Motor Control Apparatus Wall-Hitting Speed Check
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Solution Overview
Problem
Conventional motor control apparatuses face challenges in precisely controlling the rotation position of a detent plate in a shift range switchover mechanism due to excessive load on the rotation transfer part, leading to inaccurate learning of the reference position and reduced precision in position control, especially when the motor rotation speed exceeds the target speed during wall-hitting control.
Innovation Solution
A motor control apparatus that includes a shift range switchover control part, a wall-hitting control part, and a speed check part, which rotates the rotor at a lower speed during wall-hitting control and limits the power supply angular interval when the rotor's speed is within a predetermined range, thereby reducing the load on the rotation transfer part and preventing premature motor stoppage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the motor rotation speed is lowered during wall-hitting control to reduce hitting impact, then the load on the rotation transfer part is reduced, but the phase lead amount decreases when the motor rotation speed exceeds the target rotation speed, generating relatively large braking force and causing the motor to stop prematurely
Solution Approach 1:
The patent applies dynamics by making the power supply angular interval variable based on the motor rotation speed. When the rotation speed is within a predetermined range, the power supply angular interval is limited to be smaller, which dynamically adjusts the braking force to prevent premature motor stoppage while maintaining reduced hitting impact. This dynamic adjustment resolves the contradiction between reducing impact and ensuring accurate reference position learning.
Solution Approach 2:
The patent changes the parameter of power supply angular interval based on the motor rotation speed condition. By setting different power supply angular intervals for different speed ranges, the system optimizes the balance between reducing hitting impact and maintaining sufficient phase lead amount to prevent premature stopping, thereby ensuring accurate reference position learning.
2Reliability
If the power supply angular interval is limited to prevent premature motor stoppage, then the motor can maintain rotation until wall-hitting is complete, but the braking force becomes excessively large when the motor rotation speed exceeds the target rotation speed
Solution Approach 1:
The patent uses dynamics by conditionally adjusting the power supply angular interval based on the motor rotation speed. The control part only limits the power supply angular interval when the rotation speed is within the predetermined range, creating a dynamic control strategy that applies braking force selectively. This prevents excessively large braking force while ensuring the motor maintains rotation until wall-hitting is complete.
3Object-affected harmful factors
If the rotation speed of the rotor is decreased during wall-hitting control, then the hitting impact is reduced, but the precision of rotation position control may be compromised
Solution Approach 1:
The patent changes the power supply angular interval parameter based on the rotation speed condition to maintain control precision. By adjusting this parameter dynamically, the system ensures that even at lower rotation speeds during wall-hitting control, the rotation position control precision is maintained while still reducing the hitting impact on the rotation transfer part.
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 solution effectively reduces the load on the rotation transfer part, decreases the impact during wall-hitting, and ensures accurate learning of the reference position without lowering the precision of rotation position control, allowing the motor to maintain rotation until the wall-hitting operation is complete.
Implementation Method 1
A motor control apparatus rotationally drives a driven body of a shift range switchover mechanism by controlling a motor provided as a drive power source of a shift-by-wire system
Data Source
AI summary
A control circuit of a motor control apparatus includes a shift range switchover control part for rotationally driving a rotor of the motor to a target position, which corresponds to a target shift range, a wall-hitting control part for rotating the rotor until the driven body hits one of limit positions of a movable range of the driven body at a speed lower than that of the rotor controlled by the shift range switchover control part, and a speed check part for checking whether a rotation speed of the rotor is within a predetermined speed range, when the rotor is rotated by the wall-hitting control part. The wall-hitting control part limits a power supply angular interval to be smaller when the rotation speed of the rotor is within the predetermined speed range than when the rotation speed of the rotor is lower than the predetermined speed range.