Servomotor Controller for Reciprocating Motion Learning Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing servomotor controllers face challenges in applying learning control of the angle-based method to reciprocating motions, as they require precise determination of reference positions and cannot handle varying reference positions, leading to deviations during outward and return motions.

Innovation Solution

A servomotor controller that includes a position detector, positional deviation obtaining part, reference position generating part, converting parts, and a controlling part to generate and adjust correction amounts for periodic reciprocating motion, allowing for continuous correction across both directions of motion by inverting polarity and using filters to stabilize the control system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If learning control of angle based method is applied to reciprocating motion, then the control can be used without precise period determination, but the reference position varies in different directions causing deviation

Engineering Contradiction:

Improveease of use of learning controlVSAvoidcontrol precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The control method segments the reciprocating motion into outward motion and return motion phases, applying learning control separately to each phase. This allows the reference position to be properly handled for each direction while maintaining the ease of angle-based method

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention inverts the polarity of the correction amount when switching from outward motion to return motion (or vice versa). This inversion allows the correction amount generated in one direction to be properly applied in the opposite direction, resolving the precision issue while maintaining ease of use

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If memory sets are switched depending on speed of object, then learning control can be applied to reciprocating motion, but continuity between memory sets is lost causing large deviation

Engineering Contradiction:

Improveadaptability to reciprocating motionVSAvoidcontrol precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention performs preliminary inversion of the correction amount polarity before storing it in the memory set for the opposite motion phase. This preliminary action ensures continuity when switching between memory sets, preventing large deviations while maintaining adaptability to reciprocating motion

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8067918B2Servomotor controller for controlling periodic reciprocation

Publication Date: 2011.11.29 FANUC LTD

AI summary

A servomotor controller capable of properly generating reference positions, by which learning control of angle based method may be applied to the periodically reciprocating motion of an object. The learning controller obtains a first positional deviation of a driven object at every predetermined sampling period of time, and the first positional deviation is converted, by a first converting part, to a second positional deviation associated with each reference position in one periodic reciprocating motion of the driven object. After a first correction amount of an immediately previous reciprocating motion of the driven object, stored in a memory, is added to the second positional deviation, the second positional deviation is stored in the memory as a renewed first correction amount. The first correction amount is converted to a second correction amount associated with the sampling period, by a second converting part.