Robot Picking Priority Assignment to Reduce Tact Time

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Solution Overview

Problem

Existing three-dimensional measurement systems for industrial robots picking items from a pallet face inefficiencies due to the robot arm shielding candidate works, leading to prolonged tact times as they wait for the arm to retreat before capturing images of remaining candidates, and heavy calculation loads from calculating shield ratios for each candidate.

Innovation Solution

A processing apparatus assigns priorities to partial areas of the pallet based on the area shielded by the robot's arm, selecting candidate works with the highest priority and determining position changes post-picking, allowing for efficient picking without waiting for the arm to retreat, and reducing calculation load by comparing pre- and post-picking images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the robot arm picks a work from the piled works, then the picking operation is performed, but the robot arm shields the remaining candidate works making it impossible to recognize position changes

Engineering Contradiction:
Improvepicking operation efficiencyVSAvoidposition information of shielded candidate works
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The system performs preliminary three-dimensional measurement and position recognition of all candidate works before the robot arm picks any work. By capturing images and determining positions in advance, the system preserves position information of all candidate works before shielding occurs, enabling subsequent comparison to detect position changes without waiting for the arm to retreat.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the system waits for the robot arm to retreat before capturing images to determine position changes, then accurate position recognition is achieved, but the tact time is prolonged

Engineering Contradiction:
Improveposition recognition accuracyVSAvoidtact time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system captures images and performs three-dimensional measurement of all candidate works before the robot arm picks any work. By having position information ready in advance, the system can immediately compare pre-picking and post-picking images without waiting for the arm to retreat, thereby maintaining measurement precision while significantly reducing tact time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates a digital copy of the position information of all candidate works through three-dimensional measurement before picking. This digital model allows subsequent comparison with actual post-picking positions without requiring physical re-measurement, enabling fast position change detection while maintaining accuracy.

Inventive Principle:
Principle #26Copying

3Productivity

If the system calculates shield ratio for each candidate work to determine picking sequence, then optimal picking sequence is achieved, but the calculation load becomes heavy

Engineering Contradiction:
Improvepicking sequence optimizationVSAvoidcalculation load
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system divides the pallet area into multiple regions and performs three-dimensional measurement for each region separately. By segmenting the measurement task by spatial location rather than calculating shield ratios for each individual candidate work, the system reduces calculation load while still achieving optimized picking sequence through region-based priority assignment.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS10040199B2Apparatus and method for determining work to be picked
Publication Date: 2018.08.07 CANON KK

AI summary

Provided is a processing apparatus for determining a work to be picked by a robot from a plurality of works, using an image, captured by an image capture device, of an area on which the plurality of works are placed. The apparatus selects a pickable candidate work based on the image, and determines a picking target work positioned in a partial area assigned with a highest priority among the partial areas where candidate works are respectively positioned. The apparatus selects a next pickable candidate work whose position and orientation have changed within allowable ranges before and after picking, and determines a next picking target work positioned in the partial area assigned with the highest priority among the partial areas where the next pickable candidate works are respectively positioned.