Wiper Angle Estimation for Overrun-Free Reversing Control
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Solution Overview
Problem
Existing wiper control systems require a Hall IC for detecting the position of the electric motor, complicating the configuration and are prone to overruns at reversing positions, which can lead to incomplete wiping and noise.
Innovation Solution
A wiper control device that estimates the wiper angle based on current ripple periodicity, calculates a deceleration start angle, and adjusts power supply to the wiper motor to prevent overruns without a Hall IC, using a simple configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall IC is used to detect the position of the electric motor, then the wiper position detection accuracy is improved, but the device complexity increases and wiring becomes more complex
Solution Approach 1:
The patent extracts and eliminates the Hall IC position detection device from the wiper system. Instead of using a Hall IC to detect motor position, the system uses current ripple analysis from the existing motor drive circuit to estimate wiper angle and detect reversing positions, thereby removing the complex Hall IC wiring and components while maintaining position detection capability
Solution Approach 2:
The patent replaces the magnetic field-based Hall IC detection system with an electrical current analysis system. By analyzing the ripple characteristics of the motor drive current, the system substitutes the mechanical/magnetic detection method with an electrical signal processing method, eliminating the need for Hall IC wiring and components
2Productivity
If the wiper motor is driven at high speed to improve productivity, then the wiping efficiency is improved, but the risk of overrun at reversing positions increases causing noise and incomplete wiping
Solution Approach 1:
The patent applies preliminary action by estimating the wiper angle in advance using current ripple analysis and calculating a deceleration start angle that is earlier than the actual reversing position. This allows the system to prepare for deceleration before the wiper reaches the reversing position, ensuring smooth stopping and preventing overrun even at high speeds
Solution Approach 2:
The patent implements feedback control by continuously monitoring the motor current ripple to estimate the wiper angle in real-time. The estimated angle feedback is used to dynamically adjust the deceleration timing and control the motor speed, creating a closed-loop control system that maintains reliability at high speeds
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 system effectively suppresses overruns and reduces operating noise by smoothly reversing the wiper at target positions, eliminating the need for complex wiring and ensuring complete wiping.
Implementation Method 1
a wiper element to rotate a wiper motor by current passing through the wiper motor to drive a wiper that reciprocates
Implementation Method 2
an estimation unit configured to estimate a wiper angle that is a rotation angle of the wiper based on a current ripple having a periodicity corresponding drive of the wiper motor
Data Source
AI summary
A wiper control device includes: a wiper element; and a drive unit configured to control on/off of the wiper element. The drive unit is configured to decelerate a wiper by switching the wiper element from on to off to stop power supply from the wiper element to a motor of the wiper when a wiper angle reaches a deceleration start angle. The drive unit is configured to resume the power supply from the wiper element to the motor by switching the wiper element from off to on after the wiper angle reaches the deceleration start angle.