Shift Range Motor Control for Overshoot-Free Range Confirmation
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Solution Overview
Problem
Existing shift range control devices face challenges in quickly and accurately confirming the shift range, particularly when the motor overshoots due to momentary power interruptions, which can lead to incorrect range determination and delayed hydraulic control in transmissions.
Innovation Solution
A shift range control device that includes a motor position calculation unit, target setting unit, drive control unit, reversal determination unit, and range confirmation determination unit, which detects motor reversal during stop control to confirm the shift range, preventing overshoot and enabling early hydraulic control initiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the motor is controlled to reach the target rotation position, then the shift range switching accuracy is improved, but the motor may overshoot due to momentary power interruptions causing incorrect range determination
Solution Approach 1:
The control device continuously monitors the actual rotation position of the motor and compares it with the target rotation position. When the actual position reaches the target position, the control device switches to stationary phase energization control to maintain the motor at the correct position, preventing overshoot even during power interruptions.
Solution Approach 2:
The control device performs preliminary positioning by calculating the actual rotation position and switching to stationary phase energization control before the motor completes its full rotation. This preliminary action ensures the motor is ready to stop at the correct position and prevents overshoot when power is restored after interruptions.
2Speed
If the control switches to sudden braking control when angle deviation is small, then the response speed is improved, but the motor may reverse causing incorrect shift range determination
Solution Approach 1:
The control device applies preliminary anti-action by switching to stationary phase energization control when the angle deviation becomes small, which prevents motor reversal. This counteracts the tendency of the motor to overshoot and reverse by maintaining energization at the target position, ensuring stable and accurate shift range determination.
3Manufacturing precision
If the hydraulic control is delayed until motor stopping is confirmed, then the shifting precision is improved, but the overall shifting time increases
Solution Approach 1:
The control device performs preliminary positioning using stationary phase energization control to bring the motor close to the target position. Once the actual rotation position reaches the target position, the control device can initiate hydraulic control while the motor is already correctly positioned, eliminating the need to wait for complete motor stopping confirmation.
Data Source
AI summary
A shift range control device switches a shift range by controlling driving of a motor. The shift range control device calculate an actual rotation position of the motor. The shift range control device sets a target range according to a required range and a target rotation position according to the target range. The shift range control device controls the driving of the motor such that the actual rotation position reaches the target rotation position.