Robotic Depalletization Sequencing for High-Stack Reachability

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Solution Overview

Problem

Robotic systems face challenges in depalletization due to limited height range, leading to potential stack tipping and object damage when interacting with objects at high heights, and existing solutions do not effectively manage interference and collision risks.

Innovation Solution

A computer-implemented method and system for robotic depalletization that prioritizes the removal of objects based on their proximity to the stack's front side and height, using an end effector to manipulate objects within reachability constraints, with motion planning to avoid collisions and deposit objects in designated locations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a robotic system attempts to reach objects at very high heights in a stack, then the depalletization task can be completed, but the stack may be tipped over and objects may be damaged due to interference conditions

Engineering Contradiction:
Improvedepalletization capabilityVSAvoidstack stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary analysis of the stack configuration and identifies objects that block the robotic arm's path to high-height objects. Before attempting to reach high objects, the system removes blocking objects first, ensuring stack stability is maintained throughout the depalletization process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the depalletization sequence based on real-time stack configuration analysis. The removal order is optimized to maintain stack stability while enabling access to high-height objects, changing the sequence adaptively rather than following a fixed pattern

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If objects are removed from high locations in a stack, then the full height range of the stack can be depalletized, but collisions and interference with other objects increase

Engineering Contradiction:
Improveheight range coverageVSAvoidcollision risk
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary path planning and collision analysis before executing depalletization. Blocking objects that would interfere with reaching high objects are identified and removed in advance, clearing the path and eliminating collision risks before the robotic arm attempts to reach high locations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system introduces an intermediate planning layer that analyzes the stack configuration and determines the optimal removal sequence. This intermediary process mediates between the goal of accessing high objects and the risk of collisions by calculating a safe sequence of operations

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If a fixed depalletization sequence is used, then the system operation is simple, but interference conditions change based on relative positions causing stack tipping

Engineering Contradiction:
Improvesystem control simplicityVSAvoidstack stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The system transitions from a fixed depalletization sequence to a dynamic, adaptive sequence. The removal order is automatically adjusted based on the analyzed stack configuration, identifying blocking objects and prioritizing their removal to maintain stack stability while achieving depalletization goals

Inventive Principle:
Principle #15Dynamics

4Speed

If the robotic system reaches for high objects without removing blocking objects first, then the operation is faster, but the robotic arm cannot access the objects due to interference

Engineering Contradiction:
Improvedepalletization speedVSAvoidreachability
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The system performs preliminary identification of blocking objects and removes them before attempting to reach high objects. This preliminary action clears the path for the robotic arm, ensuring reachability is achieved without unnecessary delays

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4309858B1Methods, systems, and computer program products for reachability constraint manipulation for height thresholded scenarios in robotic depalletization
Publication Date: 2025.12.31 INTELLIGRATED HEADQUARTERS LLC
  • EP4309858B1 patent drawingFigure 1A
  • EP4309858B1 patent drawingFigure 1B
  • EP4309858B1 patent drawingFigure 2

AI summary

Methods, apparatuses, systems, computing devices, and/or the like are provided. An example method may include detecting a first set of objects, the first set of objects including two or more palletized objects of a plurality of palletized objects in a stack, wherein the two or more palletized objects of the first set of objects are disposed above a threshold height, wherein the stack has a front side and a back side; determining that a first object of the first set is closer than a second object of the first set is to the front side, wherein the first object of the first set is disposed lower than the second object of the first set; and manipulating an end effector to remove the first object from the stack before removing the second object from the stack and to deposit the first object in one or more deposit locations.