Shift Range Control Using Motor Angle and Stepwise Shaft Signals
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Solution Overview
Problem
Existing shift range control devices face challenges in accurately determining the shift range, especially when using multiplexed output shaft sensors, which can complicate the configuration and hinder appropriate range switching.
Innovation Solution
A shift range control device is developed, incorporating an angle calculation unit, signal acquisition unit, drive control unit, and range determination unit, utilizing both motor rotation angle signals from an encoder and output shaft signals from a magnetic sensor to accurately determine the actual shift range, even when the output shaft sensor signals change stepwise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiplexed output shaft sensors are used to detect shift range, then the device complexity is reduced, but the measurement precision and reliability of shift range determination deteriorate due to signal ambiguity
Solution Approach 1:
The patent introduces an intermediary calculation method that processes the stepwise sensor signals through range determination logic. This intermediary processing layer resolves the ambiguity of multiplexed sensor readings by calculating which shift range is most consistent with the observed signal pattern, thereby maintaining measurement precision while using simplified sensor hardware.
Solution Approach 2:
The patent changes the parameter interpretation approach by not treating sensor signals as direct shift range indicators, but rather as parameters to be processed through determination algorithms. This allows the system to extract accurate shift range information from stepwise sensor signals that would otherwise be ambiguous.
2Device complexity
If output shaft sensor signals change stepwise, then the device complexity is reduced, but the difficulty of detecting and measuring the actual shift range increases
Solution Approach 1:
The patent implements feedback through iterative range determination processes. The system continuously monitors sensor signals, compares them against expected patterns for different shift ranges, and adjusts its determination accordingly. This feedback mechanism resolves the difficulty of detecting actual shift range from stepwise signals by using continuous verification and correction.
Solution Approach 2:
The patent applies preliminary action by establishing determination algorithms and signal interpretation rules before actual shift range detection occurs. This preparatory framework enables the system to correctly interpret stepwise sensor signals as they occur, rather than attempting to resolve ambiguity in real-time without pre-established criteria.
3Ease of manufacture
If traditional sensor configurations are maintained, then the ease of manufacture is preserved, but the reliability and safety of shift-by-wire system deteriorate due to inaccurate shift range determination
Solution Approach 1:
The patent substitutes mechanical interpretation of sensor signals with computational determination methods. Instead of relying on direct mechanical correspondence between sensor position and shift range, the system uses algorithmic analysis of sensor signal patterns to determine shift range, thereby maintaining simple sensor hardware while achieving high reliability through intelligent processing.
Solution Approach 2:
The patent makes the output shaft sensor serve multiple functions: it provides both position information and shift range determination data through its stepwise signals. This multi-functionality allows the same simple sensor configuration to support both basic operation and reliable shift range detection without adding separate dedicated sensors.
Data Source
AI summary
An angle calculation unit acquires a motor rotation angle signal, output from a motor rotation angle sensor detecting a rotational position of a motor, and calculates a motor angle. A signal acquisition unit acquires an output shaft signal that is output from an output shaft sensor and has a value changing stepwise in accordance with a rotational position of an output shaft, the output shaft sensor detecting a rotational position of an output shaft to which the rotation of the motor 10 is transmitted. A drive control unit controls the drive of the motor such that the motor angle becomes a target motor angle value corresponding to a target shift range. A range determination unit determines an actual range based on the output shaft signal and the motor rotation angle signal.