TY JOUR TI INTERACTION PARAMETERS OF THE CATERPILLAR VEHICLE WITH THE OBSTACLE KW forest vehicle KW caterpillars KW threshold obstacle KW vertical wall KW tilt angle KW tightening wheel KW coupling KW equation parameters JO Bulletin of KSAU AU Kholopov, V.N. AU Labzin, V.A. PY 2015 IS PB Krasnoyarsk State Agrarian University