Striker Unit for Postural Analysis with Load Cell Feedback

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Solution Overview

Problem

Current systems for imparting mechanical perturbations to assess postural reactions lack standardization, precision, and adaptability to individual anthropometry, leading to incomplete data analysis and imprecise force control, especially when perturbing the body rather than the base of support.

Innovation Solution

A unit comprising a striker with a load cell and electronic control unit that provides controlled, adaptable, and targeted perturbations, with the load cell measuring force parallel to the axis of translation, allowing for precise impulse control and feedback, and optional additional sensors for comprehensive data collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a force sensor is placed far away from the contact surface to measure applied force, then the measurement range is increased, but the measurement precision deteriorates due to inertial loads and mass of moving parts influencing the load cell output

Engineering Contradiction:
Improvemeasurement rangeVSAvoidforce measurement precision
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

A rigid extension bar serves as an intermediary element that transmits the perturbation force from the actuator to the contact surface while providing a stable mounting point for the load cell. This intermediary structure isolates the load cell from direct contact with the moving contact surface, allowing precise force measurement without being influenced by inertial loads of the moving parts.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The device is divided into separate functional modules: the actuator generates the perturbation force, the rigid extension bar transmits this force, and the load cell measures the force independently. This segmentation allows each component to perform its function optimally without interfering with others, particularly isolating the measurement system from inertial effects.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the force sensor is placed close to the contact surface to improve measurement precision, then the measurement precision improves, but the device complexity increases and the sensor becomes vulnerable to external influences

Engineering Contradiction:
Improveforce measurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The rigid extension bar acts as a protective intermediary that shields the load cell from direct exposure to external influences such as moisture, physical damage, and interference from moving parts. This allows the load cell to be positioned closer to the contact surface for improved precision while maintaining device simplicity and reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If custom-made perturbation systems are used to adapt to individual anthropometry, then the adaptability improves, but the device complexity and lack of standardization increase

Engineering Contradiction:
Improveadaptability to individual anthropometryVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The device incorporates adjustable components that allow dynamic reconfiguration to match different individual anthropometric parameters. The actuator force, contact point position, and perturbation timing can be dynamically adjusted based on the specific subject being tested, providing adaptability without requiring complete custom design for each case.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The standardized device design with adjustable parameters serves multiple functions: it can adapt to different anthropometric measurements, control various force magnitudes, adjust perturbation timing, and work with different contact surfaces. This universal design eliminates the need for multiple custom-made systems while maintaining adaptability across diverse subjects.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Quantity of substance

If the load cell measures total force including inertial components, then the measurement is comprehensive, but the data accuracy for perturbation analysis deteriorates

Engineering Contradiction:
Improvecomprehensiveness of force measurementVSAvoidperturbation data accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The rigid extension bar structure is designed to separate and isolate the inertial force components from the perturbation force measurement. By positioning the load cell on the extension bar rather than directly on the moving contact surface, the system extracts only the relevant perturbation force data while excluding inertial components generated by the moving parts of the device.

Inventive Principle:
Principle #2Taking out (Extraction)

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 precise and tailored postural analysis by correlating sway trajectory with impulse, improving data accuracy and applicability across various clinical settings without requiring a sensorized base of support, while ensuring minimal influence from inertial loads and external stiffness.

Implementation Method 1

a load cell is connected to the contacting head to provide the electronic control unit with a force feedback during the perturbation imparting operation about the load applied to the individual

Methodology Applied
Scientific EffectStrain gauge measurement: Piezoresistive Effect

Data Source

PatentEP3876823B1Striker unit for postural analysis
Publication Date: 2024.04.03 POLITECNICO DI TORINO
  • EP3876823B1 patent drawingFigure 1
  • EP3876823B1 patent drawingFigure 2
  • EP3876823B1 patent drawingFigure 3

AI summary

A unit to provide mechanical perturbation to test the postural behavior of a patient comprises a linear actuator having a load cell to measure and control certain parameters of the perturbation.