Shift Position Controller Noise Filtering
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Solution Overview
Problem
Existing electrical drive-by-wire systems in vehicles can fail due to temporary noise misinterpreting encoder signals, leading to incorrect motor rotation control and potential system failures.
Innovation Solution
A shift position switching controller that determines noise in A and B phase signals by comparing their time intervals and phase differences, preventing noise from corrupting the encoder count and maintaining accurate motor rotation control through serial power supply phase switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the encoder output signals are used directly for motor rotation control, then the system response speed is improved, but temporary noise causes erroneous recognition leading to control failures
Solution Approach 1:
The controller performs preliminary noise determination by comparing time intervals between A phase and B phase signals before using them for motor control. This preliminary filtering action prevents noise from corrupting the encoder count, thereby maintaining both fast response and high reliability in the motor rotation control system.
2Reliability
If noise determination and filtering is added to the encoder signal processing, then control reliability is improved, but device complexity increases
Solution Approach 1:
The controller uses feedback from the time interval comparison between A phase and B phase signals to determine whether to accept or reject encoder counts. This feedback mechanism reliably filters noise while maintaining simple processing logic that checks only the temporal relationship between phase signals.
Solution Approach 2:
The encoder signal processing system performs self-diagnosis by automatically detecting noise through time interval comparison of its own A and B phase outputs. The system serves itself by internally filtering erroneous signals without requiring external intervention or complex additional processing circuits.
3Manufacturing precision
If the matching relationship between encoder count and power supply phase is maintained strictly, then manufacturing precision is improved, but the system becomes vulnerable to noise-induced mismatches
Solution Approach 1:
The controller applies preliminary anti-action by preemptively identifying and rejecting noise signals through time interval comparison before they can disrupt the matching relationship between encoder count and power supply phase. This prevents noise-induced mismatches while maintaining precise phase synchronization for motor control.
Data Source
AI summary
A motor control system controls a rotation drive of a motor by serially switching a power supply phase of the motor based on a count value of an output signal from an encoder and prevents a temporary noise from causing an abnormal rotation of such a motor. A microcomputer determines that one of an A phase signal or a B phase signal is a noise when the two signals are input at substantially at the same timing and one of the two signals has a shorter time interval from a previous input signal. Thus, a temporary noise is prevented from corrupting normal operation between the encoder count, the rotation position of the motor, and the power supply phase.