Gear Shift Position Detection Using Hall Sensor and Motor Rotation
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Solution Overview
Problem
The electric shift-by-wire system faces challenges in accurately detecting the gear shift position using expensive high-precision position sensors, which affects price competitiveness and safety, particularly in the parking stage where incorrect shifts can lead to safety accidents.
Innovation Solution
A method utilizing an inexpensive Hall sensor to detect the gear shift position by setting a reference motor position, measuring rotation amounts, and determining the shift stage based on predetermined reference values, with options to measure driving current and output warning signals for mismatched driver inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-precision position sensor is used to detect the gear shift position, then the detection accuracy is improved, but the product cost increases
Solution Approach 1:
The patent replaces expensive high-precision position sensors with inexpensive Hall sensors that can accurately detect the gear shift position by measuring magnetic field changes. This substitution maintains sufficient detection accuracy while dramatically reducing sensor cost and overall system price
Solution Approach 2:
The patent replaces mechanical position sensing mechanisms with a magnetic field-based detection system using Hall sensors. This substitution eliminates the need for complex mechanical linkages and high-precision mechanical sensors, reducing both cost and mechanical complexity while maintaining detection accuracy
2Ease of manufacture
If an inexpensive Hall sensor is used to detect the gear shift position, then the product cost is reduced, but the detection accuracy may be insufficient
Solution Approach 1:
The patent changes the detection parameter from mechanical position to magnetic field strength, which Hall sensors can measure accurately. By detecting changes in magnetic field parameters as the shift lever moves between positions, the system achieves accurate gear shift detection using low-cost Hall sensors
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the shift lever position and the detection system. Hall sensors detect magnetic field changes caused by a magnet attached to the shift lever, translating physical position into measurable electrical signals with high accuracy
3Speed
If the motor is rotated to detect the gear shift position, then the detection speed is improved, but the system complexity increases
Solution Approach 1:
The patent utilizes the motor's existing rotation during normal gear shifting to perform detection, rather than requiring a separate detection mechanism. The motor's rotation naturally brings the shift lever to different positions, which are then detected by Hall sensors, achieving rapid detection without adding system complexity
Solution Approach 2:
The patent merges the gear shifting function with the detection function. The same motor that performs gear shifting also enables detection by rotating to predetermined positions, and the Hall sensors used for position detection also serve to monitor the gear shift state, reducing overall system complexity
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 method allows for rapid and accurate detection of the gear shift position using inexpensive sensors, improving price competitiveness and ensuring reliable shift control while preventing safety accidents.
Implementation Method 1
capable of rapidly and correctly detecting the gear shift position using an inexpensive Hall sensor
Data Source
AI summary
A method of detecting a gear shift position of an electric shift-by-wire system is proposed. The method includes setting, as a reference position, a motor position at a time point when shift is completed to a target shift stage; rotating the motor until the motor no longer rotates in a P stage-engaging direction from the reference position; measuring a rotation amount of the motor with respect to the reference position; and determining the gear shift position by determining that the reference position is a P stage when the measured rotation amount of the motor is less than or equal to a predetermined first reference value, and the reference position is not the P stage when the measured rotation amount of the motor is greater than the first reference value.