Motor Feedback Control Device with Weighted Current Detection

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Solution Overview

Problem

Existing feedback control devices for motors face challenges in accurately detecting a wide range of electric currents due to differences between multiple detection systems, leading to abrupt changes in electric current values and potential instability, particularly in the electric current loop.

Innovation Solution

A feedback control device that includes a controller and a detector with multiple detection systems, where each system uses a sensor and an adjuster to output signals multiplied by weight coefficients, allowing for gradual switching between systems to minimize detection value changes, using high accuracy sensors for micro currents and wide range sensors for large currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple electric current detection systems are used to cover both micro currents and large currents, then the detection range is extended, but output differences between systems cause abrupt changes in feedback values and potential instability

Engineering Contradiction:
Improvedetection rangeVSAvoidstability of electric current loop
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent combines multiple detection systems (first detection system with amplifier for micro currents and second detection system without amplifier for large currents) into a unified detection apparatus. Both systems share common components (sensor, wiring) and their outputs are integrated through selection switching, allowing the system to leverage the advantages of both systems while maintaining stability through coordinated operation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements dynamic switching between detection systems based on the magnitude of the detected current. The selection switch dynamically selects which detection system to use: the first system (with amplifier) for micro currents and the second system (without amplifier) for large currents. This dynamic adaptation prevents abrupt changes by ensuring smooth transitions between systems at predetermined current thresholds.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If a single sensor is used for both micro currents and large currents, then the device complexity is reduced, but detection accuracy cannot be maintained across the entire range

Engineering Contradiction:
Improvenumber of detection systemsVSAvoiddetection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies different detection characteristics to different current ranges. The first detection system (with amplifier) is optimized for micro current detection with high precision, while the second detection system (without amplifier) is optimized for large current detection with wide range. Each system's characteristics are locally optimized for its specific operating range, and the selection switch ensures the appropriate system is used for each condition.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If amplifiers are used to adjust output signals from different sensors, then output differences between systems are reduced, but the amplifiers themselves experience changes over time causing drift

Engineering Contradiction:
Improveoutput signal consistencyVSAvoidstability over time
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a selection switch as an intermediary device that coordinates the operation of multiple detection systems. Rather than using amplifiers to force signal matching, the selection switch acts as a mediator that routes the appropriate system output based on current magnitude. This intermediary approach avoids the stability issues of amplifiers while maintaining output consistency through intelligent signal selection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3118582B1Feedback control device
Publication Date: 2018.05.23 MITUTOYO CORP
  • EP3118582B1 patent drawingFigure 1
  • EP3118582B1 patent drawingFigure 2
  • EP3118582B1 patent drawingFigure 3

AI summary

Motor control device includes a controller controlling a motor (a calculator controller and an electric current controller), and a detector (an electric current loop) detecting an electric current of the motor and returning the detected electric current to the controller. The electric current loop includes a first detection system, a second detection system, and an electric current calculator which sums output signals from each system. Each detection system includes a sensor detecting the electric current of the motor, and a weight adjuster outputting to the electric current calculator, a detection electric current value from each sensor multiplied by a weight coefficient.