Vehicle Wiper Load Correction for Inversion Overrun Control
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Solution Overview
Problem
Conventional wiper control systems face challenges in suppressing overrun at the upper inversion position during light rain conditions, where the wind load correction amount is smaller than the high load correction amount, leading to inadequate correction for sudden load changes and potential blade slipping.
Innovation Solution
A wiper control method that detects the outward load and corrects the wiper arm operation using a first correction value when the load exceeds a threshold, and a second correction value based on wind load when the load is below the threshold, using motor load calculations from current, voltage, vehicle speed, and air temperature to accurately identify and manage both surface and wind loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wind load correction is applied during light rain conditions, then the correction amount becomes small, but this leads to inadequate correction for sudden load changes and potential blade slipping
Solution Approach 1:
The patent changes the parameter threshold for selecting correction modes. Instead of using a fixed threshold, it dynamically adjusts the load threshold based on operating conditions. When the difference between outward and return loads exceeds a threshold, the system switches to high load correction mode, ensuring adequate correction even during light rain conditions where wind load alone would be insufficient
Solution Approach 2:
The system continuously monitors motor load during both outward and return operations, compares the load differences, and adjusts the correction mode accordingly. This feedback mechanism ensures that when sudden load changes are detected (indicating potential sticking or slipping), the system automatically applies appropriate correction to maintain reliable operation
2Area of stationary object
If the wiper blade operates closer to the upper inversion position to widen the wiping area, then the wiping area increases, but overrun at the inversion position occurs
Solution Approach 1:
The system performs preliminary correction by detecting the load difference between outward and return operations before the wiper reaches the inversion position. When an abnormal load pattern is detected, the system proactively applies correction to prevent overrun, allowing the wiper to safely operate closer to the inversion position and widen the wiping area without sacrificing position control accuracy
Solution Approach 2:
By continuously monitoring motor load and comparing outward versus return operation loads, the system provides real-time feedback on wiper behavior near the inversion position. This feedback enables dynamic adjustment of the stop position correction to prevent overrun while maximizing the usable wiping area
Data Source
AI summary
In a wiper device for vehicles, overrun at inversion positions is suppressed while a wind load and a high load are dealt with. A wiper device includes: a wiper blade; a wiper arm to which the wiper blade is attached; and a motor for driving the wiper arm. A load generated in the motor when the wiper blade moves on a windshield is estimated and calculated based on a motor supply current amount and the like. When an outward load generated in the wiper motor exceeds a predetermined threshold value, a high load correction process is performed based on the outward load. When the outward load is less than or equal to the threshold value, a wind load correction process is performed based on a wind load calculated from a difference between the outward load and the return load.