Motorized Shift Position Learning Without Dual-Control Interference
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Solution Overview
Problem
Existing shift devices with multiple microcomputers for controlling a motor face interference issues during shift position learning, leading to potential failures in acquiring shift positions when one microcomputer's learning is incomplete or abnormal.
Innovation Solution
A shift device with a motor driven by two separate drive systems, each with its own control unit, where the motor is driven by one system to move a positioning member through valley portions, preventing interference and ensuring continuous operation even if one control unit is abnormal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two microcomputers are used to control the motor for shift position learning, then the reliability of continuous operation is improved, but the control units interfere with each other during learning
Solution Approach 1:
The system designates one microcomputer as the master and another as the slave before learning begins. The master microcomputer controls the motor during the entire learning process, while the slave microcomputer only observes and records position data. This preliminary role assignment prevents control interference by ensuring only one unit actively drives the motor at any time.
Solution Approach 2:
The patent introduces a master-slave relationship as an intermediary control structure. The master microcomputer acts as the primary controller that mediates all motor control actions, while the slave microcomputer serves as a secondary observer that does not directly control the motor. This intermediary structure eliminates harmful control interference while maintaining the redundancy benefits of having two control units.
2Reliability
If one microcomputer's learning is incomplete or abnormal, then the system should maintain operation capability, but the interference prevents accurate position acquisition
Solution Approach 1:
The slave microcomputer continuously monitors the learning process and the master microcomputer's control actions. By providing feedback on the actual position data without interfering with the master's control, the system ensures accurate position acquisition even when the master encounters abnormalities. The feedback mechanism allows the system to detect and handle learning failures while maintaining measurement precision.
Solution Approach 2:
The system performs preliminary validation of learning results by having the slave microcomputer independently verify position data during the master's learning process. This preliminary verification ensures that even if the master's learning is incomplete or abnormal, the system can detect the issue and maintain accurate position information through the slave's observations.
3Productivity
If both microcomputers control the motor simultaneously, then the learning process is accelerated, but the control actions conflict and hinder learning
Solution Approach 1:
Before the learning process begins, the system preliminarily assigns the master microcomputer full control authority over the motor. This preliminary designation prevents control conflicts by ensuring that only the master microcomputer can issue motor control commands during learning, while the slave microcomputer is restricted to observation and data recording only.
Solution Approach 2:
The master-slave control architecture serves as an intermediary mechanism that resolves the productivity-reliability conflict. The master microcomputer handles all motor control operations to maintain learning speed, while the slave microcomputer provides intermediate verification and data recording without conflicting control actions. This intermediary structure eliminates control conflicts while preserving efficient learning execution.
Data Source
AI summary
A shift device includes: a shift switching member including valley portions corresponding to shift positions; a motor including a rotor and a stator and configured to drive the shift switching member; a first drive system including a first control unit configured to control a voltage for driving the motor; a second drive system provided separately from the first drive system and including a second control unit configured to control a voltage for driving the motor; and a positioning member configured to establish the shift positions in a state in which the positioning member is fitted into any one of the valley portions of the shift switching member. The shift device acquires the shift positions when the motor is driven by the voltage output from one of the first and second drive systems to move the positioning member such that the positioning member continuously passes through the valley portions.