Servo Motion Control System with Multi-Head Scale Averaging

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Solution Overview

Problem

Conventional motion control systems for precise movement, such as goniometers, face complexity in data processing, leading to difficulties in real-time feedback control and accuracy due to the need for complex calibration procedures and inconsistent calibration data across systems.

Innovation Solution

A motion control system that utilizes a plurality of scale-detecting means to calculate an average value of movement, enabling simplified processing and real-time feedback control by averaging output signals and using software interpolation, thereby reducing computational time and increasing accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex calibration procedures are used to achieve high measurement precision, then measurement accuracy is improved, but device complexity and processing time increase

Engineering Contradiction:

Improveangle measurement accuracyVSAvoidcalibration system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The calibration process is segmented into distinct phases: initial calibration to generate lookup tables, and operational phase using pre-computed correction data. This segmentation allows complex calibration to be performed once offline, while real-time operation uses simple table lookups, resolving the contradiction between measurement precision and device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Calibration data and correction tables are computed in advance during an initial calibration phase. The pre-computed lookup tables store correction values for various angle measurements, eliminating the need for complex real-time calculations during actual measurement operations, thus improving both speed and simplicity.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If complex calibration procedures are used to achieve high measurement precision, then measurement accuracy is improved, but processing time increases

Engineering Contradiction:

Improveangle measurement accuracyVSAvoidcomputational time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

All complex calibration computations are performed in advance to generate lookup tables. During actual measurement, the system simply performs table lookups and interpolations, reducing computational time from minutes or hours to microseconds, thus resolving the time consumption issue while maintaining high precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of performing complex calculations repeatedly, the system creates copies of calibration data in lookup tables. These tables contain pre-computed correction values that can be quickly retrieved and applied during measurement, eliminating redundant computations and significantly reducing processing time.

Inventive Principle:

Principle #26Copying

3Speed

If real-time feedback control is implemented, then control responsiveness is improved, but computational requirements and system complexity increase

Engineering Contradiction:

Improvecontrol responsivenessVSAvoidcontrol system complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The system replaces complex real-time mechanical computation with software-based lookup table operations. By substituting hardware computation with software table lookups and interpolations, the system achieves real-time performance without requiring complex computational hardware, thus improving responsiveness while keeping system complexity manageable.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If hardware interpolation is used to achieve high-speed processing, then processing speed is improved, but system cost and complexity increase

Engineering Contradiction:

Improveprocessing speedVSAvoidhardware complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Hardware interpolation circuits are replaced with software-based interpolation algorithms running on standard processors. The software implementation uses pre-computed lookup tables and mathematical interpolation formulas to achieve the same functionality without requiring specialized hardware, reducing system complexity and cost while maintaining high processing speed.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the implementation parameter from hardware-based to software-based processing. By using software algorithms with optimized lookup tables and interpolation methods, the system achieves comparable or superior processing speed without the complexity and cost of dedicated hardware interpolation circuits.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8712013B2Motion control system and X-ray measurement apparatus

Publication Date: 2014.04.29 RIGAKU CORP

AI summary

A motion control system comprising a servo motor for moving a rotary stage; a scale provided on the rotary stage or on an object that moves integrally with the rotary stage; a plurality of reading heads for detecting the scale and outputting a signal; a data processing part for calculating an average value of rotation angle data based on each of the output signals from the reading heads and outputting the average value as a signal; and a servo amplifier for controlling the motor based on the signal representing the average value of the rotation angle. The motion control system can cause the rotary stage to rotate to a desired rotation angle to a high degree of accuracy using the reading heads.