DC Motor Wiper Control via Armature Current Ripple
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Solution Overview
Problem
Current windshield wiper systems for motor vehicles require additional position sensors and complex methods to determine the parking position of windshield wipers, increasing manufacturing, assembly, and maintenance costs, as well as system complexity.
Innovation Solution
A control method for non-reversing commutated windshield wiper motors that determines the parking position by counting the revolutions of the motor shaft based on the ripple of the armature current, eliminating the need for additional position sensors and allowing for cost-effective, reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional position sensors are used to determine the parking position of the windshield wiper, then the measurement precision of the wiper position is improved, but the device complexity and manufacturing costs increase
Solution Approach 1:
The system uses the motor's own armature current ripple as a self-generated position signal. The commutated DC motor naturally produces current ripples during operation, which are evaluated to determine motor shaft revolutions and calculate the parking position, eliminating the need for external position sensors.
Solution Approach 2:
The patent replaces mechanical position sensors with an electrical measurement method. By evaluating the ripple of the armature current signal, the system determines motor shaft position and calculates wiper parking position electronically, substituting mechanical sensing components with signal processing.
2Reliability
If additional position sensors are installed to detect wiper position, then the reliability of position determination is improved, but the assembly effort and manufacturing costs increase
Solution Approach 1:
The motor controller utilizes the motor's inherent electrical characteristics (armature current ripple) to determine position, making the system self-sufficient without requiring additional sensors that would increase assembly complexity and manufacturing costs.
3Ease of manufacture
If the motor shaft position is determined by counting armature current ripples, then the manufacturing costs are reduced, but the measurement precision may be affected by disturbances
Solution Approach 1:
The system continuously monitors and evaluates the armature current ripple signal to track motor shaft position. By using feedback from the motor's own operational characteristics, the system achieves accurate position determination without additional sensors, resolving the contradiction between cost reduction and measurement precision.
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
This solution reduces costs, assembly effort, and weight while enhancing the reliability of the windshield wiper system by using armature current ripple evaluation to determine the parking position without additional sensors, and enables stepless speed regulation through PWM voltage signals.
Implementation Method 1
The number of revolutions of the motor shaft is determined according to the invention by evaluating the ripple or ripple of an armature current of the direct current motor.
Implementation Method 2
In a further embodiment, the control method according to the invention uses pulse-width-modulated (PWM) voltage signals to control the direct current motor, which enables stepless speed regulation of the at least one windshield wiper.
Implementation Method 3
a commutated direct current motor is usually used, the motor shaft of which is coupled to at least one windshield wiper of the windshield wiper system
Data Source
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Figure 3a
AI summary
The controlling method involves utilizing a direct current motor (3) with a stator, an armature and a motor shaft that is coupled with the anchor, and determining revolutions of the motor shaft for determining a stand-by position of the motor shaft. The revolutions of the motor shaft are determined by evaluating the ripples of an armature current of the direct current motor. An independent claim is included for a motor controller for a non reversing commutating windshield wiper motor for the execution of a controlling method.