Wiper Controller Adaptive Resistance Calibration

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Solution Overview

Problem

The existing wiper unit controllers face errors in recognizing the rotational position of the intermittent wipe cycle adjustment knob due to variations in the maximum resistance value of the variable resistor, especially under temperature changes, leading to inaccurate intermittent wiping cycles.

Innovation Solution

A wiper unit controller with a computer system that detects and renews the maximum resistance value of the variable resistor, using a storing means, detecting means, renewing means, recognizing means, and setting means to accurately determine and set the intermittent wipe cycle, and includes a mechanism to prevent temporary value renewals and ensure reliable recognition across temperature changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the maximum resistance value of the variable resistor is used to determine the intermittent wipe cycle, then the wipe cycle can be set according to the rotational position of the knob, but the large tolerance of the variable resistor causes the maximum resistance value to vary between different variable resistors, leading to inaccurate recognition of the rotational position

Engineering Contradiction:

Improveintermittent wipe cycle settingVSAvoidrotational position recognition accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The controller performs preliminary learning of the maximum resistance value during the initial operation or calibration phase. The controller stores the detected maximum resistance value in memory before normal operation begins, so that subsequent rotational position measurements can be accurately referenced against this pre-established baseline value.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The controller continuously monitors the resistance value of the variable resistor and compares it against the stored maximum resistance value. When the detected resistance exceeds the stored maximum (indicating a new maximum has been reached), the controller updates the stored maximum resistance value, creating a feedback mechanism that adapts to actual component variations.

Inventive Principle:

Principle #23Feedback

2Reliability

If the controller renews the maximum resistance value whenever a greater value is detected, then the rotational position recognition can be updated, but under low temperature conditions the resistance value temporarily exceeds the stored maximum, causing the maximum resistance value to be renewed to an incorrect larger value, and this error cannot be corrected when temperature returns to normal

Engineering Contradiction:

Improverotational position recognition reliabilityVSAvoidtemperature sensitivity of resistance value

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The controller applies preliminary anti-action by implementing validation logic before renewing the maximum resistance value. When a resistance value exceeds the current maximum, the controller checks whether this is a genuine new maximum or a temporary anomaly caused by environmental factors such as temperature. Only after confirming the exceeded value is legitimate does the controller update the stored maximum, thereby preventing premature or erroneous renewals.

Inventive Principle:

Principle #9Preliminary anti-action

3Device complexity

If the controller stores a fixed maximum resistance value, then the system is simple to implement, but the large tolerance variation of ±30% in variable resistors causes the stored value to not match the actual maximum resistance value, resulting in errors in rotational position recognition

Engineering Contradiction:

Improvecontroller implementation complexityVSAvoidrotational position recognition precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The controller performs self-calibration by automatically detecting and learning the actual maximum resistance value of the connected variable resistor during initial operation. This self-service approach eliminates the need for manual calibration or factory pre-programming of the maximum resistance value, while still achieving accurate rotational position recognition despite component tolerance variations.

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution ensures accurate recognition of the rotational position of the knob, maintaining consistent intermittent wiping cycles despite temperature fluctuations, thereby improving the reliability of the wiper unit's operation.

Implementation Method 1

When the variable resistor 112 is used under a low temperature environment (e.g., minus 30 degrees Celsius), the detected resistance value Rv may temporarily exceed the stored maximum resistance value

Methodology Applied

Scientific EffectTemperature-dependent resistance: Electrical Resistance

Data Source

PatentUS7622878B2Wiper unit controller and method for controlling wiper unit

Publication Date: 2009.11.24 MITSUBISHI MOTORS CORP

AI summary

A wiper unit controller for performing wiping at an accurate intermittent wipe cycle. The controller stores a maximum resistance value of a variable resistor having a resistance value that varies in accordance with the intermittent wipe cycle. When a reference time elapses after calculating a resistance value that exceeds the stored maximum resistance value, a computer renews the maximum resistance value with a new maximum resistance value.