Fig. 3. General images of inverters. (a) Main inverter for adjusting the rotational speed of electromotor for drive wheel; (b) Main inverter for adjusting the rotational speed of electromotor for carriage. profile in the center line of the tire and at a specified depth, the stresses caused by the tire pass under the test conditions were measured and recorded (Fig. 4 and Fig. 5). Rut Depth Measurement Part of this study focused on the use of a measurement instrument to determine and record the rut depth in real-time conditions on off-road vehicle. The rut depth may change continuously during the wheel's movement due to the wide range of different parameters of the soil-tire and vehicle. Considering the importance of rut depth as one of the most significant parameters of soil and tire interaction, it is necessary to provide an appropriate methodology and measurement tool. A two-axis inclinometer module (ZCT245AN) was used in this study. This inclinometer has the ability to measure the angle in the range of ± 45° in two X and Y axes with the tolerance degree of 0.1 as well as to adjust zero state on each plate in any given angles. This inclinometer can connect to a microcontroller using TTL and RS-232 protocols. The frequency of data acquisition is adjustable from 1 to 14 Hz. The measured data were transferred to the microcontroller for processing purposes. For the experiments conducted in this study, the highest data acquisition frequencies were used, for each of which the recorded data was determined via data acquisition time. The model of the inclinometer device Fig. 4. Stress measuring setup under the drive wheel along with its internal components and positioning in the soil. October 2021 IEEE Instrumentation & Measurement Magazine 33