Treadmill Gait Analysis Using Four Load Cells
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Solution Overview
Problem
Current gait measurement devices for rehabilitation settings are costly, complex, and provide excessive data, making them impractical for routine clinical use, especially when trying to quantify gait parameters on existing treadmills.
Innovation Solution
A gait analysis apparatus using three to four vertical force sensors between a treadmill and the ground, which measure load and calculate gait parameters, providing numeric and graphical displays, and can be easily retrofitted to existing treadmills.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple force sensors are embedded across the entire treadmill deck, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The treadmill support structure is segmented into four distinct legs, with each leg containing a force sensor. This segmentation allows the system to capture sufficient gait data through strategic placement rather than comprehensive coverage, reducing the total number of sensors needed while maintaining measurement capability.
Solution Approach 2:
The force sensors are positioned at the legs of the treadmill frame rather than embedded in the deck surface. This dimensional relocation from 2D deck embedding to 3D frame positioning simplifies installation and reduces computational requirements while still capturing the necessary vertical force data for gait analysis.
2Measurement precision
If force sensors are embedded across the entire treadmill deck, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The system uses only four force sensors positioned at the treadmill legs instead of embedding sensors across the entire deck. This segmented approach dramatically reduces the quantity of expensive force sensors required while maintaining sufficient measurement precision for clinical gait analysis.
Solution Approach 2:
The patent employs a minimal number of force sensors (four) rather than extensive arrays, reducing the overall system cost to a level accessible for clinical settings. The simplified sensor configuration lowers both hardware costs and installation expenses.
3Force
If force plates are positioned directly below the treadmill belt, then load sensing is achieved, but measurement reliability deteriorates due to friction and vibration
Solution Approach 1:
The force sensors are positioned at the treadmill legs, which serve as intermediaries between the belt and the ground. This placement eliminates direct contact between force sensing elements and the moving belt, removing the friction and vibration problems that would compromise measurement reliability.
Solution Approach 2:
The force sensing function is extracted from the treadmill belt area and relocated to the stationary leg structures. This separation removes the harmful friction and vibration effects from the measurement process while maintaining the ability to sense vertical load forces.
4Adaptability or versatility
If existing treadmills are modified to include instrumented decks, then gait measurement capability is achieved, but ease of operation deteriorates due to setup complexity
Solution Approach 1:
The measurement system is divided into four independent force sensor units, one at each treadmill leg. This modular segmentation allows for simple replacement or addition of sensors without requiring complex integration into the treadmill deck, making retrofittting straightforward.
Solution Approach 2:
The force sensors at the legs serve dual purposes: supporting the treadmill structure and measuring vertical load forces. This multi-functionality eliminates the need for separate measurement infrastructure, allowing existing treadmills to be retrofitted with minimal modification.
5Measurement precision
If comprehensive gait data is collected using multiple sensors, then measurement precision is improved, but loss of time increases due to data processing requirements
Solution Approach 1:
The system extracts only the essential vertical force data from four strategic sensor positions, eliminating the need to process the vast amounts of data that would be generated by comprehensive deck-wide sensor arrays. This focused data collection maintains precision for key gait parameters while minimizing processing time.
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
The apparatus offers a low-cost, simple, and effective means to measure essential gait parameters, reducing setup time and costs, while providing accurate and real-time data for clinical assessments.
Implementation Method 1
three, and preferably four, vertical force sensors disposed between a treadmill and the ground... each force sensor emits an electronic signal proportional to the load on the frame
Data Source
AI summary
This gait analysis apparatus comprises three, and preferably four, vertical force sensors disposed between a treadmill and the ground. When a person walks on the treadmill belt, each force sensor emits an electronic signal proportional to the load on the frame. The sensors measure the load hundreds of times per second and that data, in combination with the speed of the treadmill belt, enables a processing unit to calculate many gait parameters. The resultant calculations are displayed to the clinician in numeric and graphical formats. Due largely to the few number of force sensors, the apparatus is relatively inexpensive compared to existing gait parameter apparatuses and can be easily retrofitted to existing treadmills by either replacing the treadmill's existing ground supports with force sensors or resting the treadmill on top of a frame that has integral force sensors.