Windshield Wiper Sweep Angle Monitoring for Gear Train Faults
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Solution Overview
Problem
Conventional windshield wiper systems (WWSs) lack effective mechanisms to detect mechanical failures such as worm gear failures, which can cause undesirable movement and system failures, and do not account for losses or faults in the mechanical gear train, leading to potential visibility issues during operations like take-off or landing.
Innovation Solution
The implementation of a measurement system using an internal wiper trigger with Hall Effect sensors to monitor the sweep angle of the wiper blade assembly, generating a variable duty cycle output to provide feedback for controlling the wiper blade assembly, and a controller that adjusts operations based on this feedback, along with motor position, current, and temperature signals, to ensure accurate sweep angle maintenance and detect potential failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional windshield wiper systems are used without measurement systems, then the system structure remains simple, but mechanical failures such as worm gear failures cannot be detected, leading to undesirable movement and system failures
Solution Approach 1:
The patent replaces mechanical measurement methods with magnetic field-based Hall Effect sensors to detect sweep angle and monitor wiper trigger position. This substitution enables reliable detection of mechanical failures and sweep angle deviations without adding complex mechanical measurement devices to the wiper system.
Solution Approach 2:
The patent implements a feedback system where Hall Effect sensors continuously monitor the position of the wiper trigger and generate signals that are fed back to the control system. This feedback enables real-time detection of sweep angle deviations and mechanical failures, allowing the system to maintain reliability through continuous monitoring rather than complex mechanical interlocks.
2Measurement precision
If no measurement system is implemented, then the system is simpler, but losses or faults in the mechanical gear train cannot be accounted for, leading to potential visibility issues
Solution Approach 1:
The patent substitutes mechanical measurement mechanisms with electronic Hall Effect sensors that measure sweep angle through magnetic field detection. This provides precise measurement of the wiper trigger position and sweep angle without the complexity of mechanical encoders or potentiometers, enabling accurate accounting of gear train performance.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the mechanical wiper trigger and the electronic measurement system. The Hall Effect sensors detect changes in the magnetic field generated by the wiper trigger, providing precise measurement of trigger position and sweep angle without direct mechanical contact or complex mechanical linkages.
3Measurement precision
If Hall Effect sensors are used to monitor sweep angle, then continuous monitoring with negligible parallax error is achieved, but the device complexity increases
Solution Approach 1:
The patent uses Hall Effect sensors that detect magnetic field changes to measure sweep angle, eliminating the need for mechanical encoders, potentiometers, or optical measurement systems. This provides continuous monitoring with negligible parallax error while keeping the sensor system relatively simple, as Hall Effect sensors are compact solid-state devices requiring minimal alignment or calibration.
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 enables continuous monitoring of the sweep angle with negligible parallax error, facilitating real-time identification of ageing issues or failures in the motor, wiper blade assembly, or gear train, ensuring reliable operation and improved visibility by maintaining the required sweep angle, and providing a redundant system for speed computation during sensor failures.
Implementation Method 1
The internal wiper trigger generates a magnetic field and the measurement system is responsive to the magnetic field to monitor the position of the internal wiper trigger. The measurement system includes Hall Effect sensors positioned proximate to opposite ends of the second sweep angle and the Hall Effect sensors are configured to generate a variable duty cycle output responsive to the magnetic field
Data Source
AI summary
A windshield wiper system (WWS) is provided and includes a wiper blade assembly drivable along a first sweep angle, an internal wiper trigger disposed to move with the wiper blade assembly, a measurement system configured to monitor a position of the internal wiper trigger from which a corresponding position of the wiper blade assembly relative to the first sweep angle is measurable and to output a sweep angle feedback signal corresponding to monitoring results and a controller. The controller is receptive of the sweep angle feedback signal.