Stepping Motor Controller Position Resumption

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Solution Overview

Problem

Conventional clock input type stepping motor controllers cannot resume driving a stepping motor from the exact rotational position after a temporary power suspension, as they update the excitation phase from an initial state upon power resumption, leading to inaccuracies in image-reading devices that rely on precise motor positioning.

Innovation Solution

A stepping motor controller that outputs clock signals with specific pulse intervals to quickly update the excitation phase to the suspension excitation phase, incorporating an excitation phase control unit, driver control unit, and nonvolatile memory to store and retrieve the suspension excitation phase, ensuring accurate resumption of motor position upon power restoration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the excitation phase is updated from an initial state upon power resumption, then the motor driver can operate with a simple control mechanism, but the rotational position accuracy is lost

Engineering Contradiction:
Improvecontrol mechanism simplicityVSAvoidrotational position accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system performs preliminary action by storing the excitation phase value before power suspension occurs. The storage unit saves the excitation phase data in advance, so that when power is restored, the system can immediately retrieve and apply the stored phase value without needing to restart from an initial state, thereby maintaining rotational position accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates a copy of the excitation phase data and stores it in a separate storage unit. This copy preserves the original phase information, allowing the system to restore the exact rotational position after power interruption without affecting the normal operation of the motor driver during powered states.

Inventive Principle:
Principle #26Copying

2Productivity

If the excitation phase is quickly updated to resume motor position, then operational efficiency improves, but the control system complexity increases

Engineering Contradiction:
Improveoperational efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The control system is segmented into distinct functional units: an excitation phase control unit that manages phase updates, a storage unit that handles data persistence, and a retrieval mechanism. This segmentation allows each component to perform its specific function efficiently, enabling quick phase restoration without creating a monolithic complex control system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The storage unit acts as an intermediary between the motor driver and the excitation phase control unit. It stores the excitation phase data and provides it back when needed, mediating the restoration process without requiring direct complex interaction between the control unit and storage mechanisms, thus simplifying the overall control architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2424103B1Stepping Motor Controller and Image-reading Device
Publication Date: 2019.08.21 BROTHER KOGYO KK
  • EP2424103B1 patent drawingFigure 1
  • EP2424103B1 patent drawingFigure 2
  • EP2424103B1 patent drawingFigure 3

AI summary

A stepping motor controller for controlling a stepping motor, includes: a motor driver; and a driver control unit. The motor driver includes: an excitation phase control unit; and a drive unit. The driver control unit includes: a motor driver power control unit; a drive control unit; a clock signal output unit; and an excitation phase storing unit. The excitation phase storing unit acquires an excitation phase at a time when the motor driver power control unit stops supplying electricity to the motor driver, and stores the acquired excitation phase as a suspension excitation phase. When the motor driver power control unit resumes supplying electricity to the motor driver, the drive control unit instructs the drive unit to continue to halt the supply of the drive current until the excitation phase signal is updated, in response to each pulse of the clock signal, to an excitation phase signal specifying the suspension excitation phase, and instructs the drive unit to supply the drive current after the excitation phase signal is updated to reach the excitation phase signal specifying the suspension excitation phase.