Robot Reachable Manifold Learning for Fast Inverse Kinematics

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Solution Overview

Problem

Current robot motion planning systems face challenges in validating the feasibility of planned motions within kinematic and dynamic constraints, often resulting in time-consuming operations that can fall into local minima, especially for sequential motion planning.

Innovation Solution

A system comprising a neural network architecture with forward, inverse, and density network modules is trained to learn the reachable manifold of a robot's end effector, allowing for kinematic feasibility validation and diverse inverse mapping solutions without iterative processes, using babbling data to generate training samples and avoid self-collision and joint limit constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optimization operations are performed to validate robot motion feasibility, then motion planning accuracy is improved, but computational time increases significantly

Engineering Contradiction:
Improvemotion feasibility validation accuracyVSAvoidcomputational time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent pre-computes and stores the reachable manifold of the end effector in a lookup table during an offline phase. This preliminary action allows the system to avoid time-consuming optimization operations during online motion planning, as feasibility can be directly queried from the pre-computed manifold, thus resolving the contradiction between validation accuracy and computational time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the traditional iterative optimization-based feasibility validation with a direct lookup approach using a pre-computed reachable manifold. This substitution eliminates the need for repeated optimization operations during motion planning, significantly reducing computational time while maintaining validation accuracy.

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

2Reliability

If iterative optimization is used for sequential motion planning, then kinematic feasibility is validated, but the system falls into local minima

Engineering Contradiction:
Improvekinematic feasibility validationVSAvoidsolution optimality
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent creates a simplified copy of the robot's kinematic constraints in the form of a reachable manifold representation. This copy allows for direct feasibility checking without the complexities of iterative optimization, avoiding local minima while maintaining reliable kinematic validation through the pre-computed manifold structure.

Inventive Principle:
Principle #26Copying

3Speed

If offline manifold modeling is performed, then query speed is improved, but training data requirements increase

Engineering Contradiction:
Improvefeasibility query speedVSAvoidtraining data volume
Core Design Contradiction:
SpeedVSQuantity of substance

Solution Approach 1:

The patent samples only the essential boundary and key configurations of the reachable manifold during the offline phase, rather than exhaustively computing the entire configuration space. This partial action approach achieves sufficient query speed improvement while reducing the amount of training data required compared to complete manifold modeling.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS12151374B2Reachable manifold and inverse mapping training for robots
Publication Date: 2024.11.26 NAVER CORP
  • US12151374B2 patent drawing
  • US12151374B2 patent drawing
  • US12151374B2 patent drawing

AI summary

A system includes: a first module configured to, based on a set of target robot joint angles, generate a first estimated end effector pose and a first estimated latent variable that is a first intermediate variable between the set of target robot joint angles and the first estimated end effector pose; a second module configured to determine a set of estimated robot joint angles based on the first estimated latent variable and a target end effector pose; a third module configured to determine joint probabilities for the robot based on the first estimated latent variable and the target end effector pose; and a fourth module configured to, based on the set of estimated robot joint angles, determine a second estimated end effector pose and a second estimated latent variable that is a second intermediate variable between the set of estimated robot joint angles and the second estimated end effector pose.