Container Workpiece Removal With an 8-Axis Gripper Arm

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Solution Overview

Problem

Existing automated workpiece removal devices from containers face reliability issues, especially with non-symmetrical or rotationally non-symmetrical parts positioned unfavorably, leading to reduced accessibility and increased collision risks.

Innovation Solution

A device equipped with a gripper moved via a surface portal with at least two linear axes and two additional rotary axes, allowing for enhanced flexibility and precision in gripping and removing workpieces, including those positioned at the edge or deep within the container, using a gripper arm element with a rotating and pivoting mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a standardized six-axis robot arm is used to move the gripper, then the device structure is relatively simple, but the accessibility to workpieces in unfavorable positions (edge or deep within container) is reduced and collision risks increase

Engineering Contradiction:
Improveworkpiece removal reliabilityVSAvoidgantry system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The robot arm is divided into a standard six-axis robot arm and a separate gripper arm element with two additional axes. This segmentation allows the standard robot arm to handle general positioning while the specialized gripper arm element provides additional degrees of freedom for accessing difficult positions and orienting the gripper correctly, thereby improving reliability without completely redesigning the entire system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Two additional rotary axes are added to the gripper arm element, increasing the total degrees of freedom from six to eight. This dimensional enhancement enables the gripper to reach workpieces in unfavorable positions (at the edge or deep within the container) and to properly orient asymmetrical parts, significantly improving workpiece removal reliability while maintaining a manageable device structure through modular design.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If the gripper is positioned to access workpieces at the edge or deep within the container, then accessibility improves, but collision risks with the container increase

Engineering Contradiction:
Improvegripper accessibilityVSAvoidcollision risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The gripper arm element incorporates two rotary axes that enable dynamic adjustment of the gripper's position and orientation. This dynamic capability allows the system to adaptively navigate around obstacles and select optimal approaches to workpieces, improving accessibility while minimizing collision risks through real-time motion planning and adjustment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The additional rotary axes change the operational parameters of the gripper by adding two more degrees of freedom. This enables the gripper to reach difficult positions and properly orient asymmetrical parts, significantly improving ease of operation and accessibility to workpieces in unfavorable positions while maintaining collision avoidance through precise control.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If a gripper arm element with additional rotary axes is added, then the removal rate for asymmetrical or non-rotationally symmetrical parts improves, but the device complexity increases

Engineering Contradiction:
Improveworkpiece removal rateVSAvoidnumber of movement axes
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system is segmented into a standard six-axis robot arm for general positioning and a specialized gripper arm element with two additional rotary axes. This segmentation allows the complex functionality to be added only where needed (at the gripper end), improving productivity for asymmetrical parts while keeping the overall device complexity manageable through modular architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The gripper arm element with two additional rotary axes serves multiple functions: it enables access to difficult positions, provides proper orientation for asymmetrical parts, and maintains compatibility with the standard robot arm. This multi-functionality improves the removal rate for various workpiece types while avoiding the need for completely separate systems for different tasks.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4046755B1Device and method for the automated removal of workpieces arranged in a container
Publication Date: 2024.02.28 LIEBHER VERZAHNTECHNIK GMBH
  • EP4046755B1 patent drawingFigure 1
  • EP4046755B1 patent drawingFigure 2
  • EP4046755B1 patent drawingFigure 3

AI summary

The present invention relates to a device for the automated removal of workpieces arranged in a container, comprising a detection unit for detecting the workpieces and a gripper movable via a robot arm with at least six axes for gripping and removing the workpieces from the container, and a control system for evaluating the data of the detection unit, for path planning and for controlling the robot arm and the gripper, wherein the robot arm for moving the gripper has a gripper arm element with at least two further axes of movement.