Shift Position Switching Device Reference Position Learning
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Solution Overview
Problem
Existing shift position switching mechanisms in electrical drive-by-wire systems face issues with prolonged reference position learning time and increased power consumption, leading to motor warping and reduced durability due to forced dead-end rotation.
Innovation Solution
A shift position switching device that learns the reference position by observing a fall in motor rotation speed or acceleration to a threshold value, avoiding forced rotation and minimizing mechanical stress, thus reducing learning time and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the motor is forced to rotate for a certain period at the dead-end rotation position to learn the reference position, then the reference position can be learned, but the motor and switching mechanism warp and twist, reducing product life and durability
Solution Approach 1:
The system uses encoder feedback to detect the dead-end position by monitoring when the encoder count stops changing (remains constant at maximum or minimum value). This feedback mechanism allows the motor to learn the reference position without forcing rotation beyond the actual mechanical limits, preventing warping and twisting of the motor and switching mechanism while maintaining accurate reference position learning.
2Measurement precision
If the motor is forced to rotate for a certain period at the dead-end rotation position, then the reference position can be learned, but the learning time becomes long and power consumption increases
Solution Approach 1:
The system monitors encoder count feedback in real-time during motor rotation. When the encoder count reaches its maximum or minimum value and remains constant for a predetermined period, the system immediately identifies this as the dead-end position and stops the learning process. This feedback-based detection eliminates the need for extended forced rotation, significantly reducing reference position learning time while maintaining accurate position detection.
Solution Approach 2:
The system performs preliminary detection of the dead-end position by monitoring encoder count changes during the rotation process. By detecting the constant encoder count condition as the motor approaches the dead-end, the system can stop the rotation at the optimal point before excessive rotation occurs, thereby reducing the overall learning time and power consumption while ensuring accurate reference position learning.
3Measurement precision
If the motor is forced to rotate for a certain period at the dead-end rotation position, then the reference position can be learned, but electric power consumption increases
Solution Approach 1:
The system uses encoder feedback to detect when the motor reaches the dead-end position by monitoring constant encoder count. This feedback allows the motor to stop rotation as soon as the reference position is learned, preventing unnecessary continued rotation and the associated power consumption. The feedback mechanism ensures energy-efficient operation by eliminating wasted rotation cycles.
Data Source
AI summary
A shift position switching device for shifting gears in association with a shift position. The device includes a shift mechanism switching between shift positions using a drive power of a motor, an encoder outputting pulse signals in sync with a rotation of the motor, and a controller rotating the motor to a target rotation position corresponding to an intended gear. The controller rotates the motor toward a dead-end on a first shift position side of the shift mechanism while observing a motor rotation speed or an acceleration of rotation of the motor based on the outputted pulse signals of the encoder. Also, the controller learns, as a reference position on the first shift position side, a first rotation position of the motor.