Robot Arm Parallelogram Segments Independent Orientation

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Solution Overview

Problem

Existing robot arms used for mobility aids and end effector movement lack independent operation of segments without influencing each other, particularly in applications requiring precise control and orientation, such as dynamic arm supports for individuals with function difficulties.

Innovation Solution

A robot arm design featuring two parallelograms with specific hinge points and pulley systems, where the first parallelogram's third side is connected to the second parallelogram's first side at right angles, allowing movement without altering the cable path length and maintaining orientation independence, with pulleys at specific points ensuring consistent diameter for efficient force application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If robot arm segments are connected in a conventional manner, then the structure is simple, but movement of one segment influences and alters the orientation of other segments

Engineering Contradiction:
Improveindependent operation of segmentsVSAvoidmechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The robot arm is divided into multiple parallelogram mechanisms (first parallelogram ABCD, second parallelogram EFGH) that are connected in series. Each parallelogram acts as an independent segment that can move without affecting the orientation of other segments, enabling independent operation while maintaining structural simplicity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cable-operable device acts as an intermediary mechanism that transmits force through the cable to control the parallelogram segments. The cable routing system with pulleys at corner points A, D, F, and G serves as a mediator that transfers operational force while maintaining constant cable path length, allowing independent segment control without mutual influence.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If cable path length changes during parallelogram movement, then the mechanism can adapt to different positions, but the orientation of parallelograms becomes dependent on cable length variations

Engineering Contradiction:
Improvemovement rangeVSAvoidorientation independence
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The cable routing system is designed such that the cable path length remains constant during parallelogram movement. The pulleys at corner points A, D, F, and G are positioned to ensure that as the parallelograms move and deform, the total length of the cable path between the fixed world and the operable device remains unchanged, maintaining equipotential conditions that prevent orientation dependency.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The invention maintains the cable path length parameter as constant during operation. By keeping this critical parameter unchanged while allowing the parallelograms to deform and move, the system achieves adaptability in position and orientation without the cable length varying, thus maintaining orientation independence during movement.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables independent movement and operation of robot arm segments without affecting each other's orientation, providing a stable and efficient mechanism for dynamic arm supports, effectively addressing the need for precise control in mobility aids like wheelchairs and specially configured workplaces.

Implementation Method 1

a cable extending from the fixed world or reference body to the operable device is routed via pulleys rotating about the first corner point (A) and fourth corner point (D) of the first parallelogram and about the second corner point (F) and third corner point (G) of the second parallelogram

Methodology Applied
Scientific EffectPulley: Pulley

Data Source

PatentEP3326762B1Robot-arm
Publication Date: 2019.08.21 FOCAL MEDITECH
  • EP3326762B1 patent drawingFigure 1
  • EP3326762B1 patent drawingFigure 2

AI summary

Robot arm (1) comprising a first parallelogram with four corner points (A, B, C, D) and four sides (AB, BC, CD, DA), which corner points all form hinge points; a second parallelogram with four corner points (E, F, G, H) and four sides (EF, FG, GH, HE), which form hinge points; of which a first side (AB) of the first parallelogram comprises a cable-operable device (3), and a third side (CD) of the first parallelogram is connected to a first side (EF) of the second parallelogram; such that the points D and E coincide; wherein the third side (GH) of the second parallelogram is connected to a fixed world, wherein a cable (2) from the fixed world to the operable device (3) is routed via rotating pulleys, and wherein the pulleys at points A and D have the same diameter (r1) and the pulleys at points F and G have the same diameter (r2).