DEVELOPMENT OF AN INSTRUMENTATION SYSTEM FOR AN INDOOR SINGLE WHEEL TEST RIG FOR MEASURING MOTION RESISTANCE AND TRACTION

Abstract

Evaluating and measuring the performance parameters of wheels and tillage equipment under controlled conditions obligates the use of soil bin facility, which is why it is important to equip this facility with instrumentation system to enhance their performance. This study deals with the development of an instrumentation system for an indoor single wheel test rig to measure motion resistance and traction. The developed instrumentation system includes load cell, optocoupler, ultrasonic range finder and accelerometer. The parameters measured by these instrumentation devices were drawbar pull, wheel speed, depth of wheel sinkage and vibration. The result obtained from the instrumentation devices were used to calculate motion resistance and traction parameters. The experiment was conducted at five levels of vertical loading (5, 10, 20, 30 and 40 kg), two levels of inflation pressure of 205 kPa and 275 kPa and three levels of forward speed which are 0.3, 0.5 and 0.7 m/s. The result from experiment shows that the maximum values for the drawbar pull, depth of wheel sinkage, tractive force, motion resistance and vibration were, 1932 N, 228.86 mm 2160. 63 N, 266.63 N, 22.893 m/s2 respectively, while their minimum values were 128.8 N, 92.48 mm, 147.93 N, 22.05 N, 5.5625 m/s2 respectively. Result from analysis of variance (ANOVA) and surface response methodology show that tractive force and pull were significantly affected by vertical loading, inflation pressure and forward speed with p < 0.05 for each of the factors, whereas motion resistance and depth of wheel sinkage were only significant with vertical loading and inflation pressure. However, vertical loading does not have significant effect on vibration with p > 0.05 but inflation pressure and forward speed have significant effect on vibration. Furthermore, wheel slip was found to increase with pull and other traction parameter such as gross traction ratio and net traction ratio. The tractive efficiency was found to be optimum at 75% to 80 % between 10%- and 15%-wheel slip. Design expert (9) was used to establish model between the measure parameter and the factor with each model having coefficient of determination R2 close to 1. The developed instrumentation system will be pivotal to the teaching, learning and research in traction and soil tillage studies.