As shown in Figure 1, a near field telemetry device was used to measure the output torque on a propeller shaft in which a strain gauge with a 350 ohm full bridge was used as a torque sensor. Because tracked vehicles use a control method that divides the torque converter output torque into transmission and steering input torques, it is necessary to measure the speed of the final drive for calculating the torque converter output torque from the propeller shaft torque that should be calculated by dividing it into the existence of steering, transmission output torque (or ring gear torque), and steering torque (or sun gear torque). Figure 2 illustrates the installed encoder using the tool fabricated in this study.Figure 1.Torque sensor for the propeller shaft.Figure 2.Speed sensor for the final drive.

Engine rpms represent the degree of the duty applied to the engine during a vehicle��s operation and they are important data to calculate relative duties. To measure the engine rpm, a tacho-generator that generates voltages in proportion to the engine rpm in a vehicle, as shown in Figure 3, was used. In addition, the vehicle speed was measured using a VBOXII sensor with a GPS that consists of an antenna for receiving GPS signals and body and has the resolution of 20 km/h/V.Figure 3.Tacho-generator for the engine RPM measurement.The real-time transmission shifting stages during driving represent important information, not only about the duty level of the transmission on the measured road, operation distribution for each shifting stage, and shifting frequency, but also the reverse calculation of the torque converter output torque in a relative duties calculation process.

The shifting stage applied to the 000 tracked vehicle used a method that measures the shifting stages by measuring the pressure applied to a clutch solenoid for gear shifting generated in a shifting stage.2.2. ResultsIn general, it is necessary to consider a reference for the speed due to the significant change in the torque characteristics in actual powertrain systems, according to changes in vehicle velocities. In the civilian car industries, the vehicle speed that is determined by 90% of regular drivers is considered as a measurement speed for its corresponding roads.

Regarding the speed configuration for measuring the driving duty in the endurance test ground, GSK-3 this study configured the average driving speed presented in the previously performed endurance testing of tracked vehicles as a measurement speed for the subjective road.This study performed the measurement for three types of endurance test grounds and three mobility roads in army operation areas. In addition, the cross country course was configured as a loop type of road with about 3.0 km of length and 8 m of width as shown in Figure 4.