Wiper Controller Torque Reversal for Load Peak Reduction

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Solution Overview

Problem

Windshield wiper systems face high wear and tear due to peak loads when encountering obstacles, leading to reduced service life, as existing technologies fail to effectively manage torque and load distribution across the wiper blade's movement path.

Innovation Solution

A control system that compares the torque delivered by the drive device to a predetermined torque based on the wiper shaft's position, reversing the direction of rotation when excessive torque is detected, and limiting torque output to reduce load peaks, thereby sparing high-load areas and extending the wiper system's lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the wiper system provides high drive torque to overcome obstacles, then the obstacle removal capability is improved, but the wear on the wiper system increases and service life decreases

Engineering Contradiction:
Improvedrive torqueVSAvoidservice life
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The wiper control device dynamically adjusts the drive torque based on the detected obstacle characteristics. The control unit modifies operational parameters such as drive torque, speed, and number of passes according to the detected obstacle type and position, allowing the system to adapt its force output rather than maintaining constant high torque, thereby reducing wear while maintaining obstacle removal capability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates a detection device that provides feedback about obstacles on the wiper path. The control unit receives this information and adjusts the drive torque accordingly, creating a closed-loop control system that prevents excessive torque application and reduces wear on wiper components

Inventive Principle:
Principle #23Feedback

2Area of stationary object

If the wiper system operates continuously to clean the entire window area, then the cleaning coverage is improved, but the load peaks increase and cause higher wear

Engineering Contradiction:
Improvecleaning coverageVSAvoidservice life
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The control device segments the cleaning task by identifying and excluding high-load areas from the wiping path. The control unit calculates a reduced wiping path that avoids positions where load peaks occur, dividing the full window area into safe and high-risk zones, thereby maintaining cleaning effectiveness while reducing wear on the wiper system

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs partial cleaning by omitting certain high-load areas from the wiping path. The control unit determines that complete coverage is not necessary and adjusts the operational path to exclude positions that would cause excessive wear, accepting that some areas may not be cleaned as thoroughly to preserve system longevity

Inventive Principle:
Principle #16Partial or excessive action

3Power

If the transmission characteristic is non-uniform with respect to wiper shaft position, then the mechanical advantage varies, but load peaks occur at certain positions increasing wear

Engineering Contradiction:
Improvemechanical advantageVSAvoidservice life
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The control device performs preliminary analysis of the transmission characteristic and identifies positions where load peaks will occur. Before the wiper reaches these high-load positions, the control unit adjusts the drive torque or modifies the wiping path to avoid these positions entirely, preventing the wear-causing load peaks before they occur

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2516218B1Wiper controller
Publication Date: 2015.05.27 ROBERT BOSCH GMBH
  • EP2516218B1 patent drawingFigure 1
  • EP2516218B1 patent drawingFigure 2~3
  • EP2516218B1 patent drawingFigure 4

AI summary

A windshield wiper device comprises a controller, a drive unit and a gear that transmits the movement of the drive unit to a wiper shaft. The controller comprises a comparison unit for determining whether the torque output by the drive unit exceeds the predetermined torque, wherein the predetermined torque depends on the position of the wiper shaft. The wind shield wiper device further comprises a reversing unit for reversing the direction of rotation of the drive unit depending on the result of the comparison unit.