Wiper Position Feedback Control After Power Failure

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Solution Overview

Problem

Conventional wiper systems fail to provide accurate positional feedback of the wiper arm after a sudden power failure, leading to misalignment of the sweeping zone.

Innovation Solution

Incorporating an angular encoder and a controller to record and correct the wiper arm's actual position, ensuring it returns to the park position before resuming operation, thereby maintaining the predetermined sweep zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional wiper control scheme is used without position feedback, then the system is simple and cost-effective, but the wiper arm may take arbitrary position after power failure leading to misalignment of sweep zone

Engineering Contradiction:

Improvewiper arm position accuracyVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback by using an angular encoder to continuously monitor the wiper arm's actual position and feed this information back to the controller. The controller compares the actual position with the expected position and makes corrections, ensuring the wiper arm returns to the correct park position after power failure and maintains accurate sweep zone alignment throughout operation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces simple mechanical position assumption (where the system assumes the wiper arm is at park position) with an electronic sensing and control system. The angular encoder electronically detects the actual mechanical position, and the controller electronically adjusts the motor operation, substituting mechanical assumption with electronic measurement and control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If angular encoder and controller are added to track wiper arm position, then position accuracy is improved, but the device complexity and cost increase

Engineering Contradiction:

Improvewiper arm position measurementVSAvoidsystem component count

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The angular encoder provides continuous position feedback to the controller, enabling precise measurement of the wiper arm's actual position. The controller uses this feedback information to determine when the wiper arm has reached the park position and to make corrections if necessary, ensuring accurate position measurement and control.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The angular encoder serves multiple functions: it measures the wiper arm position during normal operation, detects when the wiper arm is at the park position, and provides data for the controller to calculate and execute position corrections. This multi-functionality reduces the need for separate sensors and control mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If the system assumes park position without verification, then the operation is fast and simple, but the sweep zone coverage becomes inaccurate after power interruption

Engineering Contradiction:

Improvewiper operation speedVSAvoidsweep zone alignment precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The controller is configured to perform preliminary action by first moving the wiper arm to the verified park position using feedback from the angular encoder before initiating the normal sweep operation. This preliminary positioning ensures that the wiper arm starts from the correct reference position, guaranteeing accurate sweep zone coverage while minimizing the impact on overall operation speed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system performs self-service by automatically detecting its own position through the angular encoder and automatically correcting any position errors without requiring manual intervention. The controller monitors the wiper arm position and autonomously executes correction movements, allowing the system to self-correct after power failure and maintain precision without adding manual calibration steps.

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

Ensures accurate and reliable wiper arm movement within the intended sweep zone, preventing misalignment and enhancing system safety and reliability.

Implementation Method 1

At least an angular encoder is operatively connected to a distal end of the wiper drive shaft configured to record an actual position of the wiper arm

Methodology Applied

Scientific EffectAngular displacement detection:

Implementation Method 2

In certain embodiments, the position sensor can be a Hall Effect sensor

Methodology Applied

Scientific EffectHall Effect: Hall Effect

Data Source

PatentUS12427949B2Dynamic position feedback for wiper control

Publication Date: 2025.09.30 ROSEMOUNT AEROSPACE INC

AI summary

In accordance with at least one aspect of this disclosure, a system include, a wiper arm configured to sweep along a sweep zone defined between a start position and an end sweep position. A wiper drive shaft is operatively connected at a proximal end to the wiper arm to drive the wiper arm between the start position and the end sweep position. At least an angular encoder is operatively connected to a distal end of the wiper drive shaft configured to record an actual position of the wiper arm. A controller is operatively connected to the encoder to receive positon wiper arm position data therefrom.