Wiper Control Device Adaptive Speed Threshold
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Solution Overview
Problem
Existing wiper control devices inaccurately detect wiper blade restrictions due to a single speed threshold and determination period applied regardless of travel distance, leading to false detection when travel distance is short.
Innovation Solution
A wiper control device that adjusts the rotation speed threshold and determination period based on the travel distance of the wiper blades, using higher speed thresholds and longer determination periods for longer distances and lower speed thresholds and shorter periods for shorter distances to accurately detect blade restrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single speed threshold is used for all travel distances, then the detection method is simple, but false detection occurs when travel distance is short
Solution Approach 1:
The patent applies parameter changes by adjusting the speed threshold based on the travel distance of the wiper blade. When the travel distance is short, a lower speed threshold is used; when the travel distance is long, a higher speed threshold is used. This dynamic parameter adjustment resolves the contradiction by maintaining detection accuracy across different operating conditions while avoiding false detections.
Solution Approach 2:
The patent implements dynamics by making the speed threshold adaptive rather than fixed. The control device dynamically selects the appropriate speed threshold based on the detected travel distance, allowing the detection criteria to change in response to varying operational conditions. This dynamic approach ensures reliable detection across different travel distances without requiring complex additional hardware.
2Device complexity
If a single determination period is used for all travel distances, then the control logic is simple, but false detection occurs when travel distance is short
Solution Approach 1:
The patent applies parameter changes by adjusting the determination period based on travel distance. A longer determination period is used for short travel distances, while a shorter determination period is used for long travel distances. This adaptive parameter adjustment maintains detection reliability across different operating conditions without significantly complicating the control logic.
Solution Approach 2:
The patent implements dynamics by making the determination period adaptive to the travel distance. The control device dynamically adjusts the determination period based on the detected travel distance, allowing the detection timing to optimize for different wiping scenarios. This dynamic adjustment prevents false detections while keeping the control logic manageable through conditional branching.
Data Source
AI summary
A wiper control device that properly detects restriction of a wiper blade according to a travel distance of the wiper blade. When a state in which a rotation speed of an output shaft calculated from a rotation angle of the output shaft detected by a rotation angle sensor is equal to or slower than a speed threshold defined according to a travel distance of the wiper blade and in which a current detected by a current detector is equal to or larger than a current threshold continues for a predetermined determination period, a microcomputer stops a wiper motor or reverses a direction of a wiping action of the wiper blade.