Robot Brake Functionality Check Using Torque Sensor Analysis

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Solution Overview

Problem

Existing methods for checking the brake functionality of robots are not flexible enough, particularly when the braking torque exceeds the motor torque, and often require non-installed state testing, which may not accurately represent operational conditions.

Innovation Solution

A method utilizing a torque sensor associated with each axis of a robot to determine and analyze the torque acting on the axis, allowing for the assessment of brake functionality by comparing the measured torque with a setpoint torque or reference profile, and optionally increasing the drive torque to determine braking torque, while preventing axis movement to reduce wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If motor current is measured to determine braking torque, then brake functionality can be checked, but the method is not suitable when braking torque exceeds engine torque

Engineering Contradiction:
Improvebrake functionality detectionVSAvoidapplicability to different braking torque conditions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the electrical measurement method (motor current measurement) with a mechanical measurement method (torque sensor measurement). The torque sensor directly measures the torque on the axis, providing accurate brake functionality detection regardless of whether the braking torque exceeds the engine torque. This substitution of measurement principle resolves the limitation of the previous method.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If brake is tested in non-installed state, then testing can be performed, but it does not accurately represent operational conditions

Engineering Contradiction:
Improvetesting feasibilityVSAvoidbrake performance measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent enables preliminary brake functionality checks to be performed during robot operation using the torque sensor, rather than requiring separate non-installed state testing. The torque sensor continuously monitors torque during normal operation, allowing brake assessment to be integrated into the operational workflow, thus maintaining both ease of testing and measurement accuracy.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If drive torque is increased to determine braking torque, then accurate measurement is achieved, but axis movement occurs causing wear

Engineering Contradiction:
Improvebraking torque determination accuracyVSAvoidwear on brake and gear
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The patent introduces the torque sensor as an intermediary measurement device that can accurately measure torque during normal operation without requiring extreme test conditions. By using the torque sensor to monitor torque during controlled brake activation, the system achieves accurate braking torque determination without needing to significantly increase drive torque, thus minimizing wear on mechanical components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2321623B1Method for checking a brake of a robot
Publication Date: 2017.01.25 KUKA DEUT GMBH
  • EP2321623B1 patent drawingFigure 1
  • EP2321623B1 patent drawingFigure 2
  • EP2321623B1 patent drawingFigure 3

AI summary

The invention relates to a method for checking a brake (22) of a robot (1) comprising a plurality of axles (A1-A6). The robot (1) comprises a drive (21) associated with one of the axles (A3) of the plurality of axles (A1-A6), a brake (22) which is associated with said axle (A3) and designed to at least reduce a movement of said axle (A3), and a torque sensor (24) which is associated with said axle (A3) and designed to determine the torque acting onto said axle (A3). The brake (22) is actuated, the torque acting upon the axle (A6) is determined by means of the torque sensor (24) while the brake (22) is activated, and the functionality of the brake (22) is assessed based on an analysis of the torque having been determined by the torque sensor (24).