**Experimental Characterization of the Coupling Stage of a Two-Stage Planetary Gearbox in Variable Operational Conditions**

#### **Claudia Aide González-Cruz 1,\* and Marco Ceccarelli 2**


Received: 16 April 2019; Accepted: 17 June 2019; Published: 20 June 2019

**Abstract:** This paper presents an experimental characterization of a two-stage planetary gearbox (TSPG) designed at the Laboratory of Robot Mechatronics (LARM2) in the University of Rome Tor Vergata. The TSPG operates differentially as function of the attached load and the internal friction forces caused for the contact between gears. Experiments under varying load conditions are developed in order to analyze the usefulness of the gearbox to avoid excessive torques on its internal elements. The analysis of the dynamic torques is presented as an indicator of stability in the gearbox operation. The results show that the actuation of the second operation stage reduces the torques 57% in the output shaft and 65% in the input shaft. The efficiency of the gearbox is estimated as 40% in presence of high internal friction forces.

**Keywords:** two-stage planetary gearbox; varying load; dynamic torque; efficiency; rotating machinery
