Motor Controller Correction Termination for Reversal

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Solution Overview

Problem

Existing motor control methods struggle to accurately determine the timing of correction termination when reversing the movement direction of a driven body, leading to potential delays due to friction and elastic energy accumulation, especially when elastic bodies are involved in the transmission.

Innovation Solution

A motor controller with dual displacement detectors for the motor and driven body, a correction part that adds and terminates adjustments based on threshold values for both, ensuring timely correction termination regardless of the transmission configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If correction is added to overcome friction during direction reversal, then movement assistance is improved, but correction termination timing becomes inaccurate

Engineering Contradiction:

Improvemovement assistanceVSAvoidcorrection termination timing

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system uses feedback from displacement detectors to monitor the actual movement of both the motor and driven body. The correction termination judgment part continuously receives displacement information and compares it against threshold values to determine when to terminate correction, ensuring accurate timing based on actual system state rather than predetermined time or displacement values.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary mechanism (the correction termination judgment part) that mediates between the correction part and the control system. This intermediary monitors displacement through detectors and uses threshold comparisons to trigger correction termination, acting as a bridge that resolves the timing inaccuracy problem by translating physical displacement into control decisions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If correction termination is based on motor displacement only, then control simplicity is maintained, but driven body movement accuracy deteriorates

Engineering Contradiction:

Improvecontrol simplicityVSAvoiddriven body movement accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The system segments the displacement detection function into two independent detectors: one for motor displacement and one for driven body displacement. This segmentation allows each detector to independently monitor its respective component, providing accurate data for correction termination judgment without requiring a complex single-detector system that would need to account for both components simultaneously.

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If correction termination is based on driven body displacement only, then movement accuracy is improved, but elastic energy accumulation causes delays

Engineering Contradiction:

Improvemovement accuracyVSAvoidcorrection termination delay

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The system dynamically adjusts correction termination timing by considering the elastic characteristics of the transmission. The correction termination judgment part uses threshold values that account for elastic energy accumulation and release, allowing the termination decision to be made at the appropriate moment when the driven body has moved sufficiently but before excessive elastic energy causes delayed movement or oscillation.

Inventive Principle:

Principle #15Dynamics

4Stability of the object's composition

If elastic bodies are present in transmission, then mechanical flexibility is improved, but correction termination timing becomes unreliable

Engineering Contradiction:

Improvemechanical flexibilityVSAvoidcorrection termination timing

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The system changes the parameter used for correction termination judgment from time-based or motor-displacement-based to driven-body-displacement-based with threshold comparison. This parameter change makes the termination decision reliable even in the presence of elastic bodies, as it directly monitors the actual position of the driven body and terminates correction when the threshold is reached, regardless of elastic energy fluctuations.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9377773B2Motor controller for performing correction when direction of rotation is reversed

Publication Date: 2016.06.28 FANUC LTD

AI summary

A motor controller is configured to judge whether or not the amount of displacement of a driven body after the direction of movement of the driven body is reversed, exceeds a predetermined threshold value, and whether or not the amount of displacement of a motor after the direction of movement of the motor is reversed, exceeds another predetermined threshold value. When the amount of displacement of the driven body exceeds the threshold value, or the amount of displacement of the motor exceeds a second threshold value, the correction of the commands to the motor is terminated.