Multi-articulated Link Knee Joint Cylinder Position Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional multi-articulated link knee joints face challenges in detecting the bending angle of the knee section due to installation space and wiring issues with rotational angle sensors.

Innovation Solution

A multi-articulated link knee joint that uses a magnet and magnetic sensor to detect the extension and contraction amount of the cylinder, allowing for the detection of the bending angle without the need for a rotational angle sensor, with the magnet accommodated in the piston rod and the sensor fixed to the cylinder tube, facilitating reduced wiring and improved precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a rotational angle sensor is used to detect the bending angle of the knee section, then the detection precision is improved, but the installation space requirement increases and wiring complexity increases

Engineering Contradiction:
Improvebending angle detection precisionVSAvoidinstallation space and wiring
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the detection function from a complex rotational angle sensor and implements it using a simple magnet and magnetic sensor combination. The magnet is attached to the piston rod while the magnetic sensor is fixed to the cylinder tube, eliminating the need for complex sensor installation and wiring while maintaining detection capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical rotational angle sensor with a magnetic detection system. By using a magnet attached to the moving piston rod and a magnetic sensor on the stationary cylinder tube, the system substitutes complex mechanical sensing with a simpler magnetic field-based detection method that requires minimal installation space and wiring.

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

2Measurement precision

If a rotational angle sensor is installed on the knee section, then the bending angle can be detected, but the installation space becomes insufficient

Engineering Contradiction:
Improvebending angle detectionVSAvoidinstallation space
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent extracts the essential detection function from a bulky rotational angle sensor and implements it using compact magnetic components. The magnet attached to the piston rod and the magnetic sensor on the cylinder tube require minimal installation space, solving the space constraint problem while maintaining detection functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the space-consuming mechanical rotational angle sensor with a compact magnetic detection system. This replacement dramatically reduces the installation space requirement while preserving the ability to detect bending angle through cylinder extension and contraction measurements.

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

3Measurement precision

If a rotational angle sensor is used, then accurate bending angle measurement is achieved, but wiring complexity increases

Engineering Contradiction:
Improvebending angle measurement accuracyVSAvoidwiring complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the core measurement function from a complex sensor system and implements it using simple magnetic components with minimal wiring. The magnet on the piston rod and magnetic sensor on the cylinder tube require only basic electrical connections, significantly reducing wiring complexity while maintaining measurement accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the wiring-intensive rotational angle sensor with a magnetic detection system that requires minimal wiring. The magnetic field-based detection method simplifies the electrical connections needed while preserving the ability to accurately measure bending angle through cylinder position changes.

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

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 accurate detection of the bending angle of the knee section without the problems associated with sensor installation space and wiring, maintaining high detection precision and simplifying the configuration.

Implementation Method 1

one of the magnet and the magnetic sensor is accommodated in a piston rod of the cylinder, the other one of the magnet and the magnetic sensor is fixed to a cylinder tube of the cylinder

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP2823791B1Multi-articulated link knee joint
Publication Date: 2016.09.28 NABTESCO CORP
  • EP2823791B1 patent drawingFigure 1
  • EP2823791B1 patent drawingFigure 2
  • EP2823791B1 patent drawingFigure 3

AI summary

A multi-articulated link knee joint capable of detecting a bending angle of a knee section without causing problems of an installation space and wiring of a sensor is provided. A four-link knee joint (10) includes a knee section (30) of a four-link mechanism, a fluid cylinder (40) that restrains an action of the knee section (30), a position detecting device (60) that detects a position of a piston rod (42) with respect to a cylinder tube (41) as an extension and contraction amount of the cylinder (40), and a computer that acquires a bending angle of the knee section (30) by converting the position detected by the position detecting device (60).