An affordable open-source 3D force platform and a wide force range calibration method
Aarón-Raúl Poyatos-Bakker, Javier López-Martínez, Daniel García-Vallejo, José M. Muyor, Jose‐Luis Blanco · Measurement · 2026
This work introduces a novel 3D force platform design grounded on the use of planar uniaxial load cells and ball wheels, easy to manufacture from off-the-self components leading to an affordable and accurate system. An accompanying open-sourced software allows an easy use of the force platforms. A novel calibration method for 3D force platforms is proposed, whose setup uses a Smith-type bodybuilding machine, a triaxial load cell and a pole, allowing in-situ calibration and the application of multidirectional loads, including those exceeding body weight. The calibration matrix is obtained by applying least squares and cross-validation methodology. Experimental results show good accuracy for the vertical force and COP position, with average relative errors in the vertical and horizontal forces under 0.2 % and 2.5 %, respectively. The mean absolute error in the COP position is 0.32 mm in the x -axis and 0.27 mm in the y -axis. Additionally, the good performance of the force platform is demonstrated through its practical application in gait analysis. • Affordable 3D force platform based on uniaxial load cells. • Calibration setup using a Smith-type machine that allows for high loads. • Good accuracy in the measurement of ground reaction forces. • Open source software for force platforms reading.