Robot Trajectory Safety Zones Using Optimized Enclosing Cuboids

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Solution Overview

Problem

Current methods for defining safety areas for robots are manual, error-prone, and lead to unnecessary blocking, reducing productivity due to the lack of automated optimization and certification in the planning phase.

Innovation Solution

A method that subdivides robot trajectories into partial trajectories, determines fine-grained extremal points, and calculates optimized enclosing cuboids to define safety areas, allowing for automated simulation and optimization of safety zones, reducing manual intervention and improving productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual methods are used to define safety areas, then safety coverage is ensured, but productivity decreases due to error-prone planning and unnecessary blocking

Engineering Contradiction:
Improvesafety coverageVSAvoidrobot productivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces manual mechanical planning methods with an automated computer-based calculation system. The controller automatically computes safety areas based on robot trajectories and safety distances, eliminating human error in manual planning while ensuring comprehensive safety coverage through systematic calculation of all trajectory points and their associated safety zones.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-verification by automatically checking whether calculated safety areas block necessary robot movements. The controller independently determines if safety area definitions create unnecessary blocking and adjusts them accordingly, enabling the system to self-optimize without external intervention while maintaining safety requirements.

Inventive Principle:
Principle #25Self-service

2Reliability

If safety areas are defined to ensure complete coverage, then safety is improved, but robot working space is restricted reducing productivity

Engineering Contradiction:
Improvesafety assuranceVSAvoidrobot working efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies different safety distances locally at different positions along the robot trajectory. Instead of using a uniform safety margin throughout the workspace, the system calculates position-specific safety distances based on the actual robot configuration and movement direction at each point, ensuring adequate safety coverage only where needed while preserving working space in other areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The safety area definition becomes dynamic rather than static. The controller continuously adapts the safety area boundaries based on the robot's current trajectory and position, allowing the safety zones to move and resize dynamically during operation. This enables the system to maintain safety margins while minimizing restrictions on the robot's working space.

Inventive Principle:
Principle #15Dynamics

3Productivity

If automated calculation of safety areas is implemented, then productivity increases through reduced manual effort, but calculation complexity increases

Engineering Contradiction:
Improveplanning efficiencyVSAvoidcalculation system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the safety area calculation into discrete steps corresponding to individual trajectory points. The controller divides the continuous robot path into multiple measurement points, calculates safety distances at each point separately, and then combines these into the complete safety area. This segmentation simplifies the overall calculation process by breaking it into manageable, systematic steps that can be executed automatically.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3819088B1Method for determining a safety area and for routing robots
Publication Date: 2022.04.06 SIEMENS AG
  • EP3819088B1 patent drawingFigure 1~2
  • EP3819088B1 patent drawingFigure 3a~3c
  • EP3819088B1 patent drawingFigure 4~5

AI summary

An automated procedure for determining a safety zone (S) for a robot (5) is proposed, wherein the robot (5) performs operations along a predefined trajectory (1). For collision-free operation, a safety zone (S) is determined by the following procedure steps: (A) Subdivision of the predefined trajectory (1) into a plurality of sub-trajectories (11T, 12T, ...); (B) Determination of a plurality of fine-grained bounding blocks (211, 212, ...) around extremal points (7) of each sub-trajectory (11T, 12T, ...); ((C) Determination of a number of optimized enclosing blocks (221, 222, ...) from an enlargement of individual fine-granular enclosing blocks (211T, 212T, ...,) against the volume occupied by the enlarged fine-granular enclosing blocks, wherein the optimized enclosing blocks (221, 222, ...) thus determined form the safety area (S) for the trajectory (1).This automated procedure can be extended to: - Multiple trajectories (11, 12, ...) of a robot (5); - Multiple robots (5, 5', ...); - Replanning of a trajectory for an occupied semaphore area (23).