Shift-By-Wire Position Learning via Motor Current and Detent Load
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric shift-by-wire systems face challenges in accurately recognizing the absolute position of a motor, as hall sensors only measure relative angles, and existing methods require separate motor driving for position learning, making them inefficient and inaccurate.
Innovation Solution
A position learning system that senses current variations from a detent plate and spring to learn positions of shift stages R and N, using a sensor and controller to perform offset operations and recognize positions of shift stages P and D without additional sensors or separate motor driving, by calculating reasonable data points and performing offset operations based on learned positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hall sensor is used to measure motor position, then the system can measure relative angle of rotation, but it cannot measure absolute angle of rotation accurately
Solution Approach 1:
The patent introduces a detent spring as an intermediary element that mechanically interacts with the detent plate to create detectable current variations. This intermediary mechanism allows the system to infer absolute position information through current sensing without requiring direct absolute position sensors on the motor.
Solution Approach 2:
The patent replaces traditional mechanical position sensing methods with an electrical sensing approach. By monitoring current variations in the motor caused by the detent spring's interaction with the detent plate, the system substitutes mechanical position measurement with electrical signal detection, enabling accurate position recognition.
2Measurement precision
If a non-contact type position sensor is attached to the motor, then absolute position measurement is possible, but the updating speed of PWM signal is low
Solution Approach 1:
The patent replaces slow mechanical position sensors with rapid electrical current sensing. The current sensor can detect position-related current variations at high speeds, eliminating the PWM signal updating bottleneck of non-contact position sensors while maintaining accurate position measurement capability.
3Measurement precision
If the motor is forcedly driven to learn position, then the absolute position of motor can be learned, but separate time is required for position learning
Solution Approach 1:
The patent enables the system to learn motor position automatically during normal operation without requiring separate forced motor driving. The current sensor continuously monitors current variations that occur naturally during shift operations, allowing the controller to learn positions of shift stages R and N and perform offset operations to recognize positions of shift stages P and D in real-time.
Solution Approach 2:
The patent transforms the position learning process from a discrete, time-consuming operation into a continuous process that occurs during normal shift operations. By continuously monitoring current variations during regular motor operation, the system maintains up-to-date position information without interrupting or pausing for separate learning cycles.
4Measurement precision
If conventional position learning methods are used, then motor position can be recognized, but the system requires additional sensors and separate motor driving operations
Solution Approach 1:
The patent makes the existing current sensor serve multiple functions: it continues to monitor motor current for control purposes while simultaneously detecting position-related current variations for position learning. This multi-functionality eliminates the need for separate position sensors and simplifies the overall system architecture.
Solution Approach 2:
The system uses its own operational characteristics (current variations during normal operation) to perform position learning, eliminating the need for external position sensors and separate learning operations. The motor and control system essentially learn their own positions through self-monitoring of current patterns.
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
Enables accurate and simple recognition of motor positions, enhancing the performance of electric shift-by-wire systems by eliminating the need for separate motor driving and improving shift control precision.
Implementation Method 1
a sensor for sensing the current generated from the motor
Data Source
AI summary
The present invention relates to a position learning system for an electric shift-by-wire system, which senses changes in the load of a motor according to operations of a four-stage detent plate and a detent spring to learn positions of shift stages of the electric shift-by-wire system, the position learning system including: a sensor for sensing the current generated from the motor; and a controller for receiving current data until a shift stage P is switched to a shift stage D or the shift stage D is switched to the shift stage P from the sensor, learning positions of shift stages R and N through the received current data, and performing offset operations on the basis of the learned positions of the shift stages R and N to learn positions of the shift stages P and D.