Shift-By-Wire Transmission Selector Calibration Against Unintended Drive
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Solution Overview
Problem
Existing shift-by-wire selector systems for automatic or semi-automatic vehicle transmissions can inadvertently switch from non-drive modes to drive modes due to vibrations or unintentional movements, leading to unsafe vehicle conditions since they lack robust locking mechanisms and calibrated sensor feedback.
Innovation Solution
A method and apparatus for controlling a vehicle transmission that includes a multi-stable selector with calibrated sensor output bands and peak/trough force feedback, ensuring that when the selector is at peak positions, it always selects a drive mode, with upper and lower limits adjusted to prevent unintended mode changes, and an electronic controller that processes sensor signals to maintain safe operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a multi-stable selector with indexing mechanism is used to select transmission modes, then the selector can maintain stable positions corresponding to different operating modes, but the selector may be left between two positions and unintentionally moved to a drive mode due to vibrations or shocks
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the sensor output range limits based on the direction of selector movement. When the selector moves toward a non-drive mode, the output range limits are set to ensure the signal falls within a safe band. When moving toward a drive mode, different limits are applied. This directional parameter adjustment ensures that even if the selector is left between positions, it cannot unintentionally activate a drive mode, thus resolving the contradiction between position stability and operational safety.
2Reliability
If a lock mechanism is added to prevent unintended mode changes, then the selector cannot be moved unintentionally, but the device complexity increases and the locking mechanism may fail to engage when the selector is in intermediate positions
Solution Approach 1:
The patent replaces the mechanical lock mechanism with an electronic control system that uses sensor feedback and calibrated output range bands to prevent unintended mode changes. Instead of relying on a physical locking mechanism that may fail to engage in intermediate positions, the system uses electronic calibration to ensure the sensor output always corresponds to a safe mode. This substitution reduces mechanical complexity while maintaining or improving reliability.
3Ease of manufacture
If the sensor output range is fixed for all positions, then the sensor calibration is simple, but the selector cannot reliably distinguish between drive and non-drive modes when positioned between stable positions
Solution Approach 1:
The patent applies dynamics by making the sensor output range limits dynamic rather than fixed. The electronic controller adjusts the lower and upper limits of the sensor output range based on the direction of selector movement and the current position. This dynamic adjustment allows the system to maintain high measurement precision in distinguishing between drive and non-drive modes while keeping the calibration process relatively simple, as the limits are adjusted programmatically rather than requiring complex physical calibration.
Data Source
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AI summary
A method for controlling a motor vehicle transmission (11) is disclosed in which a sensor (18) used to produce an indication of position of a selector (17) is calibrated such that positioning the selector (17) at a peak force feedback position produced by a peak and trough force feedback mechanism (24) connected to the selector (17) will always result in the selection of a drive mode of the transmission (11).