A device for testing the dynamic performance of in situ force plates

Area of Science:

• Biomechanics
• Instrumentation
• Motion Analysis

Background:

• Force plates are crucial components in motion capture systems for calculating kinetic variables.
• Ensuring the dynamic performance of force plates in situ is essential for accurate data collection.
• Existing methods for force plate calibration may be time-consuming or rely on external devices.

Purpose of the Study:

• To design and develop a novel system for assessing the dynamic performance of force plates in their operational environment (in situ).
• To create a reliable method for verifying force plate accuracy without relying on other force-measuring devices.
• To establish a quick and efficient testing procedure for force plates.

Main Methods:

• An eccentrically loaded wheel mounted on a weighted frame was designed.
• The wheel was spun on the force plate, and its motion was captured using a VICON™ motion analysis system.
• A simulated force profile was generated from positional data, and its root mean square error (RMSE) was calculated against force plate measurements.

Main Results:

• The eccentrically loaded wheel generated predictable centripetal forces dependent on spin speed and direction.
• RMSE calculations showed minimal differences between simulated and measured force profiles: ~2% in the x- and y-directions and <0.5% in the z-direction.
• Nine trials confirmed the system's reliability in measuring force plate performance.

Conclusions:

• The eccentrically loaded wheel system provides an effective, in situ method for dynamic force plate performance checks.
• The system is advantageous due to its independence from other measurement devices, short test duration (15 minutes per plate), and simulation of paediatric gait forces.
• This innovation offers a practical solution for ensuring the accuracy and reliability of force plate data in motion analysis.