Anti-Rollover Control and HIL Verification for an Independently Driven Heavy Vehicle Based on Improved LTR

The rollover evaluation index provides an important threshold basis for the anti-rollover control system of vehicle. Regarding the rollover risk of independently driven heavy-duty vehicles, a new rollover evaluation index is proposed, and the feasibility of the improved index was verified through hierarchical control and HIL (hardware-in-the-loop) experiments. Based on an 18-DOF spatial dynamics model of a heavy-duty vehicle, the improved LTR (load transfer rate) index was obtained to describe the dynamic change in the tire's vertical load. It replaces the suspension force and the vertical inertia force of the unsprung load mass. It avoids the problem of directly measuring or estimating the vertical load in the LTR index. Under the conditions of fishhooking and angle stepping, three types of rollover indicators were compared, and the proposed index can more sensitively identify the likelihood of rollover. In order to apply the improved rollover index to a rollover control well, a hierarchical controller based on the identification of the slip rate of the road surface, ABS control with sliding mode, variable structure and differential braking was designed. Simulations and HIL tests proved that the designed controller can accurately predict the rollover risk and avoid the rollover in time. Under the condition of J-turning, the yaw rate, slip angle and maximum lateral acceleration are reduced by 9%, 16% and 3%, respectively; under the condition of fishhooking, the maximum yaw rate, slip angle and lateral acceleration are reduced by 12%, 18% and 3%, respectively.

Automated summary

This study proposes a new rollover evaluation index to assess the rollover risk of independently driven heavy-duty vehicles and verifies the feasibility of the improved index through hierarchical control and HIL experiments. The improved LTR index, based on an 18-DOF spatial dynamics model, describes the dynamic change in the tire's vertical load and avoids the problem of directly measuring or estimating the vertical load. Comparisons of three rollover indicators under fishhooking and angle stepping conditions show that the proposed index can more sensitively identify the likelihood of rollover. A hierarchical controller designed based on road surface slip rate identification, ABS control with sliding mode, variable structure, and differential braking effectively predicts and avoids rollover risks.