Simulation of active steering control for the prevention of tractor dynamic rollover on random road surfaces

Tractor rollover is a long-term, worldwide problem that has not yet a fundamental solution. However, active steering has become a mature technology in the automobile industry, and it is widely used for anti-skidding and lane-keeping. In this study, straight-line dynamic and steering dynamic models were established to describe the dynamic behaviour of the tractor rollover process. An energy-based tractor stability indicator was derived and used to determine the steering angle to maintain stability. Random road surface classes were then generated to simulate the surfaces of actual farm roads, which are irregular and complex. The results of simulations in this study revealed that the proposed stability indicator is more accurate and effective than previous indicators. This control strategy prevents rollover within a certain range by correcting the steering angle when the indicator exceeds a threshold. Furthermore, the results of the investigation of the effectiveness of active steering under different circumstance revealed that active steering is very effective when the tractor travelling on a medium-grade road surface. What is more, a slope angle of 15° and travel speed of 6 m s −1 was the limit of tractor stability when the active steering control is engaged. For tractors operating on roads with high roughness, at speeds greater than 6 m s −1 , or on a slope angle >15°, active steering is not reliable for preventing tractor rollover. The approach developed in this study provides a reference for operators and a method for solving the problem of tractor rollover.