Link Hub Manipulation Using Rectangular-to-Posture Mapping

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Solution Overview

Problem

Existing link actuation devices face difficulties in intuitive manipulation due to the need for transformation from rectangular coordinates to angular coordinates for controlling the posture of the link hub, which requires convergence operations, making the process time-consuming and requiring specialized training.

Innovation Solution

A manipulating device that acquires and transforms target postures directly from projected spherical link center coordinates onto a two-dimensional rectangular coordinate system, allowing for easy and quick input transformation without convergence operations, using a posture acquirer to calculate bending and turning angles and setting relay points for smooth and high-speed movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If transformation from rectangular coordinates to angular coordinates is performed using convergence operation, then accurate posture control is achieved, but calculation time increases and operation becomes complex

Engineering Contradiction:
Improveposture control accuracyVSAvoidcalculation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent pre-calculates and stores the relationship between rectangular coordinates and angular coordinates in a lookup table before operation. During actual use, the system simply retrieves pre-computed values rather than performing real-time convergence calculations, thus eliminating calculation time while maintaining accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a simplified coordinate system model that mirrors the physical space but uses rectangular coordinates directly. This virtual model allows operators to input positions intuitively without understanding the complex angular coordinate transformations, copying the simplicity of Cartesian geometry into the control interface

Inventive Principle:
Principle #26Copying

2Measurement precision

If transformation from rectangular coordinates to angular coordinates is performed using convergence operation, then accurate posture control is achieved, but operation complexity increases requiring specialized training

Engineering Contradiction:
Improveposture control accuracyVSAvoidmanipulation ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent introduces an intermediary coordinate transformation layer that converts intuitive rectangular coordinate inputs into the required angular coordinates through pre-established mapping relationships. This intermediary layer shields operators from complex transformation mathematics while ensuring accurate control

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter representation from direct angular measurements to rectangular coordinates that match human spatial intuition. By transforming how positions are specified rather than how they are physically measured, the system becomes easier to operate without sacrificing control precision

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If convergence operation is used for coordinate transformation, then accurate distal end posture is achieved, but device response speed decreases

Engineering Contradiction:
Improvedistal end posture accuracyVSAvoidresponse speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent pre-computes transformation relationships and stores them in lookup tables during system initialization or calibration phases. During actual operation, the system retrieves pre-calculated transformation data instantaneously, achieving both high precision and fast response by separating computation from execution

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent divides the coordinate transformation process into discrete lookup table entries rather than continuous calculation. By segmenting the transformation space into manageable discrete points, the system can quickly interpolate between points without performing complex continuous mathematical operations, speeding up response while maintaining accuracy

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3466614B1Link actuation device manipulating device and link actuation system
Publication Date: 2021.07.21 NTN CORP
  • EP3466614B1 patent drawingFigure 1
  • EP3466614B1 patent drawingFigure 2
  • EP3466614B1 patent drawingFigure 3

AI summary

In a link actuation device (50), a distal end side link hub (3) is coupled to a proximal end side link hub (2) via three or more link mechanisms (4) such that a posture of the distal end side link hub (3) can be changed relative to the proximal end side link hub (2), and a posture of the distal end side link hub (3) relative to the proximal end side link hub (2) is arbitrarily changed by actuators (51) provided to two or more link mechanisms (4). The manipulating device (62) includes a posture acquirer (64) for acquiring a distal end posture represented by a bending angle (θ) and a turning angle (ϕ), from a coordinate position (X', Y') at which a distal end side spherical link center (PB) is projected onto a two-dimensional rectangular coordinate system that has an origin (O') located on an extension of an axis (QA) of the proximal end side link hub (2) and is orthogonal to the extension of the axis.