Acceleration Sensor Trajectory Measurement for Arbitrary Paths

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Solution Overview

Problem

Existing machine motion trajectory measurement methods are limited in accuracy and setup complexity, particularly for numerical control machine tools and robots, as they cannot accurately measure trajectory errors in arbitrary motion trajectories and relative motion between moving and fixed sides, and are prone to low measurement accuracy due to interference and deformation.

Innovation Solution

A machine motion trajectory measuring apparatus that uses an acceleration sensor to measure acceleration signals, separates these signals into frequency bands, and combines them with detection position signals to calculate and display highly accurate motion trajectories, enabling precise measurement of trajectory errors with a simple setup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the double ball bar method is used to measure trajectory error, then measurement accuracy of a few micrometers is achieved, but the measurable trajectory is limited to arc motion and complex setup is required

Engineering Contradiction:

Improvetrajectory error measurement accuracyVSAvoidmeasurable trajectory types

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical double ball bar measurement system with an acceleration sensor-based measurement system. The acceleration sensor measures acceleration signals that are then integrated to obtain trajectory information, eliminating the mechanical connection requirements and enabling measurement of arbitrary trajectories without complex setup

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from direct position/displacement measurement to acceleration measurement. By measuring acceleration and performing integration, the system can derive trajectory information for any motion type, not limited to arc motion, thereby improving adaptability while maintaining measurement accuracy

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the double ball bar method is used to measure trajectory error, then measurement accuracy of a few micrometers is achieved, but setup time and effort increase

Engineering Contradiction:

Improvetrajectory error measurement accuracyVSAvoidsetup time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical double ball bar setup with a simple acceleration sensor attachment. The sensor is fixed to the measurement object, and trajectory data is obtained through signal processing, eliminating the need for complex mechanical assembly and reducing setup time significantly

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The acceleration sensor-based system is self-contained and requires no external mechanical connections or complex alignment procedures. The sensor automatically measures acceleration and the system processes the signals to generate trajectory information, making the measurement process independent and rapid

Inventive Principle:

Principle #25Self-service

3Reliability

If position detector feedback control is used, then trajectory control is performed, but accurate position detection is impossible if detector installation position does not agree with driven body position

Engineering Contradiction:

Improvetrajectory controlVSAvoidposition detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces position detector-based feedback control with acceleration sensor-based measurement. The acceleration sensor directly measures the motion of the measurement object itself, eliminating the need for mechanical connection between the detector and the driven body, thus ensuring accurate measurement regardless of installation position

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The acceleration sensor acts as an intermediary that directly attaches to the measurement object to capture its motion characteristics. This intermediary approach bypasses the need for mechanical transmission connections, allowing accurate measurement of the object's actual trajectory without being affected by installation position mismatches

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10543574B2Machine motion trajectory measuring apparatus

Publication Date: 2020.01.28 MITSUBISHI ELECTRIC CORP

AI summary

A machine motion trajectory measuring apparatus includes a three-axis acceleration sensor measuring acceleration of a motion-trajectory measurement subject and outputting the result as an acceleration sensor signal, a sensor signal separation unit separating the acceleration sensor signal into two or more frequency bands, a motor signal separation unit separating a detection position signal into the frequency bands identical to those of the sensor signal separation unit, a data calibration unit calibrating the acceleration sensor signal in each of the two or more frequency bands by using the acceleration sensor signal separated by the sensor signal separation unit and the detection position signal separated by the motor signal separation unit and obtaining a motion trajectory component in each of the two or more frequency bands, and a motion trajectory calculation unit coupling the motion trajectory components in the two or more frequency bands and outputting the result as a motion trajectory.