Robot Learning Control Unit for Vibration Reduction

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Solution Overview

Problem

Existing robot systems face increased learning control iterations when designed for wide use ranges with varying orientations and end effector loads, leading to inefficiencies in vibration reduction.

Innovation Solution

A robot system with a learning control unit that includes multiple learning control parts assigned to specific use ranges, allowing for selection based on operation information such as position and load, to optimize vibration correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single learning control part is designed to ensure robustness across a wide use range with varying orientations and end effector loads, then the vibration reduction effectiveness is maintained, but the number of learning control iterations required increases

Engineering Contradiction:
Improvevibration reduction effectivenessVSAvoidnumber of learning control iterations
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The learning control unit is divided into multiple learning control parts, each responsible for a specific use range defined by orientation and end effector load conditions. This segmentation allows each part to specialize in correcting vibrations for particular operational scenarios, reducing the iterations needed compared to a single universal learning control part that must handle all conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different learning control parts are assigned to different use ranges (local conditions), with each part optimized for its specific orientation and load range. This local optimization ensures that each learning control part can achieve effective vibration reduction with fewer iterations for its designated range, rather than requiring many iterations across all possible conditions.

Inventive Principle:
Principle #3Local quality

2Productivity

If the robot operation is accelerated to shorten tact time, then the production efficiency is improved, but vibrations are generated at the hand tip portion due to reducer strain and arm rigidity shortage

Engineering Contradiction:
Improveproduction efficiencyVSAvoidvibrations at hand tip
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

Acceleration sensors are attached to the hand tip portion to detect vibrations during robot operation. The detected vibration data is fed back to the learning control unit, which calculates correction amounts and applies them to the servo control. This feedback mechanism enables the system to identify and correct vibrations generated during high-speed operation, allowing accelerated robot movement without excessive hand tip vibrations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The learning control performs preliminary vibration correction by calculating correction amounts based on detected vibrations and applying them before actual high-speed operation. This preliminary action allows the robot to be pre-adjusted for optimal performance at accelerated speeds, enabling production efficiency improvement while preventing harmful vibrations during actual operation.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If learning control is not terminated, then the robot cannot start actual operation, but sufficient vibration correction may not be achieved

Engineering Contradiction:
Improveoperation readinessVSAvoidvibration correction sufficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The learning control is configured to terminate after a predetermined number of iterations or when vibration correction reaches a satisfactory level. This partial action approach balances the need to enable actual operation (productivity) with achieving sufficient vibration correction (reliability). The system performs enough learning control iterations to achieve acceptable vibration reduction without indefinitely delaying operation startup.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS10618164B2Robot system having learning control function and learning control method
Publication Date: 2020.04.14 FANUC LTD
  • US10618164B2 patent drawing
  • US10618164B2 patent drawing
  • US10618164B2 patent drawing

AI summary

A robot system is provide with a robot control device that includes an operation control unit and a learning control unit. The learning control unit performs a learning control in which a vibration correction amount for correcting a vibration generated at a control target portion of a robot is calculated and the vibration correction amount is employed in the operation command at a next time. The learning control unit includes a plurality of learning control parts for calculating the vibration correction amount and a selection unit that selects one of the plurality of learning control parts on the basis of operation information of the robot when the robot is made to be operated by an operation program that is a target of the learning control.