Vehicle Traveling Control Apparatus Speed Deviation Threshold
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Solution Overview
Problem
Conventional vehicle traveling control systems may inadvertently set the target speed differently from a driver's intention when the target speed and speed limit are close, leading to potential misinterpretation of operations and reduced user control.
Innovation Solution
A vehicle traveling control apparatus with cruise control, speed limit acquisition, display, and target speed setting functions that differentiate between increasing/decreasing the target speed and setting it to the speed limit based on the driver's operation, using a speed deviation threshold to prevent unintended changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the operating unit is operated to increase or decrease the target speed when the target speed and speed limit are close, then the target speed can be adjusted freely, but the target speed may be set differently from the driver's intention
Solution Approach 1:
The system changes the operational parameters (operation threshold, operation direction) based on the relationship between target speed and speed limit. When the target speed is lower than the speed limit by more than a predetermined threshold, the operating unit responds to operations in the first direction (increasing speed). When the target speed is within the threshold of the speed limit, the operating unit responds to operations in the second direction (decreasing speed), preventing unintended speed limit setting and ensuring the target speed is set according to driver intention.
2Device complexity
If the operating unit serves dual functions for both speed adjustment and speed limit setting, then the device complexity is reduced, but the ease of operation deteriorates due to ambiguous operation interpretation
Solution Approach 1:
The system dynamically changes the function of the operating unit based on the current speed state. The control unit determines whether the operating unit should increase/decrease target speed or set target speed to speed limit, based on the relationship between target speed and speed limit. This dynamic functional switching maintains device simplicity while ensuring clear and unambiguous operation interpretation.
3Extent of automation
If the target speed is automatically set to the speed limit when the operating unit is operated toward the speed limit, then the automation level increases, but the loss of information about driver intention occurs
Solution Approach 1:
The system uses parameter changes (comparing target speed with speed limit threshold) to determine when automation should be applied. When the target speed is within the threshold of the speed limit, the system prevents automatic speed limit setting, preserving driver intention information. When the threshold is exceeded, automation is safely applied. This ensures automation increases convenience without losing critical driver intention information.
Data Source
AI summary
A driving assist ECU calculates a speed deviation ΔV which is a magnitude of a deviation between a target speed Vset and a speed limit Vlim in a situation in which the target speed Vset and the speed limit Vlim are different from each other. When the speed deviation ΔV is equal to or smaller than a threshold A, the driving assist ECU sets an accept prohibition flag to “1”. When the speed deviation ΔV is higher than the threshold A, the driving assist ECU sets the accept prohibition flag to “0”. When the accept prohibition flag is “1”, the driving assist ECU regards/treats a long-push operation of an operating unit not as an accept operation, but as an acceleration operation or a coast operation.