Sheet Metal Bending Robot Path Planning With SVSDF Collision Safety

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Solution Overview

Problem

Existing robot-assisted sheet metal bending methods face challenges with collision risks due to narrow spaces and complex non-convex geometries, inefficient path planning algorithms, and lack of safety evaluation, leading to potential device damage and reduced efficiency.

Innovation Solution

A path planning method using a Swept Volume Signed Distance Field (SVSDF) with a Water Cycle Algorithm (WCA) for multi-objective optimization, incorporating adaptive elliptical region sampling and adaptive node growth in the Rapidly-Exploring Random Tree (RRT)-Connect algorithm to balance path cost and safety, ensuring collision-free motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional path planning methods focus on reducing path length, then path efficiency is improved, but safety distance from obstacles becomes insufficient

Engineering Contradiction:
Improvepath efficiencyVSAvoidsafety distance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent transforms the path planning problem from a single-objective optimization to a multi-objective optimization by changing the parameter representation. It introduces a composite cost function that incorporates both path length and safety distance metrics, allowing the system to simultaneously optimize for efficiency and safety by adjusting the weight parameters in the cost function.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent adds a new dimension to the path planning by introducing the safety distance metric as an additional optimization dimension. Instead of only minimizing path length in the traditional configuration space, the system now operates in an extended space that includes safety margins, effectively adding another degree of freedom to the optimization problem.

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

2Productivity

If discrete sampling method is used to approximate continuous motion, then calculation efficiency is improved, but collision detection function is lost

Engineering Contradiction:
Improvecalculation efficiencyVSAvoidcollision detection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces signed distance fields as an intermediary representation between the discrete sampling and continuous collision detection requirements. The SDF provides a continuous mathematical representation of the environment geometry that can be efficiently queried at any point, serving as a mediator that enables both fast calculation and accurate collision detection without requiring dense discrete sampling.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional mechanical approach of dense discrete sampling with a field-based computational approach. Instead of using numerous discrete samples to approximate continuous space, the system uses continuous distance field representations that can be evaluated at any point, substituting the sampling mechanism with a mathematical field model that provides both efficiency and accuracy.

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

3Device complexity

If simplified shape approximation is used, then available computation space is reduced, but smooth motion trajectory generation becomes impossible

Engineering Contradiction:
Improveshape approximationVSAvoidsmooth trajectory
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent applies dynamic adaptation in the path planning process by using adaptive sampling strategies that adjust the resolution and density of the distance field representation based on the local geometric complexity and the robot's motion requirements. This allows the system to maintain smooth trajectories in complex regions while using coarser approximations in simpler areas, dynamically balancing computational efficiency with trajectory quality.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS20260048431A1Robot-assisted sheet metal bending loading and unloading path planning method based on svsdf
Publication Date: 2026.02.19 NANJING UNIV OF POSTS & TELECOMM
  • US20260048431A1 patent drawing
  • US20260048431A1 patent drawing
  • US20260048431A1 patent drawing

AI summary

A robot-assisted sheet metal bending loading and unloading path planning method based on an SVSDF is provided. The method includes the following steps: Step 1, constructing a two-dimensional pixel coordinate system; Step 2, obtaining an initial motion trajectory of loading and unloading a sheet metal part; Step 3, calculating path safety; Step 4, calculating a path cost; Step 5, calculating a fitness value of the initial motion trajectory of loading and unloading the sheet metal part; Step 6, optimizing the path cost and the path safety to obtain an optimal motion trajectory of loading and unloading the sheet metal part; and Step 7, through derivation of a bending loading and unloading motion relationship, transforming a motion trajectory of loading and unloading a workpiece itself into a motion trajectory of each axis of a bending robot.