Prediction of mechanical soil properties based on experimental and computational model of a rocker bogie rover

Abstract

Lack of knowledge on the mechanical soil properties have resulted in large inaccuracy of the rover’s mobility prediction in the past. This paper deals with the prediction of mechanical properties of the soil based on the experimental and computational model of a six-wheeled rocker bogie rover. The work is divided into two parts. First, a physical model of the rover was fabricated and was made to travel on an unknown loose soil on earth. For this, a known reference value of revolutions per minute (RPM) was given to the direct current (DC) motors and the corresponding linear speed of the rover was measured. Next, a terramechanics based dynamics model was developed for a nominal value of the mechanical soil properties. The RPM needed to maintain the same linear speed as the experimental value was computed for the assumed mechanical soil properties. These soil properties were altered within a range such that the RPM obtained from the experimental and the computational results were similar to maintain the same linear velocity. The results were tested and validated for different RPM values for the predicted mechanical soil properties, which proved to be satisfactory.