Robot Path Smoothing via RRT Intermediate Node Correction

Solution Overview

Problem

The Rapidly-exploring Random Tree (RRT) algorithm for path planning in robots often generates detour or zigzag paths, increasing motion distance and rapid changes in motion, as it extends vertically to satisfy goal score conditions and avoid obstacles.

Innovation Solution

A method and apparatus that smooth the RRT path by generating an intermediate path connecting selected points, projecting and correcting nodes to satisfy constraints in the configuration space, and low-pass filtering the overall path to ensure kinematic constraints are met, thereby reducing unnecessary detours and stabilizing the motion path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the RRT algorithm extends the tree vertically to satisfy goal score conditions and avoid obstacles, then collision avoidance is improved, but the motion path becomes detoured or zigzagged, increasing motion distance

Engineering Contradiction:

Improvecollision avoidanceVSAvoidmotion distance

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent applies preliminary action by performing path smoothing processing after the RRT algorithm generates the initial path. The smoothing apparatus预先 (in advance) processes the generated path to remove detours and zigzags before the manipulator executes the motion, thereby reducing motion distance while maintaining collision avoidance capabilities.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes parameters by adjusting path geometry parameters through smoothing operations. The system modifies the path configuration by removing unnecessary detours and zigzags while preserving the essential collision-avoiding characteristics, thereby optimizing the motion distance without compromising safety.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the RRT algorithm extends the tree vertically to satisfy goal score conditions, then the goal function is satisfied, but the manipulator motion changes rapidly, reducing motion stability

Engineering Contradiction:

Improvegoal function satisfactionVSAvoidmotion stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by performing path smoothing processing after the RRT algorithm generates the initial path. The smoothing apparatus预先 (in advance) processes the generated path to remove detours and zigzags before the manipulator executes the motion, thereby reducing motion distance while maintaining collision avoidance capabilities.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes parameters by adjusting path geometry parameters through smoothing operations. The system modifies the path configuration by removing unnecessary detours and zigzags while preserving the essential collision-avoiding characteristics, thereby optimizing the motion distance without compromising safety.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8483874B2Path planning apparatus of robot and method and computer-readable medium thereof

Publication Date: 2013.07.09 SAMSUNG ELECTRONICS CO LTD

AI summary

A path planning apparatus of a robot smoothes a motion path while satisfying a constraint. In a configuration space where a manipulator of a robot performs a task, a Rapidly-exploring Random Tree (RRT) path which extends from a start point and reaches a goal point may be smoothed while satisfying a constraint to generate a stable motion path. Accordingly, path planning performance is improved and an optimal path satisfying a kinematic constraint may be rapidly obtained.