Wiper Position Detection Using Motor Current Changes
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Solution Overview
Problem
Conventional wiper devices require complex wiring and Hall sensors to determine the position of wiper blades, increasing costs and complexity.
Innovation Solution
A wiper controller that acquires and determines the position of wiper blades based on the temporal change of electric current flowing through the wiper motor, eliminating the need for Hall sensors and their associated wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall sensors and speed reduction mechanism are used to calculate wiper position, then position measurement precision is improved, but device complexity and wiring requirements increase
Solution Approach 1:
The patent extracts and eliminates the Hall sensor from the wiper position detection system. Instead of using external sensors, the system uses the wiper motor's own current characteristics to determine position. The controller monitors current temporal changes (increases or decreases by a predetermined amount) to infer wiper blade position, thereby removing the need for separate sensing components and their associated wiring.
Solution Approach 2:
The wiper motor serves dual functions: it both drives the wiper mechanism and provides the sensing signal through its current characteristics. The motor's current consumption patterns during operation naturally indicate wiper position states, eliminating the need for separate measurement systems. The system uses the motor's own operational characteristics for self-diagnosis and position detection.
2Measurement precision
If Hall sensors are installed to detect rotor rotation speed, then wiper position calculation accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the Hall sensor component from the system architecture. Position detection is achieved by monitoring the wiper motor's current consumption patterns during operation. The controller identifies position changes by detecting predetermined current increases or decreases, eliminating the need for expensive sensor hardware and reducing manufacturing costs.
Solution Approach 2:
The patent replaces expensive, complex Hall sensors with a software-based detection method that uses existing motor current data. This approach uses inexpensive computational resources instead of costly hardware sensors, significantly reducing component costs while maintaining functional capability.
3Loss of information
If conventional wiper position detection method is used, then position information is obtained, but operation smoothness deteriorates due to noise
Solution Approach 1:
The system uses the wiper motor's own current characteristics as the detection signal source. By monitoring current temporal changes during motor operation, the system derives position information without introducing additional sensors that would generate noise. The method leverages the motor's inherent operational signals for position detection.
Solution Approach 2:
The controller continuously monitors the wiper motor's current consumption and uses this feedback to determine wiper blade position. The system detects position changes by identifying predetermined current increases or decreases in real-time, creating a closed-loop detection system that adapts to actual motor operation conditions and provides smooth, noise-free position information.
Data Source
AI summary
A wiper controller includes an acquirer and a determiner. The acquirer acquires a value related to an electric current flowing through a wiper motor driving a wiper reciprocating between a first position and a second position. The determiner determines that a position of the wiper is either the first position or the second position based on a temporal change of the electric current flowing through the wiper motor.