Robotic Picking Sensor for Article Height Detection

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Solution Overview

Problem

Current order-picking systems face challenges in accurately determining the position and orientation of articles, particularly when the Z-direction height is unknown, leading to potential damage during handling and reduced packing density due to imprecise gripping and dropping mechanisms.

Innovation Solution

An order-picking system equipped with a robot, a camera, and a horizontally aligned sensor arrangement, such as a 2D LiDAR sensor or camera, captures the source container in plan view to detect the lower edge of the article, allowing for optimized trajectory planning and controlled depositing processes, reducing the need for excessive lifting and dropping heights.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the article is lifted higher with a safety margin to avoid collision during horizontal movement, then the reliability of avoiding collision is improved, but the energy consumption and handling time increase

Engineering Contradiction:
Improvecollision avoidanceVSAvoidlifting energy
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary detection of the article's lower edge position during the lifting process, enabling the controller to calculate the actual article height before completing the lift. This preliminary information allows optimization of the lifting trajectory to avoid excessive elevation while ensuring collision avoidance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sensor arrangement provides real-time feedback on the article's lower edge position during lifting. The controller uses this feedback to dynamically adjust the lifting trajectory, reducing the safety margin to the minimum necessary amount based on actual article dimensions rather than using a conservative fixed margin.

Inventive Principle:
Principle #23Feedback

2Reliability

If the article is dropped from a larger safety distance to prevent damage, then the reliability of preventing damage is improved, but the manufacturing precision of placement deteriorates

Engineering Contradiction:
Improvedamage preventionVSAvoidplacement precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The system detects the article's lower edge position preliminarily during the lifting process, calculating the actual article height before the depositing phase. This enables precise determination of the optimal release height that prevents damage while ensuring accurate placement.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Real-time feedback from the sensor arrangement on the article's position during lifting enables the controller to calculate precise depositing parameters. The system adjusts the release height and braking point based on actual measured dimensions, achieving both damage prevention and high placement precision.

Inventive Principle:
Principle #23Feedback

3Reliability

If a larger safety margin is used for unknown article height, then the reliability of safe handling is improved, but the productivity of the picking system deteriorates

Engineering Contradiction:
Improvesafe handlingVSAvoidpicking speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The sensor arrangement performs preliminary measurement of the article's lower edge position during the lifting process, providing actual height information before the depositing phase. This eliminates the need to use conservative fixed safety margins throughout the entire process, enabling faster and more efficient handling.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Real-time feedback on article dimensions during lifting enables dynamic adjustment of safety margins. The system transitions from using large fixed margins to calculated minimum margins based on actual measurements, significantly improving picking speed while maintaining safe handling.

Inventive Principle:
Principle #23Feedback

4Productivity

If the gripper arm moves faster to increase throughput, then the productivity is improved, but the manufacturing precision of gentle depositing deteriorates

Engineering Contradiction:
ImprovethroughputVSAvoiddepositing precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system calculates the optimal depositing trajectory in advance based on preliminary detection of article dimensions during lifting. This pre-planned trajectory enables high-speed movement with precise braking at the correct release point, maintaining gentle depositing even at high speeds.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Real-time feedback on article position and dimensions enables dynamic trajectory optimization. The controller adjusts speed profiles and braking points based on actual measurements, allowing high throughput while maintaining precise and gentle depositing through adaptive control.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables precise handling and placement of articles, minimizing damage and optimizing packing density by accurately determining the article's position and orientation, thereby improving throughput and handling efficiency.

Implementation Method 1

sensor arrangement, which is aligned essentially horizontally and is designed as a surface scanner, for detecting a position of a lower edge of the article

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3838806B1Fully automated robotic picking system and picking method with sensor assembly for measuring a removed item as part of the lifting process
Publication Date: 2023.06.07 IGZ ING FUR LOGISTISCHE INFORMATIONSSYST MBH
  • EP3838806B1 patent drawingFigure 1
  • EP3838806B1 patent drawingFigure 2~3
  • EP3838806B1 patent drawingFigure 4

AI summary

The invention relates to a picking system with a robot (10) with a gripper arm (16) for removing an article (18) from a source container (20) with a container rim (20a) and for placing the article (18) into a target container (22), a camera (12a) for capturing at least the source container (20) in a top view, and a control system (14) designed to control the gripper arm (16) depending on the image data captured by the camera (12a) such that the gripper arm (16) grasps the article (18), lifts it in a lifting operation, guides it over the target container (22) and places it in the target container (22) in a depositing operation.It is proposed that the picking system includes a substantially horizontally oriented sensor arrangement (30) for detecting the position of the lower edge of the article (18) during the lifting process, and that the controller (14) is designed to control at least the placement process depending on the detected position of the lower edge of the article (18). This can speed up the picking process and prevent damage to the articles (18) being picked.