Design and development of a variable hitching system for improving stability of tractor trailer combination

A variable hitching system was designed using finite element analysis and developed to provide hitching height variable from 0.4 m to 0.75 m with respect to the ground using tractor hydraulics. This system facilitated easy attachment of unbalanced trailer to the tractor irrespective of trailer hitch position. Using this system, the front weight utilization factor of tractor improved on an average by 6.13% and 7.37% by decreasing the hitch height from 0.75 m to 0.4 m while hitching unbalanced trailer uphill on inclined unpaved road of 9° with payloads of 3 ton and 4 ton, respectively. A similar improvement of 7.99% and 9.18% was possible on 12° inclined surface. The slip of tractor on 9° inclined unpaved road was decreased by 4.35% and 5.17% for tractor with 3 ton and 4 ton payloads, respectively by increasing the hitching height from 0.4 m to 0.75 m. A similar decrease of 5.60% and 6.99% was possible on 12° inclined surface. Decreasing skid was also observed while pulling trailer downhill with decreasing hitching height. With the use of variable hitching system, front weight utilization factor, slip/skid could be controlled to improve the stability of tractor trailer combination while travelling on inclined surface.