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Published on: August 30, 2016
Measurement of posture by triangulation using potentiometers
1Department of Medical Physics and Bioengineering, University College London, UK.
Medical Engineering & Physics
|October 8, 1999
Summary
An economical system using markers and potentiometers measures paraplegic standing posture. This posture measurement method achieves high accuracy, with errors under 8.5 mm for key joint positions.
Area of Science:
- Biomechanics
- Rehabilitation Engineering
Background:
- Accurate posture measurement is crucial for understanding the biomechanics of standing in individuals with paraplegia.
- Existing methods for posture analysis can be expensive or complex.
Purpose of the Study:
- To develop an economical and accurate system for measuring paraplegic posture during standing.
- To assess the precision of the developed measurement system.
Main Methods:
- A system utilizing joint-mounted markers, strings, and rotary potentiometers on a fixed frame was designed.
- Rotary potentiometers measured string length changes, with positions calculated via triangulation.
- Second-order polynomial fitting was employed to analyze measurement errors.
Main Results:
- The system demonstrated a random error of less than +/-2 mm for potentiometer length measurements up to 1100 mm.
- In the 600 mm to 1000 mm range, error was less than +/-1 mm.
- Estimated errors for knee and hip marker positions were 4 mm and 8.5 mm, respectively, with two potentiometers per joint.
Conclusions:
- The developed system offers an economical and accurate solution for measuring paraplegic standing posture.
- The method provides reliable joint position data essential for rehabilitation and biomechanical studies.
- The system's accuracy is suitable for clinical and research applications in paraplegic mobility.
