Robot Gripper Arm Axes for Reliable Container Workpiece Removal

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Solution Overview

Problem

Conventional devices for automated removal of workpieces from containers face reliability issues, especially with non-symmetrical or non-rotationally symmetrical parts, as they often struggle to access workpieces in unfavorable positions such as the edge or deep within the container.

Innovation Solution

A device equipped with a robot arm having at least six axes, including two additional movement axes for the gripper arm element, which allows for enhanced accessibility and precision in gripping workpieces, particularly through the use of rotary axes and a slewing mechanism, enabling secure gripping even in difficult situations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a standardized industrial robot with six-axis robot arm is used to move the gripper, then the device structure is relatively simple and easy to control, but the reliability of workpiece removal is insufficient, especially for asymmetrical parts or workpieces in unfavorable positions

Engineering Contradiction:
Improveworkpiece removal reliabilityVSAvoidrobot arm structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The robot arm is divided into a main robot arm (six axes) and a separate gripper arm element (two additional axes). This segmentation allows the gripper to have independent movement capabilities through the additional axes, enabling reliable removal of workpieces from unfavorable positions while keeping the main robot arm structure standardized and simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Two additional rotational axes (azimuth and elevation angles) are added to the gripper arm element, extending the movement space from six dimensions to eight dimensions. This dimensional expansion enables the gripper to access workpieces in positions that would be unreachable with a standard six-axis robot, significantly improving removal reliability.

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 the accessibility is improved, but the risk of collision with the container increases

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

Solution Approach 1:

The gripper arm element incorporates two dynamically controllable rotational axes that allow real-time adjustment of the gripper's position and orientation. This dynamic capability enables the system to navigate around obstacles and access workpieces in difficult positions while actively avoiding collisions with the container.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters by adding two rotational degrees of freedom to the gripper assembly. This parameter expansion allows the gripper to reach edge and deep-positioned workpieces while maintaining collision-free operation through precise control of the additional angular parameters.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If additional axes are added to the robot arm to improve workpiece accessibility, then the removal rate increases, but the device complexity and space requirements increase

Engineering Contradiction:
Improveworkpiece removal rateVSAvoidgripper arm structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system segments the robotic system into a main six-axis robot arm for positioning and a separate two-axis gripper arm element for fine positioning and orientation. This segmentation achieves high removal rates by enabling the gripper to access any workpiece position while keeping each module relatively simple and manageable.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2698234B1Device and method for the automated removal of workpieces arranged in a container
Publication Date: 2023.02.15 LIEBHER VERZAHNTECHNIK GMBH
  • EP2698234B1 patent drawingFigure 1
  • EP2698234B1 patent drawingFigure 2
  • EP2698234B1 patent drawingFigure 3

AI summary

The device comprises a detecting unit (2) for detecting a workpiece movable by a robotic arm (3) with six axles gripper for gripping and removing the workpiece out of a container (1). A control unit evaluates the data of the detecting unit, for trajectory planning and for controlling the robotic arm and gripper. The robotic arm is provided with a gripper arm element (4) for moving the gripper along two movement axes. Independent claims are included for the following: (1) method for removing workpiece arranged in container; and (2) computer program for removing workpiece arranged in container.