Hall Sensor Position Detection in Orthopedic Aids

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Solution Overview

Problem

Existing orthopedic aids, such as orthoses and prostheses, face challenges in accurately determining the position of movement elements relative to reference elements, particularly in terms of speed and acceleration, while also requiring minimal energy expenditure and robustness.

Innovation Solution

The method involves using Hall sensors to detect voltage differences and calculate the position of the movement element relative to the reference element, with a permanent magnet configuration that creates a homogeneous magnetic field, allowing for precise position determination and automatic speed calculation with minimal energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If Hall sensors are used to determine position with high accuracy, then measurement precision is improved, but energy consumption increases

Engineering Contradiction:
Improveposition determination accuracyVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic measurement by only activating Hall sensors when a magnet approaches their detection range, rather than continuous operation. The control unit determines which Hall sensors are currently within the magnetic field range and activates only those sensors for measurement, creating a periodic measurement cycle that reduces overall energy consumption while maintaining position determination accuracy.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies local quality by selectively activating specific Hall sensors based on their spatial relationship to the magnet. Instead of operating all Hall sensors uniformly, the system identifies which sensors are currently within the magnetic field range and activates only those local sensors, optimizing energy consumption by applying measurement activity only where needed in space.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If multiple Hall sensors are used to improve position determination accuracy, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveposition determination accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the measurement task by dividing the detection space into multiple zones, each monitored by a specific Hall sensor. The control unit processes measurements from individual Hall sensors separately and combines them to determine overall position, breaking down the complex multi-sensor system into manageable segments that can be processed independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic sensor activation where the set of active Hall sensors changes based on the magnet's position. The control unit dynamically determines which Hall sensors are within range and activates only those sensors at any given moment, making the system adaptable and reducing complexity by avoiding static activation of all sensors throughout the entire range of motion.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If Hall sensors operate continuously to provide accurate position data, then measurement precision is improved, but loss of energy increases

Engineering Contradiction:
Improveposition determination accuracyVSAvoidenergy waste
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent implements periodic measurement by only activating Hall sensors when a magnet approaches their detection range, rather than continuous operation. The control unit determines which Hall sensors are currently within the magnetic field range and activates only those sensors for measurement, creating a periodic measurement cycle that reduces overall energy consumption while maintaining position determination accuracy.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses the magnetic field's presence itself as the trigger for measurement activation. When the magnet enters the detection range of a Hall sensor, the magnetic field automatically enables that sensor's operation, and when it leaves, the sensor automatically deactivates. This self-service mechanism eliminates the need for continuous polling or external control, reducing energy waste while maintaining measurement precision.

Inventive Principle:
Principle #25Self-service

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

This approach enables accurate and robust position determination of orthopedic aids with high measurement precision, allowing for precise speed calculation and reduced mechanical wear, while being cost-effective due to the use of standard Hall sensors.

Implementation Method 1

wird von einem Hall-Sensor ein Hall-Spannungssignal detektiert, das abhängig von der Stärke des magnetischen Feldes ist

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 2

die das magnetische Feld erzeugen und die sich abhängig von der Position des Bewegungselements zum Referenzelement entlang der Trajektorie ändert

Methodology Applied
Scientific EffectMagnetic field generation: Magnetic Field

Data Source

PatentEP3791136B1Orthopaedic aid
Publication Date: 2023.02.22 OTTO BOCK HEALTHCARE PROD GMBH
  • EP3791136B1 patent drawingFigure 1
  • EP3791136B1 patent drawingFigure 2a~2b
  • EP3791136B1 patent drawingFigure 3a~3c

AI summary

The invention relates to an orthopaedic aid (10) having (a) a reference element (26), (b) a movement element (24) which is movably fastened to the reference element (26), and (c) a position sensor (38) for determining a position of the movement element (24) relative to the reference element (26), said position sensor comprising at least one permanent magnet (40) and at least three Hall sensors (42), (d) wherein the Hall sensors (42) are arranged on the reference element (26) and, for moving along a trajectory (T) during movement of the movement element (24), are arranged relative to the reference element (26), (e) wherein the at least one permanent magnet (40) is fastened to the movement element (24), and (f) wherein the Hall sensors (42) and the permanent magnet (40) are arranged such that a movement of the movement element (24) relative to the reference element (26) and a resulting movement of the Hall sensors (42) along the trajectory (T) causes for at least one Hall sensor (42) a linear change in its Hall voltage (UHall).