional forces, often leading to repeated acceleration and deceleration, and may cause passenger discomfort by maintaining a low target vehicle speed.
Innovation Solution
A vehicle control device that determines deviation from the target trajectory, calculates a suppression amount for the target vehicle speed based on the deviation, holds the maximum suppression amount, and gradually decreases it when the vehicle returns to the target trajectory, ensuring safe and comfortable travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle speed is restricted and acceleration is restricted when deviation prevention control is performed, then the vehicle can be prevented from deviating from the target trajectory, but the vehicle may be accelerated again and deviate again, or acceleration and deceleration may be repeated by the deviation prevention control
Solution Approach 1:
The system performs preliminary action by holding the maximum suppression amount for a predetermined time period after deviation occurs. This preliminary holding action ensures that the suppression effect is maintained long enough to prevent re-deviation, addressing the problem where premature release of suppression causes the vehicle to deviate again.
Solution Approach 2:
The system dynamically adjusts the suppression amount based on the deviation state. When deviation is detected, the maximum suppression amount is held; when the vehicle returns to the target trajectory and the release condition is satisfied, the suppression amount is released. This dynamic adjustment prevents repeated acceleration and deceleration while maintaining effective deviation prevention.
2Reliability
If the target vehicle speed is continuously set low to prevent deviation, then the vehicle can be kept on the target trajectory, but the passenger feels uncomfortable
Solution Approach 1:
The system applies suppression periodically and temporarily only when deviation occurs, rather than continuously maintaining low speed. The suppression amount is held for a predetermined time after deviation detection, then released when the vehicle returns to the target trajectory. This periodic application maintains trajectory accuracy while avoiding continuous low-speed operation that would cause passenger discomfort.
Solution Approach 2:
The system changes the target vehicle speed parameter dynamically based on the deviation state. When deviation occurs, the target vehicle speed is suppressed by the maximum suppression amount; when the vehicle returns to the target trajectory and the release condition is satisfied, the suppression is released and the target vehicle speed returns to normal. This parameter change ensures trajectory following accuracy while maintaining passenger comfort during normal operation.
Data Source
AI summary
A vehicle control device can perform control for causing a vehicle to travel along a target trajectory at a target vehicle speed. The vehicle control device can include at least one processor configured to: determine whether or not the vehicle is in a deviated state in which the vehicle deviates from the target trajectory, calculate, when the vehicle is determined to be in the deviated state, a suppression amount by which the target vehicle speed is decreased based on a deviation amount indicating the deviated state, maintain a hold value at a maximum value of the suppression amount and suppress the target vehicle speed using the hold value, and decrease the hold value of the suppression amount at a predetermined speed when the vehicle returns from the deviated state to the target trajectory and a preset release condition is satisfied.