Design and experimental set-up of a hybrid dynamometer applied to a fourth axis of the vertical machining center

This paper describes a functional prototype of a hybrid dynamometer, based on strain gauges, designed to be clamped on the fourth axis of a vertical machining center, to measure axial force and torque. This study is described in five steps: design, engineering analysis, instrumentation, static calibration, and natural frequency evaluation. In order to provide reliability with regard to the signal acquisition, a small wireless data transfer system was implemented. This system was developed for signal conditioning and amplification associated with a transmission module integrated to a dynamometer. Furthermore, a wireless receiver module and data processing codes were used to measure mechanical loads. The results indicate that the design is consistent with the operating requirements that the dynamometer needs to be able withstand axial force and torque up to 1 kN and 30 Nm, respectively. The calibration results indicated that the sensing elements operate in the elastic regime for the described loading range, due to the linear trend of calculated R 2 values greater than 0.99. The wireless system approach allowed data transfer up to a distance of 3 m. The minimal natural vibration frequency of the device is 602.2 Hz.